FR2659976A1 - CATALYTIC CRACKING WITH BRUSH COOLING. - Google Patents

Abstract

Effective quenching is provided in a catalytic cracking process to decrease thermal cracking. For increased product yield, the quench is injected at special locations and a special quench is used. In the illustrated embodiment, the quench is injected into the oil product immediately downstream of a gross cut separator and the quench comprises cycle oil.

Description

BACKGROUND OF THE INVENTION

  The invention relates to catalytic cracking and more particularly to a process and a system for

  increase the yield of liquids of economic value

  than in a catalytic cracking unit. Catalytic cracking of petroleum is an important refining process, used to produce gasoline and other hydrocarbons During catalytic cracking, the feed, which is generally constituted by a cut or fraction of crude oil, is cracked in a reactor at catalytic cracking temperatures and pressures, in the presence of a catalyst, to produce hydrocarbons of lower molecular weight, with greater economic value Diesel is generally used as feedstock for cracking catalytic Diesel fillers typically contain from 55% to 80% of diesel by volume having a boiling range from about 3430 C to about 5380 C and less than 1% of carbon RAMS by weight Diesel fillers also contain 'a

  typically less than 5% by volume of naphtha and hydro-

  lighter carbides with a boiling point below 2210 C, from 10% to 30% by volume of diesel fuel and kerosene having a boiling range from about 2211 C to about 3430 C, and less than 10% by volume of waste oil having a boiling temperature above 5381 C. Waste oil is sometimes present at higher concentrations or added to

the diesel charge.

  In conventional fluid catalytic cracking units (FCCU), the products at high temperature originating from the riser reactor continue to undergo thermal cracking reactions above 4820 C downstream from this riser reactor These cracking reactions thermal degrades products, decreases yields and produces excess light gases which often unduly limit the production capacity of

the catalytic cracking unit.

  In addition, while it is often desirable to operate a riser reactor at higher temperatures, such as 5521 C or more, to increase the octane number of gasoline and the conversion of diesel. and residual oil, such high temperature cracking significantly increases the production of ethane and lighter fuel gas. This dramatic increase in fuel gas production can create an imbalance in the refinery's fuel gas system.

  also limit the capacity of these FCCU units which

  attempt to have insufficient gas compression capacity to handle the increased load Therefore, despite the advantages of increased gasoline production and

  higher octane number, the temperatures have sometimes been reduced

risers.

  Operating at higher cracking temperatures produces naphthas which are less stable and more prone to undergo unwanted oxidation reactions which form gums Previous methods for maintaining the stability of cracked naphthas and for maintaining the stability of species containing cracked naphthas have so far included: 1) the addition of chemicals constituting antioxidants, such as hindered phenylene diamines or phenols; 2) the modification of the operating variables of the cracking process, such as the lowering of the temperature of

  cracking and / or limiting the amount of oil

  dual; or 3) limiting the amount of cracked naphtha

mixed with finished gasoline.

  Typical examples of cracking units, regenerators, catalysts, equipment and refining processes in the catalytic refining technique are given in US Pat. Nos. 2,240,160;

  2,382,270; 2,382,382; 2,398,739; 2,398,759; 2,414,002;

  2,422,501; 2,425,849; 2,436,927; 2,458,862; 2,669,591;

  2,827,422; 2,884,303; 2,901,418; 2,981,676; 2,985,584;

  3,004,926; 3,039,953; 3,290,405; 3,338,821; 3,351,548;

  3,364,136; 3,513,087; 3,563,911; 3,593,968; 3,661,800;

  3,676,519; 3,692,667; 3,838,036; 3,844,973; 3,850,742;

  3,886,060; 3,907,661; 3,909,392; 4,043,899; 4,218,300;

  4,325,817; 4,331,533; 4,332,674; 4,341,623; 4,341,660;

  4,375,021; 4,446,009; 4,478,708; 4,552,645; 4,695,370;

  4,764,268; 4,814,067; 4,824,557; 4,859,310; and European patent applications No. 83 307 095 6 (publication No. 113 180 A 2); 85 307 242 9 (publication no.

  355 A 2) and 88 309 278 5 (publication no. 311 375 Al).

  These cracking units, regenerators, catalysts,

  refining processes and processes in the cracking technique

  catalytic, have met with successes of varying degrees.

  It is therefore desirable to carry out an improved process and system for increasing the gasoline yield (naphtha) in the catalytic cracking units and improving the stability of the gasoline which

contains these naphthas.

SUMMARY OF THE INVENTION

  An improved catalytic cracking process and unit are provided by the invention, which are operational, efficient, high yield and economically attractive. The process and the catalytic cracking unit according to the invention comprise the catalytic cracking of a feed oil, such as diesel, hydrotreated oil and / or oil

  waste, in a reactor of a catalytic cracking unit

  fluid tick (FCCU) in the presence of a cracking catalyst

  to produce an effluent product stream, catalytic cracked

  a higher value petroleum oil, and,

  after substantially complete termination of catalytic cracking

  that, the sudden cooling of the stream or flow of product outside and downstream of the reactor by means of a line or a sudden cooling injector after the catalytically cracked oil has left and has been discharged from the reactor, to increase the yield of naphtha and petrol and produce a more stable petrol Rapid rapid cooling also makes it possible to obtain a modification in the

  desired direction of coke production and selectivity.

  Preferably, the product performing the cooling

  abruptly exhibits a volumetric expansion, at the time of its vaporization, less than that of water and

  water vapor In the preferred form, the coolant

  sudden hardening comprises a stream of hydrocarbon which has been previously cracked or otherwise treated to remove the most reactive products Preferably, the sudden coolant should have low thermal reactivity Previously cracked hydrocarbons are very

  desirable because they are less reactive to cooling

  abrupt thermal ment that the virgin loads having no

  undergone treatment and hydrotreated loads.

  For this purpose, the sudden cooling product can include kerosene, light coke oven diesel,

  coke oven distillates (CSD), hydro distillates

  treated or untreated fresh virgin fillers, such as virgin diesel, virgin heavy naphtha, virgin light naphtha, but preferably comprises light catalytic recycling oil (LCCO or LCO), catalytic recycling oil heavy (HCCO or HCO) or heavy catalytic naphtha (HCN) or any combination of these products The LCCO boils at a temperature below that at which HCCO boils, but these two products have approximately the same heat of vaporization For the best results, the coarse coolant includes LCCO which has a higher molecular weight than water However, HCCO is also very useful as a coarse coolant

  and it is less expensive than the LCCO.

  Steam and water are generally not desirable as an abrupt coolant because they: - expand enormously during vaporization, occupy a large volume of the reactor, expand in the overhead lines, cause a pressure break, disturb the circulation of the catalyst,

  adversely affect the function

  cyclone operation; and produce substantial amounts of water

polluted which must be purified.

  Excessive amounts of water vapor are also required for sudden cooling with water vapor. Light naphtha (virgin light naphtha, light catalytic naphtha, light coke oven naphtha, etc.) is not

  also generally not desirable as a coolant

  abrupt smoothness because it occupies too much volume in the reactor In addition, light naphtha is a mixture product in gasoline and it is not desirable to crack light naphtha to result in hydrocarbons of less economic value. Decanted oil (COD) is generally not desirable as an abrupt coolant because it tends to give coke Catalyst in COD can also cause erosion of the inner walls of the

reactor and pipelines.

  Waste oil is also not desirable as an abrupt coolant because it has

  tendency to form coke and clog pipes.

  The coarse coolants consisting of liquid hydrocarbons are preferred to the gaseous cools to obtain the benefit of the heat of vaporization of the coolants

  sudden liquids Preferably, the coolant

  A sudden liquid is injected into the product stream in an amount ranging from 2% to 20%, preferably from% to 15%, of the volume flow rate of the oil.

  constituting the charge in order to obtain the best results.

  Advantageously, the sudden cooling decreases the temperature of the product stream and minimizes cracking

  thermal Sudden cooling can also increase

  be the conversion of charge oil to better oil

  quality and increase the octane number of gasoline.

  Kerosene, coke gas oil and hydrotreated distillates are less advantageous for constituting blast coolants, such as LCCO and HCCO Liquid nitrogen can be used as blunt coolant, but it is very expensive and present

  unwanted volumetric expansion.

  LCCO and HCCO have a large capacity to absorb heat, improve operations and do not significantly increase the costs of operating, maintenance and residue treatment services. LCCO and HCCO are excellent agents for sudden cooling since they are readily available in refineries, they are economical and stable, have a low volume expansion, achieve elimination of heat which is recoverable and have a low tendency to form coke The sudden cooling with recycling oil can reduce the amount of coke produced Abrupt cooling with recycling oil also allows cracking at high temperature without loss of more interesting hydrocarbons and without causing damage to internal cyclones, pressurized chambers or refractory walls Desirably the sudden cooling by means of a h recycling oil substantially reduces the

production of combustible gas.

  In the preferred process, the coked catalyst is separated from the improved oil by coarse separation in a catalyst and vapor separator, such as

  than a simplified cyclone, and the improved oil is immediate-

  subjected to sudden cooling to reduce thermal cracking of the improved oil, which would lead to lower value hydrocarbon products and gases

  of light hydrocarbons Desirably, the cooling

  The abrupt cooling is carried out downstream of a riser reactor and the product outlet in the form of vapor from the simplified cyclone of the catalytic cracking unit. It is more efficient and economical to add the abrupt cooling agent to catalytically cracked oil

  after a rough separation of the catalyst and the oil.

  The sudden cooling volumes required and the

  pumping costs are also reduced.

  In one of the illustrated embodiments, the abrupt cooling is carried out upstream of the release and stripping (or re-vaporization) container. In a preferred embodiment of the invention, the catalytic cracking unit comprises an external simplified cyclone disposed between the riser reactor and the release and stripping container, the quenching agent being injected immediately downstream of the steam outlet

  (which constitutes the product) of the external simplified cyclone.

  In other illustrated embodiments, the catalytic cracking unit comprises a release container (release unit) with an internal simplified separator, the abrupt coolant being injected into the release unit immediately downstream and at proximity of the steam outlet (s) (product) of the internal simplified separator The internal simplified separator can include an internal cyclone or a separator in the shape of a jar or overturned open box A ballistic separator and other inertial separators can also be

used.

  Advantageously, due to the sudden cooling, the selectivity of the coke can be reduced and less coke produced in the diluted phase portion of the stripping and stripping container. The spent coke catalyst is regenerated in a regenerator and it is recycled to the reactor. riser Desirably, during the new abrupt cooling process, the

  regenerator regeneration temperature is decreased.

  In the preferred embodiment, the regenerator operates

  operates with complete combustion of CO (carbon monoxide), which regenerates the coked catalyst in the presence of a combustion-supporting gas, such as air, comprising molecular oxygen in excess of the stoichiometric amount required for the complete combustion of coke on the coked catalyst to give carbon dioxide The regenerator can also operate with a

partial combustion of CO.

  The term "conversion", as used in this text, means the relative disappearance of the amount of charge boiling above 2210 C. The term "coke selectivity", as used in the text) means the ratio of coke yield to

to conversion.

  A more detailed explanation is provided in the

  description below and the appended claims,

  rees in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

  Figure 1 is a schematic flow diagram

  than a catalytic cracking unit with an external cyclone;

  Figure 2 is a schematic flow diagram

  than from another catalytic cracking unit with an external cyclone;

  Figure 3 is a schematic flow diagram

  than part of an oil refinery;

  Figure 4 is a schematic flow diagram

  than from another part of the oil refinery;

  Figure 5 is a schematic flow diagram

  that of a coking plant; Figure 6 is a schematic flow diagram of a catalytic cracking unit; Figures 7 and 8 are graphs of product temperature for different amounts of blast coolant (at 248,246 pascals pressure); Figure 9 is a graph of the volume of the coarse coolant versus the volume of product; Figures 10 and 11 are graphs showing

  the effects of an initial abrupt cooling in different

  annuities for catalytic cracking;

  Figure 12 is a schematic flow diagram

  than a catalytic cracking unit with an internal simplified separator; Figure 13 is a section through the release unit of Figure 12, taken substantially along line 13-13 of Figure 12; Figure 14 is an enlarged fragmentary section of a release unit with an overturned pot and abrupt cooling lines, taken substantially along line 14-14 of Figure 15;

  Figure 15 is a schematic flow diagram

  that of a catalytic cracking unit with a central riser reactor and an internal simplified separator comprising an inverted pot; and

  Figure 16 is a schematic flow diagram

  than from another catalytic cracking unit with a

internal simplified separator.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

  During refining, whole crude oil, as it is, unrefined, is sucked from a tank or underground storage tank 10 (Figure 3), by a pump 12 and it is pumped through the supply line 14 in one or more desalination units 16 to remove particles, such as sand, salt and metals, from petroleum or oil The desalted oil is sent, through the pipe 18 of the furnace inlet, to a tubular oven 20, in which it is heated to a temperature of the order of 400 C, at a pressure of between 858,112 and 1,372,980 pascals The heated oil is extracted from the oven through an outlet pipe 22

  by a pump 24 and it is pumped, through the pipe-

  feed 25, to the primary distillation tower

26.

  The heated oil enters the vaporization zone.

  instantaneous tion of the primary atmospheric distillation tower, tube furnace, or petroleum or crude oil unit 26 before reaching its upper rectification section or its lower stripping section The primary tower preferably operates under a pressure of less than 411,900 pascals In the primary tower, the heated oil is separated into fractions consisting of wet gas, light naphtha, intermediate naphtha, heavy naphtha, kerosene, virgin diesel and primary reduced crude A portion of the wet gas, naphtha and kerosene is preferably subjected to reflux (recycling) by return to the primary tower in order

  improve fractionation and yield.

  Wet gas is withdrawn from the primary tower 26 through a wet gas pipe 28 at the top Naphtha

  light is removed from the primary tower through a pipeline

  tion 29 with light naphtha Intermediate naphtha leaves the

  primary tower by pipeline 30 with intermediate naphtha.

  Heavy naphtha exits primary tower 26 through a pipeline

  tion 31 with heavy naphtha Kerosene and oil to produce fuel for reactors and oil for furnaces are removed from the primary tower through a kerosene line 32 Part of the kerosene and / or light naphtha

  can be sent to line 186 to coolant

  sudden blast (Figure 1) to form a part of the blast coolant, if desired Primary virgin atmospheric diesel is drawn from the primary tower through a primary diesel pipeline 33 and it is pumped to the fluid catalytic cracking (FCCU), referenced 34 in Figure 4, sometimes through a

  load catalytic hydrotreating unit.

  Primary reduced crude oil is discharged from the lower part of the primary tower 26 (FIG. 3) through a pipe 35 of primary reduced crude oil The primary reduced crude oil in line 35 is pumped by a pump 36 to an oven 38 in which it is heated for example to a temperature of approximately 270 WC at a temperature of approximately 400 ° C. The heated primary reduced crude oil is conveyed, through a pipe 40 for evacuation of the furnace, into the instant vaporization zone of the tower under empty 42 to

  tube furnace or directly to the FCU reactor.

  The vacuum tower 42 in a tube furnace (Figure 3) preferably operates under a pressure of between 4,666 and 6,666 pascals. Water vapor can be injected

  in the lower part of the vacuum tower by a pipe-

  tion 44 with steam In the vacuum tower, wet gas or vacuum condensate is withdrawn from the top of the tower by a overhead wet gas pipe 46 Heavy and / or light vacuum diesel is removed from the middle part of the vacuum tower via a diesel line 48 and can be sent to the catalytic hydrotreatment unit for the feed (CFHU), referenced 49 in FIG. 4, or to the riser reactor Du reduced vacuum crude is removed from the lower part of the vacuum tower 42 (Figure 3) by a line 50 reduced vacuum crude The reduced vacuum crude, also called residual or waste oil, typically has a point

  of initial boiling around 538 WC.

  A part of the waste can be pumped and sent to the FCCU unit 34 (Figure 4) via line 52 to the FCCU waste or improved in quality in a waste hydrotreatment unit (RHU) comprising a series of expanded bed reactors with boiling Light diesel fuel (LGO) from the RHU can also be sent to the FCCU 34 by a line 54 to LGO from RHU Part of the waste can be pumped to the coke forming unit 56 by a line 58 with waste to be coked. The coking unit 56 (Figure 5) includes a

  -15 coke oven or coke drum 62 and a combined tower 64.

  In the coke oven 62, the bottoms of the vacuum tower are coked at a coking temperature of about 479 WC to about 491 WC under a pressure of about 68,940 to about 342,715 Pa Coke is drawn off from the coke oven 62 through a slide, pipe or pipeline 66 and is transported to a coke storage area for use as solid fuel Vapors of coking products can be drawn from the coke oven 62 by a pipe 68 with coking vapors and these vapors are supplied to a combined coking tower 64 In the combined coking tower 64, the vapors of the coking product can be separated into fractions of coking gas, coking naphtha, gas oil light coking, coking distillate (coking oven distillate) and heavy coking diesel Coking gas can be drawn from the combined tower 64 pa r a coking gas line 70 Coking naphtha can be drawn from the combined tower 64 through a coking naphtha line 72 Coking distillate can be drawn from the combined tower 64 through a furnace distillate line 73 coking gas (CFD) Light coking gas oil can be drawn from the combined tower 64 through a coking gas line 74

  and sent to the FCCU 34 unit (Figure 4) or to the hydro-

  catalytic charge treatment (CFHU) 49 Part of the coke oven distillate (coking distillate), light coking gas oil and / or coking gas can be sent to line 186 with coarse coolant for use as part of the coarse coolant, if desired Heavy coking gas oil can be drawn off from the combined tower 64 (Figure 5) through the coking gas line 76

  heavy and hydrotreated in the catalytic hydrotreating unit

  only load (CFHU) 49 (Figure 4) before being cracked

  catalytically in the catalytic cracker (FCCU) 34.

  Heavy coke diesel from heavy coke diesel line 76 (Figure 5) and light vacuum diesel and / or heavy vacuum diesel from vacuum diesel line 48 (Figure 3) are transported to the riser reactor 100, or, alternatively, to the catalytic feed hydrotreatment reactor or catalytic feed hydrotreatment unit (CFHU) 49 (Figure 4) in which they are hydrotreated at

  hydrogen medium from supply line 78

  tion in hydrogen at an absolute pressure between atmospheric pressure and 13,729,800 Fa, preferably between 6,864,900 and 12,356,820 Pa, at a temperature between 3,431 C and 4,001 C in the presence of a hydrotreating catalyst Diesel fuel hydrotreated is discharged through a pipe 80 for discharging the catalytic hydrotreatment unit from the

  charge and sent to the catalytic cracker (FCCU) 34.

  The catalytic cracking reactor 34 of FIG. 1 comprises a reactor 100 with an elongated and upright vertical column having an upper portion 102 and a lower portion 104 The cracking catalyst and the feed oil are mixed with the lower part of the reactor. riser The catalytic cracker (riser reactor) 100 causes the catalytic cracking of the feed oil in the presence of a cracking catalyst under catalytic cracking conditions to produce a better quality outgoing product The cracked oil flow catalytically contains catalyst particles of

  worn cracking having undergone coking.

  An inertial separator, comprising an external simplified cyclone 106 (FIG. 1), is connected to the upper portion of the riser reactor 100 and communicates with this part through a pipe 105 for entering the cyclone. The external simplified cyclone 106 is positioned around the upper portion 102 of the riser reactor 100, at the same level as the latter The simplified cyclone performs a rough separation of the coked catalyst from the catalytically cracked oil Preferably, a proportion of at least 92% at 98% of the coked catalyst in the oil is eliminated by the simplified cyclone 106 disposed downstream of the external cyclone 106, is a container or unit

clearance clearance 108.

  The release container 108 (Figure 1) releases and separates a substantial amount of the coking catalyst remaining from the catalytically cracked oil The release container 108 operates at a temperature of 4820 C to 5240 C The release container 108 has a portion upper 110 with diluted phase with at least one internal cyclone 112, an outlet pipe 113 for the outgoing product, a lower portion 114 with dense phase and a stripping section 116 providing a stripping unit in which the volatile hydrocarbons are stripped or revaporisation from the coked catalyst The stripping or revaporisation section may include baffles or internal deflection members 115 Pipes and injectors 117 of steam

  stripping are connected to the stripping unit 116.

  Extending from the upper portion of the external cyclone 106 (FIG. 1), a pipe 118 for leaving the cyclone constitutes a part of the pipe 119 with product flow The pipe 118 with product flow has a horizontal upper section 118, a

  vertical intermediate section 120, an intermediate section

  horizontal diary 122 and a vertical elongated section 124 which constitutes a descending branch with product current extending downwardly through the upper diluted phase portion 110 of the release container 108 towards the upper section of the dense phase portion 114 La

  descending branch 124 with product flow, with a separation

  by internal inertia, provide an output 126,

  arranged in the intermediate section of the upper portion

  the diluted phase of the release container 108 and with which it communicates The pipeline 118 with product flow constitutes an inlet pipe for a clearance container, which extends between the external cyclone 116 and the upper portion with diluted phase 110 from the container of

  clearance 118, connecting and communicating them

  quer. A exhausted catalyst line, constituting an outlet from the cyclone, a pipe and a slide for this purpose forms a descending branch 128 for the catalyst which extends in the lower portion 114 with dense phase close to the stripping section 116 of the release container 108 The descending branch 128 with catalyst has a vertical upper section 130, an inclined intermediate section 132, a inclined lower section 134 and a vertical plunging end section 136 with an outlet opening 137 A water vapor aeration line 138 can be connected to the vertical upper section 130 A fluidization water vaporization pipe 139 can be connected to the lower section

tilted 134.

  A regenerator 140 (FIG. 1) comprising a regeneration container 142 is placed above the release container 108 The regenerator 140 burns substantially and regenerates the spent coked catalyst in the presence of an oxygen-containing gas and supporting combustion, such as air An elongated riser, erected vertically 144 constitutes an elevator and a pipe for the spent catalyst, which extends downwards

  from the bottom portion of the regeneration container

  tion 142 via the middle section of the dense phase portion 114 of the release container 108, for transporting the coked catalyst from the release container 108 to the head regeneration container 142 An air injector 146 of lift is positioned near the lower end of the lift pipe 144 to inject air which lifts and transports the spent catalyst to the regeneration container 142, which

  which facilitates the combustion of the coked catalyst.

  regeneration point 142 may include internal cyclones 148 and 150, an upper ring 152 of diluted phase steam, an overhead line 154 for the purging gas, a lower ring of gaseous phase fuel

dense and a pipeline 158.

  The regenerated catalyst is evacuated by a set of pipe, pipe and slide 160 for evacuating the catalyst (FIG. 1) to an evacuation well and overhead container 162 with possibly an air ring 164 in the

  lower part to compensate for increased pressure.

  A vertical pipe 166 for the regenerated catalyst extends downward from the discharge well 162 to a sliding valve 168 A pipe 170 for the regenerated catalyst, arranged horizontally, is connected to the lower portion 104 of the column reactor 100 riser, to transport the regenerated catalyst to this riser reactor A fluidization steam pipe can be connected to the regenerated catalyst pipe under the sliding valve 168 A pipe 172 for ventilation air can be connected to the middle portion of the vertical tubing 166 for the cataly-

regenerated sister.

  A pipe 176 for aeration water vapor (FIG. 1) can also be connected to the lower portion 104 of the riser reactor 100 Injection nozzles 178 (F Igure 1) can be arranged at the lower portion 104 of the riser reactor 100 for injecting feed oil into the column reactor

  In the illustrated embodiment, a pipe-

  Combined feed oil 180 is connected to the nozzles 178 and the fresh feed oil line 33 A

  line 182 for recycling oil can be connected

  feed oil to the combined line 180, with which it communicates, to supply heavy catalytic cycling oil (HCCO), decanted oil (COD) and / or oil in the form of a grout at the column reactor 100

  rising, in a proportion of up to 40%, preferably

  rate of 5 to 10%, by volume of fresh charge, in the line 33 of fresh charge oil The temperature of the regenerator is lowered from approximately 0.55 to approximately 11.110 ° C.,

  by sudden cooling using recycling oil.

  A coolant injection line 184

  abrupt dissement constituted by catalytic recycling oil, comprising an LCCO injection line and / or an HCCO injection line, with a section

  injection valve 186 for catalytic cycling oil

  that, extends downwards and connects it with communication with the vertical section 120 of the inlet pipe 118 of the release container for injecting a light recycling oil (LCCO) constituting the

  sudden cooling, and / or a cataly-

  heavy tick ACCO, constituting the abrupt cooling agent, in the hydrocarbon products after these products have left cyclone 106 downstream from the riser reactor 100 and before these products have entered the release vessel 108 The sudden cooling minimized and inhibits cracking

  substantial thermal flow of coarse oil product

  separated, catalytically cracked, which would give

  less valuable hydrocarbons, such as combustible gas

  tigu Cool cooling by recycling oil stops approximately 75% to 90% of the thermal cracking of the oil constituting the product and at the same time improves the naphtha yield to increase gasoline production During the sudden cooling, the temperature of the product stream, i.e. oil, which is discharged from the simplified cyclone 106 is lowered from about 170 C to about 1110 C, preferably from about 280 C to about 440 C, from so as to reach a range of 4821 C to approximately 5000 C. The abrupt cooling by the recycling oil

  improves the conversion of filler oil to improved oil

  and increases the octane number of the gasoline. The rate of injection of the sudden cooling agent by volume ranges from 2% to 20%, preferably from 5% to 15%, relative to the flow rate of Feed oil entering the riser 100 100 Advantageously, less coke is produced in the diluted phase portion 110 of the release vessel 108 Less combustible C 2 gas is also produced during the sudden cooling by

cycling oil.

  Mixing and spraying the coolant

  sudden hardening can be advantageously improved and achieved in less than 5 seconds, preferably in less than 3 seconds, by spraying the sudden coolant

  by means of one or more coolant injectors

  coarse atomized to achieve rapid cooling by rapid contact and ensure rapid mixing The sudden cooling agent is injected with a downward speed of 15 to 30 m / s with a residence time of 0.1 to 5 seconds, preferably less than 0.2 seconds Leaky coolant losses should be avoided. High boiling blast media enhance energy recovery The blast coolant can be preheated, preferably above 100 ° C, to improve heat recovery and minimize heat loss heat The sudden coolant is sprayed into the external cyclone vapor outlet pipe 118 to rapidly cool the products before they enter the phase

diluted from the reactor vessel.

  For best results, the coarse coolant is injected as soon as the reaction is complete and preferably immediately after the coked catalyst particles have been roughly separated from the product stream consisting of the catalytically cracked oil Additionally small amounts of sudden coolant are required after separation from the

  catalyst rather than before the separation of the catalyst.

  It has unexpectedly and surprisingly been found that the use of recycle oil as an abrupt coolant increases the yield of high value naphtha and can improve coke production and selectivity. It appears that the conversion of diesel beyond the riser reactor is substantially completed in

  the simplified cyclone in which the catalyst is present.

  The production of excess combustible gas was previously

  associated with a long residence time in the diluted phase portion of the release container, as a result of thermal cracking before the addition of recycling oil as an abrupt coolant.

  The catalytic cracking catalyst can be sent

  that regenerated in riser 100 reactor (Figure 1)

  by a line 170 with respective recovered catalyst-

  ment Fresh make-up catalyst can be added to the regenerator 140 In the riser FCC reactor, the hydrocarbon charge is vaporized by being mixed with the hot cracking catalyst and the charge is catalytically cracked to give hydrocarbons of lower molecular weight and of greater economic value The temperatures in the riser reactor 100 can be between approximately 4820 ° C. and approximately 6501 ° C., preferably between approximately 510 ° C. and approximately 5600 ° C., under an absolute pressure comprised between atmospheric pressure and approximately 343,245 Pa The hourly space velocity by weight (WHSV) in the riser reactor can be between about 5 and about 200 The speed of the oil vapors in the riser reactor can be

  between about 1.5 m / s and about 30 m / s.

  Suitable cracking catalysts include, but are not limited to, those containing silica and / or alumina, including those of the Le acid type.

  cracking catalyst may contain other metal oxides

  refractory, such as magnesia or zirconia The preferred cracking catalysts are those containing

  crystalline aluminosilicates of zeolites, molecular sieves

  in an amount sufficient to substantially increase the cracking activity of the catalyst, for example between about 1 and about 50% by weight. The crystalline aluminosilicates can have silica / alumina molar ratios of at least 2/1 , for example from about 2/1 to 12/1, preferably from about 4/1 to 6/1, for best results Crystalline aluminosilicates are generally available or manufactured in sodium form and such a compound is preferably reduced, for example, to less than about 4% and even less than about 1% by weight, by exchange with hydrogen ions or precursors of

  hydrogen, such as ammonium ions or metal ions

  versatile polyvalent Suitable versatile metals include

  calcium, strontium, barium and rare earth metals, such as ceryum, lanthanum, neodymium and / or mixtures existing in the nature of rare earth metals Such crystalline materials are capable of retaining their structure of pores under the conditions of high temperature of the manufacture of the catalyst, of the treatment of hydrocarbons and of the regeneration of the catalyst. The alkaline aluminosilicates often exhibit

  a uniform pore structure, the pores having a dimension

  extremely small ion with a transverse pore diameter of about 0.6 to 2 nm, preferably about

  1 to 1.5 nm Cracking catalysts based on silica-

  alumina comprising a major proportion of silica, for example approximately 60% to 90% by weight of silica and approximately% to 40% by weight of alumina, suitable for mixing with the alkaline aluminosilicate or for the use of cracking catalyst Other cracking catalysts and other pore sizes can be used. The cracking catalyst can also comprise or consist essentially of a promoter or catalyst which burns carbon monoxide (CO), such as a catalyst based on platinum, to increase the combustion of carbon monoxide

  in the dense phase of regenerator 140.

  Spent catalyst containing deactivating coke deposits is removed from the release container 108 and reassembled through the riser tube 144 for the spent catalyst and sent to the lower part of the regenerator or overhead burner 140 for the fluidized catalyst The column reactor

  rising and the regenerator together constitute the

  primary kills of the air catalytic cracking unit

  is injected upwards at the bottom of the regenerator

  tor by the air injection pipe 146 and the riser 144 with spent catalyst The air is injected under a pressure and with a flow such that it fluidizes the particles

  of spent catalyst as a whole upwards inside

  laugh of the regenerator Residual carbon (coke) present on

  the catalyst particles is burned substantially complete-

  ment in the regenerator 140 giving regenerated catalyst for use in the reactor The regenerated catalyst is discharged from the regenerator 140 by the line 160 with regenerated catalyst and sent to the riser reactor 100 by the line 170 with regenerated catalyst and the upright tube 166 with regenerated catalyst The combustion of the exhaust gases (combustion gas) is drawn off from the top of the burner 140 by a combustion gas pipe

evacuated 154.

  As illustrated in FIG. 6, the stream of outgoing product, constituted by catalytically cracked hydrocarbons (volatilized oil) is withdrawn, from the

  top of the release container 108, through a canali-

  sation 113 to outgoing product and sent to the fraction unit-

  main FCC 190 In the FCC fractionation unit, catalytically cracked hydrocarbons, including

* oil vapors and vapors which have been vaporized

  abrupt tion, can be split (separated) into light hydrocarbon gases, naphtha, light catalytic recycling oil (LCCO), heavy catalytic recycling oil (HCCO) and decanted oil (COD) Light hydrocarbon gases are

  withdrawn from the FCC fractionation unit by a pipe

  tion 192 with light gas The naphtha is withdrawn from the FCC fractionation unit by a line 194 to naphtha, LCCO

  is withdrawn from the FCC fractionation unit by a channeli-

  sation 196 with light catalytic recycling oil HCCO is withdrawn from the FCC fractionation unit by a line 198 with heavy catalytic recycling oil Decanted oil is withdrawn from the bottom of the FCC fractionation unit by a line s 199 with oil decanted A part of the LCCO and / or of the HCCO can be recycled to the coolant line 184, consisting of recycling oil, and can be used as an abrupt coolant. In a variant, in the main fractionation unit 42, the oil vapors and the vapors having undergone instant vaporization can be fractionated (separated) into: a) light hydrocarbons having a boiling point below about 2211 C. , b) light catalytic recycling oil (LCCO), and

c) decanted oil (COD).

  Light hydrocarbons can be withdrawn from the main fractionation unit through an overhead line and sent to a separation drum In the separation drum, light hydrocarbons can be separated into: 1) wet gas, and 2) materials light hydrocarbons from those in C 3 to those boiling under 2210 C, including

  propane, propylene, butylene and naphtha.

  Wet gas can be drawn from the separate drum

  tor by a wet gas pipe and further treated-

  in a vapor recovery unit (VRU) Materials from C 3 to 2210 C can be withdrawn from the separating drum through a discharge line and sent to the vapor recovery unit (VRU) for further processing LCCO can be withdrawn from the main fractionation unit by a pipeline to LCCO to

  be used as part of the coolant

  sudden or later refined, treated or sold settling COD decanted oil can be drawn from the main fractionation unit by one or more COD pipelines for later use The sludge recycling product comprising decanted oil (COD) can be pumped from a COD line 199 (Figure 6) to the bottom of the main fractionation unit 190 by a pump through a sludge line 182 (Figure 1) and recycled to the column reactor 100 up The remaining COD can be sent for later use

in the refinery.

  The coked and deactivated catalyst used (which constitutes a spent catalyst), discharged from the riser reactor 100 (FIG. 1) can be freed of its volatilizable hydrocarbons in the stripping section 116 by means of a stripping gas, such as light hydrocarbon gases, or water vapor The coked catalyst, having undergone the stripping operation, passes from the stripping unit 116, through the line 144 with spent catalyst, into the regenerator 140 Air is injected by the air injection pipe 146 for fluidizing and transporting the spent coked catalyst in the regenerator 140 by a riser 144 for the spent catalyst with a flow rate of approximately 0.06 m / s to approximately 1.22 m / s Preferably, an excess of air is injected into the regenerator 140 in order to completely convert the coke on the catalyst into carbon dioxide and water vapor. The excess air can be from approximately 2.5% to approximately 25% higher than stoichiometric amount of air required for complete conversion

  coke to carbon dioxide and water vapor.

  In regenerator 140 (Figure 1), the coke on the catalyst is burned in the presence of air so that the catalyst

  contains less than about 0.1% coke by weight The cataly-

  its coker is contained in the lower dense phase section of the regenerator, under an upper diluted section of the regenerator Carbon monoxide (CO) can be burned in both the dense phase and the diluted phase, although combustion carbon monoxide occurs predominantly in the dense phase with improved combustion, i.e. with the use of a CO combustion promoter The temperature in the dense phase can be understood between approximately 566 WC and approximately 760 'C The temperature in the diluted phase can be between approximately 6500 C and approximately 8200 C Chimney gas

  combustion) which leaves the regenerator 140 by the canali-

  head evacuation station 154 preferably contains less than about 0.2% CO by volume (2000 ppm) The main portion of the heat of combustion of carbon monoxide

  is preferably absorbed by the catalyst and is transferred

  rée with the catalyst regenerated by line 170 and the

  riser 166 to riser 100 reactor.

  In a catalytic cracking unit (riser reactor) 100, volatile carbonaceous materials, or coke, are deposited on the catalyst particles. Coke comprises highly condensed aromatic hydrocarbons which generally contain from 4 to 10% by weight of hydrogen As the coke builds up on the catalyst, the activity of the catalyst for cracking and the selectivity of the catalyst to produce a mixture base for gasoline decreases The particles of catalyst can recover most of it of their original qualities by removing most of the coke from the

  catalyst by a suitable regeneration process.

  The regeneration of the catalyst is carried out in

  burning coke deposits from the surface of the cataly-

  sor using an oxygen-containing gas, such as air.

  Combustion of coke deposits from the catalyst requires a large volume of oxygen or air Oxidation of coke can

  be characterized in a simplified manner as an oxidative

  tion of carbon and can be represented by the following chemical reactions: (a) C + 02 -> C 02 (b) 2 C + 02 + 2 CO (c) 2 CO + 02 + 2 CO 2 Reactions (a) and (b) both occur under typical conditions of catalyst regeneration, whereby the catalyst temperature can be between about 5700 C and about 704 ° C and are typical of gas-solid chemical interactions when

  regenerates the catalyst at temperatures in this area.

  The influence of any increase in temperature is reflected as an increased rate of carbon combustion and more complete removal of carbon, or coke, from the catalyst particles Since an increased rate of combustion is accompanied by release increased heat when oxygen is present in sufficient quantity, reaction (c) in gas phase can occur This last reaction is initiated and propagated by free radicals The additional combustion of CO to C 02 is an interesting source of energy thermal being that the reaction

(c) is highly exothermic.

  The catalytic cracker (catalytic cracking unit

  that) of Figure 2 is in general, in a structured-

  real and functional, similar to the catalytic cracker in Figure 1, except that the line 284 with abrupt coolant, of the light catalytic recycling oil (LCCO) type, forms an inclined angle of between approximately 150 and 450, of preferably about 30, relative to the vertical, to increase the path of the coarse coolant and improve the mixture by making it more uniform The regeneration container 242 is also placed laterally away from the release container 208 To facilitate understanding, the parts, elements and components of the catalytic cracker of Figure 2 have been given reference numbers similar to the parts, elements and components of the catalytic cracker of Figure 1, but increasing them by 100, that is say by distributing them in the series in 200: for example, riser reactor, external cyclone 206, release container 208, stripa unit ge 216, regenerator 240, etc. The catalytic cracking reactor preferably comprises a riser reactor Some catalytic cracker units have two column reactors

  rising, two simplified cyclones, two slide valves

  ment and two upright tubes, operatively connected

  roof with a single regenerator and a single release container.

  The catalytic cracker (catalytic cracking unit

  that) of FIGS. 12 and 13 is generally, both structurally and functionally, similar to the catalytic cracker of FIG. 2 except for the fact that four internal simplified inertial separators 306 are used comprising simplified internal cyclones instead of external cyclones to roughly separate a substantial amount of catalyst from the catalytically cracked oil after the catalytically cracked oil product stream has been discharged from the riser 300 through the horizontal line 305 to produce Four lines 384 of CCO abrupt coolant injection extend into the diluted phase portion or zone 310 of the release container

  (clearing unit) 308 to locations just below

  above the outlet 318 for the product in the vapor state of the coarse internal separators 306 for injecting and

  spray CCO coarse coolant, compres-

  nant LCCO and / or HCCO, in the oil cracked catalytically after most of the coked catalyst has been removed from the oil by the internal coarse separators 306 The coolant injection pipes

  abrupt can be arranged to form an angle of inclination

  between about 150 down and about 90 (horizontally) relative to the vertical to minimize backtracking of the coolant. In FIG. 12, an outlet assembly 328 for spent catalyst, consisting of a vertical pipe, a pipe and a slide, descends from the internal simplified separators 306 to discharge the spent spent coke catalyst in the lower portion (zone) 314 to dense phase and the stripping section (stripping unit) 316 of the release container 308 The upper part of the upper zone 310 in dilute phase of the release container 308 can comprise five secondary internal cyclones 312 Le

  release container 308 and the second internal cyclones

  daires 312, above the simplified separators 306, cooperate

  rent to remove the remaining particles or fines of coked catalyst from the gases and oil vapors which exit To facilitate understanding, the parts, elements and components of the catalytic cracker of Figures 12 and 13 have been given reference numbers similar to those of the corresponding parts, elements and components of the catalytic cracker in Figure 2, but in the 300 series: for example 300 riser reactor, internal simplified cyclone 306, stripping unit 316, regenerator 340, etc. One of the main construction changes listed in unit FCCU 600, which is similar to the cracker

  catalytic of Figures 12 and 13, is constituted by the use

  sation of HCCO in place of LCCO to suddenly cool the release unit HCCO was chosen in place of LCCO to avoid flooding, i.e. to avoid exceeding the capacity of the LCCO section of the fractionation unit, and to improve overall heat recovery in the unit, as well as to benefit from the

  greater pumping capacity of the HCCO circuit.

  The HCCO blast cooling nozzles are

  arranged to maximize the efficiency of the cooling

  Suddenly cooling the reaction gases as soon as they leave the cyclone Sudden cooling by HCCO can cool the cooling unit from 17 to 111 ° C, preferably at least about 551 C. The catalytic cracker (unit of catalytic cracking

  that) of Figures 14 and 15 is generally, both structural-

  functionally similar to the catalytic cracker

  as in FIG. 12, apart from the fact that the reactor 400, with a rising column, which is centrally arranged and erected vertically, extends vertically upwards in the portion (zone) 410 in dilute phase of the release container

  (clearing unit) 408 along the vertical axis thereof

  ci Coaxially arranged around the upper end of the riser reactor 400, there is an internal separator simplified by inertia 406 comprising an inverted jar or box The inverted box 406 comprises: a lower end 406 has open for the discharge or exit of the catalyst separated coke to the dense phase portion or area 414 and the stripping section (stripping unit) 416 of the release container 408; an upper part or flat ceiling, that is to say flat, whole, that is to say non-perforated, referenced 406 b and spaced above the upper end 409 of the riser reactor 400, this ceiling providing a receiving plate on which the stream, loaded with catalyst, of catalytically cracked oil strikes when it leaves the upper end 409 of the riser reactor; an upper cylindrical tubular wall 406 c which extends downward from the ceiling 406 b; an intermediate portion constituting a canopy or hood 406 d extending under the upper wall 406 c; and a lower cylindrical tubular wall 406 e around the open lower end 406 a which extends downwards

below the canopy 406 d.

  The canopy 406 d (Figures 14 and 15) includes an outwardly flared skirt The canopy 406 d also includes an elongated upper frustoconical wall 406 f, diverging towards

  the bottom, which extends downward from the top wall

  lower 406 c, and a frusto-conical lower wall 406 g converging downwards, which extends downward from the wall 406 f The upper frusto-conical wall 406 f has two discharge openings or windows 406 h, of rectangular shape and arranged diametrically opposite one another, these openings constituting outlet vents for the outlet of the stream of outgoing product consisting of oil catalytically cracked after the oil has been

  roughly separated from the catalyst.

  When the stream, loaded with catalyst, of catalytically cracked oil leaves the upper end 409 (FIGS. 14 and 15) of the riser reactor 400, it strikes the upper part or ceiling 406 b of the internal simplified separator 406 (constituted by an overturned box)

  with enough force and impact to separate roughly

  Rarely a substantial amount of spent coked catalyst from the catalytically cracked oil. The separated catalyst is partially discharged by gravity flow at

  through the open bottom 406a of the overturned box 406.

  The oil catalytically cracked, after being coarsely

  separated from the catalyst, is discharged through the

  windows 406 h from the overturned box 406.

  Two pipes or injectors 484 for the abrupt cooling agent, arranged horizontally and diametrically opposite to each other (Figure 14), extend horizontally in the internal portion (zone) 410 diluted phase of the container of clearance 408, in places in the vicinity of and in alignment with the windows 406 h, for injecting or spraying a coarse coolant comprising LCCO and / or HCCO into the catalytically cracked oil The lines 484 to coarse coolant can be arranged to form an inclined angle of between about 150 downward and about 900 (i.e. horizontal) relative to the vertical to minimize return

  back of the sudden coolant.

  The release container 408 (Figure 15) and the secondary internal cyclones 412 at the top of the release container, above the simplified separator 406, cooperate to remove the remaining particles or fines of coked catalyst from the gases and vapors. oil coming out To facilitate understanding, the parts, elements and components of the catalytic cracker of Figures 14 and 15 have been given reference numbers similar to those of the corresponding parts, elements and components of the catalytic cracker of Figure 14 but in the series of 400: for example riser 400 reactor, internal simplified separator 406, stripping unit 416, regenerator 440, etc.

  The catalytic cracker (catalytic cracking unit

  that) of Figure 16 is generally, both structurally and functionally, similar to the catalytic cracker of Figure 12, except that the regenerator 540 is placed under the release container (release unit) 508 To facilitate understanding, the parts, elements and components of the catalytic cracker of Figure 16 have been given reference numbers similar to those of the corresponding parts, elements and components of the catalytic cracker of F Igure 12, except that they are in the 500 series: by example riser 506 riser, stripping unit 516, regenerator 540, etc. In certain circumstances, it may be desirable to use a fluid bed reactor or a fluidized catalytic cracking reactor in place of the riser reactor or at the same time time than a riser reactor.

EXAMPLES

  The examples below serve to illustrate in a specific way the implementation of the invention, but they must in no case be interpreted as limiting the scope of the invention. Examples 1 and 2 Experimental tests were carried out in a catalytic cracking unit (unit Y) similar to that

illustrated in Figure 1.

  The test of Example 1 constitutes the basic case The catalytic cracking of Example 1 was carried out without agent

  LCCO type abrupt cooling Cracking cataly-

  tick in the test of Example 2 was carried out with LCCO as coolant by means of a pipe

  temporary cooling agent constituting a team-

  Simulation The operating conditions and the results of the tests are indicated below The cooling test by LCCO produced very good results, unexpected and surprising, since the octane numbers of naphtha increased by 0.2 RM / 2, the conversion increased by 0.64%, the naphtha yield increased by 0.5% by volume, the stability of heavy catalytic naphtha was improved, the C 2 gas yield decreased by 23% by weight and the selectivity for coke (that is to say the yield of coke / conversion) has been improved The range, the quantity and the quality of the products obtained during the catalytic cracking with an abrupt cooling agent consisting by LCCO were unexpected Such an increase caused by the sudden cooling by LCCO achieved a

  substantial increase in the value of the product obtained.

Example 1

  Sudden coolant LCCO, Kl / day 0.0 Fresh load, Kl / day 3911.4 Riser, C 512.8 Simplified cyclone head line, C 510.6 Steam line from the release container

up to the fractionation unit

  main temperature, C 504.4 Temperature difference between riser reactor and release vessel, C 8.3 Preheater temperature, C 225 HCCO recycling, 1 / day 112 890 Sludge recycling, 1 / day 111 300 Regeneration bed temperature, C 711.1 Volume conversion,% 69.15

Example 2

238.5

3,927.3

513.4 483.9 483.9 29.4 223.9 610

111,300

707.2 69.79 Delta difference

+ 238.5

+ 15.9

+ 0.6

27.6, 5

+ 21.1

1.1

+ 12,720

o O 3.9

+ 0.64

  Properties of fresh charce Specific weight A Pl Nitrogen,% by weight Sulfur,% by weight Diesel,% by volume 23.9 0.112 1.23 97.8 24.0 0.111 1, 22 97.6

+ 0.1

0.001 0.01

+ 0.2

  Conversion,% by volume TC 2% by weight TC 3,% by volume

C 3 = / TC 3

TC 4,% by volume

C 4 = / TC 4

  i C 4 / saturated in C 4 C 5/430, mixture product for gasoline,% by volume, for example pentane, pentene LCCO,% by volume COD,% by volume Coke,% by weight Recovery by volume,% by volume

C 5/430

  RON (sought octane number) MON (motor octane number)

Example 1

  69.15 3.34, 80 0.689 13.19 0.524 0.789 51.83, 54 4.62, 90, 99 93.7 81.4

Example 2

  69.79 3.11, 90 0.693 13.52 0.513 0.785 52.33 24.91 4.57 6.16

106.24

93.9 81.6

Example 1

Example 2

  LCN Induction period, in minutes RON (Octane number sought) MON (Motor octane number) HCN Induction period RON MON Delta difference

+ 0.64

0.23

+ 0.10

+ 0.004

+ 0.33

0.009 0.004

+ 0.50

0.63 0.05

+ 0.26

+ 0.24

  + 0.2 + 0.2 Delta difference 94.5, 2 92.9, 9 94.5, 2 93.4 81.4 ooo + 220 + 1.6 + 0.5 Examples 3 and 4 Tests of bench studies were carried out on kerosene to simulate catalytically cracked oil after the particles of coked catalysts were eliminated In the tests of Examples 3 and 4, the abrupt cooling rate was 60 g / hour and the rate of the oil product was 125 g / hour The coarse coolant of Example 3 was HCCO, while the coarse coolant of Example 4 was LCCO The results of coarse cooling with HCCO and

  LCCO were very similar and are shown below.

  Example 3 Example 4 Reactor temperature, OC 590.6 593.3 combustible gas C _ (% by weight) Isothermal with sudden cooling 14 16 + minutes of cooling 10 9 minutes of cooling 8 6 Examples 5 and 6 Experimental tests were carried out conducted in another catalytic cracking unit (FCCU 500) similar to that illustrated in Figure 2 The test of Example 5 a

  provided a comparative base case without the use of LCCO.

  The catalytic cracking in the test of Example 6 was carried out with LCCO as an abrupt cooling agent. The oil supply rate was 12,561 kl / day. The temperature of the riser reactor was 5,490 C. Without LCCO as a coolant, the temperature of the

  reactor at the top of the release vessel was inferior

  6.70 C higher than that of the riser reactor With

  a flow rate of 890.4 kl / day of LCCO as a cooling agent

  The temperature of the riser reactor dropped abruptly by 301 C LCCO as the abrupt coolant produced a desired decrease in the production of drying gas by approximately 16.7%, from 32,280 m 3 / hour to 27,750 m 3 / hour, significantly increased gasoline production

  4.4%, from 6,280.5 kl / day to 6,550.8 kl / day and a recovery

  tion in volume increased by approximately 1% The sudden cooling by LCCO also decreased the production of propane, propylene and isobutane The operating conditions and the results of the tests were as follows: Example 5 Example 6 No coolant With LCCO as a quenching agent for quenching LCCO flow, quenching agent O kl / day 890.4 kl / day Temperature in the riser 5490 C 5490 C Head temperature in the release container 542 C 519 C Temperature difference between the riser and the Taent release container: 7 C 30 C dry gas in C 2 32.28 km 3 / h 27.75 km 3 / h petrol in C 5 + 6280.5 kl / day 6550 , 8 kl / day Volume recovery% 108.9% 109.8%

dry gas in Cz-

  Propane Propylene Isobutane N-butane Butenes C 5 + gasoline

LCO / DCO

Coke

Example 5

No coolant

  hardening (% by weight) 4.8 2.1, 7 3.7 1.2 6.8 41.2 29.4, 1 Example 6 Difference With delta cooling agent (% by weight) (% by weight )

4.0 0.8

1.8 0.3

0.3 0.4

3.5 0.2

1.2 6.7

43.0 + 1.8

29.3, 2

Examples 7 to 9

  Additional experimental tests were carried out in catalytic cracking units with a

  recycling oil as an abrupt coolant.

  In Example 7, LCCO was injected as an abrupt coolant immediately upon exiting the product from the

  external simplified cyclone in a catalytic cracking unit

  tick (Unit Y) similar to that illustrated in Figure 1 with a temporary simulation line for the coarse coolant In Example 8, LCCO was injected as the coarse coolant immediately after the product had left two cyclones simplified external in another catalytic cracking unit (FCCU 500) similar to that illustrated in Figure 2 In

  Example 9, HCCO was injected as a coolant

  abrupt immediately after the product has left four internal simplified cyclones in a catalytic cracking unit release unit similar to that illustrated in Figures 12 and 13 The conditions and

  the results of the experimental tests are described below

  below and illustrated in the graphs of Figures 10 and 11.

Example 7

  Charge flow 3 927 300 1 / day Temperature of the riser outlet 510.50 C LCCO blast coolant

Coolant flow

  abrupt 238,500 1 / day Duration of stay of steam in the release unit 16 seconds Reduction of combustible gas 17,981 m 3 / day 17,981 m 3 / day K = = 0.286 m 3 / kl dry 3,927,300 1 / day (16 sec)

Example 8

  Charge flow Temperature of riser outlet Sudden coolant

Coolant flow

  abrupt Residual stay of steam in the release unit Reduction of combustible gas 141,600 m 3 / day 12,243,000 1 / day

547.2 C

  LCCO 874 500 1 / day 9 seconds 141 600 m 3 / day = 1.285 m 3 / kl sec 12 243 000 1 / day (9 sec)

Example 9

  Load flow rate 5 8 Temperature of the riser outlet 516, HCO blast agent

Coolant flow

  abrupt 447 00 (Residual stay of steam in the release unit 13 Reduction of combustible gas 42 (33,000 1 / day 7 C 0 1 / day (8.1%) seconds 000 m 3 / day 42,000 m 3 / day K = = 0.549 m 3 / kl sec 883 000 1 / day (13 sec) Examples 10 to 18

  An increase in the temperature of the reactor

  above 504 C, but particularly above 538 C, decreases the oxidation stability of the product consisting of naphtha and gasoline Also, the active matrix octane catalysts (catalysts cracking containing an unstable zeolite, with or without rare earth exchanged in the zeolite supported on a carrier matrix which exhibits cracking activity independently of the zeolite) provides a product consisting of naphtha and a gasoline less stable than the Y exchange catalysts rare earths, which produce larger volumes of naphtha with a lower octane number In addition, the inclusion of waste oil in the FCU feed mixture decreases the

  stability of the naphtha produced and of the gasoline.

  The sudden cooling according to the present

  invention can significantly increase the oxidative stability

  tion and storage of the naphtha produced and the gasoline by reducing the temperature in the diluted phase of the container

  de-clearance as quickly as possible after separation

  initial coarse tion of the oil vapor mixture

killing the product and catalyst.

  The oxidation stability tests were carried out in catalytic cracking units with and without cooling agents constituted by recycling oils. In Examples 10 to 13, the charge of diesel fuel was catalytically cracked in a catalytic cracking unit. (Unit Y) similar to that illustrated in Figure 1, with a temporary simulation line for the blast agent, and LCCO, as the blast agent, was injected, if indicated, immediately after the product had left the simplified external cyclone In Examples 14 to 16, the charge, consisting of diesel fuel, was catalytically cracked in a catalytic cracking unit (FCCU 500) similar to that illustrated in FIG. 2, and LCCO, as an abrupt coolant, was injected, if indicated, immediately after the release of the product from the two simplified cyclones In Examples 1 7 and 18, the charge, consisting of diesel, was catalytically cracked in a unit

  of catalytic cracking (FCCU 600) similar to that illus-

  shown in Figures 12 and 13, and, when this has been

  indicated, HCCO was injected, as a coolant

  abruptly, immediately after the product has left two simplified internal cyclones in the container or release unit The conditions and the results of the experimental tests are indicated below:

  INFLUENCE OF A SUCCESSFUL COOLING FCU IN PHASE

  DILUTE ON THE OXIDATION STABILITY OF NAPHTA FCCU

Example

10

Unit y Y Y y

FCCU-500

FCCU-500

FCCU-500

FCCU-600

FCCU-600

  Current or product flow Heavy catalytic naphtha Heavy catalytic naphtha Light catalytic naphtha Light catalytic naphtha

C 5-430

Total catalytic naphtha

C 5-430

Total catalytic naphtha

C 5-430

  Total catalytic naphtha Wild gas FCU 2045 hours Wild gas FCU 2000 hours

  INFLUENCE OF A SUCCESSFUL COOLING FCU IN PHASE

  DILUTE ON THE OXIDATION STABILITY OF NAPHTA FCCU

  (cont.) Ex riser outlet temperature C 13 18 504.5 504.5 548.3 548.9 548.3 548.9 548.9 Temperature of the Fluid constituting the diluted phase C the coolant aqent 504.5 483.9 504.5 483.9 537.2 504.5 503.9 532.2 487.8 No LCCO No LCCO No LCCO LCCO No HCCO

  INFLUENCE OF A SUCCESSFUL COOLING FCU IN PHASE

  DILUTE ON THE OXIDATION STABILITY OF NAPHTA FCCU

  (continued) Composition of the hydrotreated diesel fuel charae% o O o Stability

ASTM D-525

Residuary% in minutes

0 395

0 615

0 25

0 25

0 200

0 225

0 250

16 75

16 125

Ex. 13 18

HVGO%

  Previous Examples 10-18 show the beneficial effects of the coarse coolant on the

product stability.

  EXAMPLES 19 to 48 Additional tests of oxidation stability were carried out with recycle oil as an abrupt coolant. LCCO, as an abrupt coolant, was injected immediately after leaving the product. of two simplified cyclones in a catalytic cracking unit (FCCU 500) similar to that of the

* Figure 2 HCCO was injected as a coolant

  abruptly, immediately after the product has left two simplified internal cyclones in the release unit (release container) of a catalytic cracking unit (FCCU 600) similar to that illustrated in FIGS. 12 and 13 The catalyst complex comprises FCCU 500 and FCCU 600 The weighted average riser outlet temperature reflects the relative flow rate of the charge to each unit (FCCU 500 and FCCU 600) and the cracking temperature of each unit (FCCU 500 and FCCU 600) Stabilities of LCN and HCN were measured from their reception at a sampling point in the downward flow line The IULR consists of the mixture of LCN and HCN which have been treated with an antioxidant additive The conditions and the test results are shown below:

  INFLUENCE OF QUICK COOLING ON STABILITY

  THE OXIDATION OF NORMAL LEAD-FREE FUEL (ULR) FROM NAPHTA

CONTAINING THE FCCU PRODUCT

  Ex. Riser outlet temperature, C FCCU 500 FCCU 600 Weighted average 20 average standard deviation 28 average standard deviation 521.1 522.8 526.7 526.7 526.7 525.0 526.7 528.3 523 , 9,529.4 529, 4,529.4 529.4 528.3 526.7 526.7 526.7 526.7 526.7 526.7 527.2 528.3 529.4 529.4 529.4 529.4 529.4 528.9 523.3 524.4 526.7 526.7 526.7 525.4 526.7 528.3 528.1 529.4 529.4 529.4 529.4 528, 3 Residuary in% in the load towards the catalytic complex 4.4 4.0 4.2 4.3 4.7 4.3 4.3 0.2 4.3 4.4 4.4 4.4 4.4 4.3 4.5 4.4 0.1

  INFLUENCE OF QUICK COOLING ON STABILITY

  THE OXIDATION OF NORMAL LEAD-FREE FUEL (ULR) FROM NAPHTA

CONTAINING THE FCCU PRODUCT

  (continued) Ex. 21 mean standard deviation 24 29 mean standard deviation% HCN in ULR, 3 49.8 56.5 58.0 56.0 54.1 3.8, 3, 6 54.4 59.3 54, 3 48.5 59.0, 2 3.6 Naphtha catalytic% LCN Total in% in ULR in ULR

14.5 64.8

19.2 69.0

14.0 70.5

14.7 72.7

9.2 65.2

14.3 68.4

3.5 3.4

13.6 68.9

11.3 66.9

9.5 63.9

14.4 73.7

14.7 69.0

17.8 66.3

11.7 70.7

13.3 68.5

2.7 3.2

  INFLUENCE OF QUICK COOLING ON STABILITY

  THE OXIDATION OF NORMAL LEAD-FREE FUEL (ULR) FROM NAPHTA

CONTAINING THE FCCU PRODUCT

  Ex. 22 average standard deviation 25 30 average standard deviation ULR

ASTM D-525

Oxidation stability

LCN HCN FCCU 500 FCC

  225 yes neither 195 yes neither 200 yes neither yes neither yes neither 207 yes neither

17 16

> 240

105

> 240

> 300

-

> 300

118 -

14 -

  yes yes yes yes yes yes yes yes U 600 on on on on on on yes yes yes yes yes yes yes yes yes

  INFLUENCE OF QUICK COOLING ON STABILITY

  THE OXIDATION OF NORMAL LEAD-FREE FUEL (ULR) FROM NAPHTA

CONTAINING THE FCCU PRODUCT

  Exit temperature from the riser, C FCCU 500 FCCU 600 Weighted average 32 37 average standard deviation 45,543.3 543.3 543.3 543.3 543.3 543.3 543.3 543.3 544.4 544.5 545.0 543.9 543.3 543.3 543.3 543.3 543.3 546.1 546.1 546.1 546.1 546.1 546.1 546.1 546.1 546, 1,546.1 546.7 546.1 0.2 548.9 548.9 548.9 548.9 548.9 544.5 544.5 544.5 544.5 544, 5,544.5 544.5 544 , 5,545.0 545.0 545.5 544.4 545.5 545.5 545.5 545.5 545.5 Residual in% in the charge to the catalytic complex 6.4 6.5 6.4 6.4 6, 4, 8, 5, 4, 4, 5, 7, 4, 8 0.5, 3, 3, 8 6.0 6.0

  INFLUENCE OF QUICK COOLING ON STABILITY

  THE OXIDATION OF NORMAL LEAD-FREE FUEL (ULR) FROM NAPHTA

CONTAINING THE FCCU PRODUCT

  (continued) Ex. 33 38 mean standard deviation 46% HCN in ULR 56.0 56.0, 0 52.0 49.0 56.0, 1, 1 54.7 56.5 59.3 54.5 3, 0 52.8 52.8, 8, 0, 0 Naphtha catalytic% LCN total in% in ULR in ULR

12.3 68.3

12.6 68.6

.2 65.2

, 7 67.7

14.8 63.8

9.0 65.0

12.5 67.6

12.5 67.6

12.7 67.4

.5 67.0

13.6 72.9

12.9 67.3

2.0 2.4

12.3 65.1

12.3 65.1

8.3 64.1

.3 60.3

.3 60.3

  INFLUENCE OF QUICK COOLING ON STABILITY

  THE OXIDATION OF NORMAL LEAD-FREE FUEL (ULR) FROM NAPHTA

CONTAINING THE FCCU PRODUCT

(after)

ASTM D-525

  Oxidation stability Ex. 31 36 41 average standard deviation 44 ULR L> 2 LCCO cooling a

CN HCN FCCU 500

  -. yes> 240 yes yes yes yes yes yes yes yes 75 yes 135 yes yes> 300> 240> 240> 240 yes yes yes yes yes HCCO cooling a

FCCU 600

  no no no no no no no no no no no no yes yes yes yes yes yes Examples 49 to 54 Sudden cooling downstream of the simplified cyclone also reduces the yield of diolefins Diolefins (molecules containing two unsaturated carbon-carbon bonds) are It is believed to be the product of thermal cracking rather than catalytic cracking reactions and they are formed in regions of the FCCU unit where the temperature is high or where the residence time is long By reducing the temperature in the clearing area, applying cooling

  abruptly reduces the yield of diolefin molecules.

  The C 4 diolefins (butadienes, and in particular 1,3-butadiene) are considered to be harmful in the subsequent treatment of FCCU butylenes in an isobutane alkylation unit; they cause dilution

  larger than desired of the acidic alkylation catalyst.

  C 5 diolefins, including, in a non

  limitative, isoprene, 1,3-pentadiene and cyclopenta-

  diene, are also considered harmful in a stream of FCCU product If the C 5 of the FCCU product is loaded into an isobutane alkylation unit, the C 5 diolefins contained in this stream of C 5 hydrocarbons can cause significant dilution of the catalyst

acid alkylation.

  Alternatively, the FCCU product streams containing high molecular weight C 5 diolefins can be mixed in the gasolines produced. In gasoline, the diolefins are suspected of contributing to the product instability. The high reactivity of the chemical components containing two unsaturated bonds causes the diolefins to react quickly with oxygen or other substances,

  by forming unwanted gums.

  Therefore, a process which results in a return

  lower in diolefins is desirable Cooling

  abruptly the diluted phase of the reactor lowers the

  yield of diolefins The chemical reactions which

  drink to instability in essence are complex diolefins are thought to participate in these reactions but it is

  possible improvement in stability due to cooling

  abruptly in examples 19-48 also implies

  additional molecular compounds other than diolefi-

nes.

  An example of the beneficial influence of sudden cooling to reduce the yields of diolefins is given below.

  below The yields of C 5 diolefins in the tests are indicated It is expected that the sudden cooling will modify the yield of other diolefins of a

similar way.

  The yield tests were carried out in a catalytic cracking unit (FCCU 500) similar to that of FIG. 2 Samples of the total product constituted by naphtha C 5-430 at the head were obtained from the product pipeline in steam leaving the release container. The samples of Examples 50 and 51 were taken with one of the riser reactors out of service Only one riser reactor flowing through a single external simplified cyclone in the container

  common clearance was in operation.

  The samples of Examples 49 and 52-54 were taken when the two riser reactors were in operation The gaseous products from the two external simplified cyclones were immediately cooled, downstream from the external simplified cyclones, with LCCO, then the two abruptly cooled currents penetrate

  in the common release container.

  The rates to each riser reactor in Examples 49, 52 and 54 were identical, but were reasonably divided, roughly 50/50. For Example 53, the rate of the abrupt coolant was 397,500 liters. / day at outlet A, 651,900 liters / day at outlet B, which gives a total of 1,049,400 liters / day. Ex crack temperature

49,547

553

51,553

  Test carried out without sudden cooling Cooling agent Volume of diolefins ure Fresh suddenly loading LCCOen C 5 of aqe liters / daylitres / day fresh charqe

C 11 686 500 O 0.21

C 7,775 100 O 0.22

C 7,775 100 O 0.17

  Test carried out with sudden cooling Cooling agent Volume of diolefins Temperature Fresh sudden loading LCCO in C 5 of the cracking Ex liters / day liters / day fresh batch

52,543 C 12,815,400 1,113,000 0.08

53 548 C 12 163 500 1 049 400 0.11

54 549 C 11 861 400 1 001 700 0.11

  At substantially the same cracking temperature, the yields of C 5 diolefins are reduced by about 35-50%

  by the application of sudden cooling by LCCO.

  Selection of the quenching agent Generally, the quenching agent must have a boiling point of at least 52 C, preferably at least 221 C, to have sufficient heat capacity to effectively cool the product consisting of the catalytically cracked oil, in order to minimize the thermal cracking of the product constituted by the oil, while allowing recovery of the

  heat at the bottom rather than at the top of the fractionation unit

  Desirably, the coolant should have a molecular weight greater than 90 to limit

  the total volumetric expansion of the coolant

  and oil constituting the product upon vaporization

  100% up to 120%, preferably 103% to 105% or less, based on the volume of the product consisting of the oil without abrupt coolant, i.e. the volumetric expansion of the coarse coolant must be between 0 and 20%, preferably between 3% and 5% or less relative to the volume of the catalytically cracked oil In addition, the coarse coolant must be inactive and inert vis -with respect to thermal cracking at 4820 C up to 5931 C for a residence time of 1 to 30 seconds in the diluted phase zone of the release container Previously cracked hydrocarbons, such as LCCO, HCCO, HCN, diesel coke oven and coke oven distillates are highly desirable as blast coolants since they are less reactive to thermal cracking than fresh untreated virgin fillers, such as virgin diesel and virgin naphtha, and the charges hydrotreated, such as hydrotreated diesel

  and hydrotreated distillates In addition, the coolant

  Dissement preferably has a boiling point below 4820 C to vaporize completely in the diluted phase of the release unit in order to achieve effective cooling of the oil produced catalytically cracked and to avoid coking of the walls and pipes from

refinery equipment.

  It is also desirable that the coolant

  abruptly decreases the production of combustible gas C 2 in order to allow operating temperatures more

  high of the catalytic cracking unit.

  The properties of various cooling agents are illustrated in Table A LCCO, in the present patent application, also includes intermediate reflux.

  in a liquid recycling system after cooling

  ment, of the "tower pumparound" type with a mist field

  lition, a density A Pl and a molecular weight similar to those indicated for LCCO in Table A.

Table A

  Properties of blast coolants Light catalytic recycling oil

(LCCO)

Nominal boiling point

221-343 C

  Nominal A Pl density 11-30 average: 20 Average molecular weight -300 average: 215 Heavy catalytic recycling oil

(HCCO)

343-454 C

  2-25 medium: 10 Naphtha heavy catalytic (HCN)

149-2210 C

Light coke oven diesel

(LCGO)

343-538 C

  medium: 382 C -25 medium: 21 Coke oven distillates

221-343 C

  medium: 262 C -40 -250 medium: 215 Kerosene

-277 C

average:

204-232 C

-45 average: 35 -200 average: 175

250-350

-50 medium: -40 -250

240-350

  Hydrotreated Distillate Virgin Diesel (VGO)

Table A

(continued) Nominal boiling point

221-3430 C

average: 293 C

343-5380 C

  Nominal density A Pl -45 average: 39, 21-32 average: 25 Molar weight 6 average ring

225-265

average: 230

300-400

  medium: 350 Heavy virgin naphtha (HVN) Light virgin naphtha (LVN)

149-177 C

average: 163 C

52-790 C

  average: 66 C Diesel (HGO) hydrotreated

343-538 C

24-35 average: 29

300-400

  medium: 350 Decanted oil (COD) Water Residuary

(H 20)

371-649 O C

average: 482 C

538-8710 C

 VS

-4 to + 10

average: + 2 0-20 average: 12

400-600

average: 500

300-1000

  medium: 700 -250 l -60 -80 -150 Sudden cooling involves the injection of a fluid, preferably a liquid, into the cracking unit

  catalytic, preferably immediately downstream of the separation

  simpler cyclone to stop the reactions.

  Generally, an abrupt cooling process of higher efficiency: 1) provides maximum economic benefits by effectively reducing the loss of valuable products in thermal reactions which occur after the catalytic cracking is substantially completed; 2) has minimal adverse effects on operations; and 3) minimally affects the costs of

utilities or accessories.

  Although it is perfectly clear that we can

  use a large number of fluids as coolants

  but the fact that the requirements for a quenching process are complex, the selection of a quenching agent and the performance of quenching are neither simple nor obvious.

  fluid which is excellent in one aspect may be unacceptable

ble in another aspect.

  The abrupt coolant cools and dilutes the products from the FCC riser and thus reduces the yield of thermal products Figures 7 and 8 show the ability of the various coolants to cool the fluid stream, i.e. say show the relative cooling capacities of different fluids The temperature of the abruptly cooled product is indicated according to the amount of coolant added The LCCO / CAT ratio in Figure 7 means that the LCCO coolant was injected into the oil constituting the product before the catalyst has been roughly separated from the oil constituting the product The addition of coolant, expressed in

  percentage, is the ratio of the weight of the coolant

  abruptly compared to the weight of the product stream The thermal capacity of the abrupt coolant and its

  heat of vaporization (in case of liquid)

  influence cooling capacity Water is very

  effective and cooled to 11.10 C by 1% addition by weight.

  Hydrocarbons are also effective and produce a

  cooling of about 3.85 C by 1% addition by weight.

  Less effective is water vapor (2.2 C per 1% addition by weight) since it is already vaporized Le

  cooling of the products before elimination of the cataly-

  sor uses enormous amounts of coolant

  abrupt since the catalyst contains large amounts of heat and a large amount of catalyst is present (typically oil) Although water provides one it has disadvantages which is advantageous. 6 times the weight of good cooling, counterbalance this molecular weight of the cooling agent

Table B

Craquabi lity Concen-

  relative product thermic

Concentra-

agent's tion

to cool

  abrupt Reduction in% by weight

of combustion gas

tible in C-

Water

Hydro-

  carbides Il Il ll l II il 0.00 0.36 0.59 1.37 0.65 1.06 2.46 1.05 1.71 3.96 0.737 0.846 0.856 0.871 0.913 0.918 0.927 0.946 0.950 0.956 0.263 0, 154 0.144 0.129 0.087 0.082 0.073 0.054 0.050 0.044 78.0 69.4 68.0 64.4, 7 64.0, 8 63.1 62.1 59.1 The addition of an abrupt coolant reduces the gas fuel by decreasing the temperature of the product which dilutes the concentration of the products of the riser The rate of thermal degradation of the products of the riser (and also of the coolant constituted by the hydrocarbon) depends on the temperature, the duration in the system, the concentration of the vapor and the inherent reactivity (thermal crackability) of the product Reducing the concentration of the products in the riser reduces the rate of degradation provided that the sudden coolant itself exhibits a craquality lower than the product of the riser Table B gives the con relative molecular centers of the riser product initially at 5381 C and the abrupt coolant for different

  sudden coolants with molecular weights

  various res, injected at a rate of about 15% by weight per

  relation to the product In Table B and the tables below

  afterwards, the reduction in combustible gas to C 2 relates to the instantaneous cooling of the hydrocarbon products of

  5381 C at 482 WC with a residence time of approximately 13 seconds.

  Sudden coolants (injected as liquids) expand to occupy different volumes depending on their molecular weights The lower molecular weights achieve maximum expansion and, therefore, maximum dilution of the riser product Le Table B also shows an estimate of the reduction in C 2 fuel gas production based on laboratory tests and includes the relative thermal reactivity of the abrupt coolants.

  abrupt cooling that have low molecular weight

  provide the maximum reduction in C 2 fuel gas production since the supplied C 2 fuel is a measure of the extent of thermal degradation, provided that the coolant itself

  has a low susceptibility to thermal cracking

  than. Coolant stability is important A sudden coolant that is unstable requires excessive replacement and contributes itself

  at C 2 yield Table B includes thermal stability

  only different fluids Thermal stability (cracking -

  lity) was determined from laboratory tests on various sudden cooling fluids The values in the table relate to the thermal stability of heavy catalytic naphtha, which has properties similar to those of the riser products Of course, water which is not a hydrocarbon does not crack and its behavior establishes the goal for hydrocarbons Hydrocarbons with low crackability give

satisfactory results.

  Mixing time is also an important factor in overheating When the overhead coolant is injected into the hot product stream, the overhead coolant and product streams must mix as quickly

  as possible in order to obtain the maximum cooling rate

  An ineffective mixture of the two streams provides additional time for carrying out the thermal reactions. By using nozzles or atomizing nozzles to inject the sudden coolant, very small drops are formed which disperse and vaporize rapidly. The influence of the duration of the mixture on the reduction of thermal products is indicated in Table C based on laboratory results for LCCO as a

sudden cooling.

Table C

  Effect of the cooling time on the reduction in combustible gas to C 2 for LCCO as a sudden cooling agent Temperature Duration of the% by weight of agent Reduction in% of the product cooling sudden cooling of combustible gas in seconds compared to the product in C 2

5380 C 1 15 92.4

5380 C 5 15 64.0

6490 C 1 60 92.4

* 6490 C 5 60 68.5

  The expansion or expansion of the vapor is an important factor in the choice of the suitable blast agent. The vaporized blast agent enters the product recovery system and must be compatible with the equipment and the operational device. and process control Improper selection of the abrupt coolant can lead to disturbances in the flow of the riser discharge, in the separation of the catalyst from the product vapors, and cause interference with efficient operation of the product fractionator In order to minimize these malfunctions, the sudden coolant must cause minimal expansion of the vapor so that erratic and extreme pressure levels are avoided Figure 9 shows the ratio of the volume of product flow abruptly cooled compared to the current of product alone in operation of the drop in temperature during the sudden cooling for different sudden cooling fluids The legend or indication LCCO / CAT of Figure 9 means that LCCO, as sudden cooling agent, was injected into the oil constituting the product before the catalyst has been roughly separated from the product consisting of Les oil

  gas, water vapor and propane exhibit the increases

  largest since substantial quantities

  These must be added to cool the stream and the low molecular weight results in large volumes of

  gas Water also has substantial vapor expansion

  A stream suddenly quenched with water will contain almost 20% more volume than the stream of product alone This extent of expansion can adversely affect operation and must be

  avoided On the other hand, liquid hydrocarbons present

  try an almost neutral volume change For liquid hydrocarbons, the molecular weight is typically high enough for the gas volume to be good

  lower whereas this is not the case for equal water-

  ment, the expansion of the hydrocarbon is counterbalanced by the contraction of the cooled product so that an almost constant volumetric flow rate is obtained This criterion is to be considered in contrast with the benefit of the

  low molecular weight diluting product vapor.

  There are practical limits to the amount of coarse coolant that is used.

  benefits decrease when the amount of coolant

  Also increases, the benefits are greatest when the product temperature of the column

  rising is highest Table D illustrates this.

  Each pair of conditions in the table corresponds to two

  abrupt coolant addition levels.

  At 538 WCs, doubling the amount of coolant

  ment reduces the C 2 yield by only 45% At 6490 C, the increase in the coolant by a factor

  of 4 only produces a 30% improvement.

Table D

Duration of

pre-cooling

  Sudden flashing (seconds) Sudden coolant Water 1 Water 1 Temperature

pre-cooling

sudden squeal

538 C

538 C

Post duration

cool

  abrupt (seconds) Temperature Report Reduction of gas agent post cool to cool abruptly abruptly has in C 2 in% the load in%

510 C

482 C

2.33 71.2

99.3 +

LCCO LCCO

LCCO

LCCO Water Water LCCO

LCCO

LCCO LCCO

1,538 C

1,538 C

538 C

538 C

1,649 C

1,649 C

1,649 C

1,649 C

649 C

649 C

  Another important criterion in determining the suitable blast agent is coking. A strong tendency to form coke is detrimental to a rapid coolant. Coke deposits can restrict flow during

  operation and force the installation to be closed.

  Coke in large quantities in the regenerator can affect

510 C

482 C

510 C

482 C

593 C

482 C

593 C

482 C

  64.0 92.4 43.9 64.0 74.3 97.5 67.2 92.4, 8 68.5

593 C

482 C

  unfavorably the thermal balance and the economy of the unit On the other hand, an abrupt cooling fluid which reduces the coke by interaction with the catalyst in the diluted zone of the release vessel improves the selectivity relative to the coke and the economy of unity. The use of a blast coolant increases the ancillary costs A high quality blast coolant reduces these costs The costs are associated with the following: replacement of the coolant

  sudden cooling lost; pumping coolant

  sudden squeal; incomplete recovery and heat loss; water requirement for cooling and as a feedstock to the boiler; and treatment of dirty water

resulting from the process.

  Some abrupt cooling matters

  consisting of hydrocarbons can degrade thermi-

  Only C 2 combustible gas is produced by the degradation

  tion Table E shows the predictions, modeled on computer, of the influences of the properties of different

  abrupt cooling media on the reduction of seed

  ble in C 2 A sudden coolant which degrades the products shows a lower reduction in combustible gas in C 2.

Table E

  Influence of the properties of the abrupt cooling material on the predicted results Mass Point Weight CrunchabilityConcentrationSpecific boiling reduction Molecular thermal of the agent in% of average gas ABP, OC relative coarse fuel cooling in C 2

0.825 148.9 130 1.38 0.129 91.3

0.825 301.7 245 2.46 0.073 89.5

0.825 426.7 414 4.00 0.044 88.6

0.93 148.9 114 0.59 0.144 94.5

0.93 301.7 216 1.06 0.082 92.4

0.93 426.7 365 1.72 0.050 91.4

0.99 148.9 106 0.37 0.154 95.6

0.99 301.7 201 0.66 0.087 93.4

0.99 426.7 339 1.06 0.054 92.4

  The additional costs for process water, associated with the use of hydrocarbon fluids such as

  Sudden cooling agents are zero or very weak.

  Water for treatment must be provided when water is the abrupt coolant Use of treatment water comes at an additional cost Water becomes contaminated as it passes through the process and must be treated to meet control regulations

of pollution.

  Heat recovery is another important factor in choosing the appropriate blast coolant Substantial amounts of heat are absorbed by the blast coolant This heat must be recoverable in a usable form if the blast chill process In general, the higher the temperature at which heat is available, the easier it is to recover. This is why sudden coolants that boil at higher temperatures allow better

  heat recovery In the cataly-

  tick FCC, heat recovery is integrated in the product fractionation system Energy at low temperature in the fractionation system is typically lost in cooling water Energy in streams or flows at a temperature below about 1000 C and up to 177 WC is not recovered This is why water is an abrupt cooling agent unsuitable from the point of view of energy recovery since it condenses to 1000 C under atmospheric pressure and since most of its energy is released when it condenses A fluid that boils just above the sudden cooling temperature that is desired

  reaching provides maximum heat recovery.

  In Table F, the enthalpies of some sudden cooling fluids candidates for the implementation of the process (LCCO, HCCO, HVGO, diesel, water) are

  given and they correspond to the temperatures in the Table.

  The heats Q 1, Q 2, Q 3, Q 4, which are indicated, constitute the absorbable heats above (a) 3291 C, (b) between 3290 C and 2461 C, (c) between 2461 C and 1630 C and (d) between 1630 C and 16 c C, respectively Materials which absorb large quantities of heat at high temperatures (eg having a large Ql) are preferred and those which absorb heat at low temperatures (eg Q 4 high) are not preferred For the materials in Table F, the order of preference, to constitute an abrupt cooling medium is (1) HCCO, (2) LCCO, (3) diesel and finally (4) water The temperature of the quenched product and the upper limit Ql for each quenching agent was 4820 C. The enthalpies were

  determined under a pressure of 238 k Pa.

Table F

  Sudden coolant enthalpies for FCCU product and available heat Temperature o C 648.9 634.4 607.2

565.2

523.9 482.2 440.6 398.9

357.2

329.4 315.6 273.9 246.1

232.2

, 6,162.8 148.9 107.2

65.6

  23.9, 6 0.0 LCCO Joules / Heat available gram Joules / gram

2013.9

1969.0

1884.4

1757.9

1635.2

1516.1

1401.3

1,290.6

1182.0

  971.6 866.3 757.7 689.1 654.9 557.8 729.6 466.6 382.5 305.3 236.7 223.0 197.4 ≤ Maximum product temperature

Q 1 = 544.5

≤ = liquid

Q 2 = 282.2

Q 3 = 192.3

Q 4 = 274.1

  Temperature o C 648.9 634.4 607.2 565.2 523.9 482.2 440.6 398.9 357.2 329, 4,315.6 273.9 246.1 232.2, 6,162.8 148.9 107.2, 6 23.9, 6 0.0 HCCO Joules / Heat available gram Joul es / gram

1886.7

1844.4 ≤ = Temperature.

1764.4 maximum 1645.4 of the product

1,529.4

1417.1

1308.7

1006.7 ≤ = liquid 892.8

822.3 Q 1 = 594.7

787.2 687.0

623.8 Q 2 = 198.5

592.2 503.1

448.0 Q 3 = 175.8

420.6 345.0 277.4 218.5

206.7 Q 4 = 241.3

  184.8 Table F (continued) Heat enthalpy of sudden coolants for the FCCU product and available heats Temperature o C LCCO Joules / Heat available gram Joules / grarm Temperature o C HCCO Joules / gram Available heat Joules / log 648.9 634 , 4,607.2

565.6

523.9 482.2 440.6 398.9

357.2

329.4 315.6 273.9 246.1

232.2

, 6,162.8 148.9 107.2

65.6

23.9, 6 0.0

2152.0

2103.0

2010.7

1872.2

1,737.2

1577.7

1317.8

1,184.8

1056.7

  974.6 933.5 815.4 740.3 702.6 595.9 528.9 495.4 402.2 316.9 240.6 225.3 196.9 Temperature ≤ = maximum of the product ≤ = liquid Ql = 603.1

Q 2 = 234.4

Q 3 = 211.3

Q 4 = 303.6

  648.9 634.4 607.2 565.6 523.9 482.2 440.6 398.9 357.2 329.4 315.6 273.9 246.1 232.2, 6,162.8 148.9 107.2, 6 23.9, 6 0.0

3810.7 Temp.

3780.4 ≤ = maximum 3720 of the product

3627.0

3538.6

3,448.0

3359.6

3,273.6

3,187.6

3131.8 Q 1 = 316.5

3103.9

3020.2

2,964.4 Q 2 = 167.4

2,936.5

2,852.8

2797.0 Q 3 = 167.4

2,769.1

448.7 274.3 104.6 ≤ = liquid

46.5 Q 4 = 406.9

  Selection of blast coolant: Some blast coolants are estimated in Table G Different refineries may use different blast coolants to meet specific requirements or to

  be able to benefit from certain special possibilities.

  Among the fluids examined below, LCCO is the best and HCCO is the second best Water has certain serious disadvantages The remaining agents have certain characteristics which can reduce their attractiveness in

  as sudden coolants.

Table G

  Assessment of candidates as sudden cooling aqents Sudden cooling aqent Steam Water water Propane

HCN LCCO HCCO

  Cooling capacity EPP Product dilution EEE Stability EEE Volume expansion PPP Cracking tendency EEE Pumping / transport GFF Heat recovery PPP Use of water PPE Disposal of used products PPE Legend: P bad, F = suitable, A = medium, G = good, E = excellent

A A A

A G G

G G G

A E E

E G F

A A A

F G E

E E E

E E E

  Table G (cont.) Evaluation of the candidates as sudden cooling agents Cooling aqent (HVGO) diesel LCCO abrupt COD diesel diesel Hydrotreated hydrotreated kerosene Cooling capacity AAAAA Dilution of the product FFAFA Stability GAA AA Volume expansion EEEEE Tendency to crack PGEEE Pumping / transport AAAAA Heat recovery EGGGG Use of water EEEEE Disposal of used products EEEEE Legend: P = bad, F = suitable, A = average, G = good, E = excellent

  ________________________________________________________

  Among the numerous advantages of the process and of the catalytic cracking system with sudden cooling, according to the present invention, there may be mentioned: 1) Improved economic value and quality of the product

  2) Higher yield of more interesting hydrocarbons

  economically healthy 3) Increased production of naphtha and gasoline completed 4) Higher flow rate) Better flow rate and better oxidation stability of the naphtha produced 6) Reduced thermal cracking and reduced product degradation, which minimizes overcracking of gasoline in ethane and light combustible gas 7) Reduced content of pentadiene in the naphtha which constitutes the product 8) Decreased production of low-value combustible gas 9) Increased octane number of naphtha and of finished gasoline) Economic 11) Good yields

12) Effective.

  Although embodiments of the invention have been illustrated and described, it is understood that different

  modifications and replacements, as well as rearrangements-

  operating steps, can be carried out by those skilled in the art without departing from the object and the

scope of the invention.

Claims (18)

  1 Catalytic cracking process comprising the following operating phase: catalytic cracking of the feed oil in a reactor of a catalytic cracking unit in the presence of a cracking catalyst to produce a stream of effluent catalytically cracked oil of higher degree; and characterized in that it further comprises the operating phase of: sudden cooling of said product stream, externally and downstream of said reactor, by means of a sudden cooling agent comprising at least one member chosen from the group consisting of l light catalytic recycling oil, heavy catalytic recycling oil, heavy catalytic naphtha, kerosene, distillates   coke oven, light coke oven diesel, hydro distillate   treated, fresh untreated virgin diesel and virgin naphtha untreated fresh.   2 Catalytic cracking process according to the claim   cation 1, characterized in that: said filler oil comprises diesel; and the sudden cooling further comprises: decreasing the temperature of said product stream; minimizing thermal cracking of said product stream; and injecting said abrupt coolant into said product stream in an amount between about 2% and about   20% by volume compared to the filler oil.   3 Catalytic cracking process according to the claim   cation 1 or 2, characterized in that: said reactor comprises a riser reactor; said product stream is suddenly quenched after the catalytic cracking is substantially completed; and said coolant contacts said product stream in an amount between about 5% and about 15% of the feed oil. 4 Catalytic cracking process, characterized in that it comprises the operating phase consisting in: catalytically cracking a feed oil in the presence of a cracking catalyst; and characterized in that it further comprises the operating phase consisting in:   cooling said cracked catalytic filler oil   only after the catalytic cracking is substantial-   ment finished, to reduce to a minimum the thermal cracking of said catalytically cracked oil into combustible gas, by bringing said catalytically cracked oil into contact with a liquid hydrocarbon, which constitutes   the sudden coolant, having a boiling point   higher than that of water, a higher molecular weight   less than 90 and a volumetric expansion of less than about   % of the volume of said catalytically cracked oil.   Catalytic cracking process according to claim 4 or 5, characterized in that:   said abrupt coolant is sensitive-   inert to thermal cracking at about 482 C to about 5931 C; said feed oil is catalytically cracked in a reactor; said catalytic cracking agent is chosen from the group consisting of previously cracked hydrocarbons, a fresh untreated fresh feed and hydrotreated hydrocarbons; and said catalytically cracked oil is cooled by said abrupt coolant by an O C number ranging from around 17 to around 111.   6 Catalytic cracking process according to the claim   cation 4, characterized in that: said volumetric expansion of said sudden coolant is less than about 5%; said abrupt cooling agent improves the stability, with respect to oxidation, of the product consisting of naphtha and of petrol; and   a substantial portion of said coolant   has a boiling point of at least 2211 C and   at most about 4821 C and vaporizes substantially completely- ment in the diluted phase.   7 Catalytic cracking process according to the claim   cation 4, 5 or 6, characterized in that said cooling agent is chosen from the group consisting of light catalytic recycling oil, heavy catalytic recycling oil, heavy catalytic naphtha, diesel fuel from   coking plant and coking plant distillates.   8 Catalytic cracking process according to one   any of claims 4 to 7, characterized in that it   comprises substantially separating said catalyst from said catalytically cracked oil in a coarse separator having a vapor outlet providing a   product outlet and injection of said coolant   ment in said catalytically cracked oil, after said separation, in the vicinity of said product outlet from the coarse separator.   9 Catalytic cracking process, comprising the operating phases consisting in: catalytically cracking the feed oil in a catalytic cracking unit comprising a regenerator and at least one catalytic cracking reactor chosen from the group consisting of a riser reactor and a fluidized bed reactor, in the presence of a   cracking to produce a higher grade oil   the coked catalyst; carrying out a rough separation of said coked catalyst from higher grade oil and this substantially after the previous operation; and characterized in that it further comprises the following operating phases: abruptly cooling said improved degree oil to substantially reduce the thermal cracking of said higher degree oil into lower value hydrocarbon products and into light hydrocarbon gases;   regenerate the coked catalyst in a regeneration   guardian; and recycle this regenerated catalyst to the reactor catalytic cracking.   A catalytic cracking process according to claim 9, characterized in that: the oil of improved degree is quenched by about 2% to about 15% of said quench coolant by volume of said filler oil; said abrupt cooling agent is chosen from the group consisting of light recycling oil, heavy recycling oil, heavy catalytic naphtha and combinations of these products; and the sudden cooling is carried out downstream of said riser reactor.   11 A catalytic cracking process, comprising the operating phases consisting in: catalytically cracking feed oil in a reactor of a catalytic cracking unit, in the presence of a cracking catalyst, to produce a catalytically cracked effluent stream of higher grade oil containing catalyst; substantially separating said catalyst from higher grade oil in an external coarse separator and in a release vessel; and characterized in that it further comprises the following operating phases: abruptly cooling said stream of higher grade oil, downstream of the external coarse separator and upstream of said release container, by means of a cooling agent comprising at least one member chosen from the group consisting of light catalytic recycling oil,   heavy catalytic recycling oil, catalytic naphtha   that heavy, kerosene, coke oven distillates, light coke oven diesel, hydrotreated distillate, fresh untreated virgin diesel and fresh untreated virgin naphtha; and injecting said abrupt coolant into said stream in an amount between about 2% and   about 20% by volume of the charge oil.   12 A catalytic cracking process comprising the following operating phases: substantial oil desalting comprising crude oil or crude oil; heating in a furnace said desalted crude oil; pumping of heated crude oil to a primary distillation tower; separating said heated crude oil in the primary distillation tower into streams of naphtha, primary diesel and primary reduced crude oil; pumping primary reduced crude oil to a vacuum tube tower; separating said primary reduced crude oil in said manifold vacuum tower with a stream of wet gas, heavy diesel and reduced vacuum crude oil providing waste oil; sending a feed oil comprising said primary diesel from the primary distillation tower to a reactor with an elongated riser raised from a catalytic cracking unit; supply of fresh and regenerated crystalline cracking catalyst to said riser reactor; catalytic cracking of said charge oil in   said riser reactor in the presence of said cataly-   cracker under catalytic cracking conditions to produce a stream of higher grade effluent product of catalytically cracked oil containing spent coke catalyst; and characterized in that it further comprises the following operating phases: separation of a substantial quantity of said cracked catalyst used from said product stream in an external coarse separator downstream from the riser reactor for carrying out a coarse separation said catalyst coked from said product stream; abrupt injection and cooling of said product stream shortly after this product stream leaves said external separator by means of an abrupt cooling agent constituted by recycling oil to substantially reduce the thermal cracking of said product stream in lower value hydrocarbons and at the same time improve the naphtha yield in order to substantially increase gasoline production, said cooling agent comprising a recycling oil chosen from the group consisting of light catalytic recycling oil and the heavy catalytic recycling oil and said coarse coolant being injected into said product stream in an amount between about 5% and about 15% by volume based on the feed oil;   transport of said abruptly cooled product stream   to an upper portion of diluted phase of a release container;   release and separation of a substantial amount   as much of the coked catalyst fines used remaining from the product stream quenched in at least one internal cyclone in a diluted phase portion of said release container; stripping volatile hydrocarbons from the coked catalyst in a stripping section of said release container; passage of said coked catalyst having undergone stripping towards a regenerator of said catalytic cracking unit; injecting air into said regenerator regeneration of said spent catalyst by substantial combustion of coke on said catalyst used in the presence of air in said regenerator; recycling the regenerated catalyst to the riser reactor; separation of said cracked oil in a fractionation unit into streams of light hydrocarbon gases,   Catalytic Naphtha, Compressed Catalytic Recycling Oil   using light recycling oil and decanted oil; and recycling said light catalytic recycling oil from the fractionation unit to an abrupt coolant injection line of said release container disposed between said external cyclone and the fluidized bed for use as a sudden cooling.   13 Catalytic cracking unit, characterized in that it comprises in combination: an elongated riser reactor erected to catalytically crack a feed oil in the presence of a cracking catalyst to produce a stream of effluent product of higher degree of catalytically cracked oil leaving coke catalyst, said column reactor   rising with an upper portion and a lower portion   superior; an external coarse separator connected to and communicating with said upper portion of the riser reactor being spaced therefrom and positioned at a substantially similar level and around the upper portion of said riser reactor, to effect coarse separation of said catalyst coked from catalytically cracked oil; a clearing container erected for substantial clearing and separation of a substantial amount of the coked catalyst remaining from the catalytically cracked oil, said clearing container comprising an upper zone of diluted phase with at least one internal separator, a zone dense phase lower and a stripping section constituting a stripper; a product line extending between the external separator and the upper diluted phase portion of said container and connecting them to each other; a spent catalyst line extending between said external separator and said dense phase portion of said release container and connecting them together; a regenerator comprising a container, an elongated riser pipe erected to transport the coked catalyst to a regenerator, a communicating air injector   with said riser to inject air and facilitate   ter combustion of said coked catalyst, and a pipe-   tion for regenerated catalyst connected to said riser reactor in order to conduct the regenerated catalyst to said riser reactor; and   a coolant injection line   coarse ment consisting of recycling oil connected to and communicating with said inlet pipe for injecting an abrupt cooling agent comprising recycling oil, chosen from the group consisting of light catalytic recycling oil and l heavy catalytic recycling oil, in said catalytically cracked oil after this catalytically cracked oil has left said external separator downstream from said riser reactor and has been roughly separated from said catalyst and before this catalytically cracked oil   enters the aforementioned release container, in order to improve   improve the naphtha yield and substantially reduce the thermal cracking of said oil product stream, said line for the quenching agent consisting of recycling oil comprising a substantially vertical catalytic recycling oil injector, for   inject said substantially vertical coolant   downwardly into said inlet line or at an inclined angle of between about 150 and about 450 with respect to a vertical reference line to increase the mixing of said abrupt coolant with said products.   14 Catalytic cracking process, characterized in that it comprises the operating phases consisting in: catalytically cracking feed oil in a reactor of a catalytic cracking unit in the presence of a cracking catalyst to produce an effluent stream catalytically cracked improved quality oil containing catalyst; substantially separating said catalyst from said improved grade oil in an internal coarse separator in a release vessel, said internal coarse separator comprising an inertial separator selected from the group consisting of an internal cyclone and an inverted box separator; and abruptly cooling said improved grade oil   downstream of said internal coarse separator in said container   release point by means of an abrupt cooling agent comprising at least one member chosen from the group consisting of light catalytic recycling oil,   heavy catalytic recycling oil, catalytic naphtha   heavy, kerosene, coke oven distillate, light coke oven diesel, hydrotreated distillate, fresh untreated virgin diesel and fresh untreated virgin naphtha, said coolant being injected into the stream in an amount of between about 2% and around 20% by volume compared to the filler oil.   15 A catalytic cracking process, characterized in that it comprises the operating phases consisting in: substantially desalting oil comprising crude oil or crude oil; heating said desalted crude oil in an oven; pumping said heated crude oil to a primary distillation tower; separating said heated crude oil in said primary distillation tower into streams of naphtha, primary diesel and primary reduced crude oil; pumping said primary reduced crude oil to a tubular vacuum tower; separating said primary reduced crude oil in said tube vacuum tower into humid gas streams,   heavy diesel and reduced vacuum crude oil supplied   health residual oil; conveying a feed oil comprising said primary diesel from the primary distillation tower to an elongated rising column reactor of a catalytic cracking unit; feeding fresh and regenerated crystalline cracking catalyst to said riser reactor; catalytically cracking said charge oil in   said riser reactor in the presence of said cataly-   cracker under catalytic cracking conditions to produce a degree effluent stream   improved catalytically cracked oil containing cataly-   spent coker; separating a substantial amount of said spent coke catalyst from said product stream in an internal simplified separator into a diluted phase portion of a release vessel disposed downstream of said riser reactor to effect coarse separation of said coked catalyst from said product stream; suddenly injecting and cooling said product stream shortly after it has left the separator   external with recycling oil as a coolant   abruptly, to reduce to a minimum the thermal cracking of said product stream into lower value hydrocarbons and at the same time improve the naphtha yield in order to substantially increase gasoline production, said abrupt coolant comprising a recycling oil chosen from the group consisting of light catalytic recycling oil and heavy catalytic recycling oil and this sudden cooling agent being injected into said product stream in an amount of between approximately 5% and approximately 15% by volume relative to filler oil; releasing and separating a substantial amount of spent coked catalyst fines remaining from the product stream quenched in at least one internal cyclone in said diluted phase portion of the release container; stripping volatile hydrocarbons to remove them from the coked catalyst in a stripping section of said release container; conducting said coked catalyst having undergone stripping to a regenerator of said catalytic cracking unit; injecting air into said regenerator; regenerating said spent catalyst by substantial combustion of coke on the spent catalyst in the presence of air in said regenerator; recycling the regenerated catalyst to said riser reactor; separating said oil, catalytically cracked and quenched, in a stream fractionation unit of light hydrocarbon gases, catalytic naphtha, catalytic recycling oil comprising light recycling oil, and decanted oil; and recycle said catalytic recycling oil   slight from the fractionation unit to the container   release point for use as a sudden cooling.   16 A catalytic cracking method according to claim 12 or 15, characterized in that it comprises sending a part of said residual oil to the riser reactor for use as a part of   said filler oil, while said coolant   abruptly contains catalytic recycling oil heavy.   17 A catalytic cracking method according to claim 12 or 15, characterized in that light catalytic recycling oil is injected into said feed oil as at least a part of said agent. sudden cooling.   18 A catalytic cracking method according to claim 15, characterized in that: the separation phase comprises the projection of said stream of effluent product, when it leaves said riser reactor, against a striking wall of a separator reverse box, the discharge of said separated catalyst through the open bottom of said box separator   reversed, and the passage of said cracked catalytic oil-   separated through at least one window comprising a product outlet from said inverted box separator; and   said sudden cooling includes spraying   tion of said recycling oil in the vicinity of said   window of said inverted box separator.   19 Catalytic cracking unit, characterized in that it comprises: an elongated riser reactor erected to catalytically crack a feed oil in the presence of a cracking catalyst in order to produce a stream of higher quality effluent product by abandoning the coked catalyst, said riser reactor having an upper portion and a lower portion; an upright release vessel communicating with said riser reactor for releasing and substantially separating a substantial amount of coked catalyst from said catalytically cracked oil, said release container comprising an upper diluted phase zone with at least one internal cyclone, a zoned   dense phase lower and a realistic stripping section   sant a stripping unit; an internal coarse separator positioned in said diluted phase zone of said release container for carrying out a coarse separation of said coked catalyst from catalytically cracked oil, said internal coarse separator defining an evacuation of vapor which constitutes an oil outlet and having a lower portion providing an outlet for the catalyst; a regenerator comprising a container, an elongated riser pipe drawn up to transport the coked catalyst from the release container to said regenerator, an air injector communicating with said riser pipe to inject air and facilitate the combustion of said coked catalyst and a regenerated catalyst line connected to said riser reactor for transporting the regenerated catalyst to said riser reactor; and at least one recycle oil injection line constituting the quenching coolant which extends into the interior of said release container and which is substantially aligned opposite said oil outlet of the internal coarse separator for injecting an abrupt cooling agent comprising recycling oil chosen from the group consisting of light recycling oil and heavy recycling oil, into said catalytically cracked oil after said catalytically cracked oil has left said outlet for the oil   of said internal coarse separator and has been coarsely separated   rement from said catalyst, to improve substantial-   the naphtha yield and substantially reduce the thermal cracking of said product stream consisting of oil.   Catalytic cracking unit as claimed   cation 19, characterized in that said pipe for the abrupt cooling agent constituted by the recycling oil forms an inclined angle, between approximately 150   and about 900 with respect to a vertical reference line   shim, extending through said release unit, to substantially reduce the return current of said release coolant.   21 Catalytic cracking unit as claimed   cation 19, characterized in that said regenerator is arranged below the release container and said unit   catalytic cracking system includes a sensitive line-   horizontal line extending between the top portion of said riser reactor and said internal coarse cyclone by connecting them together.