阅读说明：本技术 一种炼厂干气制乙苯组合工艺 (Combined process for preparing ethylbenzene from refinery dry gas ) 是由 李春晓 张仲利 李网章 刘乾辰 于 2020-05-09 设计创作，主要内容包括：本发明公开了石油化工技术领域炼厂干气制乙苯组合工艺,采用干气制乙苯+尾气回收+裂解组合工艺,利用干气中的乙烯和乙烷生产乙苯,并充分回收氢气,采用本发明一种炼厂干气制乙苯的组合工艺的优点是：流程合理,最大程度回收干气中有效成分；采用组合工艺,充分发挥各单元优势；能量消耗低,投资低,装置效益好。(The invention discloses a combined process for preparing ethylbenzene from refinery dry gas in the technical field of petrochemical industry, which adopts a combined process of preparing ethylbenzene from dry gas, recovering tail gas and cracking, utilizes ethylene and ethane in the dry gas to produce ethylbenzene, and fully recovers hydrogen, and the combined process for preparing ethylbenzene from refinery dry gas has the advantages that: the process is reasonable, and the effective components in the dry gas are recovered to the maximum extent; the advantages of each unit are fully exerted by adopting a combined process; low energy consumption, low investment and good device benefit.)

1. A combined process for preparing ethylbenzene from refinery dry gas adopts a combined process of preparing ethylbenzene from dry gas, recovering tail gas and cracking, utilizes ethylene and ethane in the dry gas to produce ethylbenzene, and fully recovers hydrogen, and is characterized by comprising the following steps of:

1) the ethylene-containing refinery dry gas and benzene are used for generating an ethylbenzene product in an ethylbenzene preparation unit by the dry gas, the byproduct alkylation reaction tail gas is sent to a tail gas recovery unit, and the byproduct noncondensable gas is sent to a cracking unit;

2) the alkylation reaction tail gas in the step 1) is separated into hydrogen, carbon-rich secondary gas and fuel gas in a tail gas recovery unit, and the carbon-rich secondary gas is sent to a cracking unit;

3) the non-condensable gas from the dry gas ethylbenzene preparation unit in the step 1) and the carbon-rich secondary gas from the tail gas recovery unit in the step 2) are generated into cracked dry gas in a cracking unit, and the cracked dry gas is sent back to the part for preparing ethylbenzene from dry gas.

2. The combined process for preparing ethylbenzene from refinery dry gas as claimed in claim 1, wherein the refinery dry gas (containing ethylene dry gas) is a processing tail gas generated by refinery equipment, and mainly comprises hydrogen, nitrogen, methane, ethane, ethylene, a small amount of carbon dioxide, hydrogen sulfide, a recombinant gas with a carbon number of above C3, specifically one or more of catalytic cracking dry gas, catalytic cracking dry gas and L TAG dry gas, and can also be a gas containing hydrogen and ethylene ethane components generated by other production equipment of a refinery.

3. The integrated process for ethylbenzene production from refinery dry gas as claimed in claim 1, wherein: the unit for preparing ethylbenzene by using dry gas is provided with a raw material pretreatment part and mainly comprises dry gas washing, depropylene removing, drying and hydrogenation facilities.

4. The integrated process of ethylbenzene production from refinery dry gas as claimed in claim 3, wherein: the propylene removing facility adopts an absorption desorption method, and the absorbent adopts the material produced by the device and consists of one or more than one of benzene, ethylbenzene, propyl benzene, diethylbenzene and triethyl benzene.

5. The integrated process of ethylbenzene production from refinery dry gas as claimed in claim 3, wherein: washing ethylene-containing dry gas with water, performing depropylene treatment with the cracked dry gas from a cracking part, drying, introducing into a hydrogenation reactor, removing acetylene, propyne and propadiene in the dry gas to below 5ppm, and introducing into an alkylation reaction part; and the tail gas of the alkylation reaction is removed to a tail gas recovery unit, and the non-condensable gas is sent to a cracking unit.

6. The integrated process for ethylbenzene production from refinery dry gas as claimed in claim 1, wherein: the tail gas recovery unit comprises tail gas compression, a membrane separation component and pressure swing adsorption.

7. The integrated process of ethylbenzene production from refinery dry gas as claimed in claim 6, wherein: the alkylation reaction tail gas enters a membrane separation component after being compressed, most of hydrogen and partial methane are taken as permeation gas and come out of the membrane separation component, then the permeation gas enters pressure swing adsorption to recover and purify the hydrogen, 99.9% mol hydrogen products are produced, and the ethane-rich carbon-enriched second gas is sent to a cracking part.

8. The integrated process for ethylbenzene production from refinery dry gas as claimed in claim 1, wherein: the cracking dry gas of the cracking reaction product of the cracking unit enters an absorption tower after heat is recovered by a heat exchanger to remove heavy components in the cracking gas, and the absorbent adopts the material of the dry gas-to-ethylbenzene unit and consists of one or more of benzene, ethylbenzene, propylbenzene, diethylbenzene, triethylbenzene, butylbenzene, methyl ethylbenzene and high-boiling-point substances.

9. The integrated process for ethylbenzene production from refinery dry gas as claimed in claim 1, wherein: the ethylene content in the ethylene-containing dry gas is 3-99% mol.

10. The integrated process for ethylbenzene production from refinery dry gas as claimed in claim 1, wherein: the pressure of the cracking dry gas after compression and pressure boosting in the cracking part is 0.5-2.0 MPaG.

Technical Field

The invention belongs to the technical field of petrochemical industry, and particularly relates to a process for preparing ethylbenzene from refinery dry gas.

Background

The refinery dry gas comprises catalytic dry gas, coking dry gas, reforming dry gas,Aromatized gas, disproportionated dry gas, PSA tail gas, etc., the main components of these gases including H₂、CH₄、C₂H₆、C₂H₄、C₃～C₅And inert gas components such as nitrogen, which refineries typically use as fuel gas. With the increase in size of the apparatus, how to effectively utilize the refinery dry gas is becoming more urgent. The further utilization of the dry gas in the prior art mainly surrounds the utilization of olefin in the dry gas, and the alkane in the dry gas is not further processed, so that the resource waste is caused.

Chinese patent CN 1273575a discloses a combined process for the production of ethylene, ethylbenzene and styrene, involving an ethylene production plant in which the gaseous and fluid products in the cracking zone are fractionated in a demethanizer zone to form a dilute ethylene feed containing about 5 to 40% of the ethylene in the feed, which is sent to an ethylbenzene plant and reacted with impure benzene. The product ethylbenzene is typically converted to styrene. Chinese patent CN1630700A discloses a process for producing a dilute ethylene stream and a dilute propylene stream, which can be used as a feedstock for the production of olefin-based derivatives.

The above scheme does not effectively utilize hydrogen in the dilute ethylene stream, and has no control means for impurities in the dilute ethylene stream, such as acid gas, alkyne, dialkene, methanol and the like, so that the equipment investment is high, and reaction byproducts are more.

Chinese patent CN 108424345 a discloses an ethylbenzene production device and process, the device comprises a cracking unit, a quenching unit, a compression unit, a cold separation unit, an ethylbenzene synthesis unit and a tail gas recovery unit which are connected in sequence. The cracking unit, the quenching unit, the compression unit and the cold separation unit are used for converting cracking raw materials to obtain dilute ethylene material flow; the compression unit comprises a primary booster compressor, an alkaline washing tower, a dryer and a secondary booster compressor which are sequentially connected; the cold separation unit comprises a deethanizer, a catalytic hydrogenation reactor and a condenser which are connected in sequence, and the cold energy of the condenser is provided by a propylene refrigeration system. The tail gas recovery unit comprises a first-stage pressure swing adsorption system, a second-stage pressure swing adsorption system and an ethane supercharger which are sequentially connected, and is used for separating reaction tail gas generated by the ethylbenzene synthesis unit into by-product hydrogen, tail gas recovery methane and tail gas recovery ethane, and sending the tail gas recovery ethane back to the cracking unit. Compared with the device for producing polymer-grade ethylene, the process device can effectively reduce investment and energy consumption, but the process flow is complex and the device investment is still higher because the process needs to be provided with a propylene refrigeration system and other processes due to the requirement of the adopted cold separation unit.

Disclosure of Invention

The invention aims to provide a combined process for preparing ethylbenzene from refinery dry gas, which is characterized in that gas rich in ethylene and ethane in refinery gas is subjected to a series of process processing processes, and effective components such as hydrogen, ethane, ethylene and the like in the gas are fully utilized, so that the problems of low raw material utilization degree, complex process, high device investment and energy consumption and the like in the existing process are solved.

In order to solve the technical problems, the invention adopts the technical scheme that:

a combined process for preparing ethylbenzene from refinery dry gas adopts a combined process of preparing ethylbenzene from dry gas, recovering tail gas and cracking, utilizes ethylene and ethane in the dry gas to produce ethylbenzene, and fully recovers hydrogen, and is characterized by comprising the following steps of:

1) the method comprises the steps that ethylene-containing refinery dry gas and benzene are used for generating an ethylbenzene product in an ethylbenzene preparation unit by the dry gas, the byproduct alkylation reaction tail gas is sent to a tail gas recovery unit, and the byproduct noncondensable gas is sent to a cracking unit;

2) the alkylation reaction tail gas in the step 1) is separated into hydrogen, carbon-rich secondary gas and fuel gas in a tail gas recovery unit, and the carbon-rich secondary gas is sent to a cracking unit;

3) the non-condensable gas from the dry gas ethylbenzene preparation unit in the step 1) and the carbon-rich secondary gas from the tail gas recovery unit in the step 2) are generated into cracked dry gas in a cracking unit, and the cracked dry gas is sent back to the part for preparing ethylbenzene from dry gas.

The invention relates to a combined process for preparing ethylbenzene from refinery dry gas, which is further characterized in that the refinery dry gas (containing ethylene dry gas) is processing tail gas generated by a refinery device, and mainly comprises hydrogen, nitrogen, methane, ethane, ethylene, a small amount of carbon dioxide, hydrogen sulfide, recombination of more than C3 and the like, specifically one or more of catalytic cracking dry gas, catalytic cracking dry gas and L TAG dry gas, and can also be gas containing hydrogen and ethylene ethane components generated by other production devices of a refinery.

The invention relates to a combined process for preparing ethylbenzene from refinery dry gas, which is further characterized by comprising the following steps of: the unit for preparing ethylbenzene by using dry gas is provided with a raw material pretreatment part and mainly comprises dry gas washing, depropylene removing, drying and hydrogenation facilities. The propylene removing facility adopts an absorption desorption method, and the absorbent adopts the materials produced by the device, such as one or more of benzene, ethylbenzene, propyl benzene, diethyl benzene and triethyl benzene. The refinery dry gas is washed by water and is subjected to depropenization treatment together with the cracked dry gas from the cracking part, then the refinery dry gas is dried and enters a hydrogenation reactor, acetylene, propine and propadiene in the gas are removed to be below 5ppm, and then the refinery dry gas enters an alkylation reaction part. And the tail gas of the alkylation reaction is removed to a tail gas recovery unit, and the non-condensable gas is sent to a cracking unit.

The invention relates to a combined process for preparing ethylbenzene from refinery dry gas, which is further characterized by comprising the following steps of: the tail gas recovery unit comprises tail gas compression, a membrane separation component and pressure swing adsorption. The alkylation reaction tail gas enters a membrane separation assembly after being compressed, and the membrane separation assembly can adopt a first-stage membrane, a two-stage membrane or a multi-stage membrane. Most of hydrogen, partial methane and a small amount of other components are taken as permeation gas and are discharged from the membrane separation component, then the permeation gas enters pressure swing adsorption to recover and purify hydrogen, 99.9% mol of hydrogen products are produced, and simultaneously the byproduct methane gas can be used as fuel gas. Obtaining carbon-rich second gas rich in ethane and sending the carbon-rich second gas to the cracking unit.

The invention relates to a combined process for preparing ethylbenzene from refinery dry gas, which is further characterized by comprising the following steps of: the cracking unit comprises an ethane cracking furnace, a cracked gas heat recovery part, an absorption part, an alkali washing part and a compression part. The non-condensable gas from the unit for preparing ethylbenzene from dry gas and the ethane-rich gas from the tail gas recovery unit enter the cracking unit, the cracked dry gas as a reaction product enters an absorption tower to remove heavy components in the cracked gas after heat recovery by a heat exchanger, and an absorbent adopts the material of the unit for preparing ethylbenzene from dry gas and consists of one or more of benzene, ethylbenzene, propylbenzene, diethylbenzene, triethylbenzene, butylbenzene, methyl ethylbenzene and high-boiling residues. And cooling the materials at the top of the absorption tower, then removing hydrogen sulfide in the cracked dry gas by alkali washing, sending the materials to a cracked dry gas compression part, compressing, cooling and separating liquid, and returning the cracked dry gas to a dry gas ethylbenzene preparation unit.

The invention relates to a combined process for preparing ethylbenzene from refinery dry gas, which is further characterized by comprising the following steps of: the ethylene content in the ethylene-containing refinery dry gas is 3-99% mol; preferably 10 to 90% mol.

The invention relates to a combined process for preparing ethylbenzene from refinery dry gas, which is further characterized by comprising the following steps of: the pressure of the cracking dry gas after compression and pressure boosting in the cracking part is 0.5-2.0 MPaG, and preferably 0.8-1.6 MPaG.

The invention relates to a combined process for preparing ethylbenzene from refinery dry gas, which is further characterized by comprising the following steps of: the hydrogen content in the product hydrogen of the tail gas recovery unit is not less than 99.9% mol.

The combined process for preparing ethylbenzene by refinery dry gas has the following beneficial effects:

ethylene, ethane and hydrogen in the refinery dry gas are fully utilized, and effective components in the dry gas are recovered to the maximum extent;

the method for producing ethylbenzene by cracking ethane in refinery dry gas into ethylene and then utilizing the dry gas to produce ethylbenzene has higher yield than the method for directly processing the refinery dry gas by independently adopting the dry gas to produce ethylbenzene, and can improve the scale of an ethylbenzene device under the condition of the same refinery dry gas yield.

The alkylation tail gas treatment of the tail gas recovery part adopts a membrane separation component to separate most of hydrogen and part of methane, and ethane-rich gas can be directly sent to a cracking unit, so that the process flow is simple, and the investment and energy consumption are reduced;

the cracked dry gas of the self-cracking part is compressed and then sent to a dry gas ethylbenzene preparation unit for propylene removal treatment, and due to the adoption of an absorption desorption method, the operation temperature is above 0 ℃, a propylene refrigeration system is not required, the grade of equipment materials is low, the pressure of the compressed cracked dry gas is low, the process is simple, and the investment is relatively low.

In conclusion, the combined process for preparing ethylbenzene from refinery dry gas has the advantages that:

1. the process is reasonable, and the effective components in the dry gas are recovered to the maximum extent;

2. the advantages of each unit are fully exerted by adopting a combined process;

3. the device has high ethylbenzene yield, low energy consumption, low investment and good device benefit.

The present invention will be described in further detail with reference to the following drawings and detailed description, but the present invention is not limited to the scope of the present invention.

Drawings

FIG. 1 is a schematic flow diagram of a combined heat exchange reactor of the present invention.

Wherein the reference symbols shown are: 1-preparing ethylbenzene from dry gas, 2-recovering tail gas, 3-cracking, 4-refinery dry gas, 5-benzene, 6-ethylbenzene, 7-alkylated tail gas, 8-noncondensable gas, 9-hydrogen, 10-fuel gas, 11-ethane-rich gas and 12-cracking dry gas.

Detailed Description

The invention patent is further described below with reference to the accompanying drawings.

As shown in figure 1, a specific embodiment of the invention is that a refinery dry gas 4 and a cracking dry gas 12 from a cracking unit 3 are subjected to depropylene treatment, then are dried and hydrogenated, and then react with benzene 5 to produce ethylbenzene 6, meanwhile, alkylation tail gas 7 and noncondensable gas 8 are byproducts, the alkylation tail gas 7 is sent to a tail gas recovery unit 2, is compressed, then enters a membrane separation component, methane and hydrogen are taken as permeation gases, come out from the membrane separation component, enter a pressure swing adsorption part, are purified and recovered, hydrogen 9 and fuel gas 10 are obtained, and an obtained ethane-rich gas 11 is sent to the cracking unit 3. The non-condensable gas 8 from the unit 1 for preparing ethylbenzene from dry gas also enters the cracking unit 3, and after the cracking unit 3 is subjected to cracking reaction and heat recovery, the non-condensable gas is sent to the unit 1 for preparing ethylbenzene from dry gas after compression treatment.

The method comprises the steps of firstly, introducing dry refinery gas which contains ethylene, processing tail gas generated by a refinery device, wherein the main components comprise hydrogen, nitrogen, methane, ethane, ethylene, a small amount of carbon dioxide, C3 and the like, the dry refinery gas can be one or more of catalytic cracking dry gas, catalytic cracking dry gas and L TAG dry gas, or gas containing hydrogen, ethylene and ethane components generated by other production devices of a refinery, taking the catalytic dry gas as an example, the temperature is 40 ℃, the pressure is 1.0MPaG, the volume content of the main components is 24.6% of hydrogen, 32.1% of methane, 13.5% of ethane, 13.6% of ethylene, 0.5% of propane, 1.6% of propylene, 0.5% of carbon, 0.3% of carbon five and components heavier than carbon, 9.15% of nitrogen, introducing the dry gas into a dry gas preparation ethylbenzene unit and cracking gas from a cracking unit through a raw material pre-alkali treatment, the impurities in the dry gas preparation ethylbenzene unit and the cracking gas from the cracking unit are subjected to raw material of propylene, acetylene, fuel gas, propylene, water and a small amount of alkaline matter, a small amount of a product, a partial dry product is reduced by-ethane-enriched dry ethane cracking gas, a partial dry ethane-enriched dry ethane cracking reaction product obtained by-gas-absorbing dry ethane cracking reaction product obtained by-absorbing dry-gas-absorbing dry-cracking reaction-gas-absorbing dry-cracking reaction-gas-cracking reaction-absorbing dry-gas-absorbing dry-cracking reaction-absorbing dry-gas-absorbing dry-gas-absorbing dry-gas-absorbing dry-gas-absorbing dry-gas-absorbing dry-gas-absorbing dry-gas-absorbing dry-gas-absorbing dry-gas-absorbing dry-.

The technical solution of the present invention is described in detail with reference to the attached drawings, which are only drawn for illustrating the basic contents of the invention, and it does not limit the contents and usage forms of the invention, and in fact, some pipes need to be provided with conventional equipments or pipe elements such as pumps, heat exchangers, etc. according to the specific operation conditions.