CN117945832A - Method for preparing ethylene and propylene from low-carbon alkane - Google Patents

Method for preparing ethylene and propylene from low-carbon alkane Download PDF

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CN117945832A
CN117945832A CN202211352516.3A CN202211352516A CN117945832A CN 117945832 A CN117945832 A CN 117945832A CN 202211352516 A CN202211352516 A CN 202211352516A CN 117945832 A CN117945832 A CN 117945832A
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reactor
catalyst
uplink
reaction
oil
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马文明
袁起民
朱根权
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Sinopec Petrochemical Research Institute Co ltd
China Petroleum and Chemical Corp
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Sinopec Petrochemical Research Institute Co ltd
China Petroleum and Chemical Corp
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    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C4/00Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms
    • C07C4/02Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by cracking a single hydrocarbon or a mixture of individually defined hydrocarbons or a normally gaseous hydrocarbon fraction
    • C07C4/06Catalytic processes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/18Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
    • B01J8/24Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2523/00Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
    • C07C2523/70Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper
    • C07C2523/76Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36
    • C07C2523/83Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36 with rare earths or actinides
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2527/00Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • C07C2527/14Phosphorus; Compounds thereof
    • C07C2527/185Phosphorus; Compounds thereof with iron group metals or platinum group metals
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00Technologies relating to chemical industry
    • Y02P20/50Improvements relating to the production of bulk chemicals
    • Y02P20/52Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

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  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
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Abstract

The invention provides a method for preparing ethylene and propylene from low-carbon alkane, which is carried out in a catalytic conversion reactor, and comprises the steps of enabling raw oil rich in low-carbon alkane to contact with a first fluidization catalyst in a downlink reactor for carrying out a first catalytic conversion reaction, and separating materials after the first catalytic conversion reaction through a downlink oil agent separator to obtain a first spent catalyst and a first oil gas product; directing the first spent catalyst out of the downstream reactor; and the first oil gas product enters the uplink reactor to contact with a second fluidization catalyst in the uplink reactor for carrying out a second catalytic conversion reaction, so as to generate a second oil gas product and a second spent catalyst. The invention uses the reactor type of combining the downstream reactor and the upstream reactor, and can realize the relay performance of alkane dehydrogenation reaction and alkene catalytic cracking reaction, thereby improving the conversion rate of low-carbon alkane and the yields of ethylene and propylene.

Description

Method for preparing ethylene and propylene from low-carbon alkane
Technical Field
The invention relates to the field of petrochemical industry, in particular to a method for preparing ethylene and propylene from low-carbon alkane.
Background
Owing to the rapid development of the downstream derivative market, the demand for ethylene and propylene has been on the rise, with major gaps in the market. The existing methods for producing ethylene and propylene mainly comprise steam cracking technology, catalytic cracking technology, low-carbon alkane dehydrogenation technology, methanol-to-olefin technology and the like. Along with the continuous breakthrough of shale gas exploitation technology, the yield of low-carbon alkane is greatly improved, and the price is inevitably and continuously reduced. On the other hand, a large amount of lower alkanes, mainly including C4-C8 alkanes, are also produced during petroleum refining. If the low-carbon alkane can be converted into ethylene and propylene through reasonable processing, higher economic benefit can be brought to refineries.
Olefins produced by the dehydrogenation of light alkanes can be converted into ethylene and propylene by catalytic cracking. For example, CN105585408B provides a process for preparing low-carbon olefins from a mixture of small-molecular hydrocarbons, which comprises: the micromolecular hydrocarbon mixture is sent into a dehydrogenation reactor, contacts with a dehydrogenation catalyst in the dehydrogenation reactor and generates dehydrogenation reaction to obtain oil gas rich in olefin; the oil gas rich in olefin is sent into a riser reactor, contacts with a cracking catalyst in the riser reactor and generates a cracking reaction, and the oil gas rich in low-carbon olefin and a spent cracking catalyst are obtained; separating the oil gas rich in the low-carbon olefin from the spent cracking catalyst, and sending the separated oil gas rich in the low-carbon olefin into a product separation and recovery system; the separated spent cracking catalyst is sent into a fluidized bed regenerator after steam stripping, and is burnt and regenerated in the regenerator to obtain a regenerated cracking catalyst; delivering the regenerated cracking catalyst back to the riser reactor; the dehydrogenation reaction is carried out using a portion of the heat generated by the char regeneration using the dehydrogenation reactor disposed within the fluidized bed regenerator catalyst bed.
The process of preparing ethylene and propylene by catalytic cracking of low-carbon alkane is longer, the operation is complex, the investment of the device is high, and the economic benefit is not obvious.
CN109678634B discloses a catalytic cracking process for the production of more ethylene and propylene, which comprises: contacting a heavy raw material with a regenerated catalyst from a regenerator in a first reactor and performing a first catalytic cracking reaction to obtain a first reaction product and a first spent catalyst; C5-C9 hydrocarbon raw materials are contacted with regenerated catalyst and fresh catalyst in a second reactor and subjected to a second catalytic cracking reaction to obtain a second reaction product and a second spent catalyst; wherein the C5-C9 hydrocarbon feedstock has an olefin content of 3 to 10 wt% and an alkane content of 90 to 97 wt%; the first spent catalyst and the second spent catalyst are subjected to burning regeneration in the regenerator, and the obtained regenerated catalyst is respectively introduced into the first reactor and the second reactor; the micro-reaction activity of the fresh catalyst is 80-95, the micro-reaction activity of the regenerated catalyst is 50-70, and the micro-reaction activity is measured by adopting a RIPP-90 catalytic cracking industrial balance catalyst micro-reaction activity test method; in the second reactor, the weight ratio of the fresh catalyst to the regenerated catalyst is 1 (40-50); the weight ratio of the heavy raw material to the C5-C9 hydrocarbon raw material is 1: (10-500); the first reactor and the second reactor are each independently a riser reactor or a downer reactor.
However, it is found through experimental tests that when the existing catalytic conversion method and device are used for converting low-carbon olefin to prepare ethylene and propylene, the yield of ethylene and propylene still needs to be further improved.
Disclosure of Invention
The invention aims to further improve the yield of ethylene and propylene by converting low-carbon olefin.
In order to achieve the above object, the present invention provides a method for producing ethylene and propylene from light alkane, which is carried out using a catalytic conversion reactor comprising a downstream reaction unit and an upstream reaction unit; the downlink reaction unit comprises a downlink reactor and a downlink oil separator which are sequentially communicated from top to bottom; the uplink reaction unit comprises an uplink catalyst distributor, an uplink reactor and a discharge hole which are sequentially communicated from bottom to top; the oil gas outlet of the downlink oil agent separator is arranged at a position, close to the bottom and far away from the top, in the interior of the uplink reactor, and the catalyst outlet of the downlink oil agent separator is arranged at the exterior of the uplink reactor; the method comprises the steps of enabling raw oil rich in low-carbon alkane to contact with a first fluidization catalyst in the downlink reactor to carry out a first catalytic conversion reaction, and separating materials after the first catalytic conversion reaction through the downlink oil agent separator to obtain a first spent catalyst and a first oil gas product; directing the first spent catalyst out of the downstream reactor; the lower alkane is C4-C12 alkane; and the first oil gas product enters the uplink reactor and contacts with a second fluidization catalyst in the uplink reactor to carry out a second catalytic conversion reaction, so that a second oil gas product is generated.
By the technical scheme, the invention further improves the yield of ethylene and propylene prepared by dehydrogenating and cracking the low-carbon alkane.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate the invention and together with the description serve to explain, without limitation, the invention. In the drawings:
FIG. 1 is a schematic structural view of a reaction apparatus according to a preferred embodiment of the present invention.
Description of the reference numerals
In FIG. 1, 1-1 is a downstream catalyst distributor; 1-2 is a downlink reactor; 1-3 is a downstream oil separator; 1-4 are first regenerators; 11 is raw oil rich in low-carbon alkane; 12 is a first fluidization catalyst; 13 is a first hydrocarbon product; 14 is a first spent catalyst; 15 is the first main wind; 16 is a first cyclone; 17 is a first plenum; 18 is the first regenerated flue gas; 2-1 is a stripper; 2-2 is an upstream catalyst distributor; 2-3 is an uplink reactor; 2-4 is a second catalyst regenerator; 21 is a second fluidization catalyst; 22 is a second spent catalyst; 23 is a stripping gas; 24 is an upstream oil separator; 25 is an upward reaction oil gas collecting area; 26 is a second reaction oil gas; 27 is the second prevailing wind; 28 is a second cyclone; 29 is a second plenum; 30 is the second regeneration flue gas.
Detailed Description
The following describes specific embodiments of the present invention in detail. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
The invention provides a method for preparing ethylene and propylene from low-carbon alkane, which is carried out in a catalytic conversion reactor, wherein the catalytic conversion reactor comprises a downlink reaction unit and an uplink reaction unit; the downlink reaction unit comprises a downlink reactor and a downlink oil separator which are sequentially communicated from top to bottom; the uplink reaction unit comprises an uplink catalyst distributor, an uplink reactor and a discharge hole which are sequentially communicated from bottom to top; the oil gas outlet of the downlink oil agent separator is arranged at a position, close to the bottom and far away from the top, in the interior of the uplink reactor, and the catalyst outlet of the downlink oil agent separator is arranged at the exterior of the uplink reactor; the method comprises the steps of enabling raw oil rich in low-carbon alkane to contact with a first fluidization catalyst in the downlink reactor to carry out a first catalytic conversion reaction, and separating materials after the first catalytic conversion reaction through the downlink oil agent separator to obtain a first spent catalyst and a first oil gas product; directing the first spent catalyst out of the downstream reactor; the lower alkane is C4-C12 alkane; and the first oil gas product enters the uplink reactor to contact with a second fluidization catalyst in the uplink reactor for carrying out a second catalytic conversion reaction, so as to generate a second oil gas product and a second spent catalyst.
The invention uses the reactor type of combining the downstream reactor and the upstream reactor, can realize the relay performance of alkane dehydrogenation reaction and olefin catalytic cracking reaction, and can realize the independent and flexible regulation and control of the reaction environments of the two reaction areas, thereby improving the conversion rate of low-carbon alkane and the yield of ethylene and propylene.
Wherein the lower alkane is preferably a C4-C8 alkane. The content of the lower alkane in the raw oil rich in the lower alkane can be 90-100 wt%. The raw oil rich in light paraffins may contain 10 wt% or less of light olefins in addition to the light paraffins. The lower olefins may be C4-C12 olefins, preferably C4-C8 olefins.
Wherein, optionally, the first fluidization catalyst comprises a first carrier and a first active component, wherein the first carrier is selected from one or more of alumina, silica and titania, and the first active component is selected from one or more of K, ce, pt, cr, ga, fe, ni, V, W. The first support is present in an amount of from 50 to 99%, preferably from 80 to 99%, and the first active component is present in an amount of from 1 to 50%, preferably from 1 to 20%, based on the weight of the first fluidization catalyst. The first fluidization catalyst is particularly suitable for catalyzing a reaction for converting lower alkanes to corresponding lower alkenes.
Wherein, optionally, the second fluidization catalyst comprises a second active component, clay and a binder, wherein the second active component is a molecular sieve with an MFI structure or a molecular sieve with a modified MFI structure, the clay is selected from one or more of kaolin, montmorillonite and bentonite, and the binder is selected from one or more of silica sol, alumina sol and pseudo-boehmite. The content of the molecular sieve of the MFI structure or the modified molecular sieve of the MFI structure is 10 to 60%, preferably 20 to 50%, the content of the matrix is 10 to 80%, preferably 20 to 70%, and the content of the binder is 10 to 30%, preferably 10 to 20%, based on the total weight of the second fluidized catalyst. The second fluidization catalyst is particularly suitable for catalyzing the reaction of converting low-carbon olefins into ethylene and propylene.
Wherein, optionally, the conditions of the first catalytic conversion reaction include: the reaction temperature is 520-720 ℃, preferably 560-660 ℃, the weight hourly space velocity is 5-30 h -1, preferably 10-20 h -1, and the reaction pressure (gauge pressure) is 0-0.4 MPa, preferably 0.05-0.3 MPa.
Wherein, optionally, the conditions of the second catalytic conversion reaction include: the temperature is 520-700 ℃, preferably 560-620 ℃, the weight hourly space velocity is 1-30 h -1, preferably 5-20 h -1, the catalyst density is 100-500 kg/m 3, preferably 150-300 kg/m 3, the catalyst bed height is 1/2-4/5, preferably 1/2-3/4 of the reactor height, and the pressure (gauge pressure) in the reactor is 0-0.4 MPa, preferably 0-0.2 MPa.
Wherein, optionally, the upper end of the downer reactor is also provided with a downer catalyst distributor, a downer raw material inlet and a downer fluidization medium inlet; passing the first fluidized catalyst through the downstream catalyst distributor into the downstream reactor; allowing the raw oil rich in low-carbon olefin to enter the downlink reactor through the downlink raw oil inlet; so that a downstream fluidizing medium enters the downstream reactor through the downstream fluidizing medium inlet.
Wherein, optionally, a part or the whole of the downlink reactor is also arranged in the uplink reactor; and heat conduction exists between the downstream reactor and the upstream reactor. The embodiment that the downlink reactor is arranged in the uplink reactor can save the space of the device, simultaneously make the downlink reactor fully utilize the heat in the uplink reactor, and reduce the energy consumption of the device operation.
Wherein, optionally, the bottom of the upward reactor is also provided with an upward fluidization medium inlet and an upward catalyst distributor; allowing an upgoing fluidizing medium to enter the upgoing reactor through the upgoing fluidizing medium inlet; the second fluidized catalyst is passed through the upstream catalyst distributor into the upstream reactor.
Wherein, optionally, the uplink reactor is an equal-diameter uplink reactor or a variable-diameter uplink reactor; the diameter-variable reactor is a bottom-up diameter-expansion uplink reactor or a bottom-up diameter-reduction uplink reactor. In the preferred embodiment in which the up-reactor is a bottom-up expanded diameter up-reactor, the yields of ethylene and propylene can be further increased.
Wherein, optionally, the first to-be-regenerated catalyst is returned to the downlink reactor after first regeneration by a first regenerator; and returning the second spent catalyst to the uplink reactor after performing second regeneration through a second regenerator. The conditions of the first regeneration and the second regeneration may include: the regeneration temperature is 680-750 ℃ and 650-730 ℃. The regenerated gas may be a mixture of one or more of oxygen, air and other gases having an oxidizing effect.
Wherein, optionally, the top in the upward reactor is also provided with an upward oil separator; the oil gas outlet of the upward oil agent separator is communicated with the discharge port; preferably, an uplink reaction oil gas collecting area is further arranged between the oil gas outlet of the uplink oil agent separator and the discharge port.
Wherein optionally, the ratio of the diameter of the downstream reactor to the diameter of the upstream reactor is 1:1.5 to 10; the ratio of the height of the downstream reactor to the height of the upstream reactor is 1:0.5 to 2.
Particularly preferably, the raw oil 11 rich in low-carbon alkane from the raw material tank is preheated to 100-150 ℃ and then is introduced into the downlink reactor 1-2 to be contacted with the first fluidized catalyst 12 introduced into the downlink reactor 1-2 through the downlink catalyst distributor 1-1 and subjected to a first catalytic conversion reaction, and the generated materials after the first catalytic conversion reaction are separated through the downlink oil agent separator 1-3 to obtain a first spent catalyst 14 and a first oil gas product 13; the obtained first spent catalyst 14 is led out of the downstream reactor 1-2, enters the first regenerator 1-4 for regeneration, the regenerated first fluidized catalyst 12 is led into the downstream reactor again for recycling, the obtained first oil gas product 13 is led into the bottom of the upstream reactor 2-3, contacts with the second fluidized catalyst 21 from the upstream catalyst distributor 2-2 in the upstream reactor 2-3, carries out the second catalytic conversion reaction, the produced second catalytic conversion reaction material is separated by the upstream oil agent separator 24, the obtained second spent catalyst is led into the stripper 2-1 for stripping, the stripped second spent catalyst 22 is led into the second regenerator 2-4 for regeneration, the regenerated second fluidized catalyst 21 is led into the upstream reactor 2-3 for recycling, and the second oil gas product is collected in the upstream reaction oil gas collecting area 25 and led out of the upstream reactor 2-3.
The invention is illustrated in further detail by the following examples. The starting materials used in the examples were all available commercially without any particular explanation.
The lower alkane used in examples 1-2 and comparative examples 1-3 was a mixture of mixed butane and C5-C8 alkane, and the compositions of the raw materials are shown in Table 1 and Table 2. The first catalyst used was DH-1 and the second catalyst was RAG-6. The chemical compositions and properties of the two catalysts are shown in Table 2.
TABLE 1 chemical composition of Mixed butanes
Project Chemical composition/%
Isobutane 69.54
N-butane 30.46
Totalizing 100.00
TABLE 2C 5-C8 chemical composition of alkane mixtures
Project Chemical composition/%
Isopentane 15.96
N-pentane 8.43
Isohexane 11.69
N-hexane 5.73
Isoheptanoid process 29.36
N-heptane 10.85
Isooctane 8.77
N-octane 9.21
Totalizing 100.00
TABLE 3 composition and Properties of the catalysts
Project DH-1 RAG-6
Chemical composition/%
Al2O3 93.4 50.4
SiO2 1.2 43.5
K2O 0.375 0.302
P2O5 1.43
Fe2O3 0.106 1.04
Cr2O3
La2O3 0.17
CeO2 1.24 0.244
Ga2O3 3.06
Relative crystallinity/% 78.1 26.9
BET total analysis
BET total area/(m 2·g-1) 137.00 199.44
Total pore volume/(cm 3·g-1) 0.4680 0.1485
Example 1
The experiment was carried out on the apparatus shown in FIG. 1, in which the diameter of the downer reactor was 10mm, the length was 1000mm, the diameter of the fluidized bed reactor was 500mm, and the length was 1300mm. The mixed butane is preheated and then introduced into a downlink reactor to carry out a first reaction with a first catalyst DH-1 from a downlink catalyst distributor, the reacted first oil mixture is separated by a cyclone type rapid separator, the obtained first spent catalyst is introduced into the downlink reactor to be recycled after regeneration, the first reaction oil gas is introduced into the bottom of the fluidized bed reactor to carry out a second reaction with a second catalyst RAG-6 from an uplink catalyst distributor, the reacted second oil mixture is separated by a separating device, the generated second reaction oil gas is introduced into the fluidized bed reactor, and the second spent catalyst is introduced into a second regenerator to be recycled after regeneration after steam stripping. The conditions and product distribution of the different reaction units are shown in Table 3.
Example 2
The procedure of example 1 was followed except that the lower alkane used was a mixture of C 5-C8 alkanes. The conditions and product distribution of the different reaction units are shown in Table 6.
Comparative example 1
The experiment was carried out in a single fluidized bed reactor having a diameter of 500mm and a length of 1300mm. And (3) preheating the mixed butane, introducing the preheated butane into a fluidized bed reactor to react with a catalyst in the fluidized bed reactor to obtain an oil-solvent mixture, and separating the oil-solvent mixture by a cyclone separator to generate reaction oil gas. The catalyst is obtained by proportioning DH-1 and RAG-6 according to the mass ratio of 1:1. The conditions and product distribution of the different reaction units are shown in Table 3.
Comparative example 2
The experiment was carried out in a single fluidized bed reactor having a diameter of 500mm and a length of 1300mm. C 5-C8 alkane is preheated and then introduced into a fluidized bed reactor to react with a catalyst in the fluidized bed reactor, so that an oil-gas mixture is obtained, and the oil-gas mixture is separated by a cyclone separator to produce reaction oil gas. The catalyst is obtained by proportioning DH-1 and RAG-6 according to the mass ratio of 1:1. The conditions and product distribution of the different reaction units are shown in Table 3.
Comparative example 3
The procedure of example 1 was followed, except that no downstream oil separator was provided, and all of the material after the first catalytic conversion reaction obtained in the downstream reactor 1-2 was fed into the upstream reactor 2-3 to participate in the second catalytic conversion, and the catalyst was a mixed catalyst prepared from DH-1 catalyst and RAG-6 catalyst in a mass ratio of 1:1. The conditions and product distribution of the different reaction units are shown in Table 3.
Comparative example 4
The procedure of example 1 was followed except that the downstream reactor was replaced with a fixed bed tubular reactor, the first oil and gas product after the first catalytic conversion reaction obtained in the fixed bed tubular reactor was fed into the upstream reactor 2-3 to participate in the second catalytic conversion, the catalyst in the fixed bed tubular reactor was DH-1 catalyst, and the catalyst in the upstream reactor 2-3 was RAG-6 catalyst. The conditions and product distribution of the different reaction units are shown in Table 3.
In table 3, the conversion was calculated as:
Conversion= (mass of lower alkane in feedstock-mass of corresponding lower alkane in product)/mass of lower alkane in feedstock x 100%;
The yield was calculated as:
Yield = mass of a component in the product/mass of lower alkane in the feedstock x 100%;
TABLE 3 Table 3
Project Example 1 Example 2 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4
Raw oil Mixed butane C5-C8 alkane Mixed butane C5-C8 alkane C5-C8 alkane C5-C8 alkane
Down reactor Tubular fixed bed
Catalyst DH-1 DH-1 Mixed catalyst DH-1
Reaction temperature/. Degree.C 620 600 600 600
Reaction pressure/kPa (gauge pressure) 0.13 0.13 0.13 0.13
Mass space velocity/h -1 2.4 6 6 6
Up-flow fluidized bed reactor
Catalyst RAG-6 RAG-6 DH-1+RAG-6 Mixed catalyst Mixed catalyst RAG-6
Reaction temperature/. Degree.C 600 580 620 600 580 580
Reaction pressure/kPa (gauge pressure) 0.15 0.14 0.14 0.14 0.14 0.14
Mass space velocity/h -1 6 10 6 10 10 10
Conversion/wt% 55.98 58.73 40.00 54.78 56.85 53.23
Ethylene yield/wt% 11.03 19.89 5.87 16.51 17.33 15.61
Propylene yield/wt% 27.56 32.45 20.96 28.78 29.46 24.37
From the results shown in Table 3, the method provided by the invention can improve the yield of ethylene and propylene prepared by catalytic conversion of light alkane.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications belong to the protection scope of the present invention.
In addition, the specific features described in the above embodiments may be combined in any suitable manner without contradiction. The various possible combinations of the invention are not described in detail in order to avoid unnecessary repetition.
Moreover, any combination of the various embodiments of the invention can be made without departing from the spirit of the invention, which should also be considered as disclosed herein.

Claims (10)

1. A method for preparing ethylene and propylene from low-carbon alkane, which is characterized in that the method is carried out in a catalytic conversion reactor, and the catalytic conversion reaction device comprises a downlink reaction unit and an uplink reaction unit; the downlink reaction unit comprises a downlink reactor and a downlink oil separator which are sequentially communicated from top to bottom; the uplink reaction unit comprises an uplink catalyst distributor, an uplink reactor and a discharge hole which are sequentially communicated from bottom to top; the oil gas outlet of the downlink oil agent separator is arranged at a position, close to the bottom and far away from the top, in the interior of the uplink reactor, and the catalyst outlet of the downlink oil agent separator is arranged at the exterior of the uplink reactor;
the method comprises the steps of enabling raw oil rich in low-carbon alkane to contact with a first fluidization catalyst in the downlink reactor to carry out a first catalytic conversion reaction, and separating materials after the first catalytic conversion reaction through the downlink oil agent separator to obtain a first spent catalyst and a first oil gas product; directing the first spent catalyst out of the downstream reactor; the lower alkane is C4-C12 alkane;
and the first oil gas product enters the uplink reactor to contact with a second fluidization catalyst in the uplink reactor for carrying out a second catalytic conversion reaction, so as to generate a second oil gas product and a second spent catalyst.
2. The method of claim 1, wherein the lower alkane is a C4-C8 alkane; the content of the low-carbon alkane in the raw oil rich in the low-carbon alkane is 90-100 wt%.
3. The method of claim 1, wherein the first fluidization catalyst comprises a first carrier selected from one or more of alumina, silica, titania, and a first active component selected from one or more of K, ce, pt, cr, ga, fe, ni, V, W; the second fluidization catalyst comprises a second active component, clay and a binder, wherein the second active component is a molecular sieve with an MFI structure or a molecular sieve with a modified MFI structure, the clay is selected from one or more of kaolin, montmorillonite and bentonite, and the binder is selected from one or more of silica sol, alumina sol and pseudo-boehmite.
4. The method of claim 1, wherein the conditions of the first catalytic conversion reaction comprise: the reaction temperature is 520-720 ℃, preferably 560-660 ℃, the weight hourly space velocity is 5-30 h -1, preferably 10-20 h -1, and the reaction pressure is 0-0.4 MPa, preferably 0.05-0.3 MPa.
5. The method of claim 1 or 4, wherein the conditions of the second catalytic conversion reaction comprise: the temperature is 520-700 ℃, preferably 560-620 ℃, the weight hourly space velocity is 1-30 h -1, preferably 5-20 h -1, the catalyst density is 100-500 kg/m 3, preferably 150-300 kg/m 3, the catalyst bed height is 1/2-4/5, preferably 1/2-3/4 of the reactor height, and the pressure in the reactor is 0-0.4 MPa, preferably 0-0.2 MPa.
6. The process of claim 1, wherein the upper end of the downer reactor is further provided with a downer catalyst distributor, a downer feed inlet, and a downer fluidization medium inlet; passing the first fluidized catalyst through the downstream catalyst distributor into the downstream reactor; allowing the feed oil enriched in light alkanes to enter the downgoing reactor through the downgoing feed inlet; so that a downstream fluidizing medium enters the downstream reactor through the downstream fluidizing medium inlet.
7. The method of claim 1 or 2, wherein a portion or all of the downstream reactor is also disposed inside the upstream reactor; and heat conduction exists between the downstream reactor and the upstream reactor.
8. The process of claim 1, wherein the bottom of the upgoing reactor is further provided with an upgoing fluidization medium inlet and an upgoing catalyst distributor; allowing an upgoing fluidizing medium to enter the upgoing reactor through the upgoing fluidizing medium inlet; passing the second fluidized catalyst through the upstream catalyst distributor into the upstream reactor;
The uplink reactor is an equal-diameter uplink reactor or a variable-diameter uplink reactor; the diameter-variable reactor is a bottom-up diameter-expansion uplink reactor or a bottom-up diameter-reduction uplink reactor.
9. The process of claim 1, wherein the first spent catalyst is returned to the downstream reactor after a first regeneration by a first regenerator; and returning the second spent catalyst to the uplink reactor after performing second regeneration through a second regenerator.
10. The method of claim 1 or 2, wherein the top within the upgoing reactor is further provided with an upgoing oil separator; the oil gas outlet of the upward oil agent separator is communicated with the discharge port; preferably, an uplink reaction oil gas collecting area is further arranged between the oil gas outlet of the uplink oil agent separator and the discharge port;
the ratio of the diameter of the downstream reactor to the diameter of the upstream reactor is 1:1.5 to 10; the ratio of the height of the downstream reactor to the height of the upstream reactor is 1:0.5 to 2.
CN202211352516.3A 2022-10-31 2022-10-31 Method for preparing ethylene and propylene from low-carbon alkane Pending CN117945832A (en)

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