DE1047771B - Process for the splitting of hydrocarbons that cannot be completely evaporated - Google Patents

Description

GERMAN

The present invention relates to a process for the splitting of hydrocarbons for the purpose of production valuable, especially olefin-rich gases.

According to an earlier proposal, which was not part of the state of the art, one can do the splitting of hydrocarbons, in particular of liquid hydrocarbons, with a particularly high yield carry out on olefins, if the starting material by means of a highly preheated gaseous or vaporous Heat transfer medium with the finest division of the oil into one at an elevated temperature Blows in the reaction space and ensures that the deformation reactions are essentially without contact drain with solid wall surfaces. During the cleavage carried out in this way, a gas-vapor mixture falls which may consist of more than 50% ethylene. In addition, there is an unevaporated, pitch-like residue that is liquid at elevated temperature.

The special conditions that must be observed during the cleavage (temperature of the carrier gas, pressure, residence time, cooling, etc.) are primarily based on the starting material. If there is one with a comparatively narrow boiling range, e.g. B. a sharp-cut petroleum fraction, other conditions must be observed than when a very broad-boiling hydrocarbon mixture is to be split ■. It has been shown that in some cases, especially when using a starting material which contains non-evaporable fractions (for example pitch, asphalt), it is difficult to find conditions in which, in addition to a maximum yield of valuable Gases or a minimal accumulation of solid fission products, the quality of the fission gases can also be adjusted in the desired manner, in particular with regard to a main production of ethylene.

It has therefore already been suggested that when cleavage of not completely evaporable Hydrocarbons for the purpose of producing valuable, especially olefin-rich gases in the way work that the starting material initially in the presence of an inert gas or steam under partial Evaporation of the same is heated and from the resulting vapor mixture the not evaporated Parts of the starting material are separated. The evaporation takes place in a tube furnace, i. H. by touching the material to be evaporated with the inner wall of pipes that are hot on the outside Flame gases are heated. This creates the risk of undesired decomposition and coke deposits given, which can occur due to local overheating of the pipes.

The present invention avoids these difficult methods of cleavage

of not completely evaporable

Hydrocarbons

Applicant:
Heinrich Koppers

Company with limited liability,
Essen, Moltkestr. 29

Dr. Heinrich Merkel, Essen,
has been named as the inventor

rigkeit by the fact that the starting material is heated in a room to which no heat is supplied through walls rather, the heat required for evaporation comes exclusively from the hot Carrier gas is supplied.

Apart from the mentioned advantage of avoiding undesired decomposition and coke deposits, the inventive method also has the advantage that when using a Tubular furnace necessary separator device for the separation of the non-evaporable fractions are omitted can because evaporation zone and separation zone can be combined in a single room. In the context of the present invention, the vapor component of the starting material is understood here not only understood the proportion of the starting material that is obtained by evaporation in the usual sense but also the part that arises when certain molecules of the starting material split up are divided into those with a low carbon number per molecule and those with a comparative very low hydrogen content per molecule. This latter operation is intended in the context of the present Invention can be referred to as so-called precracking.

If one proceeds in the manner according to the invention, one also achieves that the olefin-containing Useful gas contains relatively little pitch, what for the cleaning of the useful gas and the Exploitation of the sensible heat is beneficial. In particular, the possibly applied

809 727/479

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electrostatic precipitator is withdrawn under diversion 3, can in any way

Stands with considerably smaller dimensions can be used, for example to provide air under

leads to be. Generating a hot flue gas to be burned

The method according to the invention can also be used to generate the hot

retention of the basic principle in very different 5 carrier gases.

be realized in a like manner. In the drawing In the device according to Fig. 2, one is preferred three embodiments of devices, the wise cylindrical vessel 20 for thermal front Implementation of the method according to the invention treatment provided in which a layer 21 can serve, shown in schematic form. made of fine-grained material, e.g. B. fine coke, upright

Fig. 1 shows a device in which the thermal io is obtained. The fine coke can with suitable

Pretreatment of the starting material can be mixed in one of one-contact contacts, if necessary the

built free space is done; Coke also with appropriate salt solutions that

Fig. 2 shows a device in which the ther- catalytic ^ effect exert, be soaked. Premix Pretreatment within a fluidized bed is preferably carried out using such catalysts, and 15 dung, which have a chain-splitting effect.

Fig. 3 a device in which the pretreatment

takes place within a fixed bed. Movement held, which by the nozzles 22 to 25

The facilities shown in the figures are introduced into the bed from below. The water include only the parts that are part of the thermal pre-steam treatment may have a temperature of 600 to 800 ° C of the initial goods serve. The instru- ments. In the fluidized bed is then through line 26 processing parts, which are the actual split of the ent- the oil is injected, which is due to the strong wrapped vapors with the highly heated carrier gas swirling motion quickly distributed in the bed and Serve, as they are used to understand the present through exposure to the hot water invention are not absolutely necessary, away-steam in a vaporous and non-exited one. 25 steamed portion is decomposed. The vaporous one

In Fig. 1, the device intended for the thermal pre-component escapes from the surface of the vortex action is formed by a cylindrical layer and passes through an opening 27 into the drical vessel 1, which has a cyclone separator 28 on both of them and from there into a From the ends tapers conically and at the top into a vapor draft line 29, where the mixture of hydrocarbon discharge line 2 empties, while at the lower 30 material vapors and water vapor with the high upstream end of the vessel, a discharge line 3 for the heated carrier gas comes into contact, which is carried by liquid Residue of the starting material provided is fed to line 30 and the mixture to which is. A damping line 4, which conveys in the area of the discharge, leads through the axis of the cylindrical vessel 1, also not shown here. The developed hydrocarbon traction line 3 led out laterally and is connected to a fine dust content of the device not shown here, in the cyclone due to the softening of the catalytic converter, for example to a temperature reduction of the flow rate and from 1100 to 1200 ° C preheated carrier gas, which changes the direction of flow and is generated from a mixture of flue gas and water vapor through the outlet nozzle 31 again into which can exist. The carrier gas line 4 40 fluidized bed back,
ends in the area of the steam outlet line 2. The non-evaporated portion of the starting material

The oil to be split is clogged through the nozzle 5. the fine particles of coke solid; given-

together with a relatively small amount of if one can lead the precracking so far that

Water vapor, the temperature of which is about 600 to 800 ° C, is cracked down to elemental carbon, like this

which is fed through line 6, 45 that significant amounts of liquid residue

do not occur in the treatment vessel 1 at such speeds. In order to remove these residues from the

speed and direction blown to remove the oil-water drive, can be continuous or incremental

vapor mixture a helical upwardly part of the mass of the fluidized bed from the

movement along the cylinder wall. In the process, treatment room 20 is removed and replaced by fresh mass

if a partial evaporation of oil components occurs, 50 must be replaced.

With the device according to Fig. 3, there is this Reaction chamber wall. In order to turn all possible evaporation vessels for thermal pretreatment or obtainable by a pre-cracking from a cylinder 40, in which, however, on a The sieve-like grate 41 creates a solid bed 42 of comparatively broader hydrocarbons to set free Nozzles 7, 8 and 9 water vapor in such a way in the 55 white coarse-grained inert material or coarse Treatment room blown in that the original pieces of coke or coarse porcelain fragments or sun-screw lines Movement supports or permanent ceramic materials is accumulated. The oil is maintained. Also in the upper part of the loading is fed through line 43 and in the form of a treatment vessel 1, liquid residues are atomized in a fine jet that hits the top from above Flung through the wall and run downwards through the surface of the fixed bed. At the same time will Discharge line 3 out of the treatment vessel. water vapor introduced through lines 44 and 45, The resulting mixture of oil vapors and water - which mixes with the finely atomized oil and Steam enters exhaust line 2 at 10, with the transfer of heat from water vapor mixes there with the highly heated carrier steam, the oil a partial evaporation and precracking which causes the mixture of hydrocarbon vapors 65 of the same. That down through the fixed bed and water vapor in the extracting mixture, not shown here, of oil vapors and water-splitting space entrains, in which then the crack steam is drawn off through the line 46 and obtained in the intended way under generation then reaches the line 47, in which the association Ethylene-rich gas takes place. mixture with the highly preheated carrier gas

The liquid residue that takes place through the vent 70. The mixture is then in the already

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described manner supplied to the actual splitting device.

The residues of the starting material resulting from the thermal pretreatment run, as far as they are liquid at the treatment temperature, through the exhaust line 48 out of the device, while the solid residues are initially retained between the coarse grains of the fixed bed and occasionally be eliminated by incineration.

Examples:

In an embodiment of the invention using the device shown in FIG was worked as follows:

The raw material used was Kuwait crude oil with the following properties

C content 84.6 percent by weight

H content 12.3

Other 2.1 ,,

Specific weight . 0.9077 "

Conradson-C 6.3 "

The crude oil was pumped in through nozzle 6 under the pressure of a Bosch pump, namely in one Quantity of about 4 kg per hour. At the same time, steam at a temperature of about 800 ° C. was passed through nozzle 5 in one Quantity of 1 kg per hour introduced. With a smaller amount of additional steam (about 0.1 kg per hour), which was introduced through the nozzles 7, 8 and 9, allowed the helical movement over the Maintain the entire length of the evaporator 1. In channel 2 the mixture of oil vapors and Water vapor a larger amount of carrier water vapor, about 3.8 kg per hour with one temperature of about 1200 ° C added. The residence time of the fabrics was about 4 seconds.

The result was a cracked gas with the following composition:

Methane 22.5 percent by volume

Ethylene 38.1 "

Hydrogen 22.7

Propylene 6.9 "

Other 9.8 "

The gas yield was 0.756 Nm ³ cracking gas per kg of feed oil; the olefin yield was 0.477 kg per kg of feed oil.

If the method according to the invention was carried out with a device according to FIG. 2, the result was the following numbers:

In the container 20 there were 201 fine-grained Coke, heated by 800 ° C, introduced through the nozzles 22 to 25 water vapor in the fluidized state being held. A Ragusa crude oil was injected through the nozzle 26, which following bis Fractions boiling at 315 ° C had:

Aromatics 22.6 percent by volume

Olefins 7.7

Paraffins (naphthenes) .. 69.7

The constituents of the oil evaporated in the fluidized bed were used together with those for the evaporation used water vapor passed through the cyclone separator 28 and in line 29 with 1250 ° C hot Carrier water vapor from line 30 is mixed and passed into the cracking room. The residence time of the good in the fluidized bed was about 12 seconds. The result was a cracked gas of the following composition:

Methane 20.6 percent by volume

Ethylene 30.7

Propylene 10.6

Hydrogen 20.8

Ethane 6.5 "

Other 10.8 "

The gas yield was 0.652 Nm ^{3 of} cracked gas each

kg of oil. The olefin yield was 0.445 kg per kg of oil.

Claims (4)

Patent claims: 1. Process for the splitting of hydrocarbons which cannot be completely evaporated for the purpose of production valuable, especially olefin-rich gases, the starting material initially in the presence an inert gas or vapor heated with partial evaporation of the same and off the non-evaporated portions of the starting material are separated from the resulting vapor mixture before the steam mixture is introduced into the cleavage zone, characterized in that the for the partial evaporation of the starting material required heat exclusively by the The heat content of the inert gas or vapor is available within the evaporation chamber is provided. 2. The method according to claim 1, characterized in that the starting material to be split with moderate, e.g. B. to temperatures of 600 to 800 ° C, preheated steam tangentially and at an angle is blown upwards into a vertical cylindrical space and the released Vapors at the top of the cylinder with the highly preheated carrier gas for complete cleavage are mixed, while the liquid or solid hurled against the inner cylinder surface Residue of the starting material is withdrawn from the bottom of the cylinder. 3. The method according to claim 1, characterized in that the starting material in a fluidized bed Introduced from fine-grained contact material and hot the fluidized bed through 600 to 800 ° C Water vapor is whirled up, releasing the hydrocarbon vapors from the surface of the fluidized bed withdrawn and after at least partial separation of the entrained Contact dust are mixed with highly preheated carrier gas for complete cleavage, while the liquid or solid residues of the starting material remaining in the fluidized bed are included be withdrawn from the catalyst. 4. The method according to claim 1, characterized in that the starting material together with about 600 to 800 ° C hot steam from above onto a fixed bed of lumpy inert bodies is passed, the released hydrocarbon vapors through the fixed bed down withdrawn and then mixed with highly preheated carrier gas for the purpose of complete cleavage while at least the residue of the starting material that is liquid during the pretreatment is withdrawn from the fixed bed in liquid form. Considered publications:
German patent specification No. 753 849. 1 sheet of drawings