CN116410049A - Combined process and system for producing low-carbon olefin by catalytic cracking of olefin - Google Patents
Combined process and system for producing low-carbon olefin by catalytic cracking of olefin Download PDFInfo
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- 150000001336 alkenes Chemical class 0.000 title claims abstract description 177
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 title claims abstract description 162
- 238000004523 catalytic cracking Methods 0.000 title claims abstract description 111
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 96
- 238000000034 method Methods 0.000 title claims abstract description 48
- 230000008569 process Effects 0.000 title claims abstract description 38
- 239000002994 raw material Substances 0.000 claims abstract description 101
- 239000000463 material Substances 0.000 claims abstract description 87
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 72
- 238000006243 chemical reaction Methods 0.000 claims abstract description 47
- 238000000926 separation method Methods 0.000 claims abstract description 28
- -1 ethylene, propylene Chemical group 0.000 claims abstract description 22
- 150000001335 aliphatic alkanes Chemical class 0.000 claims abstract description 16
- 239000012535 impurity Substances 0.000 claims abstract description 14
- 238000009835 boiling Methods 0.000 claims abstract description 10
- 230000008859 change Effects 0.000 claims abstract description 7
- 238000000066 reactive distillation Methods 0.000 claims description 18
- 238000004064 recycling Methods 0.000 claims description 12
- 239000003054 catalyst Substances 0.000 claims description 10
- 239000002808 molecular sieve Substances 0.000 claims description 6
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims description 6
- 230000002378 acidificating effect Effects 0.000 claims description 5
- 238000005265 energy consumption Methods 0.000 abstract description 19
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 17
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 17
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 16
- 239000000047 product Substances 0.000 description 16
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 11
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 10
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 10
- 239000003245 coal Substances 0.000 description 8
- 238000006116 polymerization reaction Methods 0.000 description 8
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 7
- 239000005977 Ethylene Substances 0.000 description 7
- 230000003197 catalytic effect Effects 0.000 description 7
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical class CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 7
- VQTUBCCKSQIDNK-UHFFFAOYSA-N Isobutene Chemical group CC(C)=C VQTUBCCKSQIDNK-UHFFFAOYSA-N 0.000 description 5
- 230000008901 benefit Effects 0.000 description 5
- BFAKENXZKHGIGE-UHFFFAOYSA-N bis(2,3,5,6-tetrafluoro-4-iodophenyl)diazene Chemical compound FC1=C(C(=C(C(=C1F)I)F)F)N=NC1=C(C(=C(C(=C1F)F)I)F)F BFAKENXZKHGIGE-UHFFFAOYSA-N 0.000 description 5
- 239000001282 iso-butane Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 238000007233 catalytic pyrolysis Methods 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000003377 acid catalyst Substances 0.000 description 2
- 235000013844 butane Nutrition 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 238000006356 dehydrogenation reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000004230 steam cracking Methods 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000003456 ion exchange resin Substances 0.000 description 1
- 229920003303 ion-exchange polymer Polymers 0.000 description 1
- 239000011344 liquid material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 239000011949 solid catalyst Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 125000000383 tetramethylene group Chemical group [H]C([H])([*:1])C([H])([H])C([H])([H])C([H])([H])[*:2] 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C4/00—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms
- C07C4/02—Preparation 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
- C07C4/06—Catalytic processes
Abstract
The application relates to the field of petrochemical industry, in particular to a combined process and system for producing low-carbon olefin by catalytic cracking of olefin. The process comprises the following steps: pretreating a carbon four raw material and a light gasoline raw material to remove impurities, thereby obtaining a pretreated carbon four raw material and a first olefin-rich material; enriching the pretreated carbon four raw material to change the boiling points of the alkene and alkane so as to obtain a second alkene-rich material and an alkane-rich material; carrying out catalytic cracking on the first olefin-rich material and the second olefin-rich material to obtain reaction oil gas; and separating the reaction oil gas to obtain ethylene, propylene and circulating materials. The boiling points of the alkene and the alkane are changed through enrichment, so that the second alkene-rich material and the alkane-rich material are easier to separate, and the energy consumption of separation is reduced; the concentration of the olefin-rich material is improved, the first olefin-rich material and the second olefin-rich material are subjected to catalytic cracking simultaneously, the investment of an olefin catalytic cracking device is reduced, and the energy consumption of an olefin catalytic cracking reaction process is reduced.
Description
Technical Field
The application relates to the field of petrochemical industry, in particular to a combined process and system for producing low-carbon olefin by catalytic cracking of olefin.
Background
From the aspect of propylene supply and demand, on one hand, domestic propylene resource shortage and yield cannot meet the demand, and the effective propylene productivity is increased after the demand of downstream derivative industries is increased; on the other hand, the traditional propylene production is relatively monopoly, the downstream supporting device of the propylene production enterprise can basically consume the propylene yield, the domestic propylene flow can not meet the demands of other downstream enterprises, and the demand gap is larger.
Propylene is mainly from catalytic cracking units in refineries, steam cracking units in ethylene plants, units for producing olefins from methanol, and propane dehydrogenation units. The steam cracking device, the catalytic cracking device and the methanol-to-olefin device can produce a large amount of C4-C8 olefin fractions as byproducts, and the byproducts are converted into propylene, so that the propylene yield is improved, the contradiction between propylene supply and demand can be relieved, and the economic benefit of petrochemical enterprises can be increased. The existing mature olefin catalytic cracking technology mainly comprises an OCP process of UOP company, an OCC process of Shanghai petrochemical institute and the like, and is mainly used for treating mixed carbon four with high olefin content of an MTO device, wherein the mass content of the olefin can reach more than 90%. The catalytic cracking device of the refinery can produce a large amount of carbon four and light gasoline and the like, and the mass content of olefin can reach 50-65% generally, and the catalytic cracking device is also suitable for being used as a raw material for catalytic cracking of olefin, and can bring remarkable economic benefit to enterprises by converting the catalytic cracking device into low-carbon olefin. However, compared with the method of mixing the four-carbon with the MTO, the quality content of the four-carbon and catalytic light gasoline olefin after ether is lower in a refinery, so that the amount of non-reactant materials circulating in the system is large, the energy consumption and the production cost of the device are increased, and the popularization and the application of the olefin catalytic cracking technology in the refinery are restricted.
Patent CN101205162a discloses a combined process for producing olefins from refinery carbon four, which uses a special rectification method (e.g. extractive rectification) to separate butenes from butanes. However, the separation of butene and butane by means of special near rectification, while it is possible to increase the olefin content in the inlet of the olefin catalytic cracking reactor, has a problem of higher energy consumption.
Disclosure of Invention
The application provides a combined process and a system for producing low-carbon olefin by catalytic cracking of olefin, which are used for solving the technical problem of high energy consumption of the existing process.
In a first aspect, the present application provides a combined process for producing light olefins by catalytic cracking of olefins, wherein the process comprises the steps of:
pretreating a carbon four raw material and a light gasoline raw material to remove impurities, thereby obtaining a pretreated carbon four raw material and a first olefin-rich material;
enriching the pretreated carbon four raw material to change the boiling points of the alkene and alkane so as to obtain a second alkene-rich material and an alkane-rich material;
carrying out catalytic cracking on the first olefin-rich material and the second olefin-rich material to obtain reaction oil gas;
and separating the reaction oil gas to obtain ethylene, propylene and circulating materials.
Optionally, the mass fraction of the olefin in the carbon four raw material is 30% -100%, and the mass fraction of the olefin in the light gasoline raw material is 30% -100%.
Alternatively, the enrichment means comprises reactive distillation with the addition of an acidic catalyst.
Optionally, the temperature of the reactive distillation is 30-100 ℃, and the pressure during the reactive distillation is 0.5-2 MPag.
Optionally, the temperature of the first catalytic cracking is 500-650 ℃, and the reaction pressure of the catalytic cracking is 0.02-0.2 MPag.
Optionally, a molecular sieve catalyst is added during the first catalytic cracking.
Optionally, the process further comprises:
recycling the circulating material to the catalytic cracking.
In a second aspect, the present application provides a system for a combined process according to the first aspect, the system comprising:
a raw material pretreatment unit which is communicated with a feed pipeline and is used for treating a carbon four raw material and a light gasoline raw material in the feed pipeline;
the olefin enrichment unit is communicated with the raw material pretreatment unit and is used for enriching and separating the pretreated carbon four raw materials;
the olefin catalytic cracking unit is used for carrying out catalytic cracking on the olefin-rich material, and the olefin enrichment unit and the raw material pretreatment unit;
and the product separation unit is communicated with the olefin catalytic cracking unit and is used for separating each component obtained by the olefin catalytic cracking unit.
Optionally, the outlet end of the product separation unit is communicated with the inlet end of the olefin catalytic cracking unit, and is used for carrying out catalytic cracking and recycling on the recycled materials obtained in the product separation unit.
Optionally, the olefin catalytic cracking unit comprises a fixed bed reactor.
Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:
according to the method provided by the embodiment of the application, the carbon four raw materials and the light gasoline raw materials are pretreated to remove impurities, then the carbon four olefins are enriched, the boiling points of the olefins and the paraffins are changed through an enrichment process, so that the second olefin-rich materials and the paraffin-rich materials are more easily separated, and the energy consumption of separation is reduced; the concentration of the second olefin-rich material is improved, the first olefin-rich material and the second olefin-rich material are subjected to first catalytic cracking at the same time, so that the investment of devices for olefin catalytic cracking reaction is reduced, the energy consumption of an olefin catalytic cracking reaction process is reduced, the production cost is reduced, and the method has good competitiveness.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.
FIG. 1 is a schematic flow chart of a combined process for producing light olefins by catalytic cracking of olefins according to an embodiment of the present disclosure;
fig. 2 is a schematic diagram of a system for producing light olefins by catalytic cracking of olefins according to an embodiment of the present application.
Wherein, 1, a raw material pretreatment unit, 2, an olefin enrichment unit, 3, an olefin catalytic cracking unit, 4, a product separation unit, 5, a carbon four raw material, 6, a light gasoline raw material.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.
In a first aspect, the present application provides a combined process for producing light olefins by catalytic cracking of olefins, wherein the process comprises the steps of:
s1, pretreating a carbon four raw material and a light gasoline raw material to remove impurities, so as to obtain a pretreated carbon four raw material and a first olefin-rich material;
specifically, the pretreatment can remove trace impurities such as water, metal and the like. The light components of the carbon four material may include: n-butane, isobutane, butene-1, isobutylene, fumaric-2, cis-2 and butadiene.
S2, enriching the pretreated carbon four raw materials to change the boiling points of the alkene and the alkane so as to obtain a second alkene-rich material and an alkane-rich material;
specifically, the pretreatment of the carbon four raw material is carried out to enrich the olefin so that the boiling point of the olefin is changed from the original temperature of-7 ℃ to 5 ℃ to be more than 100 ℃, so that the concentration of the effective components of the second olefin-rich material which is separated later is more than 90%, the subsequent first catalytic cracking is facilitated, and the energy consumption of the whole process is reduced.
S3, carrying out catalytic cracking on the first olefin-rich material and the second olefin-rich material to obtain reaction oil gas;
specifically, the reaction oil gas is low-carbon olefin containing ethylene, propylene and the like.
S4, separating the reaction oil gas to obtain ethylene, propylene and circulating materials.
Specifically, the reaction oil gas is separated, heavy components can be obtained, the heavy components comprise alkane, unreacted alkene and arene, and the circulating material is unreacted carbon four raw materials.
In some embodiments, the mass fraction of olefins in the carbon four feedstock is 30% to 100%, and the mass fraction of olefins in the light gasoline feedstock is 30% to 100%.
In the embodiment of the application, the reason for controlling the mass fraction of the olefin in the carbon four raw material and the light gasoline raw material to be 30-100% is that the control of the circulation ratio, for example, the mass fraction of the olefin is less than 30%, can cause the adverse effects of overlarge circulation ratio and overlarge energy consumption.
In some embodiments, the enrichment mode includes reactive distillation and addition of an acidic catalyst.
In the embodiment of the application, the reason for enrichment by adopting reactive distillation is to change the boiling point difference of olefin and alkane, the reason for adding the acid catalyst during enrichment is that the enrichment efficiency is high, and the acid catalyst can be solid phosphorus, a molecular sieve and ion exchange resin.
In some embodiments, the temperature of the reactive distillation is from 30 to 100 ℃ and the pressure at the time of the reactive distillation is from 0.5 to 2MPag.
In the examples herein, the reason for controlling the temperature of the reactive distillation to 30 to 100℃is high reaction efficiency, and the reason for controlling the pressure at the time of the reactive distillation to 0.5 to 2MPag is high reaction efficiency.
In some embodiments, the temperature of the first catalytic cracking is 500 to 650 ℃, and the reaction pressure of the catalytic cracking is 0.02 to 0.2MPag.
In the embodiment of the application, the reason for controlling the temperature of the first catalytic cracking to be 500-650 ℃ is that the reaction selectivity is good, and the reason for controlling the reaction pressure of the catalytic cracking to be 0.02-0.2 MPag is that the production of low-carbon olefin is facilitated.
In some embodiments, the molecular sieve catalyst is added at the time of the first catalytic cracking.
Specifically, the addition of the molecular sieve catalyst has the beneficial effects of reducing the reaction severity and improving the distribution of reaction products, and the molecular sieve catalyst comprises any one of ZSM-5, MCM-22 and SAPO-34.
In some embodiments, the process further comprises:
recycling the circulating material to the catalytic cracking.
In this application embodiment, the circulating material includes unreacted four raw materials of carbon, carries out catalytic cracking once more, can improve the yield of low-carbon olefin, makes four raw materials of carbon can directly carry out catalytic cracking simultaneously, improves economic benefits, avoids the waste of resource.
In a second aspect, the present application provides a system for a combined process according to the first aspect, the system comprising:
a raw material pretreatment unit which is communicated with a feed pipeline and is used for treating a carbon four raw material and a light gasoline raw material in the feed pipeline;
the olefin enrichment unit is communicated with the raw material pretreatment unit and is used for enriching and separating the pretreated carbon four raw materials;
the olefin catalytic cracking unit is used for carrying out catalytic cracking on the olefin-rich material, and the olefin enrichment unit and the raw material pretreatment unit;
and the product separation unit is communicated with the olefin catalytic cracking unit and is used for separating each component obtained by the olefin catalytic cracking unit.
Specifically, the product separation unit can be matched with an independent separation system, such as a low-temperature oil absorption separation measure to obtain polymerization-grade ethylene and polymerization-grade propylene or a conventional absorption stabilization and gas separation to obtain polymerization-grade propylene and ethylene-rich dry gas, and can also be combined with an existing catalytic cracking device or an MTO device or a propane dehydrogenation device to share the product separation system.
In some embodiments, the outlet end of the product separation unit is communicated with the inlet end of the olefin catalytic cracking unit, and is used for carrying out catalytic cracking and recycling on the recycled materials obtained in the product separation unit.
In this application embodiment, product separation unit exit end with olefin catalytic cracking unit entrance end intercommunication can recycle the circulating material, reduce cost.
In some embodiments, the olefin catalytic cracking unit comprises a fixed bed reactor.
In the embodiment of the application, the fixed bed reactor refers to a reactor filled with a granular solid catalyst or a solid reactant to form a stacked bed layer with a certain height, and gas or liquid materials flow through a static fixed bed layer through a particle gap, and meanwhile, a heterogeneous reaction process is realized, so that the selectivity can be improved.
The method of the present invention will be described in detail with reference to examples, comparative examples and experimental data.
Example 1
The olefin-rich material of the refinery is used as a raw material to prepare low-carbon olefins such as ethylene, propylene and the like at low cost. The embodiment provides a combined process for producing low-carbon olefin by catalytic pyrolysis of olefin in a refinery, which mainly comprises the following steps:
s1, pretreating a carbon four raw material and a light gasoline raw material to remove impurities, so as to obtain a pretreated carbon four raw material and a first olefin-rich material; specifically, the pretreatment can remove trace impurities such as water, metal and the like. The light components of the carbon four material may include: n-butane, isobutane, butene-1, isobutylene, fumaric-2, cis-2 and butadiene.
S2, enriching the pretreated carbon four raw materials to change the boiling points of the alkene and the alkane so as to obtain a second alkene-rich material and an alkane-rich material;
s3, carrying out catalytic cracking on the first olefin-rich material and the second olefin-rich material to obtain reaction oil gas; specifically, the reaction oil gas is low-carbon olefin containing ethylene, propylene and the like.
S4, separating the reaction oil gas to obtain ethylene, propylene and circulating materials. Specifically, the recycle material is unreacted carbon four feedstock.
S5, recycling the circulating materials to the catalytic cracking, and continuing the reaction.
The mass fraction of olefin in the carbon four raw material is 30% -100%, and the mass fraction of olefin in the light gasoline raw material is 30% -100%. The enrichment mode comprises reactive distillation and adding an acidic catalyst. The temperature of the reactive distillation is 30-100 ℃, and the pressure during the reactive distillation is 0.5-2 MPag. The temperature of the first catalytic cracking and the second catalytic cracking is 500-650 ℃, and the reaction pressure of the catalytic cracking is 0.02-0.2 MPag.
Embodiments of the present application provide a system for a combined process according to the first aspect, the system comprising:
a raw material pretreatment unit 1 which is communicated with a feed line and is used for treating a carbon four raw material 5 and a light gasoline raw material 6 in the feed line;
an olefin enrichment unit 2 which is communicated with the raw material pretreatment unit and is used for enriching and separating the pretreated carbon four raw materials;
the olefin catalytic cracking unit 3 is used for carrying out catalytic cracking on the olefin-rich material, and is connected with the olefin enrichment unit and the raw material pretreatment unit; the olefin catalytic cracking unit comprises a fixed bed reactor;
and the product separation unit 4 is communicated with the olefin catalytic cracking unit and is used for separating each component obtained by the olefin catalytic cracking unit. The outlet end of the product separation unit is communicated with the inlet end of the olefin catalytic cracking unit and is used for carrying out catalytic cracking and recycling on the circulating materials obtained in the product separation unit.
Specifically, the catalytic light gasoline with the flow rate of 34748kg/h, namely the post-ether carbon four and 21325kg/h, is used as a raw material, wherein the olefin mass content of the post-ether carbon four is 49%, the olefin content of the catalytic light gasoline is 61%, and the total olefin concentration of the raw material is 54%. After pretreatment and olefin enrichment, the carbon number four after the ether is used as the raw material of an olefin catalytic cracking reactor together with catalytic light gasoline, and the olefin concentration of the raw material is increased to 78%. The reaction is carried out under the conditions of 550 ℃ and 0.3MPag, 5155kg/h of polymerization grade ethylene and 18698kg/h of polymerization grade propylene are obtained through separation, the total selectivity of the reaction (based on olefin) reaches 17.2 percent and 62.2 percent, and the energy consumption is 817.5 kg of standard coal/ton of olefin. If the concentration of the raw material olefin fed into the olefin catalytic cracking reactor is 64% after enrichment, the energy consumption is 942 kg of standard coal per ton of olefin.
Example 2
The olefin-rich material produced by the MTO device is used as a raw material to prepare low-carbon olefins such as ethylene, propylene and the like at low cost. The embodiment provides a combined process for producing low-carbon olefin by catalytic cracking of olefin, which mainly comprises the following steps:
s1, pretreating a carbon four raw material to remove impurities, so as to obtain a pretreated carbon four raw material and a first olefin-rich material; specifically, the pretreatment can remove trace impurities such as water, metal and the like. The light components of the carbon four material may include: n-butane, isobutane, butene-1, isobutylene, fumaric-2, cis-2 and butadiene.
82. Enriching the pretreated carbon four raw material to change the boiling points of the alkene and alkane so as to obtain a second alkene-rich material and an alkane-rich material;
s3, carrying out catalytic cracking on the first olefin-rich material and the second olefin-rich material to obtain reaction oil gas; specifically, the reaction oil gas is low-carbon olefin containing ethylene, propylene and the like.
S4, separating the reaction oil gas to obtain ethylene, propylene and circulating materials. Specifically, the recycle material is unreacted carbon four feedstock.
S5, recycling the circulating materials to the catalytic cracking, and continuing the reaction.
The mass fraction of olefin in the carbon four raw material is 30% -100%. The enrichment mode comprises reactive distillation and adding an acidic catalyst. The temperature of the reactive distillation is 30-100 ℃, and the pressure during the reactive distillation is 0.5-2 MPag. The temperature of the first catalytic cracking and the second catalytic cracking is 500-650 ℃, and the reaction pressure of the catalytic cracking is 0.02-0.2 MPag.
Embodiments of the present application provide a system for a combined process according to the first aspect, the system comprising:
a raw material pretreatment unit 1 which is communicated with a feed line and is used for treating a carbon four raw material 5 in the feed line;
an olefin enrichment unit 2 which is communicated with the raw material pretreatment unit and is used for enriching and separating the pretreated carbon four raw materials;
the olefin catalytic cracking unit 3 is used for carrying out catalytic cracking on the olefin-rich material, and is connected with the olefin enrichment unit and the raw material pretreatment unit; the olefin catalytic cracking unit comprises a fixed bed reactor;
and the product separation unit 4 is communicated with the olefin catalytic cracking unit and is used for separating each component obtained by the olefin catalytic cracking unit. The outlet end of the product separation unit is communicated with the inlet end of the olefin catalytic cracking unit and is used for carrying out catalytic cracking and recycling on the circulating materials obtained in the product separation unit.
Specifically, the method takes the post-ether carbon four with the flow rate of 24000kg/h as a raw material, wherein the mass content of olefin of the post-ether carbon four is 76%. After pretreatment and olefin enrichment, the carbon number four after the ether is used as the raw material of an olefin catalytic cracking reactor, and the olefin concentration of the raw material is increased to 99%. Under the conditions of 550 ℃ and 0.3MPag, 3180kg/h of polymerization grade ethylene and 11812kg/h of polymerization grade propylene are obtained through separation, and the total selectivity of the reaction (based on olefin) reaches 17.5% and 65.0%, and the energy consumption is 646.7 kg of standard coal/ton of olefin. If the concentration of the raw material olefin fed into the olefin catalytic cracking reactor after enrichment is 86%, the energy consumption is 686.5 kg of standard coal per ton of olefin.
Comparative example 1
The olefin-rich material of the refinery is used as a raw material to prepare low-carbon olefins such as ethylene, propylene and the like at low cost. The comparative example provides a combined process for producing low-carbon olefin by catalytic cracking of olefin in a refinery, which mainly comprises the following steps:
s1, pretreating a carbon four raw material and a light gasoline raw material to remove impurities, so as to obtain a pretreated carbon four raw material and a first olefin-rich material; specifically, the pretreatment can remove trace impurities such as water, metal and the like. The light components of the carbon four material may include: n-butane, isobutane, butene-1, isobutylene, fumaric-2, cis-2 and butadiene.
S2, carrying out catalytic pyrolysis on the first olefin-rich material and the carbon-four raw material to obtain reaction oil gas; specifically, the reaction oil gas is low-carbon olefin containing ethylene, propylene and the like.
S3, separating the reaction oil gas to obtain ethylene, propylene and circulating materials. Specifically, the recycle material is unreacted carbon four feedstock.
S4, recycling the circulating materials to the catalytic cracking, and continuing the reaction.
The mass fraction of olefin in the carbon four raw material is 30% -100%, and the mass fraction of olefin in the light gasoline raw material is 30% -100%. The temperature of the first catalytic cracking and the second catalytic cracking is 500-650 ℃, and the reaction pressure of the catalytic cracking is 0.02-0.2 MPag.
Specifically, the catalytic light gasoline with the flow rate of 34748kg/h and 21325kg/h and the post-ether carbon four is taken as a raw material, wherein the olefin mass content of the post-ether carbon four is 49%, and the olefin content of the catalytic light gasoline is 61%. The pretreated carbon four is used as the raw material of an olefin catalytic cracking reactor together with catalytic light gasoline, reacts at 550 ℃ and under the condition of 0.3MPag, then 4956kg/h of polymerization grade ethylene and 18622kg/h of polymerization grade propylene are obtained through separation, and the total selectivity of the reaction (based on olefin) reaches 165% and 62%, and the energy consumption is 1078.9 kg of standard coal/ton of olefin.
Comparative example 2
The olefin-rich material produced by the MTO device is used as a raw material to prepare low-carbon olefins such as ethylene, propylene and the like at low cost. The comparative example provides a combined process for producing low-carbon olefin by catalytic cracking of olefin in a refinery, which mainly comprises the following steps: :
s1, pretreating a carbon four raw material and a light gasoline raw material to remove impurities, so as to obtain a pretreated carbon four raw material and a first olefin-rich material; specifically, the pretreatment can remove trace impurities such as water, metal and the like. The light components of the carbon four material may include: n-butane, isobutane, butene-1, isobutylene, fumaric-2, cis-2 and butadiene.
S2, carrying out catalytic pyrolysis on the first olefin-rich material and the carbon-four raw material to obtain reaction oil gas; specifically, the reaction oil gas is low-carbon olefin containing ethylene, propylene and the like.
S3, separating the reaction oil gas to obtain ethylene, propylene and circulating materials. Specifically, the recycle material is unreacted carbon four feedstock.
S4, recycling the circulating materials to the catalytic cracking, and continuing the reaction.
The mass fraction of olefin in the carbon four raw material is 30% -100%, and the mass fraction of olefin in the light gasoline raw material is 30% -100%. The temperature of the first catalytic cracking and the second catalytic cracking is 500-650 ℃, and the reaction pressure of the catalytic cracking is 0.02-0.2 MPag.
Specifically, the method takes the post-ether carbon four with the flow rate of 24000kg/h as a raw material, wherein the mass content of olefin of the post-ether carbon four is 76%. After pretreatment and olefin enrichment, the carbon four after ether is used as a raw material of an olefin catalytic cracking reactor, reacts at 550 ℃ and under the condition of 0.3MPag, and then is separated to obtain 3101kg/h of polymerization grade ethylene and 11765kg/h of polymerization grade propylene, wherein the total selectivity of the reaction (based on olefin) reaches 17.0% and 64.5%, and the energy consumption is 732.4 kg of standard coal/ton of olefin.
From the examples and comparative examples, the same raw materials are used in comparative example 1 and example 1, the same raw materials are used in comparative example 2 and example 2, the energy consumption is obviously reduced based on the comparative examples, the energy consumption of the examples is 646.7-817.5 kg standard coal/ton olefin, the energy consumption of the comparative examples is 732.4-1078.9 kg standard coal/ton raw material, and the effect of reducing the energy consumption can be achieved through enriching the carbon tetraolefin.
It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing is only a specific embodiment of the invention to enable those skilled in the art to understand or practice the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A combined process for producing low-carbon olefins by catalytic cracking of olefins, which is characterized by comprising the following steps:
pretreating a carbon four raw material and a light gasoline raw material to remove impurities, thereby obtaining a pretreated carbon four raw material and a first olefin-rich material;
enriching the pretreated carbon four raw material to change the boiling points of the alkene and alkane so as to obtain a second alkene-rich material and an alkane-rich material;
carrying out catalytic cracking on the first olefin-rich material and the second olefin-rich material to obtain reaction oil gas;
and separating the reaction oil gas to obtain ethylene, propylene and circulating materials.
2. The process of claim 1, wherein the mass fraction of olefins in the carbon four feedstock is 30% to 100%, and the mass fraction of olefins in the light gasoline feedstock is 30% to 100%.
3. The process of claim 1 wherein the enrichment means comprises reactive distillation and addition of an acidic catalyst.
4. A process according to claim 3, wherein the temperature of the reactive distillation is 30-100 ℃, and the pressure at the time of the reactive distillation is 0.5-2 MPag.
5. A process according to claim 3, wherein the temperature of the first catalytic cracking is 500-650 ℃, and the reaction pressure of the catalytic cracking is 0.02-0.2 MPag.
6. A process according to claim 3, wherein a molecular sieve catalyst is added during the first catalytic cracking.
7. A process according to claim 3, further comprising:
recycling the circulating material to the catalytic cracking.
8. A system for a combined process as claimed in any one of claims 1-7, characterized in that the system comprises:
a raw material pretreatment unit which is communicated with a feed pipeline and is used for treating a carbon four raw material and a light gasoline raw material in the feed pipeline;
the olefin enrichment unit is communicated with the raw material pretreatment unit and is used for enriching and separating the pretreated carbon four raw materials;
the olefin catalytic cracking unit is used for carrying out catalytic cracking on the olefin-rich material, and the olefin enrichment unit and the raw material pretreatment unit;
and the product separation unit is communicated with the olefin catalytic cracking unit and is used for separating each component obtained by the olefin catalytic cracking unit.
9. The system of claim 8, wherein the product separation unit outlet is in communication with the olefin catalytic cracking unit inlet for catalytic cracking and recycling of the recycle material obtained in the product separation unit.
10. The system of claim 8, wherein the olefin catalytic cracking unit comprises a fixed bed reactor.
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