WO2023131052A1

WO2023131052A1 - Tail gas recovery system

Info

Publication number: WO2023131052A1
Application number: PCT/CN2022/143556
Authority: WO
Inventors: 段滨; 赵领航; 姚宏; 杜路路; 黄志鹏
Original assignee: 隆基绿能科技股份有限公司
Priority date: 2022-01-05
Filing date: 2022-12-29
Publication date: 2023-07-13
Also published as: CN217526934U

Abstract

The present application relates to the technical field of tail gas recovery, and provides a tail gas recovery system. The tail gas recovery system comprises a pressurization member for pressurizing the tail gas of a carbon hydrocarbon gas thermal cracking reaction, a long-chain carbon hydrocarbon removal member for removing long-chain carbon hydrocarbon in the tail gas, a conversion member for converting unsaturated carbon hydrocarbon in the tail gas into saturated carbon hydrocarbon, and a first liquefaction and recovery member for liquefying and recovering methane in the tail gas; the pressurization member, the long-chain carbon hydrocarbon removal member, the conversion member, and the first liquefaction and recovery member are sequentially connected; and the tail gas of the carbon hydrocarbon gas thermal cracking reaction sequentially passes through the pressurization member, the long-chain carbon hydrocarbon removal member, the conversion member, and the first liquefaction and recovery member. Tail gas recovery treatment is performed in a gas-liquid separation mode, and methane having a large proportion in the tail gas is liquefied and recovered; the tail gas recovery system is simple in structure and simple in recovery process, so that environmental pollution is reduced, methane can be applied to a subsequent carbon hydrocarbon gas thermal cracking reaction, and the production cost can be greatly reduced.

Description

A tail gas recovery system

This application claims the priority of the Chinese patent application with the application number 202220023472.9 and the invention title "A Tail Gas Recovery System" submitted to the China Patent Office on January 5, 2022, the entire contents of which are incorporated by reference in this application.

technical field

The present application relates to the technical field of tail gas recovery, in particular to a tail gas recovery system.

Background technique

Carbon-carbon composite materials have the advantages of low density, high strength, high specific modulus, high thermal conductivity, low expansion coefficient, good friction performance, good thermal shock resistance and high dimensional stability, and have broad application prospects in high temperature fields.

Carbon-carbon composites are usually prepared by thermal cracking of carbon-containing hydrocarbon gases. For example, in the process of producing monocrystalline silicon in the thermal field, pyrolytic carbon is obtained by pyrolysis of carbon hydrocarbon gas, and the pyrolytic carbon is deposited on the pre-woven prefabricated body for densification, and the carbon-carbon embryo body with the required density can be obtained .

In the process of thermal cracking of hydrocarbon gas, the reaction is usually not sufficient, and the exhausted tail gas also contains a large amount of raw material gas. The related technologies are to burn or directly empty the tail gas, which will not only pollute the environment, but also waste resources. waste.

Contents of the invention

The application provides a tail gas recovery system, which aims to solve the problems of burning or directly emptying the tail gas from thermal cracking of hydrocarbon gas, polluting the environment and wasting resources.

The embodiment of the present application provides a tail gas recovery system, including: a pressurization unit for pressurizing the tail gas of the thermal cracking reaction of carbon hydrocarbon gases, a long-chain carbon hydrocarbon removal unit for removing long-chain carbon hydrocarbons in the tail gas, and removing the long-chain carbon hydrocarbons in the tail gas A conversion unit for converting unsaturated hydrocarbons into saturated hydrocarbons, and a first liquefaction recovery unit for liquefying and recovering methane in the tail gas;

The pressurization part, the long-chain hydrocarbon removal part, the conversion part, and the first liquefaction recovery part are connected in sequence, and the tail gas from the pyrolysis reaction of hydrocarbon gas passes through the pressurization part, the long-chain hydrocarbon gas The chain hydrocarbon removal part, the conversion part, and the first liquefaction recovery part.

In the embodiment of the present application, the pressure booster pressurizes the tail gas of the thermal cracking reaction of hydrocarbon gas, and through the pressurization, on the one hand, the volume of the compressed tail gas is smaller, which can reduce the volume of each component in the tail gas recovery system. The volume of the exhaust gas recovery system can be greatly reduced. On the other hand, the supercharging provides circulation force for the movement of each part of the exhaust gas in the exhaust gas recovery system, so that the exhaust gas can move smoothly in the exhaust gas recovery system. The long-chain hydrocarbon removal part removes long-chain hydrocarbons in the exhaust gas after pressurization. The boiling point of long-chain hydrocarbons is relatively high, which can prevent long-chain hydrocarbons from being converted into solid state in the exhaust gas recovery system and block the channels of the exhaust gas recovery system. wait. The boiling point of unsaturated hydrocarbons is relatively high, while the boiling point of saturated hydrocarbons is relatively low. Converting unsaturated hydrocarbons into saturated hydrocarbons can prevent unsaturated hydrocarbons from turning into solids in the exhaust gas recovery system and clogging the exhaust gas recovery system. channel etc. Gas-liquid separation is used for tail gas recovery and treatment, and the methane that accounts for a large proportion in the tail gas is liquefied and recovered. The structure of the tail gas recovery system is simple and the recovery process is simple, which not only reduces environmental pollution, but the above methane can be used in subsequent carbon In the thermal cracking reaction of hydrocarbon gas, the production cost can be greatly reduced.

Optionally, the first liquefaction recovery part includes: a cold box, and the cold box includes: a heat exchanger and a gas-liquid separation tank, the heat exchanger has a cold source material inlet port and a cold source material outlet port, and the tail gas flows from The outlet end of the cold source material enters the first path of the heat exchanger, the cold source material enters the second path of the heat exchanger from the inlet end of the cold source material, and the cold source material cools the tail gas to the boiling point of methane Next, liquid methane and hydrogen-rich gas are obtained, and the liquid methane and hydrogen-rich gas enter the gas-liquid separation tank;

The gas-liquid separation tank includes a gas-liquid separation chamber, and the gas-liquid separation chamber performs gas-liquid separation on liquid methane and hydrogen-rich gas to obtain liquid methane and hydrogen-rich gas; the gas-liquid separation chamber has a hydrogen-rich gas outlet end and liquid methane outlet end.

Optionally, the gas-liquid separation tank also includes a methane reheating chamber, the outlet of the liquid methane is connected to the methane reheating chamber, and the liquid methane flows into the methane reheating chamber from the liquid methane outlet, and the The methane reheating chamber also has a hot gas inlet port, a hot gas outlet port, and a hot gas movement pipe between the hot gas inlet port and the hot gas outlet port, and part of the tail gas treated by the conversion element enters from the hot gas inlet port. The hot gas movement pipeline reheats liquid methane into gaseous methane, and the part of tail gas is discharged from the methane reheating chamber through the hot gas outlet;

The part of tail gas discharged from the methane reheating chamber is connected to the outlet port of the heat exchanger for the cold source substance.

Optionally, the hydrogen-rich gas discharged from the gas-liquid separation chamber enters the heat exchanger from the inlet port of the cold source material as part of the cold source material;

And/or, the gaseous methane discharged from the methane reheating chamber, as a part of the heat sink material, enters the heat exchanger from the inlet port of the heat sink material.

Optionally, the flow rate of part of the tail gas entering the hot gas inlet port accounts for 10-40% of the flow rate of the tail gas treated by the conversion element.

Optionally, the long-chain hydrocarbon removal component includes: at least one first adsorption tower, and first adsorbents filled in each first adsorption tower, each first adsorption tower has a tail gas inlet port and a tail gas outlet port , the tail gas after the pressurization enters the first adsorption tower from the tail gas inlet port, and the first adsorbent in the first adsorption tower decomposes the long-chain carbon hydrocarbons in the tail gas after the pressurization and the oil gas volatilized by the pump oil 1. At least one of the small particles is adsorbed, and the tail gas after adsorption is discharged from the first adsorption tower from the outlet end of the tail gas;

The long-chain hydrocarbon removal part also includes an inert gas heating part, and the inert gas heating part is located at the tail gas outlet end of each of the first adsorption towers. Next, the tail gas inlet port of the first adsorption tower is temporarily fed into the tail gas, and the heated inert gas is introduced from the tail gas outlet port of the first adsorption tower to absorb the long-chain hydrocarbons, At least one of the oil gas and small particles volatilized by the pump oil is desorbed, and the heated inert gas will desorb at least one of the desorbed long-chain hydrocarbons, oil gas volatilized by the pump oil, and small particles from the tail gas inlet port Take out the first adsorption tower.

Optionally, when the number of the first adsorption towers is greater than 1, when at least one first adsorption tower is in the desorption working state, at least another first adsorption tower is in the adsorption working state; , the pressurized tail gas enters the first adsorption tower from the tail gas inlet port; in the desorption working state, the tail gas inlet port of the first adsorption tower stops feeding the tail gas.

Optionally, at least one first pressure sensor is provided at the tail gas inlet port of each of the first adsorption towers, and at least one second pressure sensor is provided at the tail gas outlet port of each of the first adsorption towers. When the difference between the average value of the pressure detected by each second pressure sensor of the adsorption tower and the average value of the pressure detected by each first pressure sensor of the first adsorption tower is greater than the preset pressure value, the first The tail gas inlet port of the adsorption tower is suspended from feeding the tail gas.

Optionally, the transition member includes: at least one hydrogenation reactor and a hydrogenation catalyst located in each hydrogenation reactor.

Optionally, it also includes: a filter element for filtering at least one of large particles, oil and gas volatilized by pump oil, and coal tar in the tail gas of the pyrolysis reaction of hydrocarbon gases before the pressurized element, The pressurization element is located between the long-chain hydrocarbon removal element and the filter element.

Optionally, it also includes: at least one second adsorption tower for recovering hydrogen from hydrogen-rich gas, and a second adsorbent filled in each of the second adsorption towers, each of the second adsorption towers is connected to the first A liquefaction recovery part; each of the second adsorption towers has a hydrogen-rich gas inlet port and a hydrogen gas outlet port;

In the case that the second adsorbent of a second adsorption tower is saturated, the hydrogen-rich gas inlet port of the second adsorption tower is suspended to feed the hydrogen-rich gas, and the hydrogen gas outlet port of the second adsorption tower is fed into a large Molecular gas desorption medium, the desorbed macromolecular gas is discharged from the second adsorption tower from the hydrogen-rich gas inlet port of the second adsorption tower.

Optionally, the tail gas recovery system further includes: a second liquefaction recovery unit for liquefying and recovering the desorbed long-chain hydrocarbons, and the second liquefaction recovery unit is located at the tail gas inlet end of each of the first adsorption towers.

Optionally, the tail gas recovery system further includes: a third liquefaction recovery component for liquefying and recovering saturated hydrocarbons in the macromolecular gas;

The third liquefied recovery part is located at the hydrogen-rich gas inlet end of each of the second adsorption towers.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments of the present application. Obviously, the accompanying drawings in the following description are only some embodiments of the present application , for those skilled in the art, other drawings can also be obtained according to these drawings without paying creative labor.

Figure 1 shows a schematic structural view of a tail gas recovery system in an embodiment of the present application;

Fig. 2 shows a partial working schematic diagram of a tail gas recovery system in an embodiment of the present application.

Explanation of reference signs:

101 - pressurized part, 102 - long chain hydrocarbon removal part, 103 - conversion part, 104 - first liquefaction recovery part, 105 - filter part, 106 - second adsorption tower, 107 - second liquefaction recovery part, 1011 - Compressor, 1021 - first adsorption tower, 1022 - inert gas heating part, 1031 - hydrogen reactor, 1041 - heat exchanger, 1042 - gas-liquid separation tank, 200 - tail gas from thermal cracking reaction of hydrocarbon gas, 300 - cold source material.

specific embodiment

The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this application.

Figure 1 shows a schematic structural view of a tail gas recovery system in an embodiment of the present application, and Figure 2 shows a partial working schematic diagram of a tail gas recovery system in an embodiment of the present application. Referring to Fig. 1 and Fig. 2, the tail gas recovery system includes: a pressurized part 101, a long-chain hydrocarbon removal part 102, a conversion part 103, and a first liquefaction recovery part 104 connected in sequence. The tail gas from the pyrolysis reaction of hydrocarbon gas passes through the pressurization unit 101 , the long-chain hydrocarbon removal unit 102 , the conversion unit 103 and the first liquefaction recovery unit 104 in sequence.

The pressurizing part 101 pressurizes the tail gas of the pyrolysis reaction of carbon hydrocarbon gas. Through pressurization, on the one hand, the volume of the compressed tail gas is smaller, which can reduce the volume of each component in the tail gas recovery system, and can greatly reduce the exhaust gas. The volume of the recovery system, on the other hand, the pressurization provides circulation force for the movement of the exhaust gas in each part of the exhaust gas recovery system, so that the exhaust gas can move smoothly in the exhaust gas recovery system.

The long-chain hydrocarbon removal part 102 removes the long-chain hydrocarbons in the exhaust gas after pressurization. The boiling point of the long-chain hydrocarbons is relatively high, which can prevent the long-chain hydrocarbons from being converted into a solid state in the exhaust gas recovery system and block the exhaust gas recovery system. channel etc.

The unsaturated carbon hydrocarbons in the tail gas for removing long-chain carbon hydrocarbons are mainly ethylene, acetylene, propylene, etc., and the conversion part 103 for saturated carbon hydrocarbons converts the unsaturated carbon hydrocarbons in the tail gas for removing long-chain carbon hydrocarbons into saturated carbon hydrocarbons, such as Convert ethylene and acetylene to ethane and propylene to propane. The boiling point of the above unsaturated hydrocarbons is relatively high, while the boiling point of saturated hydrocarbons is relatively low. Converting unsaturated hydrocarbons into saturated hydrocarbons can prevent unsaturated hydrocarbons from turning into a solid state in the exhaust gas recovery system and blocking the exhaust gas recovery. system channels, etc.

In the thermal cracking process of hydrocarbon gas, the tail gas components of the reaction are relatively complex, mainly including methane, nitrogen, hydrogen, and other carbon hydrocarbons. The high utilization value of the tail gas is mainly methane, and the boiling point difference between methane and other components is relatively large. Therefore, the inventor adopts the method of gas-liquid separation to recover the tail gas to recover the methane in the tail gas. The structure of the tail gas recovery system Simple, and the recycling process is simple. The first liquefaction recovery unit 104 liquefies and recovers methane, which accounts for a large proportion of the tail gas treated by the conversion unit, which not only reduces environmental pollution, but the above methane can be used in the subsequent thermal cracking reaction of hydrocarbon gases, which can greatly reduce production cost.

Optionally, as shown in FIG. 2 , the pressure booster 101 may include a compressor 1011 , which has a simple structure and mature technology.

Optionally, after pressurization, the pressure of the exhaust gas in the pressurizing member 101 is 1.5-1.8MPa, within this pressure range, not only is it beneficial for the exhaust gas to move more smoothly in the exhaust gas recovery system, but it is also conducive to the liquefaction of methane.

Optionally, as shown in Figure 2, the tail gas recovery system also includes: before the pressurized part, in the tail gas 200 of the thermal cracking reaction of carbon hydrocarbon gas: large particles, oil and gas volatilized by pump oil, and coal tar At least one filtering element 105 further reduces the probability of exhaust gas blocking the passage of the exhaust gas recovery system.

Optionally, the above-mentioned filter element 105 may be a filter element, which has a simple structure, low cost, and good adsorption effect.

Optionally, as shown in FIG. 2, the long-chain hydrocarbon removal element 102 includes: at least one first adsorption tower 1021, an inert gas heating part 1022, and the tail gas outlet ports located at each of the first adsorption towers, filled in each The first adsorbent (not shown in Fig. 2) in the first adsorption tower 1021, each first adsorption tower 1021 all has tail gas inlet port and tail gas outlet port, and the tail gas after pressurization enters the first adsorption from the tail gas inlet port. Tower 1021, the first adsorbent in the first adsorption tower 1021 adsorbs at least one of the long-chain hydrocarbons in the pressurized tail gas, the oil gas volatilized by the pump oil, and small particles, and the adsorbed tail gas is extracted from the tail gas The outlet port is discharged from the first adsorption tower 1021, which can greatly reduce the probability of blocking the channel of the tail gas recovery system. It should be noted that the first adsorbent in the first adsorption tower 1021 can be mainly used to adsorb long-chain hydrocarbons in the tail gas.

The inert gas heating part 1022 is located at the tail gas outlet end of each first adsorption tower 1021. When the first adsorbent corresponding to one first adsorption tower 1021 is saturated with adsorption, the tail gas inlet port of the first adsorption tower 1021 is temporarily fed with tail gas. Pass the heated inert gas from the tail gas outlet end of the first adsorption tower to desorb at least one of the long-chain hydrocarbons adsorbed on the first adsorbent, the oil gas volatilized by the pump oil, and small particles, and after heating The inert gas will take at least one of desorbed long-chain hydrocarbons, oil gas volatilized by pump oil, and small particles out of the first adsorption tower 1021 from the tail gas inlet end, and clean the first adsorption tower 1021. It is convenient for the first adsorption tower 1021 to be recycled. At the same time, at least one of the desorbed long-chain hydrocarbons, oil gas volatilized by pump oil, and small particles is brought out from the tail gas inlet, which can avoid pollution to the tail gas outlet and reduce the number of inlet and outlet ports. Simple. In the embodiment of the present application, there is no specific limitation on the composition of the first adsorbent.

The first adsorption tower 1021 uses the tail gas outlet as the heated inert gas inlet, and the tail gas inlet as the heated inert gas outlet, which reduces the number of inlets and outlets and makes the structure simpler.

Optionally, when the number of the first adsorption towers 1021 is greater than 1, when at least one first adsorption tower 1021 is in the desorption working state, at least another first adsorption tower 1021 is in the adsorption working state. state, there is still the first adsorption tower that can be in the adsorption working state, which means that the adsorption will not stop, and the first adsorption towers work together to achieve high recovery efficiency. In the adsorption working state, the pressurized exhaust gas enters the first adsorption tower 1021 from the inlet port of the exhaust gas, and the first adsorbent in the first adsorption tower 1021 depletes the long-chain carbon hydrocarbons in the exhaust gas, the oil gas volatilized by the pump oil, and the small particles in the exhaust gas. At least one is adsorbed. In the desorption working state, the tail gas inlet port of the first adsorption tower 1021 is temporarily fed with tail gas, and the heated inert gas is fed through the tail gas outlet port for desorption treatment.

Optionally, as shown in FIG. 2 , the tail gas inlet port and the tail gas outlet port of the first adsorption tower 1021 are relatively distributed, and the movement paths of the tail gas and the inert gas are relatively long, and the adsorption or desorption is relatively thorough.

Optionally, the inert gas used for desorption in the first adsorption tower 1021 includes nitrogen, which is easy to obtain and low in cost. The temperature of the heated inert gas is 140-180°C, within this temperature range, the desorption effect is better.

Optionally, at least one first pressure sensor is provided at the tail gas inlet port of each first adsorption tower 1021, and at least one second pressure sensor is provided at the tail gas outlet port of each first adsorption tower 1021. When the difference between the average value of the pressure detected by each second pressure sensor of 1021 and the average value of the pressure detected by each first pressure sensor of the first adsorption tower 1021 is greater than the preset pressure value, it may indicate that the first adsorption tower 1021 The first adsorbent in the adsorption tower 1021 is saturated with adsorption. In this case, the tail gas inlet port of the first adsorption tower 1021 is temporarily fed with tail gas, and the heated inert gas is fed through the tail gas outlet port of the first adsorption tower 1021 for desorption. The number of the first pressure sensor and the number of the second pressure sensor of each first adsorption tower are not specifically limited, and the preset pressure value is not specifically limited, so as to be able to characterize the first adsorbent corresponding to the first adsorption tower 1021 Adsorption saturation was taken as a reference.

Optionally, as shown in FIG. 2 , the conversion element 103 includes: a hydrogenation reactor 1031 and a hydrogenation catalyst (not shown in FIG. 2 ) located in the hydrogenation reactor 1031 . The above-mentioned tail gas itself contains a relatively high content of hydrogen, and the above-mentioned hydrogen mainly comes from the process of generating deposited carbon by thermal cracking of hydrocarbon gases. Therefore, it is only necessary to add at least one hydrogenation reactor 1031, and in the hydrogenation reactor 1031 By adding a hydrogenation catalyst, the unsaturated hydrocarbons in the tail gas can be converted into saturated hydrocarbons under the action of hydrogen in the tail gas, making full use of the original hydrogen in the tail gas, and the structure is simple, and the above reactions do not require additional reactions material, and the implementation method is simple.

Optionally, as shown in FIG. 2, the first liquefaction recovery unit 104 includes: a cold box, and the cold box includes: a heat exchanger 1041 and a gas-liquid separation tank 1042, and the heat exchanger 1041 has a cold source material inlet port and a cold source material outlet End, the tail gas treated by the conversion element 103 enters the first path of the heat exchanger 1041 from the outlet of the cold source material, and the second path of the heat exchanger 1041 enters the cold source material 300 from the inlet end of the cold source material. The first path and The second path may be the same path with only a reverse direction, which is not specifically limited in this embodiment of the present application. The cold source material 300 cools the exhaust gas below the boiling point of methane to obtain liquid methane and hydrogen-rich gas. The liquid methane and hydrogen-rich gas enter the gas-liquid separation tank 1042. The boiling point of methane is about -150°C. The main components of hydrogen-rich gas are usually hydrogen and nitrogen, and a small amount of methane. The cold source substance 300 may be liquid argon or the like, which is not specifically limited in this embodiment of the new use model.

The gas-liquid separation tank 1042 includes a gas-liquid separation chamber (not shown in FIG. 2 ), and the gas-liquid separation chamber performs gas-liquid separation on liquid methane and hydrogen-rich gas to obtain liquid methane and hydrogen-rich gas. The gas-liquid separation chamber has a hydrogen-rich gas outlet port and a liquid methane outlet port.

The gas-liquid separation tank 1042 also includes a methane recuperation chamber (not shown in Figure 2), the liquid methane outlet port is connected to the methane reheating chamber, and the liquid methane flows into the methane reheating chamber from the liquid methane outlet end, and the methane reheating chamber also has a hot gas The inlet end, the hot gas outlet end, and the hot gas movement pipe between the hot gas inlet end and the hot gas outlet end. Part of the tail gas treated by the conversion part enters the hot gas movement pipe from the hot gas inlet end to reheat liquid methane into gaseous methane, and part of the tail gas The methane reheating chamber is discharged from the hot gas outlet, which means that part of the heat of the tail gas is used to reheat liquid methane into gaseous methane without additional heat, which reduces costs. The tail gas discharged from the methane reheating chamber is connected to the outlet of the cold source material of the heat exchanger 1041, that is to say, part of the tail gas that provides reheating heat for the liquid methane also enters the heat exchanger after reheating the liquid methane for recovery processing to avoid waste of resources and pollution of the environment. The volume or quality of the part of tail gas entering the methane recuperation chamber is not specifically limited, and it is a reference to be able to reheat liquid methane in the methane reheating chamber into gaseous methane.

Optionally, the flow rate of part of the tail gas entering the hot gas movement pipeline accounts for 10-40% of the flow rate of the tail gas treated by the conversion element, and the tail gas in the above flow range can provide suitable reheating heat for liquid methane.

The hydrogen-rich gas discharged from the gas-liquid separation chamber enters the heat exchanger 1041 from the inlet port of the cold source material as part of the cold source material, thereby reducing the consumption of the cold source material 300 , saving resources, and reducing costs. It may be that all the hydrogen-rich gas enters the heat exchanger 1041 , or part of the hydrogen-rich gas enters the heat exchanger 1041 , which is not specifically limited in this embodiment of the present application.

Similarly, the gaseous methane discharged from the methane reheating chamber can be used as a part of the cold source material and enter the heat exchanger from the cold source material inlet port, thereby reducing the consumption of the cold source material 300 , saving resources and reducing costs. It may be that all the gaseous methane enters the heat exchanger 1041, or part of the gaseous methane enters the heat exchanger 1041, which is not specifically limited in this embodiment of the present application.

Optionally, as shown in FIG. 2 , the tail gas recovery system also includes: at least one second adsorption tower 106 for recovering hydrogen from hydrogen-rich gas, and second adsorbents filled in each second adsorption tower 106, each first The second adsorption tower 106 is connected to the first liquefaction recovery unit 104 . The usual pressure of the hydrogen-rich gas is 1.4-1.6MPa, and the hydrogen-rich gas enters the second adsorption tower 106 from the hydrogen-rich gas inlet port of each second adsorption tower 106, and the second adsorbent can convert macromolecular gases, such as nitrogen, methane , saturated hydrocarbons, etc., the hydrogen is discharged from the hydrogen outlet of the second adsorption tower 106, and then the hydrogen is recovered, which can also reduce environmental pollution. The above hydrogen can be used in the subsequent thermal cracking reaction of hydrocarbon gases, which can greatly reduce manufacturing cost. In the embodiment of the present application, the composition of the second adsorbent is not specifically limited.

When the second adsorbent in the second adsorption tower 106 is saturated with adsorption, the inlet port of the hydrogen-rich gas of the second adsorption tower 106 suspends the introduction of the hydrogen-rich gas, and the hydrogen gas outlet port of the second adsorption tower 106 passes into a large Molecular gas desorption medium, the desorbed macromolecular gas is discharged from the second adsorption tower 106 from the hydrogen-rich gas inlet port of the second adsorption tower 106, so that the second adsorption tower 106 can be recycled. The above-mentioned second adsorption tower 106 may be a pressure swing adsorption tower, which is not specifically limited in this embodiment of the present application. The desorbed macromolecular gas is discharged from the hydrogen-rich gas inlet of the second adsorption tower 106, which can avoid pollution to the hydrogen outlet and reduce the number of inlet and outlet ports, with a simple structure.

Optionally, when the number of the second adsorption towers is greater than or equal to 2, when at least one second adsorption tower 106 is in the desorption working state, at least another second adsorption tower 106 is in the adsorption working state, and at least two second adsorption towers 106 are in the adsorption working state. The two adsorption towers 106 cooperate to ensure uninterrupted adsorption and high recovery efficiency.

Optionally, as shown in FIG. 2 , the tail gas recovery system may also include: a second liquefaction recovery unit 107 that liquefies and recovers the desorbed long-chain hydrocarbons, and the second liquefaction recovery unit 107 is located in each of the first adsorption towers 1021 Exhaust outlet port. The second liquefaction recovery unit also utilizes the differences in the boiling points of the desorbed long-chain hydrocarbons from the first adsorption tower 1021, oil vapor volatilized from the pump oil, and small particles to recover long-chain hydrocarbons. In this new usage embodiment, the specific structure and the like of the second liquefaction recovery part are not specifically limited.

It should be noted that if the content of long-chain hydrocarbons in the tail gas of the thermal cracking reaction of hydrocarbon gases is lower than the preset volume or quality, the above-mentioned second liquefaction recovery unit may not be provided, which can reduce the cost instead. A torch can be set to burn long-chain hydrocarbons desorbed from the first adsorption tower, oil and gas volatilized from the pump oil, and small particles, etc., which are not specifically limited in this embodiment of the new use model. For example, if the volume content of long-chain carbon hydrocarbons in the tail gas of the thermal cracking reaction of hydrocarbon gases is less than or equal to 1% of the total volume of the tail gas, the above-mentioned second liquefaction recovery unit may not be provided.

Optionally, the tail gas recovery system may also include: a third liquefaction recovery unit for liquefying and recovering saturated hydrocarbons in the macromolecular gas, the third liquefaction recovery unit is located at the hydrogen-rich gas inlet end of each second adsorption tower 106, and After desorbing macromolecular nitrogen, methane, saturated carbon hydrocarbons, etc., the saturated carbon hydrocarbons are also recovered by using the difference in boiling point of macromolecular nitrogen, methane, saturated carbon hydrocarbons, etc. desorbed from the second adsorption tower 106 . Nitrogen can also be recovered. In this embodiment of the new use model, the specific structure of the third liquefaction recovery part is not specifically limited.

It should be noted that if the content of the converted saturated hydrocarbons is lower than the preset volume or quality, the above-mentioned third liquefaction recovery unit may not be provided, which can reduce the cost instead. A torch can be set up to burn the macromolecular gas desorbed from the second adsorption tower, which is not specifically limited in this embodiment of the new use model.

It should be noted that, in this document, the term "comprising", "comprising" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, It also includes other elements not expressly listed, or elements inherent in the process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus comprising that element.

The embodiments of the present application have been described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementations. The above-mentioned specific implementations are only illustrative and not restrictive. Those of ordinary skill in the art will Under the enlightenment of this application, many forms can also be made without departing from the purpose of this application and the scope of protection of the claims, and these all belong to the protection of this application.

Claims

A tail gas recovery system, characterized in that it includes: a pressure booster for tail gas pressurization of carbon hydrocarbon gas pyrolysis reaction, a long chain carbon hydrocarbon removal member for removing long chain carbon hydrocarbons in tail gas, and unsaturated Conversion parts for converting carbon hydrocarbons into saturated carbon hydrocarbons, the first liquefaction recovery part for liquefying and recovering methane in tail gas;

The pressurization part, the long-chain hydrocarbon removal part, the conversion part, and the first liquefaction recovery part are connected in sequence, and the tail gas from the pyrolysis reaction of hydrocarbon gas passes through the pressurization part, the long-chain hydrocarbon gas The chain hydrocarbon removal part, the conversion part, and the first liquefaction recovery part.
The tail gas recovery system according to claim 1, wherein the first liquefied recovery part comprises: a cold box, the cold box comprises: a heat exchanger and a gas-liquid separation tank, and the heat exchanger has a cold source material The inlet end and the cold source material outlet end, the exhaust gas enters the first path of the heat exchanger from the cold source material outlet end, and the cold source material enters the second path of the heat exchanger from the cold source material inlet end , the cold source material cools the tail gas below the boiling point of methane to obtain liquid methane and hydrogen-rich gas, and the liquid methane and hydrogen-rich gas enter the gas-liquid separation tank;

The gas-liquid separation tank includes a gas-liquid separation chamber, and the gas-liquid separation chamber performs gas-liquid separation on liquid methane and hydrogen-rich gas to obtain liquid methane and hydrogen-rich gas; the gas-liquid separation chamber has a hydrogen-rich gas outlet end and liquid methane outlet end.
The tail gas recovery system according to claim 2, wherein the gas-liquid separation tank also includes a methane reheating chamber, the liquid methane outlet port is connected to the methane reheating chamber, and the liquid methane is discharged from the liquid methane outlet. end flows into the methane reheating chamber, and the methane reheating chamber also has a hot gas inlet port, a hot gas outlet port, and a hot gas movement pipeline between the hot gas inlet port and the hot gas outlet port, and the conversion part handles The final part of the tail gas enters the hot gas movement pipe from the hot gas inlet port to reheat the liquid methane into gaseous methane, and the part of the tail gas is discharged from the methane reheating chamber through the hot gas outlet port;

The part of tail gas discharged from the methane reheating chamber is connected to the outlet port of the heat exchanger for the cold source substance.
The tail gas recovery system according to claim 2 or 3, wherein the hydrogen-rich gas discharged from the gas-liquid separation chamber enters the heat exchanger from the inlet of the cold source material as a part of the cold source material ;

And/or, the gaseous methane discharged from the methane reheating chamber, as a part of the heat sink material, enters the heat exchanger from the inlet port of the heat sink material.
The tail gas recovery system according to claim 3, characterized in that the flow rate of part of the tail gas entering the hot gas inlet accounts for 10-40% of the flow rate of the tail gas treated by the conversion element.
The tail gas recovery system according to any one of claims 1-3, characterized in that, the long-chain hydrocarbon removal component comprises: at least one first adsorption tower, and first adsorption towers filled in each first adsorption tower Each first adsorption tower has a tail gas inlet port and a tail gas outlet port, and the pressurized tail gas enters the first adsorption tower from the tail gas inlet port, and the first adsorbent in the first adsorption tower will increase At least one of the long-chain carbon hydrocarbons in the compressed exhaust gas, the oil and gas volatilized by the pump oil, and the small particles is adsorbed, and the adsorbed exhaust gas is discharged from the first adsorption tower from the outlet end of the exhaust gas;

The long-chain hydrocarbon removal part also includes an inert gas heating part, and the inert gas heating part is located at the tail gas outlet end of each of the first adsorption towers. Next, the tail gas inlet port of the first adsorption tower is temporarily fed into the tail gas, and the heated inert gas is introduced from the tail gas outlet port of the first adsorption tower to absorb the long-chain hydrocarbons, At least one of the oil gas and small particles volatilized by the pump oil is desorbed, and the heated inert gas will desorb at least one of the desorbed long-chain hydrocarbons, oil gas volatilized by the pump oil, and small particles from the tail gas inlet port Take out the first adsorption tower.
The tail gas recovery system according to claim 6, characterized in that, when the number of the first adsorption towers is greater than 1, when at least one first adsorption tower is in the desorption working state, at least another first adsorption tower It is in the adsorption working state; in the adsorption working state, the pressurized tail gas enters the first adsorption tower from the tail gas inlet; in the desorption working state, the tail gas inlet of the first adsorption tower is temporarily not fed into the tail gas.
The tail gas recovery system according to claim 6, wherein at least one first pressure sensor is provided at the tail gas inlet end of each of the first adsorption towers, and at least one first pressure sensor is provided at the tail gas outlet end of each of the first adsorption towers. At least one second pressure sensor, the average value of the detection pressure of each second pressure sensor in a first adsorption tower, and the average value of the detection pressure of each first pressure sensor of the first adsorption tower, the difference between the two is greater than the preset When the pressure value is set, the exhaust gas inlet end of the first adsorption tower is suspended from feeding the exhaust gas.
The tail gas recovery system according to any one of claims 1-3, characterized in that the conversion element comprises: at least one hydrogenation reactor and a hydrogenation catalyst located in each of the hydrogenation reactors.
The tail gas recovery system according to any one of claims 1-3, characterized in that it also includes: before the pressurized part, in the tail gas of the pyrolysis reaction of carbon hydrocarbon gas: large particles, pump oil volatilization A filter element for filtering at least one of oil gas and coal tar, and the pressurization element is located between the long-chain hydrocarbon removal element and the filter element.
The tail gas recovery system according to claim 2 or 3, further comprising: at least one second adsorption tower for recovering hydrogen from hydrogen-rich gas, and second adsorption towers filled in each of the second adsorption towers. Each of the second adsorption towers is connected to the first liquefaction recovery unit; each of the second adsorption towers has a hydrogen-rich gas inlet port and a hydrogen gas outlet port;

In the case that the second adsorbent of a second adsorption tower is saturated, the hydrogen-rich gas inlet port of the second adsorption tower is suspended to feed the hydrogen-rich gas, and the hydrogen gas outlet port of the second adsorption tower is fed into a large Molecular gas desorption medium, the desorbed macromolecular gas is discharged from the second adsorption tower from the hydrogen-rich gas inlet port of the second adsorption tower.
The tail gas recovery system according to claim 6, further comprising: a second liquefaction recovery unit for liquefying and recovering the desorbed long-chain hydrocarbons, the second liquefaction recovery unit is located in each of the first adsorption units The tail gas inlet end of the tower.
The tail gas recovery system according to claim 11, further comprising: a third liquefaction recovery component for liquefying and recovering saturated hydrocarbons in the macromolecular gas;

The third liquefied recovery part is located at the hydrogen-rich gas inlet end of each of the second adsorption towers.