CN114606021B

CN114606021B - Method and system for producing ethylene and propylene

Info

Publication number: CN114606021B
Application number: CN202011447724.2A
Authority: CN
Inventors: 马文明; 朱根权; 杨超
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2020-12-09
Filing date: 2020-12-09
Publication date: 2025-02-14
Anticipated expiration: 2040-12-09
Also published as: CN114606021A

Abstract

The present disclosure provides a method and system for producing ethylene and propylene, the method comprising: contacting and reacting a heavy raw material with a catalytic cracking catalyst in a catalytic cracking reaction unit; contacting and reacting a light raw material with a dehydrogenation cracking catalyst in a dehydrogenation cracking reaction unit; wherein the dehydrogenation cracking catalyst to be regenerated obtained after the dehydrogenation catalytic cracking reaction is introduced into a catalytic cracking regeneration unit for heat exchange treatment, and after reaching the initial regeneration temperature, enters the dehydrogenation cracking regeneration unit for regeneration reaction to obtain a dehydrogenation cracking regeneration catalyst. The method organically combines the catalytic cracking of the heavy raw material with the dehydrogenation cracking of the light raw material, which can promote the effective conversion of the heavy raw material and the light raw material into ethylene and propylene. In addition, the heat generated during the regeneration of the catalytic cracking catalyst can be further utilized to provide heat for the regeneration process of the dehydrogenation cracking catalyst, thereby greatly reducing energy consumption, and has important industrial application value.

Description

Process and system for producing ethylene and propylene

Technical Field

The present disclosure relates to the field of petrochemical technology, and in particular, to a method and a system for producing ethylene and propylene.

Background

With the continuous development of the chemical industry, the demand of ethylene and propylene has a trend of rapid increase, and the ethylene and the propylene have a large gap in the market. The current methods for producing ethylene and propylene mainly comprise steam cracking technology, catalytic cracking technology, propane dehydrogenation technology, technology for preparing olefin from methanol and the like. Among them, the steam cracking technology is a main source of ethylene and propylene, and the produced ethylene accounts for more than 95% of the total yield of ethylene, the propylene accounts for about 61% of the total yield of propylene, and the propylene produced by the catalytic cracking technology accounts for about 34% of the total yield of propylene. Steam cracking, propane dehydrogenation and methanol to olefins technologies all use light feedstocks, whereas catalytic cracking processes can process heavy feedstocks and can produce more ethylene and propylene. In addition, the catalytic cracking technology produces more C ₄～C₈ hydrocarbons while producing ethylene and propylene, wherein, C ₄～C₈ olefins can convert part of the hydrocarbons into ethylene and propylene through recycling, but the conversion rate is lower, and C ₄～C₈ alkanes are difficult to convert. In recent years, the dehydrogenation and cracking technology of the low-carbon alkane has greatly advanced, and the dehydrogenation reaction and the cracking reaction of the low-carbon alkane can be coupled by using a catalyst with double activities of catalytic dehydrogenation and catalytic cracking, so that the dehydrogenation reaction and the cracking reaction are carried out in the same reactor, the flow path of the device is shortened, and the yield of ethylene and propylene is improved.

CN1031834a discloses a catalytic conversion process for producing light olefins. The method takes petroleum fractions, residual oil or crude oil with different boiling ranges as raw materials, takes a mixture containing Y zeolite and pentasil zeolite as a catalyst, adopts a fluidized bed or a moving bed as a reactor, and has the reaction conditions of 500-650 ℃ of temperature, 0.15-0.30 MPa of pressure, 0.2-20 hours ^-1 of weight hourly space velocity and 2-12 of catalyst-to-oil ratio, and returns the reacted catalyst to the reactor for recycling after being burnt and regenerated. The present process is capable of producing more propylene and butene than conventional catalytic cracking and steam cracking.

CN104560149a discloses a catalytic conversion process for the production of butenes. The method is provided with 4 reactors in total, besides adopting a reactor configuration of double lifting pipes and a fluidized bed, a fluidized bed reactor is arranged outside a settler for cracking middle gasoline fraction, reaction products enter the lifting pipe reactor for continuous cracking reaction, and the reacted catalyst returns to the reactor for recycling after being burnt and regenerated. The method uses the mixture containing Y zeolite and beta zeolite as catalyst, and can obtain higher propylene and butene yield.

CN102206509a discloses a hydrocarbon catalytic conversion process for producing propylene and light aromatic hydrocarbons. The method adopts a combined reactor form of double lifting pipes and a fluidized bed reactor, wherein heavy hydrocarbon and a cracking catalyst containing modified beta zeolite are in contact reaction in a first reactor, C ₄ hydrocarbon fraction and/or light gasoline fraction and the cracking catalyst containing modified beta zeolite are introduced into a third reactor for continuous reaction after being in contact reaction in a second reactor, and the third reactor is the fluidized bed reactor, thereby creating conditions for the secondary cracking reaction of the gasoline fraction and further improving the yield of propylene and light aromatic hydrocarbon.

CN1506342A discloses a method for producing propylene by catalytic cracking of olefins with four or more carbon atoms. According to the method, a ZSM molecular sieve loaded with at least one alkaline earth metal of Mg, ca or Ba is used as a catalyst, and the olefin with the carbon four or more than four as a reaction raw material is subjected to cracking reaction under the conditions of the reaction temperature of 400-600 ℃, the reaction pressure of 0-0.15 MPa and the liquid phase space velocity of 10h ^-1～50h^-1. The method can obviously improve the selectivity and the yield of propylene.

CN105085143a discloses a process for producing ethylene propylene by mixing carbon penta-carbon hexaalkane and carbon tetra-alkane. The raw material rich in carbon five-carbon hexaalkane is firstly fed into a reactor filled with a dehydrogenation catalyst to carry out alkane dehydrogenation reaction under the conditions of 480-700 ℃ of temperature, 0.01-3 MPa of pressure and 0.1h ^-1～10h^-1 of volume space velocity, and the dehydrogenation product is mixed with the carbon four-hydrocarbon and then fed into the reactor filled with a catalytic cracking catalyst to carry out catalytic cracking reaction under the conditions of 450-650 ℃ of temperature, 0.1-0.3 MPa of pressure and 0.1h ^-1～10h^-1 of volume space velocity. The method can improve the yield of ethylene and propylene and reduce the energy consumption.

The above technology processes heavy feedstocks by catalytic cracking techniques and uses dehydrogenation cracking techniques to process light feedstocks, but the two are not effectively combined and the ethylene and propylene yields of light hydrocarbon feedstocks are low.

It is noted that the information disclosed in the foregoing background section is only for enhancement of understanding of the background of the disclosure and therefore it may comprise information that does not form the prior art that is already known to a person of ordinary skill in the art.

Disclosure of Invention

It is a primary object of the present disclosure to overcome at least one of the above-mentioned drawbacks of the prior art, and to provide a method and a system for producing ethylene and propylene, which solve the problems of low yield, high energy consumption, etc. when ethylene and propylene are produced by the existing system or method.

In order to achieve the above purpose, the present disclosure adopts the following technical scheme:

The invention provides a production method of ethylene and propylene, which comprises the steps of enabling a heavy raw material to contact and react with a catalytic cracking catalyst in a catalytic cracking reaction unit to obtain a catalytic cracking oil-gas mixture, separating the catalytic cracking oil-gas mixture to obtain a catalytic cracking oil-gas product and a catalytic cracking spent catalyst, enabling the light raw material to contact and react with a dehydrogenation cracking catalyst in the dehydrogenation cracking reaction unit to obtain the dehydrogenation cracking oil-gas mixture, separating the dehydrogenation cracking oil-gas product and the dehydrogenation cracking spent catalyst to obtain the ethylene and the propylene, separating the catalytic cracking oil-gas product and the dehydrogenation cracking oil-gas product to obtain the ethylene and the propylene, introducing the catalytic cracking spent catalyst into a catalytic cracking regeneration unit to perform a regeneration reaction to obtain the catalytic cracking regenerated catalyst, introducing the dehydrogenation cracking spent catalyst into the catalytic cracking regeneration unit to perform heat exchange treatment, and introducing the dehydrogenation cracking spent catalyst into the dehydrogenation cracking regeneration unit to perform the regeneration reaction after reaching the regeneration initial temperature to obtain the dehydrogenation cracking regenerated catalyst.

According to one embodiment of the present disclosure, the catalytic cracking catalyst includes a catalytic cracking active component, clay and a binder, wherein the catalytic cracking active component includes a molecular sieve having an MFI structure and a Y molecular sieve, and the mass ratio of the Y molecular sieve to the molecular sieve having an MFI structure is 1:0 to 2, preferably 1:0.1 to 0.8.

According to one embodiment of the present disclosure, the dehydrogenation cracking catalyst comprises a dehydrogenation cracking active component, clay and a binder, wherein the dehydrogenation cracking active component comprises a molecular sieve with an MFI structure and a metal active component, the metal active component is selected from one or more of metal simple substances and oxides thereof, wherein the metal active component comprises iron, chromium and vanadium, and the content of iron is 0% -5%, preferably 0% -1%, the content of chromium is 0% -8%, preferably 0% -2%, and the content of vanadium is 0% -15%, preferably 0% -8% based on the total weight of the molecular sieve with the MFI structure.

According to one embodiment of the present disclosure, the catalytic cracking regenerated catalyst is introduced into the catalytic cracking reaction unit for recycling, and the dehydrogenation cracking regenerated catalyst is introduced into the dehydrogenation cracking reaction unit for recycling.

According to one embodiment of the present disclosure, in a catalytic cracking reaction unit, a heavy raw material is introduced into a first riser reactor to contact and react with a catalytic cracking regeneration catalyst from a catalytic cracking regeneration unit, and the obtained product is introduced into a first fluidized bed reactor to continue to react, so as to obtain a catalytic cracking oil agent mixture.

According to one embodiment of the present disclosure, the reaction temperature of the first riser reactor is 540 ℃ to 640 ℃, preferably 560 ℃ to 620 ℃, the catalyst-to-oil ratio is 3 to 25, preferably 5 to 20, the reaction time is 1s to 20s, preferably 2s to 10s, the reaction temperature of the first fluidized bed reactor is 520 ℃ to 620 ℃, preferably 540 ℃ to 600 ℃, the weight hourly space velocity is 1 hour ^-1 to 25 hours ^-1, preferably 2 hours ^-1 to 10 hours ^-1, the catalytic cracking catalyst density is 50kg/m ³～400kg/m³, preferably 100kg/m ³～250kg/m³, the bed height is 1/2 to 4/5, preferably 1/2 to 3/4 of the bed height, the pressure in the first fluidized bed reactor is 0.1MPa to 0.4MPa, preferably 0.15MPa to 0.3MPa.

According to one embodiment of the disclosure, the method further comprises introducing cracked heavy oil into the middle or upper part of the first riser reactor, wherein the mass ratio of the cracked heavy oil to the heavy raw material is 0.01-0.1:1.

According to one embodiment of the present disclosure, in the dehydrogenation-cracking reaction unit, the light feedstock is introduced into the second fluidized bed reactor, and the dehydrogenation-cracking regeneration catalyst is introduced into the second fluidized bed reactor through the second riser to contact and react with the light feedstock, thereby obtaining a dehydrogenation-cracking oil mixture.

According to one embodiment of the present disclosure, the reaction temperature of the second fluidized bed reactor is 560 ℃ to 660 ℃, preferably 580 ℃ to 640 ℃, the weight hourly space velocity is 1 hour ^-1 to 20 hours ^-1, preferably 2 to 8 hours ^-1, the catalyst density is 50kg/m ³～450kg/m³, preferably 100kg/m ³～350kg/m³, the bed height is 1/2 to 4/5, preferably 1/2 to 3/4 of the bed reactor height, and the pressure in the second fluidized bed reactor is 0.1mpa to 0.4mpa, preferably 0.15 to 0.3mpa.

According to one embodiment of the present disclosure, the heavy feedstock is selected from one or more of vacuum wax oil, atmospheric residuum, vacuum residuum, coker wax oil, deasphalted oil, furfural extract oil, coal liquefaction oil, oil sand oil, shale oil, distillate oil obtained by F-T synthesis, animal oil, and vegetable oil, and the light feedstock is selected from C ₄～C₈ hydrocarbons.

According to one embodiment of the present disclosure, the content of C ₄～C₈ alkanes is not less than 20% based on the total weight of the light feedstock.

According to one embodiment of the present disclosure, the light feedstock is selected from the group consisting of a catalytic pyrolysis oil and gas product and a dehydrogenated pyrolysis oil and gas product, which are separated to yield C ₄～C₈ hydrocarbons.

The utility model also provides a production system of ethylene and propylene, comprising a catalytic cracking reaction unit, a catalytic cracking regeneration unit, a dehydrogenation cracking reaction unit and a dehydrogenation cracking regeneration unit, wherein the catalytic cracking reaction unit is configured to perform catalytic cracking reaction of heavy raw materials, the catalytic cracking regeneration unit is configured to regenerate a catalytic cracking spent catalyst obtained by separation after the catalytic cracking reaction to obtain a catalytic cracking regeneration catalyst, the dehydrogenation cracking reaction unit is configured to perform dehydrogenation cracking reaction of light raw materials, the dehydrogenation cracking regeneration unit is configured to regenerate the dehydrogenation cracking spent catalyst obtained by separation after the dehydrogenation cracking reaction to obtain a dehydrogenation cracking regeneration catalyst, the catalytic cracking regeneration unit further comprises a heat exchange device, and the heat exchange device is configured to heat the dehydrogenation cracking spent catalyst generated by the dehydrogenation cracking reaction unit by utilizing heat generated by the catalytic cracking spent catalyst to enable the dehydrogenation cracking spent catalyst to reach the regeneration initial temperature and then enter the dehydrogenation cracking regeneration unit.

According to one embodiment of the disclosure, the catalytic cracking reaction unit comprises a first riser reactor, a first stripper, a first fluidized bed reactor and a first settler, wherein a heavy raw material inlet is formed in the bottom of the first riser reactor, an outlet of the first riser reactor is communicated with the inlet of the first fluidized bed reactor, the first stripper is positioned below the first fluidized bed reactor and wraps part of the first riser reactor, and the first settler is positioned above the first fluidized bed reactor and is communicated with the first fluidized bed reactor.

According to one embodiment of the present disclosure, the middle or upper portion of the first riser reactor is also provided with a cracked heavy oil inlet.

According to one embodiment of the present disclosure, the catalytic cracking regeneration unit includes a catalytic cracking regenerator and a heat exchange device disposed within the catalytic cracking regenerator, the catalytic cracking regenerator is in communication with the first stripper, and the catalytic cracking regenerator is connected to the first riser reactor by a catalytic cracking regenerated catalyst transfer line.

According to one embodiment of the disclosure, the heat exchange device is a heat exchange tube, the ratio of the cross-sectional area of the heat exchange tube to the cross-sectional area of the catalytic cracking regenerator is 1:2-10, preferably 1:3-6, and the ratio of the length of the heat exchange tube to the length of the catalytic cracking regenerator is 1:1.5-5, preferably 1:2-3.

According to one embodiment of the disclosure, the dehydrogenation-cracking reaction unit comprises a second riser, a second stripper, a second fluidized bed reactor and a second settler, wherein a light raw material inlet is arranged at the bottom of the second fluidized bed reactor, the second riser is connected in series below the second fluidized bed reactor, the second stripper is positioned below the second fluidized bed reactor and wraps part of the second riser, and the second settler is positioned above the second fluidized bed reactor and is communicated with the second fluidized bed reactor.

According to one embodiment of the present disclosure, the dehydrogenation-cracking regeneration unit comprises a dehydrogenation-cracking regenerator, wherein an inlet of the heat exchange device is connected to the second stripper, an outlet of the heat exchange device is connected to the dehydrogenation-cracking regenerator, and the dehydrogenation-cracking regenerator is connected to the second riser through a dehydrogenation-cracking regeneration catalyst transfer line.

The beneficial effects of the present disclosure are:

The method and the system can realize the organic combination of the catalytic cracking of the heavy raw material and the dehydrogenation cracking of the light raw material, can promote the conversion of the heavy raw material and the light raw material into the ethylene and the propylene, and can effectively improve the conversion rate. In a word, the production method and the production system can realize higher hydrocarbon conversion capability, lower production cost and higher yield of ethylene and propylene, and have important industrial application value.

Drawings

The following drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate the disclosure and together with the description serve to explain, but not limit the disclosure.

FIG. 1 is a schematic diagram of the connection of an ethylene and propylene production system in accordance with one embodiment of the present disclosure;

FIG. 2 is a schematic view of the apparatus structure of an ethylene and propylene production system according to one embodiment of the present disclosure;

FIG. 3 is a schematic view of a heat exchange device in a production system of ethylene and propylene according to one embodiment of the present disclosure;

FIG. 4 is a schematic view showing a sectional structure of a heat exchange device A-A in a production system of ethylene and propylene according to one embodiment of the present disclosure.

Wherein reference numerals are as follows:

1 catalytic cracking reaction unit

1-1 First riser reactor

1-2 First stripper

1-3 First fluidized bed reactor

1-4 First settler

11 Heavy raw material

12 Pre-lift gas line

13 Cracking heavy oil

14 Stripping gas

15 Catalytic cracking spent catalyst delivery line

16 Catalytic cracking oil and gas product pipeline

2 Catalytic cracking regeneration unit

2-1 Catalytic cracking regenerator

2-2 Heat exchanger

21 Main wind inlet pipeline

22 Catalytic cracking regenerated catalyst conveying pipeline

23 Regenerated flue gas outlet pipeline

24 Catalyst delivery line

3 Dehydrogenation cracking reaction unit

3-1 Second riser

3-2 Second stripper

3-3 Second fluidized bed reactor

3-4 Second settler

31 Light raw material

32 Pre-lift gas line

33 Stripping gas

34 Catalyst delivery line

35 Dehydrogenation cracking oil gas product pipeline

4 Dehydrogenation cracking regeneration unit

4-1 Dehydrogenation cracking regenerator

41 Main wind inlet line

42 Dehydrogenation cracking regenerated catalyst conveying pipeline

43 Regenerated flue gas outlet pipeline

Detailed Description

Exemplary embodiments that embody features and advantages of the present disclosure are described in detail in the following description. It will be understood that the present disclosure is capable of various modifications in the various embodiments, all without departing from the scope of the present disclosure, and that the description and drawings are intended to be illustrative in nature and not to be limiting of the present disclosure.

In the following description of various exemplary embodiments of the present disclosure, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various exemplary structures, systems, and steps in which aspects of the present disclosure may be practiced. It is to be understood that other specific arrangements of parts, structures, example devices, systems, and steps may be used, and structural and functional modifications may be made without departing from the scope of the present disclosure. Moreover, although the terms "over," "between," "within," and the like may be used in this specification to describe various exemplary features and elements of the disclosure, these terms are used herein for convenience only, e.g., in accordance with the directions of the examples depicted in the drawings. Nothing in this specification should be construed as requiring a particular three-dimensional orientation of structures to fall within the scope of this disclosure.

Referring to fig. 1, a schematic diagram of the connection of an ethylene and propylene production system according to an exemplary embodiment of the present disclosure is representatively illustrated. The ethylene and propylene production system proposed in the present disclosure is described as applied to the production of ethylene and propylene. Those skilled in the art will readily appreciate that numerous modifications, additions, substitutions, deletions, or other changes may be made to the specific embodiments described below in order to apply the relevant designs of the present disclosure to the production of other hydrocarbon products while remaining within the principles of the ethylene and propylene production systems set forth in the present disclosure.

As shown in fig. 1, in the present embodiment, the production system of ethylene and propylene proposed in the present disclosure mainly includes a catalytic cracking reaction unit 1, a catalytic cracking regeneration unit 2, a dehydrogenation cracking reaction unit 3, and a dehydrogenation cracking regeneration unit 4. It should be noted that fig. 1 is only a partial schematic view of the ethylene and propylene production system. Referring now to FIG. 2, FIG. 2 is a schematic diagram of an apparatus for producing ethylene and propylene according to one embodiment of the present disclosure. Fig. 3 is a schematic view showing the structure of a heat exchange device in a production system of ethylene and propylene according to one embodiment of the present disclosure, and fig. 4 is a schematic view showing the sectional structure of a heat exchange device A-A in a production system of ethylene and propylene according to one embodiment of the present disclosure. The structure, connection and functional relationship of the main components of an exemplary embodiment of an ethylene and propylene production system according to the present disclosure will be described in detail with reference to the above-mentioned drawings.

As shown in fig. 1, the present disclosure provides a production system of ethylene and propylene, comprising a catalytic cracking reaction unit 1, a catalytic cracking regeneration unit 2, a dehydrogenation cracking reaction unit 3, and a dehydrogenation cracking regeneration unit 4.

The catalytic cracking reaction unit 1 is configured to perform catalytic cracking reaction of heavy raw materials to obtain catalytic cracking oil gas products. In the present embodiment, as shown in conjunction with fig. 1 and 2, the catalytic cracking reaction unit 1 includes a first riser reactor 1-1, a first stripper 1-2, a first fluidized bed reactor 1-3, and a first settler 1-4.

Specifically, the first riser reactor 1-1 of the catalytic cracking reaction unit 1 is selected from one or a combination of more than one of an equal diameter riser reactor, an equal linear velocity riser reactor and a variable diameter riser reactor, and is mainly used for cracking reaction of heavy raw materials, and the heavy raw materials 11 are fed from a heavy raw material inlet arranged at the bottom of the first riser reactor 1-1 of the catalytic cracking reaction unit. In some embodiments, further comprising introducing cracked heavy oil 13 as a feedstock, wherein cracked heavy oil 13 is fed from a mid-upper portion of first riser reactor 1-1 as shown in FIG. 2. By introducing the cracked heavy oil 13 to make it contact with the catalytic cracking regenerated catalyst preferentially, part of the strong acid center on the catalytic cracking regenerated catalyst can be covered, improving the cracking performance of the catalyst.

The first fluidized bed reactor 1-3 of the catalytic cracking reaction unit 1 is positioned at the upper part of the first riser reactor 1-1, and the first fluidized bed reactor 1-3 and the first fluidized bed reactor are connected in series, wherein the first fluidized bed reactor 1-3 is selected from one or more than one of a fixed fluidized bed reactor, a bulk fluidized bed reactor, a bubbling bed reactor, a turbulent bed reactor, a rapid bed reactor, a conveying bed reactor and a dense-phase fluidized bed reactor. The first fluidized bed reactors 1-3 can extend the reaction time of heavy raw materials therein, thereby enabling more thorough conversion.

The catalytic cracking reaction unit 1 is further provided with a pre-lift gas line 12, through which pre-lift gas line 12a lift gas is introduced into the riser reactor 1-1 of the catalytic cracking reaction unit. The lifting gas used is well known to those skilled in the art and may be selected from one or more of steam, nitrogen, dry gas, preferably steam.

The first stripper 1-2 is located below the first fluidized bed reactor 1-3 of the catalytic cracking reaction unit 1 and communicates with the first fluidized bed reactor 1-3, and wraps a portion of the first riser reactor 1-1.

The first stripper 1-2 is provided with a stripping baffle and a stripping gas distribution ring, which are used for reducing the falling speed of the catalyst to be regenerated in catalytic cracking and enabling the distribution of the stripping gas 14 to be more uniform, so that the residual reaction oil gas on the catalyst to be regenerated in catalytic cracking is fully removed from the catalyst to be regenerated in catalytic cracking.

The oil mixture obtained after the reaction in the first fluidized bed reactor 1-3 is separated by a cyclone separator to obtain an oil gas product and a catalytic cracking spent catalyst, wherein the oil gas product is led out of the reactor through a catalytic cracking oil gas product pipeline 16 to enter a subsequent product separation system, and the catalytic cracking spent catalyst is led into the first stripper 1-2 for stripping.

The first settler 1-4 is communicated with the first fluidized bed reactor 1-3 and the first riser reactor 1-1, stripping gas in the first stripper 1-2 can directly enter the first settler 1-4, enter a gas collection chamber after being separated by a cyclone separator together with other oil gas, and then are led out of the catalytic cracking reaction unit 1 through a catalytic cracking oil gas product pipeline 16.

As shown in fig. 1 and 2, the catalytic cracking regeneration unit 2 is connected to the catalytic cracking reaction unit 1, and the catalytic cracking regeneration unit 2 is configured to perform a regeneration reaction on a catalytic cracking spent catalyst generated by the catalytic cracking reaction unit 1 to obtain a catalytic cracking regenerated catalyst, and the catalytic cracking regenerated catalyst enters the catalytic cracking reaction unit through a catalytic cracking regenerated catalyst conveying pipeline 22 to be recycled.

Specifically, the catalytic cracking regeneration unit 2 includes a catalytic cracking regenerator 2-1 and a heat exchange device 2-2, and the catalytic cracking regenerator 2-1 communicates with the first stripper 1-2 and is connected to the first riser reactor 1-1 through a catalytic cracking regeneration catalyst line 22. The catalyst to be regenerated by catalytic cracking from the first stripper 1-2 enters the catalytic cracking regenerator 2-1 through a catalytic cracking catalyst conveying pipeline 15 for burning regeneration, so that the catalyst to be regenerated by catalytic cracking is converted into a catalyst to be regenerated by catalytic cracking. The catalytic cracking regenerated catalyst in the catalytic cracking regenerator 2-1 returns to the first riser reactor 1-1 for recycling through a catalytic cracking regenerated catalyst pipeline 22, wherein a catalytic cracking spent catalyst conveying pipeline 15 and the catalytic cracking regenerated catalyst conveying pipeline 22 can be provided with valves, and the conveying speed of the catalyst can be adjusted by controlling the valves on the valves.

The bottom of the catalytic cracking regenerator 2-1 is provided with a main air inlet line 21, and a regeneration gas, which is a gas known to those skilled in the art, including but not limited to one or more of air, oxygen and other gases having oxidizing property, can be introduced into the catalytic cracking regenerator 2-1, and the flue gas generated after regeneration enters the gas collection chamber through the cyclone separator, and is discharged through a regenerated flue gas outlet line 23 after being treated.

The catalytic cracking regenerator 2-1 is further provided therein with a heat exchange device 2-2, as shown in fig. 3 and 4, wherein in this embodiment, the heat exchange device 2-2 is a heat exchange tube, the ratio of the cross-sectional area of the heat exchange tube to the cross-sectional area of the catalytic cracking regenerator 2-1 is 1:2-10, preferably 1:3-6, for example, 1:3, 1:4, 1:5, 1:5.5, 1:6, etc., and the ratio of the length of the heat exchange tube to the length of the catalytic cracking regenerator is 1:1.5-5, preferably 1:2-3. The heat exchange device 2-2 is configured to heat the dehydrogenation-cracking spent catalyst generated by the dehydrogenation-cracking reaction unit 3 by using heat generated when the catalytic-cracking spent catalyst is regenerated, so that the dehydrogenation-cracking spent catalyst reaches the regeneration initial temperature and then enters the dehydrogenation-cracking regeneration unit 4.

According to the present disclosure, since coke generated by the dehydrogenation cracking reaction is low, sufficient heat cannot be generated at the time of regeneration to maintain the efficiency of regeneration. Therefore, the heat compensation is needed, and the heat exchange device 2-2 is arranged in the catalytic cracking regenerator 2-1, so that the excessive heat of the catalytic cracking regenerator 2-1 can be utilized to preheat the catalyst, the regeneration efficiency of the dehydrogenation cracking spent catalyst can be improved, and the energy consumption is reduced.

The structure of the dehydrogenation-cracking reaction unit 3, the dehydrogenation-cracking regeneration unit 4, and the connection relationship and the function with the heat exchange device 2-2 will be specifically described below.

The dehydrolysis reaction unit 3 is configured to perform a dehydrolysis reaction of the light feedstock 31 to obtain a dehydrolysed oil gas product. In the present embodiment, as shown in conjunction with fig. 1 and 2, the dehydrolysis reaction unit 3 includes a second riser 3-1, a second stripper 3-2, a second fluidized bed reactor 3-3, and a second settler 3-4.

Specifically, the second riser 3-1 is selected from one or a combination of more than one of an equal diameter riser, an equal linear velocity riser and a variable diameter riser, and is mainly used for conveying the dehydrogenation cracking catalyst.

The second fluidized bed reactor 3-3 is positioned at the upper part of the second riser 3-1, the two fluidized bed reactors are connected in series, the second fluidized bed reactor 3-3 is selected from one or more of a fixed fluidized bed reactor, a bulk fluidized bed reactor, a bubbling bed reactor, a turbulent bed reactor, a fast bed reactor, a conveying bed reactor and a dense-phase fluidized bed reactor, and is mainly used for cracking reaction of light raw materials, and the light raw materials 31 are fed from the bottom of the second fluidized bed reactor 3-3.

Lift gas is introduced into the second riser 3-1 through a pre-lift gas line 32. The lifting gas used is well known to those skilled in the art and may be selected from one or more of steam, nitrogen, dry gas, preferably steam.

The second stripper 3-2 is located below the second fluidized bed reactor 3-3 and is in communication with the second fluidized bed reactor 3-3, wrapping a portion of the second riser 3-1.

The second stripper 3-2 is provided with a stripping baffle and a stripping gas distribution ring, which are used for reducing the falling speed of the dehydrogenation-cracking spent catalyst and enabling the distribution of the stripping gas 33 to be more uniform, so that the residual reaction oil gas on the dehydrogenation-cracking spent catalyst is fully removed from the dehydrogenation-cracking spent catalyst.

The reacted oil mixture in the second fluidized bed reactor 3-3 is separated by a cyclone separator to obtain an oil gas product and a dehydrogenation cracking spent catalyst, the oil gas product is led out by a dehydrogenation cracking oil gas product pipeline 35 to separate the subsequent products, and the dehydrogenation cracking spent catalyst is led into a second stripper 3-2 to be stripped.

The second settler 3-4 is communicated with the second fluidized bed reactor 3-3 and the second riser 3-1, and the stripping gas in the second stripper 3-2 can directly enter the second settler 3-4, enter a gas collection chamber after being separated by a cyclone separator together with other oil gas, and then are led out of the dehydrogenation cracking reaction unit 3 through a dehydrogenation cracking oil gas product pipeline 35.

Referring to fig. 1 and 2, the dehydrogenation-pyrolysis regeneration unit 4 is connected to the dehydrogenation-pyrolysis reaction unit 3, and the dehydrogenation-pyrolysis regeneration unit 4 is configured to perform a regeneration reaction on the dehydrogenation-pyrolysis spent catalyst generated by the dehydrogenation-pyrolysis reaction unit 3 to obtain a dehydrogenation-pyrolysis regenerated catalyst, and the dehydrogenation-pyrolysis regenerated catalyst enters the dehydrogenation-pyrolysis reaction unit through a dehydrogenation-pyrolysis regenerated catalyst conveying pipeline 42 to be recycled.

Specifically, the dehydrogenation cracking regeneration unit 4 includes a dehydrogenation cracking regenerator 4-1, and the dehydrogenation cracking regenerator 4-1 communicates with the heat exchange device 2-2 and is connected to the second riser 3-1 through a dehydrogenation cracking regeneration catalyst transfer line 42. Wherein the inlet of the heat exchange device 2-2 is connected to the second stripper 3-2 through a delivery line 34, and the outlet of the heat exchange device 2-2 is connected to the dehydrogenation cracking regenerator 4-1 through a catalyst delivery line 24.

The dehydrogenation-cracking spent catalyst from the second stripper 3-2 enters the heat exchange device 2-2 in the catalytic cracking regenerator 2-1 through the dehydrogenation-cracking spent catalyst conveying pipeline 34, the dehydrogenation-cracking spent catalyst is heated to the regeneration initial temperature by utilizing the heat in the catalytic cracking regenerator 2-1, and then enters the dehydrogenation-cracking regenerator 4-1 for burning regeneration, so that the dehydrogenation-cracking spent catalyst is converted into the dehydrogenation-cracking regenerated catalyst. The dehydrogenation cracking regenerated catalyst in the dehydrogenation cracking regenerator 4-1 returns to the second riser 3-1 for recycling through a dehydrogenation cracking regenerated catalyst conveying pipeline 42, wherein valves are arranged on the catalyst conveying pipelines 34, 24 and 42, and the conveying speed of the catalyst can be adjusted through the valves on the catalyst conveying pipelines.

The bottom of the dehydrogenation-cracking regenerator 4-1 is provided with a main air inlet line 41, and a regeneration gas, which is a gas well known to those skilled in the art, including but not limited to one or more of air, oxygen and other gases having oxidizing property, can be introduced into the dehydrogenation-cracking regenerator 4-1, and the flue gas generated after regeneration enters the gas collection chamber through the cyclone separator, and is discharged through a regeneration flue gas outlet line 43 after being treated.

The present disclosure also provides a process for producing ethylene and propylene using the above system, comprising:

The heavy raw material 11 and the catalytic cracking catalyst enter a catalytic cracking reaction unit 1 to carry out contact reaction to obtain a catalytic cracking oil-gas mixture, the catalytic cracking oil-gas product and the catalytic cracking spent catalyst are obtained through separation, the light raw material 31 and the dehydrogenation cracking catalyst enter a dehydrogenation cracking reaction unit 3 to carry out contact reaction to obtain the dehydrogenation cracking oil-gas mixture, the dehydrogenation cracking oil-gas product and the dehydrogenation cracking spent catalyst are obtained through separation, the catalytic cracking oil-gas product and the dehydrogenation cracking oil-gas product are separated to obtain ethylene and propylene, the catalytic cracking spent catalyst is introduced into a catalytic cracking regeneration unit 2 to carry out regeneration reaction to obtain a catalytic cracking regeneration catalyst, the catalytic cracking regeneration catalyst is introduced into a catalytic cracking reaction unit 1 to carry out cyclic utilization, the dehydrogenation cracking spent catalyst is introduced into a heat exchange device 2-2 of the catalytic cracking regeneration unit 2 to carry out heat exchange, and then enters a dehydrogenation cracking regeneration unit 4 to carry out regeneration reaction to obtain a dehydrogenation cracking regeneration catalyst, and the dehydrogenation cracking regeneration catalyst is introduced into the dehydrogenation cracking reaction unit 3 to carry out cyclic utilization.

In accordance with the present disclosure, existing processes typically treat heavy feedstocks by catalytic cracking techniques, use dehydrogenation cracking techniques to treat light feedstocks, but the two are not effectively combined and the ethylene and propylene yields of light hydrocarbon feedstocks are low. Therefore, the system is designed to organically combine the catalytic cracking of the heavy raw material with the dehydrogenation cracking of the light raw material, so that the heavy raw material and the light raw material can be promoted to be effectively converted into ethylene and propylene, and heat generated in the regeneration process of the catalytic cracking catalyst can be further utilized to supply heat for the regeneration process of the dehydrogenation cracking catalyst, so that the energy consumption is greatly reduced.

The process for producing ethylene and propylene of the present disclosure is specifically described below.

The heavy raw material 11 and the catalytic cracking catalyst enter a catalytic cracking reaction unit 1 to carry out contact reaction to obtain a catalytic cracking oil-gas mixture, and the catalytic cracking oil-gas product and the catalytic cracking spent catalyst are obtained through separation. Wherein, the catalyst to be regenerated by catalytic cracking is introduced into a catalytic cracking regeneration unit 2 for regeneration reaction to obtain a catalytic cracking regenerated catalyst, and the catalytic cracking regenerated catalyst is introduced into a catalytic cracking reaction unit 1 for recycling.

Specifically, heavy raw materials are usually preheated to 180-300 ℃ and then introduced into the bottom of a first riser reactor 1-1 of a catalytic cracking reaction unit 1, the heavy raw materials are contacted and reacted with a catalytic cracking regeneration catalyst from the catalytic cracking regeneration unit 2 at a reaction temperature of 540-640 ℃, preferably 560-620 ℃, a catalyst-oil ratio of 3-25, preferably 5-20, a reaction time of 1-20 seconds, preferably 2-10 seconds, the generated oil-gas mixture is introduced into a first fluidized bed reactor 1-3, the generated oil-gas mixture is introduced into a cyclone reactor at a reaction temperature of 520-620 ℃, preferably 540-600 ℃, a weight hourly space velocity of 1-25 hours ^-1, preferably 2-10 hours ^-1, a catalyst density of 50kg/m ³～400kg/m³, preferably 100kg/m ³～250kg/m³, a bed height of 1/2-4/5, preferably 1/2-3/4 MPa, a catalyst-1.4 MPa, and a catalyst-1.4 MPa are continuously separated by a cyclone system after the catalyst-gas mixture is introduced into the cyclone reactor for further separation of the catalyst-1.4 MPa, and the catalyst-gas mixture is subjected to the cyclone reactor after the catalyst-gas mixture is subjected to the separation.

In some embodiments, the heavy feedstock 11 is selected from one or more of vacuum wax oil, atmospheric residuum, vacuum residuum, coker wax oil, deasphalted oil, furfural extract oil, coal liquefaction oil, oil sand oil, shale oil, distillate oil obtained by F-T synthesis, animal oil and vegetable oil, and the heavy feedstock is subjected to a primary cracking reaction in a riser reactor and a fluidized bed reactor of a catalytic cracking reaction unit, and is converted from a macromolecular reactant to a micromolecular product.

In some embodiments, the method further comprises introducing a cracked heavy oil into the middle or upper portion of the first riser reactor, wherein the mass ratio of the cracked heavy oil to the heavy feedstock is 0.01-0.1:1, e.g., 0.01:1, 0.03:1, 0.05:1, 0.08:1, 0.1:1, etc.

The light raw material 31 and the dehydrogenation catalyst enter a dehydrogenation reaction unit 3 for contact reaction to obtain a dehydrogenation oil-gas mixture, and the dehydrogenation oil-gas mixture and the dehydrogenation spent catalyst are obtained through separation, wherein the dehydrogenation spent catalyst is introduced into a heat exchange device 2-2 of a catalytic cracking regeneration unit 2 for heat exchange, enters a dehydrogenation regeneration unit 4 for regeneration reaction after reaching the initial regeneration temperature to obtain a dehydrogenation regeneration catalyst, and the dehydrogenation regeneration catalyst is introduced into the dehydrogenation reaction unit 3 for recycling.

Specifically, the light raw material 31 is usually preheated to 100 ℃ to 150 ℃ and then is introduced into the second fluidized bed reactor 3-3 of the dehydrogenation cracking reaction unit 3, the light raw material is contacted and reacted with the dehydrogenation cracking regenerated catalyst introduced into the second fluidized bed reactor 3-3 through the second riser 3-1 at the reaction temperature of 560 ℃ to 660 ℃, preferably 580 ℃ to 640 ℃, the weight hourly space velocity is 1 hour ^-1 to 20 hours ^-1, preferably 2 to 8 hours ^-1, the catalyst density is 50kg/m ³～450kg/m³, preferably 100kg/m ³～350kg/m³, the bed height is 1/2 to 4/5, preferably 1/2 to 3/4 of the bed reactor height, the pressure in the second fluidized bed reactor is 0.1MPa to 0.4MPa, preferably 0.15 to 0.3MPa, the reacted oil mixture is separated through a cyclone separator, the dehydrogenation cracking regenerated catalyst is introduced into the reactor 3-2 of the dehydrogenation cracking reaction unit, the dehydrogenation cracked product is led out through a stripping system, and then the oil-gas separation product is led out through a stripping system (the separation system is not shown in the figure).

In some embodiments, the catalytic pyrolysis oil gas product and the dehydrogenation pyrolysis oil gas product may be introduced into respective product separation systems, or may be introduced into the same product separation system for further separation. The oil gas products are separated into dry gas, cracked gas, gasoline, light oil, slurry oil and other products, the dry gas can be separated by a separation method well known to the person skilled in the art to obtain ethylene, the separation method can adopt cryogenic separation to recover ethylene, an ethylbenzene-styrene device is introduced to react to recover ethylene and the like, the cracked gas can be separated and refined in the subsequent products to obtain a polymerization-grade propylene product and C ₄ hydrocarbon rich in olefin, and the gasoline can be separated and refined in the subsequent products to obtain C ₅～C₈ hydrocarbon and heavy gasoline. The separation device in the dehydrogenation cracking reaction unit can rapidly separate oil gas from the reacted carbon deposition catalyst, so that the yield of dry gas can be reduced, and the conversion of propylene after the generation is inhibited.

In some embodiments, the light feedstock 31 is selected from C ₄～C₈ hydrocarbons. Preferably, the content of C ₄～C₈ alkanes is not less than 20% based on the total weight of the light feedstock. The C ₄～C₈ hydrocarbons may be derived from the isolated products of the present disclosure, as well as from other sources, preferably from the C ₄～C₈ hydrocarbons obtained from the present disclosure. For the purposes of this disclosure, because a dedicated dehydrogenation cracking catalyst can be used in the dehydrogenation cracking reactor, the range of light feedstock that can be used is relatively wider, and a suitable reaction environment can be provided for the light feedstock, thereby improving the yields of ethylene and propylene.

In the method of the present disclosure, the pyrolysis heavy oil 13 may be introduced into the middle upper portion of the first riser reactor 1-1 of the catalytic pyrolysis reaction unit 1, and mixed with the heavy raw material 11 and the catalytic pyrolysis catalyst to perform the reaction. The cracked heavy oil may be a cracked heavy oil produced by the present disclosure or a cracked heavy oil produced by other apparatuses, preferably a cracked heavy oil produced by the present disclosure.

According to the present disclosure, the catalytic cracking catalyst used in the first riser reactor 1-1 of the catalytic cracking reaction unit 1 is a regenerated catalyst obtained through the catalytic cracking regenerator 2-1, the catalyst including a cracking active component, clay, and a binder, wherein the cracking active component includes a molecular sieve having an MFI structure and a Y molecular sieve. The molecular sieve having MFI structure is selected from, for example, one or more of ZRP zeolite, phosphorus-containing ZRP zeolite, rare earth-containing ZRP zeolite, phosphorus-and alkaline earth-containing ZRP zeolite, and phosphorus-and transition metal-containing ZRP zeolite, preferably phosphorus-and rare earth-containing ZRP zeolite, and the Y molecular sieve may be selected from one or more of HY, USY, REUSY, REY, REHY, DASY, REDASY or a Y-type molecular sieve obtained by treatment with various metal oxides. The clay is selected from various clays which can be used as catalyst components, such as kaolin, montmorillonite, bentonite, etc. The binder is selected from one or two or three of silica sol, alumina sol and pseudo-boehmite, wherein the preferred binder is a double-aluminum binder of alumina sol and pseudo-boehmite. The catalyst comprises, by weight, 10-70% of clay, preferably 15-45% of binder, 10-40% of binder, preferably 20-35% of cracking active component, and 15-60% of cracking active component, wherein the mass ratio of Y molecular sieve to molecular sieve with MFI structure is 1:0-2, i.e. the catalyst does not contain molecular sieve with MFI structure, preferably the mass ratio of the Y molecular sieve to the molecular sieve is 1:0.1-0.8.

According to the present disclosure, the dehydrogenation catalyst used in the second fluidized bed reactor 3-3 of the dehydrogenation-cracking reaction unit 3 is a dehydrogenation-cracking regenerated catalyst obtained through the dehydrogenation-cracking regenerator 4-1, the catalyst including a dehydrogenation-cracking active component, clay, and a binder, wherein the dehydrogenation-cracking active component includes a molecular sieve having an MFI structure and a metal active component. The molecular sieve having the MFI structure is, for example, one or more selected from ZRP zeolite, phosphorus-containing ZRP zeolite, rare earth-containing ZRP zeolite, phosphorus-and alkaline earth-containing ZRP zeolite, and phosphorus-and transition metal-containing ZRP zeolite, preferably phosphorus-and rare earth-containing ZRP zeolite. The metal active component is selected from one or more metals or oxides of iron (Fe), chromium (Cr) and vanadium (V), wherein the content of Fe is 0% -5%, preferably 0% -1%, the content of Cr is 0% -8%, preferably 0% -2%, and the content of V is 0% -15%, preferably 0% -8% in terms of weight percentage of the molecular sieve with the MFI structure. That is, the molecular sieve having the MFI structure may not contain a metal active component or may contain 1 to 3 active components of metal elements. The clay is selected from various clays which can be used as catalyst components, such as kaolin, montmorillonite, bentonite, etc. The binder is selected from one or two or three of silica sol, alumina sol and pseudo-boehmite, wherein the preferred binder is a double-aluminum binder of alumina sol and pseudo-boehmite.

In summary, the system and the method realize the organic combination of the catalytic cracking of the heavy raw material and the dehydrogenation cracking of the light raw material, can promote the effective conversion of the heavy raw material and the light raw material into ethylene and propylene, can further utilize the separated products of the heavy raw material to effectively improve the conversion rate of the raw material, and can further utilize the heat generated in the regeneration process of the catalytic cracking catalyst to supply heat for the regeneration process of the dehydrogenation cracking catalyst, thereby greatly reducing the energy consumption, and the catalytic cracking regeneration catalyst and the dehydrogenation cracking regeneration catalyst can be recycled to corresponding reactors for reuse, so that the production cost is effectively reduced. In a word, the system and the method can realize higher hydrocarbon conversion capability, achieve higher ethylene and propylene yields, greatly reduce energy consumption and have important industrial application value.

The present disclosure will be further illustrated by the following examples, but the present disclosure is not limited thereby. Reagents, materials, and the like employed in the present disclosure are commercially available unless otherwise specified.

Reagents, instruments and tests

In the embodiment and the comparative example, the gas product is tested by adopting a petrochemical analysis method RIPP-90, the coke content is measured by adopting a petrochemical analysis method RIPP-107-90, the composition of the organic liquid product is measured by adopting an SH/T0558-1993 method, the cut points of the fractions of gasoline and diesel oil are 221 ℃ and 343 ℃ respectively, and the light aromatic hydrocarbon in the gasoline is measured by adopting a petrochemical analysis method RIPP-90.

In the examples below, the conversion of the feedstock and the yield of cracked products were calculated according to the following formulas:

The RIPP petrochemical analysis method used in the present invention is selected from the group consisting of "petrochemical analysis method (RIPP test method)", code Yang Cuiding, et al, science Press, 1990.

The reagents used hereinafter are all chemically pure reagents unless otherwise specified.

The MFI structure molecular sieve is produced by Qilu catalyst factories and has the industrial trade name:

ZRP-1, in which the content of SiO ₂/Al₂O₃＝30,Na₂ O is 0.17% by weight, the content of rare earth oxide RE ₂O₃ is 1.4% by weight, the content of lanthanum oxide is 0.84% by weight, the content of cerium oxide is 0.18% by weight and the content of other rare earth oxides is 0.38% by weight.

The Y-type molecular sieve is produced by Qilu catalyst factories and has the industrial trade name:

DASY, physical properties parameters are that the unit cell constant is 2.447 nm, and the Na ₂ O content is 0.85 wt%;

The precursors of the metal active components are metal salt solutions, including Fe (NO ₃)₃·9H₂O、Cr(NO₃)₃·9H₂ O and NH ₄VO₃).

The clay used is kaolin, and the binder used is water-thinned aluminum-like stone.

The heavy raw materials used in examples and comparative examples were taken from Daqing wax oil, and specific properties of Daqing wax oil and light raw materials are shown in tables 1 and 2.

The catalyst used in the examples and the comparative examples is a self-made catalyst, wherein the catalytic cracking catalyst is denoted as CCAT, and the preparation method comprises the steps of mixing a DASY molecular sieve, a ZRP-1 molecular sieve and water in a mass ratio of 2:1:5 to obtain a first slurry, mixing kaolin, pseudo-boehmite and water in a mass ratio of 2:0.2:5 to obtain a second slurry, mixing the first slurry and the second slurry in a mass ratio of 1:2, and washing, filtering, drying and roasting to obtain the catalytic cracking catalyst CCAT. The dehydrogenation cracking catalyst is named as DHC, and the preparation method comprises the steps of mixing Fe(NO₃)₃·9H₂O、Cr(NO₃)₃·9H₂O、NH₄VO₃、ZRP-1 molecular sieve and water in a mass ratio of 2:3:1:10:25 to obtain first slurry, mixing kaolin, pseudo-boehmite and water in a mass ratio of 2:0.2:5 to obtain second slurry, mixing the first slurry and the second slurry in a mass ratio of 1:1, and washing, filtering, drying and roasting to obtain the dehydrogenation cracking catalyst DHC. The specific properties of the two catalysts are shown in Table 3.

TABLE 1 Properties of Daqing wax oil

TABLE 2 Properties of light feed

TABLE 3 composition and Properties of the catalysts

Examples 1-4 and comparative examples 1-4 are provided to illustrate that the use of the systems and methods of the present disclosure can increase hydrocarbon conversion to higher ethylene and propylene yields.

Example 1

The test was performed on a medium-sized test apparatus as shown in fig. 1 and 2. The device comprises a catalytic cracking reaction unit 1, a catalytic cracking regeneration unit 2, a dehydrogenation cracking reaction unit 3 and a dehydrogenation cracking regeneration unit 4. Wherein the inner diameter of the first riser reactor of the catalytic cracking reaction unit 1 is 16mm, the length is 3200mm, the inner diameter of the first fluidized bed reactor is 80mm, the length is 500mm, and the inner diameter of the second fluidized bed reactor of the dehydrogenation cracking reaction unit 2 is 60mm, and the length is 400mm. The cross-sectional area of the heat exchange tube array is 1600mm ² and the length is 300mm.

Heavy raw materials are introduced into a first riser reactor 1-1 to be in contact reaction with a regenerated catalyst CCAT from a catalytic cracking regenerator 2-1, the reacted oil mixture is introduced into a first fluidized bed reactor 1-3 to continue the reaction, and the reacted oil mixture is separated by a cyclone separator. The catalyst to be regenerated by catalytic pyrolysis is introduced into the first stripper 1-2 and then introduced into the catalytic pyrolysis regenerator 2-1 for regeneration, the regenerated catalyst is returned to the first riser reactor 1-1 for recycling, and the oil gas is introduced into the catalytic pyrolysis product separation system 5 for separation.

The light raw material is introduced into the bottom of the second fluidized bed reactor 3-3 to be in contact reaction with the regenerated catalyst DHC from the dehydrogenation cracking regenerator 4-1, and the reacted oil mixture is separated by a cyclone separator. The spent catalyst of dehydrogenation cracking is introduced into a second stripper 3-2, then introduced into a heat exchange tube array for heat exchange, then introduced into a dehydrogenation cracking regenerator 4-1 for regeneration, the regenerated catalyst is returned to the fluidized bed reactor 3-3 of the dehydrogenation cracking reaction unit 4 for recycling, and oil gas is introduced into a dehydrogenation cracking product separation system 6 for separation. The mass ratio of the light raw materials to the heavy raw materials is 0.2:1. The reaction conditions and the results are shown in Table 4.

Example 2

The process of example 1 was followed except that cracked heavy oil was also introduced into the first riser reactor 1-1 at a position 300mm from the top of the middle upper part, the mass ratio of cracked heavy oil to heavy feedstock was 0.05:1. The reaction conditions and the results are shown in Table 4.

Example 3

The procedure of example 1 was followed except that the mass ratio of light feedstock to heavy feedstock was 0.3:1. The reaction conditions and the results are shown in Table 4.

Example 4

The process of example 2 is followed except that the mass ratio of cracked heavy oil to heavy feedstock is 0.1:1. The reaction conditions and the results are shown in Table 4.

TABLE 4 Table 4

Comparative example 1

An existing medium-sized test apparatus is provided wherein the apparatus comprises a cracking reactor and a regenerator connected thereto, the cracking reactor comprising a riser reactor (first riser reactor) and a fluidized bed reactor. The inner diameter of the riser reactor is 16mm, the length is 3200mm, the inner diameter of the fluidized bed reactor is 64mm, and the height is 500mm.

Heavy raw materials are introduced into the bottom of a riser reactor, contacted with a regenerated catalyst CCAT from a regenerator and reacted, the produced oil mixture is introduced into a fluidized bed reactor, the reacted oil mixture is separated by a quick separation device, reaction oil gas is passed through a cyclone separator, and the catalyst is introduced into a stripper for stripping. The catalyst enters a stripper and then enters a catalytic cracking regenerator for regeneration, the regenerated catalyst returns to the riser reactor for recycling, and the oil gas is introduced into a separation system for separation. The reaction conditions and results are shown in Table 5.

Comparative example 2

An existing medium-sized test apparatus is provided wherein the apparatus comprises a cracking reactor and a regenerator coupled thereto, the cracking reactor comprising a riser reactor (first riser reactor) and a fluidized bed reactor. The inner diameter of the riser reactor is 16mm, the length is 3200mm, the inner diameter of the fluidized bed reactor is 64mm, and the height is 500mm.

The light raw material is introduced into the bottom of a riser reactor, contacts with a regenerated catalyst CCAT from a regenerator and reacts, the generated oil mixture is introduced into a fluidized bed reactor, the reacted oil mixture is separated by a quick separation device, the reaction oil gas passes through a cyclone separator, and the catalyst is introduced into a stripper for stripping. The catalyst enters a stripper and then enters a regenerator for regeneration, the regenerated catalyst returns to the riser reactor for recycling, and the oil gas is introduced into a fractionation system for separation. The reaction conditions and results are shown in Table 5.

Comparative example 3

An existing pilot plant is provided that includes two riser reactors and a fluidized bed reactor. The first riser reactor has an inner diameter of 16mm and a length of 3200mm, the second riser reactor has an inner diameter of 16mm and a height of 3000mm, and the fluidized bed reactor has an inner diameter of 64mm and a height of 500mm.

The heavy raw material is introduced into the bottom of the first riser reactor, contacts with the regenerated catalyst CCAT from the regenerator and reacts, the reacted oil mixture is introduced into the fluidized bed reactor, the light raw material is introduced into the bottom of the second riser reactor, contacts with the regenerated catalyst CCAT from the regenerator and reacts, the generated oil mixture is introduced into the fluidized bed reactor, the reacted oil mixture is separated by a quick separation device, the reaction oil gas passes through a cyclone separator, and the catalyst is introduced into a stripper for steam stripping. The catalyst enters a stripper and then enters a regenerator for regeneration, the regenerated catalyst returns to the riser reactor for recycling, and the oil gas is introduced into a fractionation system for separation. The mass ratio of the light raw materials to the heavy raw materials is 0.2:1. The reaction conditions and results are shown in Table 5.

Comparative example 4

The process of comparative example 3 was followed except that cracked heavy oil was also introduced into the first riser reactor at a position 300mm from the top of the middle upper portion, with a mass ratio of cracked heavy oil to heavy feedstock of 0.05:1. The reaction conditions and results are shown in Table 5.

TABLE 5

Project	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4
					First riser reactor
Raw materials	Heavy raw material	Light raw material	Heavy raw material	Heavy raw material
					Outlet temperature/°c	570.8	620.1	570.6	571.2
Ratio of agent to oil	8	10	8	8
					Atomized vapor to raw oil weight ratio	0.25	0.25	0.25	0.25
Cracking heavy oil and heavy raw material mass ratio				0.05
					Second riser reactor
Raw materials			Light raw material	Light raw material
					Weight ratio of light raw materials to heavy raw materials			0.2	0.2
Reaction temperature/°c			620.8	619.6
					Weight hourly space velocity/h ^-1			6	6
Atomized water vapor and light raw material mass ratio
					Fluidized bed reactor
Reaction temperature/°c	561.2	613.6	580.9	581.2
					Weight hourly space velocity/h ^-1	6	8	8	8
Material balance/wt%
					Dry gas	8.53	11.38	9.21	9.51
Liquefied gas	36.75	30.69	39.77	39.96
					Gasoline	27.88	48.56	23.18	23.85
Diesel oil	13.69	3.89	13.15	13.14
					Slurry oil	5.46	1.57	5.68	4.09
Coke	7.69	3.91	9.01	9.45
					Ethylene yield/wt%	4.31	4.62	5.01	5.12
Propylene yield/wt%	17.98	19.58	19.89	20.01

As can be seen from tables 4 and 5, the use of the methods and systems provided by the present disclosure can achieve higher hydrocarbon conversion capacities and higher ethylene and propylene yields than comparative examples 1-4.

Example 2 and comparative example 5 are used to illustrate that in the present disclosure, a heat exchange device is disposed in a catalytic cracking regenerator, and the dehydrogenation cracking spent catalyst generated by the dehydrogenation cracking reaction unit is heated by heat generated when the catalytic cracking spent catalyst is regenerated, so that the dehydrogenation cracking spent catalyst reaches the regeneration initial temperature, thereby improving the regeneration efficiency of the dehydrogenation cracking spent catalyst and reducing energy consumption.

Comparative example 5

The procedure of example 2 was followed, except that the spent catalyst from the dehydrogenation-cracking was directly introduced into the dehydrogenation-cracking regenerator 4-1 for regeneration without preheating by a heat exchange device. The reaction conditions and results are shown in Table 6.

TABLE 6

Project	Example 2	Comparative example 5
			Catalytic cracking regeneration unit
Regeneration temperature/°c	690.5	705.8
			Regeneration pressure/MPa	0.12	0.13
Dehydrogenation cracking regeneration unit
			Regeneration temperature/°c	612.3	665.6
Regeneration pressure/MPa	0.13	0.12
			Dehydrogenation cracking spent catalyst carbon content/%	0.531	0.525
Dehydrogenation cracking regenerated catalyst carbon content/%	0.025	0.183

As can be seen from table 6, compared with comparative example 5, the method and system provided by the present disclosure can increase the regeneration temperature of the dehydrogenation cracking regeneration unit, reduce the carbon content of the dehydrogenation cracking regenerated catalyst, increase the regeneration efficiency of the dehydrogenation cracking spent catalyst, and reduce the energy consumption.

It should be noted by those skilled in the art that the embodiments described in this disclosure are merely exemplary and that various other substitutions, modifications and improvements may be made within the scope of this disclosure. Thus, the present disclosure is not limited to the above-described embodiments, but is only limited by the claims.

Claims

1. A process for producing ethylene and propylene comprising:

The heavy raw material and the catalytic cracking catalyst are contacted and reacted in a catalytic cracking reaction unit to obtain a catalytic cracking oil-gas mixture, and a catalytic cracking oil-gas product and a catalytic cracking spent catalyst are obtained through separation;

The light raw material and the dehydrogenation catalyst are contacted and reacted in a dehydrogenation reaction unit to obtain a dehydrogenation cracking oil agent mixture, and a dehydrogenation cracking oil gas product and a dehydrogenation cracking spent catalyst are obtained through separation;

the catalytic cracking spent catalyst is introduced into a catalytic cracking regeneration unit to carry out a regeneration reaction to obtain a catalytic cracking regenerated catalyst, and the catalytic cracking spent catalyst is introduced into the catalytic cracking regeneration unit to carry out heat exchange treatment to reach the initial regeneration temperature and then enters into a dehydrogenation cracking regeneration unit to carry out a regeneration reaction to obtain the dehydrogenation cracking regenerated catalyst;

In the catalytic cracking reaction unit, the heavy raw material is introduced into a first riser reactor to be in contact reaction with a catalytic cracking regeneration catalyst from the catalytic cracking regeneration unit, and the obtained product is introduced into a first fluidized bed reactor to be continuously reacted to obtain the catalytic cracking oil agent mixture;

In the dehydrogenation-cracking reaction unit, the light raw material is introduced into a second fluidized bed reactor, and a dehydrogenation-cracking regeneration catalyst is introduced into the second fluidized bed reactor through a second riser to contact and react with the light raw material, so as to obtain the dehydrogenation-cracking oil mixture;

the first riser reactor is selected from one or a combination of more than one of a constant diameter riser reactor, a constant linear velocity riser reactor and a variable diameter riser reactor;

The first fluidized bed reactor is selected from one or more than one of a fixed fluidized bed reactor, a bulk fluidized bed reactor, a bubbling bed reactor, a turbulent bed reactor, a rapid bed reactor, a conveying bed reactor and a dense phase fluidized bed reactor;

The second fluidized bed reactor is selected from one or more than one of a fixed fluidized bed reactor, a bulk fluidized bed reactor, a bubbling bed reactor, a turbulent bed reactor, a rapid bed reactor, a conveying bed reactor and a dense phase fluidized bed reactor;

The reaction temperature of the first riser reactor is 540-640 ℃, the catalyst-to-oil ratio is 3-25, the reaction time is 1 s-20 s, the reaction temperature of the first fluidized bed reactor is 520-620 ℃, the weight hourly space velocity is 1 hour ^-1 -25 hours ^-1, the catalytic cracking catalyst density is 50kg/m ³～400kg/m³, the bed height is 1/2-4/5 of the bed reactor height, and the pressure in the first fluidized bed reactor is 0.1-0.4 mpa;

The reaction temperature of the second fluidized bed reactor is 560 ℃ to 660 ℃, the weight hourly space velocity is 1 hour ^-1 to 20 hours ^-1, the catalyst density is 50kg/m ³～450kg/m³, the bed height is 1/2 to 4/5 of the bed reactor height, and the pressure in the second fluidized bed reactor is 0.1MPa to 0.4MPa;

The dehydrogenation cracking catalyst comprises a dehydrogenation cracking active component, clay and a binder, wherein the dehydrogenation cracking active component comprises a molecular sieve with an MFI structure and a metal active component.

2. The production method according to claim 1, wherein the catalytic cracking catalyst comprises a catalytic cracking active component, clay and a binder, wherein the catalytic cracking active component comprises a molecular sieve with an MFI structure and a Y molecular sieve, and the mass ratio of the Y molecular sieve to the molecular sieve with the MFI structure is 1:0-2.

3. The production method according to claim 2, wherein the mass ratio of the Y molecular sieve to the molecular sieve having an MFI structure is 1:0.1 to 0.8.

4. The production method according to claim 1, wherein the metal active component is selected from one or more of elemental metals and oxides thereof, wherein the elemental metals comprise iron, chromium and vanadium, and the elemental metals comprise 0% -5% of iron, 0% -8% of chromium and 0% -15% of vanadium, based on the total weight of the molecular sieve having an MFI structure.

5. The production method according to claim 4, wherein the total weight of the molecular sieve having an MFI structure is 0-1%, the content of iron is 0-2%, and the content of vanadium is 0-8%.

6. The production method according to claim 1, wherein the catalytic cracking regenerated catalyst is introduced into the catalytic cracking reaction unit for recycling, and the dehydrogenation cracking regenerated catalyst is introduced into the dehydrogenation cracking reaction unit for recycling.

7. The production method according to claim 1, wherein the reaction temperature of the first riser reactor is 560-620 ℃, the catalyst-to-oil ratio is 5-20, the reaction time is 2-10 s, the reaction temperature of the first fluidized bed reactor is 540-600 ℃, the weight hourly space velocity is 2- ^-1 -10 hours ^-1, the catalytic cracking catalyst density is 100kg/m ³～250kg/m³, the bed height is 1/2-3/4 of the bed reactor height, and the pressure in the first fluidized bed reactor is 0.15-0.3 MPa.

8. The production method according to claim 1, further comprising introducing a cracked heavy oil in a middle or upper portion of the first riser reactor, wherein a mass ratio of the cracked heavy oil to the heavy feedstock is 0.01 to 0.1:1.

9. The production method according to claim 1, wherein the reaction temperature of the second fluidized bed reactor is 580 ℃ to 640 ℃, the weight hourly space velocity is 2 to 8 hours ^-1, the catalyst density is 100kg/m ³～350kg/m³, the bed height is 1/2 to 3/4 of the bed reactor height, and the pressure in the second fluidized bed reactor is 0.15 to 0.3mpa.

10. The production method according to claim 1, wherein the heavy raw material is one or more selected from the group consisting of vacuum wax oil, atmospheric residuum, vacuum residuum, coker wax oil, deasphalted oil, furfural refining raffinate oil, coal liquefied oil, oil sand oil, shale oil, distillate oil obtained by F-T synthesis, animal oil and vegetable oil, and the light raw material is selected from the group consisting of C ₄～C₈ hydrocarbons.

11. The method according to claim 1, wherein the content of C ₄～C₈ alkane is not less than 20% based on the total weight of the light feedstock.

12. The method of claim 1, wherein the light feedstock is selected from the group consisting of C ₄～C₈ hydrocarbons after separation of the catalytic cracking hydrocarbon gas product and C ₄～C₈ hydrocarbons after separation of the dehydrogenated cracking hydrocarbon gas product.

13. A system for producing ethylene and propylene comprising:

A catalytic cracking reaction unit configured to perform a catalytic cracking reaction of a heavy feedstock;

A catalytic cracking regeneration unit configured to regenerate the catalytic cracking spent catalyst separated after the catalytic cracking reaction to obtain a catalytic cracking regenerated catalyst;

a dehydrogenation-cracking reaction unit configured to perform a dehydrogenation-cracking reaction of the light feedstock;

The dehydrogenation-cracking regeneration unit is configured to regenerate the dehydrogenation-cracking spent catalyst obtained by separation after the dehydrogenation-cracking reaction to obtain a dehydrogenation-cracking regenerated catalyst;

The catalytic cracking regeneration unit further comprises a heat exchange device, wherein the heat exchange device is configured to heat the dehydrogenation cracking spent catalyst generated by the dehydrogenation cracking reaction unit by utilizing heat generated when the catalytic cracking spent catalyst is regenerated, so that the dehydrogenation cracking spent catalyst reaches the regeneration initial temperature and then enters the dehydrogenation cracking regeneration unit;

The catalytic cracking reaction unit comprises a first riser reactor, a first stripper, a first fluidized bed reactor and a first settler, wherein a heavy raw material inlet is formed in the bottom of the first riser reactor, an outlet of the first riser reactor is communicated with the inlet of the first fluidized bed reactor, the first stripper is positioned below the first fluidized bed reactor and wraps part of the first riser reactor, and the first settler is positioned above the first fluidized bed reactor and is communicated with the first fluidized bed reactor;

The dehydrogenation cracking reaction unit comprises a second riser, a second stripper, a second fluidized bed reactor and a second settler, wherein a light raw material inlet is arranged at the bottom of the second fluidized bed reactor, the second riser is connected in series below the second fluidized bed reactor, the second stripper is positioned below the second fluidized bed reactor and wraps part of the second riser, and the second settler is positioned above the second fluidized bed reactor and is communicated with the second fluidized bed reactor;

14. The production system of claim 13, wherein the first riser reactor is further provided with a cracked heavy oil inlet in the middle or upper portion.

15. The production system of claim 13, wherein the catalytic cracking regeneration unit comprises a catalytic cracking regenerator and a heat exchange device, the heat exchange device is disposed within the catalytic cracking regenerator, the catalytic cracking regenerator is in communication with the first stripper, and the catalytic cracking regenerator is connected to the first riser reactor by the catalytic cracking regeneration catalyst transfer line.

16. The production system of claim 15, wherein the heat exchange device is a heat exchange tube, the ratio of the cross-sectional area of the heat exchange tube to the cross-sectional area of the catalytic cracking regenerator is 1:2-10, and the ratio of the length of the heat exchange tube to the length of the catalytic cracking regenerator is 1:1.5-5.

17. The production system of claim 16, wherein the ratio of the cross-sectional area of the heat exchange tube array to the cross-sectional area of the catalytic cracking regenerator is 1:3-6, and the ratio of the length of the heat exchange tube array to the length of the catalytic cracking regenerator is 1:2-3.

18. The production system of claim 13, wherein the dehydrolysis regeneration unit comprises a dehydrolysis regenerator, wherein an inlet of the heat exchange device is connected to the second stripper, an outlet of the heat exchange device is connected to the dehydrolysis regenerator, and the dehydrolysis regenerator is connected to the second riser via the dehydrolysis regeneration catalyst transfer line.