CN111795543A - Equipment and method for recovering propane, propylene and ethylene from chemical tail gas - Google Patents

Equipment and method for recovering propane, propylene and ethylene from chemical tail gas Download PDF

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Publication number
CN111795543A
CN111795543A CN202010847202.5A CN202010847202A CN111795543A CN 111795543 A CN111795543 A CN 111795543A CN 202010847202 A CN202010847202 A CN 202010847202A CN 111795543 A CN111795543 A CN 111795543A
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China
Prior art keywords
pipeline
gas
heat exchanger
tail gas
cooling
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Pending
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CN202010847202.5A
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Chinese (zh)
Inventor
张武
郝凯钟
赵杰
史红兵
陈亮亮
任剑峰
刘利伟
赵南
保雄飞
田园
马鹏
何彦涛
李宗荣
李伟
李国太
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Zhongke Ruiao Energy Technology Co ltd
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Zhongke Ruiao Energy Technology Co ltd
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Priority to CN202010847202.5A priority Critical patent/CN111795543A/en
Publication of CN111795543A publication Critical patent/CN111795543A/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
    • F25J3/0219—Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0233—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 1 carbon atom or more
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0238—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 2 carbon atoms or more
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0242—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 3 carbon atoms or more
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0252—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of hydrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/74—Refluxing the column with at least a part of the partially condensed overhead gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2210/00—Processes characterised by the type or other details of the feed stream
    • F25J2210/12—Refinery or petrochemical off-gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2215/00—Processes characterised by the type or other details of the product stream
    • F25J2215/64—Propane or propylene
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/04—Internal refrigeration with work-producing gas expansion loop
    • F25J2270/06—Internal refrigeration with work-producing gas expansion loop with multiple gas expansion loops

Abstract

The invention relates to equipment and a method for recovering propane, propylene and ethylene from chemical engineering tail gas, wherein the equipment comprises the following components: a primary heat exchanger; the rectifying tower is connected with the main heat exchanger through a pipeline; the product separator is connected with the tower bottom outlet of the rectifying tower through a pipeline; the tower top condenser is connected with the rectifying tower through a pipeline; the cooling tower top separator, the noncondensable gas export of cooling tower top separator and first tube coupling, cooling tower top separator passes through the pipeline and is connected with the rectifying column. The method for recovering propane, propylene and ethylene from chemical engineering tail gas comprises the following steps: cooling chemical tail gas; rectifying the cooled chemical tail gas; separating the liquid phase; cooling the gas phase; for separating the cooled gas phase. The technical scheme of the invention has low energy consumption, saves energy, protects environment, can change waste into valuable, and greatly improves the added value of products.

Description

Equipment and method for recovering propane, propylene and ethylene from chemical tail gas
Technical Field
The invention relates to the field of chemical industry, in particular to equipment and a method for recovering propane, propylene and ethylene from chemical tail gas.
Background
Ethylene, propylene and propane are important chemical raw materials.
Ethylene, propylene and propane products are valuable resources in refining and chemical enterprises and are the most basic chemical raw materials. In the production process of preparing olefin from methanol, a part of products such as ethylene, propylene, propane and the like are taken away along with methane tail gas in an olefin separation unit and are used as torch gas or fuel gas, so that resource waste is caused. However, if the products such as ethylene, propylene, propane and the like in the methane tail gas are extracted for independent use, the added value of the products is greatly improved. Wherein the value of the fuel gas is about 1000 yuan/ton, and the value of the products of ethylene, propylene and propane is about 3500 yuan/ton, and huge waste is caused by directly burning the products of ethylene, propylene and propane in the fuel gas.
Disclosure of Invention
The invention aims to solve the technical problem of providing equipment and a method for recovering propane, propylene and ethylene from chemical tail gas, wherein the equipment and the method can fully extract components in the tail gas of a methane tower and prepare a hydrocarbon mixture product.
The equipment for recovering propane, propylene and ethylene from chemical engineering tail gas comprises:
the main heat exchanger is used for cooling chemical tail gas;
the rectifying tower is used for rectifying the cooled chemical tail gas to obtain a gas phase and a liquid phase and is connected with the main heat exchanger through a pipeline;
the product separator is used for separating the liquid phase to obtain a C2+ product and fuel gas and is connected with the bottom outlet of the rectifying tower through a pipeline;
the tower top condenser is used for cooling the gas phase and is connected with the rectifying tower through a pipeline;
the cooling tower top separator is used for separating the cooled gas phase to obtain non-condensable gas, a non-condensable gas outlet of the cooling tower top separator is connected with a first pipeline, and the cooling tower top separator is connected with the rectifying tower through a pipeline;
the first pipeline is connected with an inlet of a first-stage expander after sequentially passing through the tower top condenser and the main heat exchanger, so that the non-condensable gas in the first pipeline is subjected to expansion, temperature and pressure reduction treatment by the first-stage expander after being reheated by the tower top condenser and the main heat exchanger, an outlet of the first-stage expander is connected with a second pipeline, the second pipeline is connected with an inlet of a second-stage expander after passing through the main heat exchanger, so that the non-condensable gas in the second pipeline is subjected to expansion, temperature and pressure reduction treatment by the second-stage expander after being cooled by the main heat exchanger, an outlet of the second-stage expander is connected with a third pipeline, and the third pipeline sequentially passes through the tower top condenser and the main heat exchanger, so that the non-condensable gas in the third pipeline provides cold for the tower top.
The equipment for recovering propane, propylene and ethylene from the chemical engineering tail gas comprises a product separator, a rectifying tower, a low-temperature hydrocarbon mixing pump, a high-temperature hydrocarbon mixing pump and a high-temperature hydrocarbon mixing pump.
According to the equipment for recovering propane, propylene and ethylene from the chemical engineering tail gas, the fourth pipeline passes through the main heat exchanger and then is connected with the product separator, so that the liquid phase in the fourth pipeline provides cold energy for the main heat exchanger.
The method for recovering propane, propylene and ethylene from chemical engineering tail gas comprises the following steps:
cooling chemical tail gas;
rectifying the cooled chemical tail gas to obtain a gas phase and a liquid phase;
separating the liquid phase to obtain a C2+ product and a fuel gas;
cooling the gas phase;
used for separating the cooled gas phase to obtain the non-condensable gas.
The invention discloses a method for recovering propane, propylene and ethylene from chemical engineering tail gas, which further comprises the following steps:
the non-condensable gas is expanded, cooled and depressurized after being reheated;
and cooling the non-condensable gas again, and then expanding, cooling and depressurizing to provide cooling capacity for the main heat exchanger.
The technical scheme of the invention has stable and reliable flow, low energy consumption, energy conservation and environmental protection, can change waste into valuable, and greatly improves the added value of products. The technical scheme of the invention can fully extract the components in the tail gas of the methane tower to prepare the hydrocarbon mixture product, thereby improving the economic benefit, improving the utilization efficiency of the methane tail gas and greatly improving the additional value of the methane tail gas.
Drawings
Fig. 1 is a schematic structural diagram of a device for recovering propane, propylene and ethylene from chemical tail gas.
Detailed Description
As shown in fig. 1, the apparatus for recovering propane, propylene and ethylene from chemical off-gas of the present invention comprises:
a main heat exchanger E102 for cooling chemical tail gas;
the rectifying tower T101 is used for rectifying the cooled chemical tail gas to obtain a gas phase and a liquid phase and is connected with the main heat exchanger through a pipeline;
a product separator V101 for separating the liquid phase to obtain a C2+ product and a fuel gas, which is connected with the bottom outlet of the rectifying tower through a pipeline;
the tower top condenser E103 is used for cooling the gas phase and is connected with the rectifying tower through a pipeline;
a cooling tower top separator V102 for separating the cooled gas phase to obtain non-condensable gas, wherein a non-condensable gas outlet of the cooling tower top separator is connected with the first pipeline 10, and the cooling tower top separator is connected with the rectifying tower through a pipeline;
the first pipeline 10 is connected with an inlet of a first-stage expander C101 after sequentially passing through a tower top condenser and a main heat exchanger, so that the noncondensable gas in the first pipeline is subjected to expansion, temperature reduction and pressure reduction treatment by the first-stage expander after the tower top condenser and the main heat exchanger are rewarming, an outlet of the first-stage expander is connected with a second pipeline 20, the second pipeline is connected with an inlet of a second-stage expander C102 after passing through the main heat exchanger, so that the noncondensable gas in the second pipeline is subjected to expansion, temperature reduction and pressure reduction treatment by the second-stage expander after being cooled by the main heat exchanger, an outlet of the second-stage expander is connected with a third pipeline, and the third pipeline 30 sequentially passes through the tower top condenser and the main heat exchanger, so that the noncondensable gas in the third pipeline provides cold for the.
According to the equipment for recovering propane, propylene and ethylene from the chemical engineering tail gas, the product separator is connected with the outlet of the bottom of the rectifying tower through the fourth pipeline, and the fourth pipeline 40 is provided with the low-temperature hydrocarbon mixing pump P101.
According to the equipment for recovering propane, propylene and ethylene from the chemical engineering tail gas, the fourth pipeline passes through the main heat exchanger and then is connected with the product separator, so that the liquid phase in the fourth pipeline provides cold energy for the main heat exchanger.
The method for recovering propane, propylene and ethylene from chemical engineering tail gas comprises the following steps:
cooling chemical tail gas;
rectifying the cooled chemical tail gas to obtain a gas phase and a liquid phase;
separating the liquid phase to obtain a C2+ product and a fuel gas;
cooling the gas phase;
used for separating the cooled gas phase to obtain the non-condensable gas.
The invention discloses a method for recovering propane, propylene and ethylene from chemical engineering tail gas, which further comprises the following steps:
the non-condensable gas is expanded, cooled and depressurized after being reheated;
and cooling the non-condensable gas again, and then expanding, cooling and depressurizing to provide cooling capacity for the main heat exchanger.
The invention discloses equipment and a method for recovering propane, propylene and ethylene from chemical tail gas, and relates to a process method for recovering effective components of propane, propylene, ethylene and the like from tail gas at the top of a methanol-to-olefin demethanizer. The method is characterized in that: a demethanizer of an olefin separation unit of an MTO device recovers C2 and above components in raw material gas by adopting a low-temperature propane or propylene washing mode, and tail gas obtained by washing and dissolving propane in the demethanizer contains a large amount of methane, hydrogen, nitrogen, carbon monoxide, ethylene, propane, propylene, C4 and the like. The tail gas at the top of the methane tower is firstly cooled to a certain temperature by a heat exchanger, the cooled feed gas is separated by a low-temperature rectifying tower, and qualified C2+ products are produced at the bottom of the tower and are sent out of a battery compartment after being pressurized and reheated by a low-temperature hydrocarbon mixing pump. The noncondensable gas (fuel gas) produced from the top of the tower is reheated to a certain temperature by a heat exchanger, enters a first-stage expansion machine to be expanded to a certain pressure, enters the heat exchanger again to exchange heat to a certain temperature, enters a second-stage expansion machine to be expanded to a certain pressure and temperature to provide cold energy of the lowest temperature region for the top of the rectifying tower. And the tail gas after being reheated at the top of the rectifying tower is reheated again by the main heat exchanger and is sent to a fuel gas pipe network.
The process utilizes the tail gas at the top of the demethanizer, extracts C2+ products from the tail gas of the demethanizer by means of expansion refrigeration and cryogenic rectification separation of an expansion machine, and the residual gas is used as fuel gas and sent to a fuel gas pipe network.
The tail gas after propane washing and dissolving in the demethanizer contains a large amount of methane, hydrogen, nitrogen, carbon monoxide, ethylene, propane, propylene, C4, etc. The tail gas at the top of the methane tower is firstly cooled to a certain temperature by a heat exchanger, the cooled feed gas is separated by a low-temperature rectifying tower, and qualified C2+ products are produced at the bottom of the tower and are sent out of a battery compartment after being pressurized and reheated by a low-temperature hydrocarbon mixing pump. The noncondensable gas (fuel gas) produced from the top of the tower is reheated to a certain temperature by a heat exchanger, enters a first-stage expansion machine to be expanded to a certain pressure, enters a heat exchanger again to exchange heat to a certain temperature, then enters a second-stage expansion machine to be expanded to a certain pressure and temperature to provide cold energy for the top of the rectifying tower. And the tail gas after being reheated at the top of the rectifying tower is reheated again by the main heat exchanger and is sent to a fuel gas pipe network.
The main heat exchanger can be plate-fin type, wound tube type or plate type.
The tail gas at the top of the methane tower is firstly cooled to a certain temperature by a heat exchanger, and the cooled feed gas is separated by a low-temperature rectifying tower, wherein the cooling temperature range is generally from-30 ℃ to-120 ℃.
Qualified C2+ products are produced from the bottom of the tower, and C2+ generally comprises ethylene, propylene, propane, isobutane, n-butane and the like.
The non-condensable gas (fuel gas) produced from the tower top is firstly passed through a heat exchanger and reheated to a certain temperature, and the reheating range is generally between-130 deg.C and-50 deg.C.
The non-condensable gas enters a primary expansion machine to be expanded to a certain pressure, and the pressure range after expansion is generally between 1.8MPa and 1.2 MPa.
The expander is of a turbine type, and an oil bearing expander and a gas bearing expander can be generally selected.
The non-condensable gas enters the heat exchanger again to exchange heat to a certain temperature, then enters the secondary expansion machine to be expanded to a certain pressure and temperature, and the temperature range of the non-condensable gas entering the secondary expansion machine is generally between 60 ℃ below zero and 120 ℃ below zero. The pressure range after secondary expansion is generally between 1.6MPa and 0.1 MPa.
The non-condensable gas provides cold energy of the lowest temperature region for the top of the rectifying tower, and the temperature of the top of the rectifying tower is generally between-120 ℃ and-145 ℃.
The recovery rate of the C2+ hydrocarbon mixture can reach between 92% and 98%.
And C2+ products are pressurized and reheated by a low-temperature hydrocarbon mixing pump and then are sent out of a battery limit area, and the products are directly sent to an olefin separation device for separation after being reheated.
The C2+ product passes through a low-temperature hydrocarbon mixing pump which can be a shield pump, a low-temperature immersed pump, a centrifugal pump and a reciprocating pump.
The technical scheme of the invention has stable and reliable flow and low energy consumption, and plays a role in saving energy, protecting environment, changing waste into valuable and greatly improving the added value of products.
The tail gas of the demethanizer passes through a reboiler E101 and a main heat exchanger, is cooled to minus 30 ℃ to minus 130 ℃, enters a low-temperature rectifying tower, liquid-phase products are extracted from the top of the tower, are subjected to pressure boosting through a low-temperature hydrocarbon mixing pump, are re-heated through the main heat exchanger and are sent out of a battery limit.
The gas phase at the top of the tower can be condensed by a condenser at the top of the tower, then the liquid phase flows back to the tower, the gas phase enters a first-stage expansion machine through a cooler for reheating to-120 ℃ to-60 ℃ through a main heat exchanger, the expanded tail gas enters a second-stage expansion machine for heat exchange after heat exchange and reheating, the expanded tail gas and the tail gas at the top of the low-temperature rectification tower exchange heat, and finally the tail gas is reheated by the main heat exchanger and sent out of a boundary area. The cooling capacity of the whole system is provided by the expansion machine.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be construed as the protection scope of the present invention.

Claims (5)

1. The utility model provides an equipment of propane, propylene, ethylene are retrieved to chemical industry tail gas which characterized in that includes:
the main heat exchanger is used for cooling chemical tail gas;
the rectifying tower is used for rectifying the cooled chemical tail gas to obtain a gas phase and a liquid phase and is connected with the main heat exchanger through a pipeline;
the product separator is used for separating the liquid phase to obtain a C2+ product and fuel gas and is connected with the bottom outlet of the rectifying tower through a pipeline;
the tower top condenser is used for cooling the gas phase and is connected with the rectifying tower through a pipeline;
the cooling tower top separator is used for separating the cooled gas phase to obtain non-condensable gas, a non-condensable gas outlet of the cooling tower top separator is connected with a first pipeline, and the cooling tower top separator is connected with the rectifying tower through a pipeline;
the first pipeline is connected with an inlet of a first-stage expander after sequentially passing through the tower top condenser and the main heat exchanger, so that the non-condensable gas in the first pipeline is subjected to expansion, temperature and pressure reduction treatment by the first-stage expander after being reheated by the tower top condenser and the main heat exchanger, an outlet of the first-stage expander is connected with a second pipeline, the second pipeline is connected with an inlet of a second-stage expander after passing through the main heat exchanger, so that the non-condensable gas in the second pipeline is subjected to expansion, temperature and pressure reduction treatment by the second-stage expander after being cooled by the main heat exchanger, an outlet of the second-stage expander is connected with a third pipeline, and the third pipeline sequentially passes through the tower top condenser and the main heat exchanger, so that the non-condensable gas in the third pipeline provides cold for the tower top.
2. The equipment for recovering propane, propylene and ethylene from the chemical engineering tail gas as claimed in claim 1, wherein the product separator is connected with the outlet at the bottom of the rectifying tower through a fourth pipeline, and a cryogenic hydrocarbon mixing pump is arranged on the fourth pipeline.
3. The equipment for recovering propane, propylene and ethylene from the chemical engineering tail gas according to claim 2, wherein the fourth pipeline passes through the main heat exchanger and then is connected with the product separator, so that the liquid phase in the fourth pipeline provides cold energy for the main heat exchanger.
4. A method for recovering propane, propylene and ethylene from chemical engineering tail gas is characterized by comprising the following steps:
cooling chemical tail gas;
rectifying the cooled chemical tail gas to obtain a gas phase and a liquid phase;
separating the liquid phase to obtain a C2+ product and a fuel gas;
cooling the gas phase;
used for separating the cooled gas phase to obtain the non-condensable gas.
5. The method for recovering propane, propylene and ethylene from chemical engineering tail gas according to claim 4, further comprising the following steps:
the non-condensable gas is expanded, cooled and depressurized after being reheated;
and cooling the non-condensable gas again, and then expanding, cooling and depressurizing to provide cooling capacity for the main heat exchanger.
CN202010847202.5A 2020-08-21 2020-08-21 Equipment and method for recovering propane, propylene and ethylene from chemical tail gas Pending CN111795543A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010847202.5A CN111795543A (en) 2020-08-21 2020-08-21 Equipment and method for recovering propane, propylene and ethylene from chemical tail gas

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010847202.5A CN111795543A (en) 2020-08-21 2020-08-21 Equipment and method for recovering propane, propylene and ethylene from chemical tail gas

Publications (1)

Publication Number Publication Date
CN111795543A true CN111795543A (en) 2020-10-20

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