Integrated device for co-producing hydrogen, nitrogen and liquefied natural gas through three towers

Abstract

The utility model relates to an integrated device for co-producing hydrogen, nitrogen and liquefied natural gas through three towers. The integrated device comprises a low-temperature rectification unit, a liquid nitrogen washing unit and a refrigerant circulating unit. According to the integrated device, liquid nitrogen washing and low-temperature rectification are integrated, overhead gas of the dehydrogenation tower is directly introduced into the washing tower, bottom liquid of the washing tower is reheated, the overall structure is simpler, and higher reliability is achieved; the integrated device not only can produce hydrogen, nitrogen and LNG by taking coke oven gas as a raw material, but also can produce LNG and hydrogen, nitrogen and LNG by taking synthesis gas as a raw material, and the liquid nitrogen wash unit can be conveniently closed by closing the eighth regulating valve and the fourth regulating valve in the device so as to be matched with the gas forming working condition, so that flexible switching of two modes of one set of device is realized.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of liquefied natural gas production, concretely relates to an integrated device for three-tower co-production of hydrogen, nitrogen and liquefied natural gas. BACKGROUND

[0002] Coke oven gas contains methane, nitrogen, hydrogen, carbon monoxide, carbon dioxide and other components, and is usually converted into synthesis gas by methane synthesis, and then subjected to low-temperature rectification to purify the methane in the gas stream to produce liquefied natural gas (LNG), while recovering the remaining hydrogen and nitrogen as raw materials for synthetic ammonia, achieving main production of LNG and by-product synthetic ammonia; or it can be directly subjected to low-temperature rectification without methane synthesis to achieve main production of synthetic ammonia and by-product LNG, but the carbon monoxide contained in the coke oven gas will be mixed in the recovered hydrogen, which will cause poisoning of the synthetic ammonia catalyst if not removed.

[0003] Patent CN106642988A discloses a system for preparing synthesis ammonia raw gas and LNG by using liquid nitrogen washing, which comprises a first heat exchanger, a second heat exchanger, a dehydrogenation tower, a nitrogen washing tower, a methane tower, a nitrogen gas refrigeration system and a medium-pressure nitrogen gas input pipe; when the system is working, the raw gas is cooled by the heat exchanger, enters the dehydrogenation tower to remove most of the methane, then enters the nitrogen washing tower to remove the methane and carbon monoxide, and finally obtains nitrogen and hydrogen gas; the liquid phase condensed from the raw gas enters the methane tower to obtain products and tail gas rich in carbon monoxide. However, the overall structure of the system is relatively complex, and it can only be used for preparing synthesis ammonia raw gas and LNG from coke oven gas raw gas. UTILITY MODEL CONTENTS

[0004] The first technical problem to be solved by the utility model is the problem of the complex overall structure of the existing system for preparing synthesis ammonia raw gas and LNG by using liquid nitrogen washing, and the second technical problem to be solved by the utility model is the problem that the existing system for preparing synthesis ammonia raw gas and LNG by using liquid nitrogen washing can only be used for preparing synthesis ammonia raw gas and LNG from coke oven gas raw gas, and therefore the utility model provides an integrated device for three-tower co-production of hydrogen, nitrogen and liquefied natural gas.

[0005] The utility model integrates liquid nitrogen washing and low-temperature rectification into one, has a simpler overall structure and higher reliability; it can not only produce hydrogen, nitrogen and LNG from coke oven gas, but also produce LNG and hydrogen, nitrogen from synthesis gas, and realizes flexible switching between the two modes of a device.

[0006] In this invention, the feed gas is cooled and heated by the main heat exchanger before entering the dehydrogenation tower, while the bottom liquid enters the denitrification tower. The nitrogen-rich gas discharged from the top of the denitrification tower is reheated and sent out of the boundary area. Liquefied natural gas is drawn from the bottom of the tower, cooled, and then sent to a storage tank. The top gas from the dehydrogenation tower enters the scrubbing tower, where carbon monoxide is absorbed by liquid nitrogen and discharged with the bottom liquid phase. The gas phase, after reheating, is discharged from the top of the tower as hydrogen-rich gas. The cooling capacity required for feed gas liquefaction is provided by a mixed refrigerant compression system, and the cooling capacity required for cryogenic distillation separation is provided by a nitrogen refrigerant compression system.

[0007] This invention utilizes the feed gas itself as a heat source, ensuring operational isolation of the unit. The overhead gas from the dehydrogenation tower is directly introduced into the scrubbing tower, and the bottom liquid in the scrubbing tower is reheated. The system architecture is simple, and operational reliability is high. The liquid nitrogen scrubbing unit can be easily shut down to adapt to gasification conditions.

[0008] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution:

[0009] This utility model provides an integrated device for the co-production of hydrogen, nitrogen, and liquefied natural gas from three towers, including: a cryogenic distillation unit, a liquid nitrogen washing unit, and a refrigerant circulation unit. The refrigerant circulation unit includes a nitrogen refrigeration circulation unit and a mixed refrigerant refrigeration circulation unit. The cooling capacity required for cryogenic distillation separation is provided by the nitrogen refrigeration circulation unit (i.e., the nitrogen refrigerant for the dehydrogenation tower condenser, washing tower, and denitrification tower condenser is supplied by the nitrogen refrigeration circulation unit of the refrigerant circulation unit), and the cooling capacity required for feed gas liquefaction is provided by the mixed refrigerant refrigeration circulation unit.

[0010] The low-temperature rectification unit comprises a main heat exchanger, a denitrogenation column, a denitrogenation column reboiler, a dehydrogenation column, a dehydrogenation column condenser, a dehydrogenation column liquid separator, a denitrogenation column condenser, a denitrogenation column liquid separator, and a supercooling heat exchanger. A raw material gas feed pipeline is connected to a first cold channel inlet of the main heat exchanger. A first cold channel outlet is connected to an inlet of the denitrogenation column reboiler through a pipeline. An outlet of the denitrogenation column reboiler is connected to a second cold channel inlet of the main heat exchanger through a pipeline. A second cold channel outlet is connected to an inlet of the dehydrogenation column through a pipeline. A column top outlet of the dehydrogenation column is connected to a tube side inlet of the dehydrogenation column condenser through a pipeline. A tube side outlet of the dehydrogenation column condenser is connected to an inlet of the dehydrogenation column liquid separator through a pipeline. A bottom liquid phase outlet of the dehydrogenation column liquid separator is returned to a top portion of the dehydrogenation column through a pipeline. A column kettle outlet of the dehydrogenation column is connected to an inlet (a middle portion inlet) of the denitrogenation column through a pipeline. A column top outlet of the denitrogenation column is connected to a tube side inlet of the denitrogenation column condenser through a pipeline. An upper portion inlet of the denitrogenation column condenser is connected to the refrigerant circulation unit through a pipeline. A bottom tube side outlet of the denitrogenation column condenser is connected to an inlet of the denitrogenation column liquid separator through a pipeline. A bottom liquid phase outlet of the denitrogenation column liquid separator is returned to a top portion of the denitrogenation column through a pipeline. A top gas phase outlet of the denitrogenation column liquid separator is sequentially connected to a first channel of the supercooling heat exchanger and a first hot channel of the main heat exchanger through a pipeline. A first hot channel outlet of the main heat exchanger is connected to a nitrogen-rich gas discharge pipeline. A column bottom outlet of the denitrogenation column is connected to a third cold channel inlet of the main heat exchanger through a pipeline. A third cold channel outlet is connected to an LNG discharge pipeline.

[0011] The liquid nitrogen washing unit comprises a washing column. A top outlet of the dehydrogenation column liquid separator is connected to a lower portion inlet of the washing column through a pipeline. A column bottom outlet of the washing column is sequentially connected to a second channel of the supercooling heat exchanger and a second hot channel of the main heat exchanger through a pipeline. A second hot channel outlet is connected to a nitrogen-rich gas discharge pipeline through a pipeline. A column top outlet of the washing column is sequentially connected to a third channel of the supercooling heat exchanger and a third hot channel of the main heat exchanger through a pipeline. A third hot channel outlet is connected to a hydrogen-rich gas discharge pipeline through a pipeline.

[0012] Further, in the integrated device, the nitrogen refrigeration circulation unit comprises a nitrogen refrigeration compression system. A nitrogen refrigerant feed pipeline from the nitrogen refrigeration compression system is sequentially connected to a fourth cold channel of the main heat exchanger and a fourth channel (which is a cold channel) of the supercooling heat exchanger. A fourth channel outlet is divided into three paths through a pipeline. A first path is connected to a shell side inlet of the dehydrogenation column condenser. A second path is connected to a shell side inlet of the denitrogenation column condenser. A third path is connected to a column top inlet of the washing column. A top shell side outlet pipeline of the dehydrogenation column condenser is combined with a top shell side outlet pipeline of the denitrogenation column condenser, and then sequentially connected to a fifth channel (which is a hot channel) of the supercooling heat exchanger and a fourth hot channel of the main heat exchanger. A fourth hot channel outlet is connected to a low-pressure nitrogen gas discharge pipeline. The other end of the low-pressure nitrogen gas discharge pipeline is connected to an inlet of the nitrogen refrigeration compression system.

[0013] The mixed refrigerant refrigeration cycle unit comprises a mixed refrigerant compression system, a gas-phase high-pressure refrigerant feed pipeline from the mixed refrigerant compression system is connected with a fifth cold channel inlet of the main heat exchanger, a fifth cold channel outlet is returned to a fifth hot channel of the main heat exchanger after being led out of the main heat exchanger, a liquid-phase high-pressure refrigerant feed pipeline is connected with a sixth cold channel inlet of the main heat exchanger, a sixth cold channel outlet is returned to the fifth hot channel of the main heat exchanger after being led out of the main heat exchanger, and a fifth hot channel outlet is connected with an inlet of the mixed refrigerant compression system through a reflux refrigerant pipeline.

[0014] In another embodiment, similar to the above-mentioned integrated device for co-production of hydrogen, nitrogen and liquefied natural gas, only the fourth channel of the subcooling heat exchanger is divided into three paths through pipelines, the first path is connected with an inlet of the shell side of the dehydrogenation column condenser, the second path is closed by a valve, and the third path is connected with an inlet of the shell side of the denitrogenation column condenser. This scheme is suitable for the integrated device for co-production of hydrogen, nitrogen and liquefied natural gas when the raw material gas to be treated is synthetic gas.

[0015] Further, in the above-mentioned integrated device, a first regulating valve is arranged on the pipeline of the outlet of the dehydrogenation column, and the first regulating valve is a pressure reducing valve;

[0016] a second regulating valve is arranged on the pipeline of the outlet of the first hot channel, and the second regulating valve is a pressure reducing valve; and / or

[0017] the pipeline of the outlet of the second hot channel is connected with the nitrogen-rich gas discharge pipeline downstream of the second regulating valve, and a fourth regulating valve is arranged on the pipeline of the outlet of the second hot channel, and the fourth regulating valve is a pressure reducing valve; and / or

[0018] a fifth regulating valve is arranged on the pipeline of the outlet of the third hot channel, and the fifth regulating valve is a pressure reducing valve.

[0019] Further, a third regulating valve is arranged on the pipeline of the outlet of the third cold channel, and the third regulating valve is a throttle valve.

[0020] Further, a sixth regulating valve is arranged on the pipeline between the outlet of the fourth channel and the upper inlet of the dehydrogenation column condenser, and the sixth regulating valve is a pressure reducing valve; and / or

[0021] a seventh regulating valve is arranged on the pipeline between the outlet of the fourth channel and the upper inlet of the denitrogenation column condenser, and the seventh regulating valve is a pressure reducing valve; and / or

[0022] an eighth regulating valve is arranged on the pipeline between the outlet of the fourth channel and the overhead inlet of the washing column, and the eighth regulating valve is a pressure reducing valve.

[0023] Further, a ninth regulating valve is arranged on the pipeline between the outlet of the fifth cold channel and the inlet of the fifth hot channel, and the ninth regulating valve is a throttle valve.

[0024] Further, a tenth regulating valve is arranged on the pipeline between the sixth cold channel outlet and the fifth hot channel inlet, and the tenth regulating valve is a throttle valve.

[0025] Further, in the integrated device, the denitrogenation tower reboiler is arranged at the bottom of the denitrogenation tower and used as a heat source of the denitrogenation tower.

[0026] Further, the main heat exchanger is a multi-flow plate fin heat exchanger, and a plurality of parallel hot channels and a plurality of parallel cold channels are arranged in the multi-flow plate fin heat exchanger, the hot medium flows in the hot channels, and the cold medium flows in the cold channels, so that the heat exchange between the hot medium and the cold medium is realized.

[0027] Further, the supercooling heat exchanger is a multi-flow plate fin heat exchanger.

[0028] Further, the washing tower is a low-temperature separation tower.

[0029] The integrated device for three-tower co-production of hydrogen, nitrogen and liquefied natural gas according to the present application co-produces hydrogen, nitrogen and liquefied natural gas according to the following process:

[0030] (1) Low-temperature rectification: the raw gas (35-45 ℃, 1.5-2.0 MPag, preferably 1.7-1.9 MPag) is extracted after being cooled by the first cold channel of the main heat exchanger (cooled to -120--100 ℃, preferably cooled to -110--102 ℃) through the raw gas feed pipeline, and is used as the heat source of the denitrogenation column 2 auxiliary denitrogenation column reboiler 3, while heating the denitrogenation column bottom liquid, the raw gas itself is cooled (cooled to -145--120 ℃, preferably cooled to -140--130 ℃), and then enters the second cold channel of the main heat exchanger for further cooling (cooled to -165--160 ℃, preferably cooled to -164--161 ℃), and then enters the dehydrogenation column (operating pressure 1.5-2.0 MPag, preferably 1.6-1.8 MPag), the overhead gas of the dehydrogenation column (rich in hydrogen and carbon monoxide) is first cooled by the dehydrogenation column condenser (cooled to -190--160 ℃, preferably cooled to -185--170 ℃), and then separated into gas and liquid phases by the dehydrogenation column liquid separator, the liquid phase is returned to the dehydrogenation column, and the gas phase is introduced into the washing column (operating pressure 1.5-2.0 MPag, preferably 1.6-1.8 MPag), the dehydrogenation column bottom liquid (rich in methane) is depressurized (depressurized to 0.3-0.6 MPag, preferably depressurized to 0.35-0.45 MPag) by the first regulating valve (pressure reducing valve) and then enters the denitrogenation column for rectification, nitrogen and the remaining carbon monoxide in the liquid stream are discharged from the top of the denitrogenation column with the gas phase, first cooled by the denitrogenation column condenser (cooled to -190--160 ℃, preferably cooled to -185--170 ℃), and then separated into gas and liquid phases by the denitrogenation column liquid separator, the liquid phase is returned to the denitrogenation column, and the gas phase discharged from the denitrogenation column liquid separator (nitrogen-rich gas) is reheated (reheated to 30-40 ℃, preferably reheated to 32-38 ℃) by the first channel of the subcooling heat exchanger and the first hot channel of the main heat exchanger, depressurized to atmospheric pressure by the second regulating valve (pressure reducing valve), and then sent out of the boundary area as a nitrogen-rich gas product through the nitrogen-rich gas discharge pipeline, the denitrogenation column bottom liquid (LNG) is discharged from the bottom (temperature -145--130 ℃, preferably -140--135 ℃) and further cooled (cooled to -165--160 ℃, preferably cooled to -164--161 ℃) by the third cold channel of the main heat exchanger, throttled by the third regulating valve (throttle valve) and then sent to the outside, and the LNG product is output through the LNG discharge pipeline for storage;

[0031] (2) Liquid nitrogen washing: the gas stream from the dehydrogenation column liquid separator is in counter-current contact with the liquid nitrogen from the top of the washing column, so that the carbon monoxide in the gas stream is absorbed by the liquid nitrogen. The liquid phase at the bottom of the washing column is vaporized and reheated (reheated to 30-40 DEG C, preferably reheated to 32-38 DEG C) through the second passage of the subcooling heat exchanger and the second hot passage of the main heat exchanger, depressurized to normal pressure through the fourth regulating valve (decompression valve), and then combined with the gas phase of the de-nitrogenation column liquid separator which has been vaporized and reheated, and sent out of the system as a nitrogen-rich gas product through a nitrogen-rich gas discharge pipeline. The gas phase (hydrogen-rich gas with a carbon monoxide content of not higher than 20 ppm) at the top of the washing column is reheated (reheated to 30-40 DEG C, preferably reheated to 32-38 DEG C) through the third passage of the subcooling heat exchanger and the third hot passage of the main heat exchanger, depressurized (depressurized to 1.4-1.8 MPag, preferably depressurized to 1.5-1.6 MPag) through the fifth regulating valve (decompression valve), and then sent out of the system as a hydrogen-rich gas product through a hydrogen-rich gas discharge pipeline.

[0032] The refrigerant circulation in the integrated device for co-production of hydrogen and nitrogen gas and liquefied natural gas in the three-column system of the utility model comprises a nitrogen refrigeration cycle and a mixed refrigerant refrigeration cycle:

[0033] The cold energy required for low-temperature rectification separation is provided by the nitrogen refrigeration compression system. The nitrogen refrigerant from the nitrogen refrigeration compression system enters the fourth cold passage of the main heat exchanger and the fourth passage of the subcooling heat exchanger to be cooled to become liquid nitrogen (temperature -190 to -160 DEG C, preferably -185 to -170 DEG C) through a nitrogen refrigerant feed pipeline (temperature 35-45 DEG C, pressure 2.0-4.0 MPag, preferably 2.5-3.5 MPag), and then depressurized (depressurized to 0-1.0 MPag, preferably 0.2-0.5 MPag) through the sixth regulating valve (decompression valve) and the seventh regulating valve (decompression valve) to enter the dehydrogenation column condenser and the de-nitrogenation column condenser, respectively, to provide cold energy for the dehydrogenation column condenser and the de-nitrogenation column condenser. The nitrogen in the dehydrogenation column condenser and the de-nitrogenation column condenser which is changed back to the gas phase is reheated (reheated to 30-40 DEG C, preferably 32-38 DEG C) through the fifth passage of the cold heat exchanger and the fourth hot passage of the main heat exchanger, and then returned to the nitrogen refrigeration compression system through a low-pressure nitrogen gas discharge pipeline as low-pressure nitrogen gas. The liquid nitrogen is depressurized (depressurized to 1.5-2.0 MPag, preferably 1.6-1.8 MPag) through the eighth regulating valve (decompression valve) to enter the washing column to provide cold energy for the washing column.

[0034] The cold energy required for raw gas liquefaction is provided by a mixed refrigerant compression system (the mixed refrigerant can be a mixture of nitrogen, methane, ethylene, propane, and isopentane), the gas-phase high-pressure refrigerant (temperature 35-45 DEG C, pressure 2.0-4.0 MPag, preferably 2.5-3.5 MPag) from the mixed refrigerant compression system enters the fifth cold channel of the main heat exchanger through a gas-phase high-pressure refrigerant feed pipeline, is reduced in pressure and temperature at different positions, after leaving the main heat exchanger, is throttled (reduced in pressure to 0-1.0 MPag, preferably 0.2-0.5 MPag) by a ninth regulating valve (throttle valve) and returned to the fifth hot channel of the main heat exchanger, the liquid-phase high-pressure refrigerant (temperature 35-45 DEG C, pressure 2.0-4.0 MPag, preferably 2.5-3.5 MPag) enters the sixth cold channel of the main heat exchanger through a liquid-phase high-pressure refrigerant feed pipeline, is reduced in pressure and temperature at different positions, after leaving the main heat exchanger, is throttled (reduced in pressure to 0-1.0 MPag, preferably 0.2-0.5 MPag) by a tenth regulating valve (throttle valve) and returned to the fifth hot channel of the main heat exchanger, and the return flow refrigerant is reheated (reheated to 30-40 DEG C, preferably 32-38 DEG C) from the fifth hot channel of the main heat exchanger and returned to the mixed refrigerant compression system through a return flow refrigerant pipeline for recycling.

[0035] The washing tower is supplied with nitrogen refrigerant by the nitrogen refrigeration cycle unit when the raw gas is coke oven gas, and the washing tower does not need to be supplied with nitrogen refrigerant by the nitrogen refrigeration cycle unit when the raw gas is synthesis gas without carbon monoxide, that is, liquid nitrogen does not need to go to the washing tower, and the eighth regulating valve and the fourth regulating valve are closed at this time.

[0036] The three-tower co-production hydrogen-nitrogen gas and liquefied natural gas integrated device has the following beneficial effects:

[0037] (1) The three-tower co-production hydrogen-nitrogen gas and liquefied natural gas integrated device of the utility model, comprising: a low-temperature rectification unit, a liquid nitrogen washing unit and a refrigerant circulation unit, integrates the liquid nitrogen washing and the low-temperature rectification as a whole, directly introduces the dehydrogenation tower top gas into the washing tower, reheats the washing tower bottom liquid, the overall structure is simpler, and has higher reliability.

[0038] (2) The three-tower co-production hydrogen-nitrogen gas and liquefied natural gas integrated device can not only produce hydrogen-nitrogen gas and LNG by taking coke oven gas as raw material, but also can produce LNG and hydrogen-nitrogen gas by taking synthesis gas as raw material, and the liquid nitrogen washing unit can be conveniently closed by closing the eighth regulating valve and the fourth regulating valve in the device, so that the device can be switched between two modes flexibly.

[0039] (3) The three-tower co-production hydrogen-nitrogen gas and liquefied natural gas integrated device takes the raw gas itself as a heat source for heating the rectification tower bottom, thereby ensuring the operation isolation of the unit. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to make the content of the utility model more easily be clearly understood, the following according to the specific embodiment of the utility model and combining with the drawings, the utility model is further described in detail, wherein,

[0041] Figure 1 It is the structural diagram of the integrated device of three-tower co-production hydrogen, nitrogen and liquefied natural gas of the utility model,

[0042] Among them, 1, main heat exchanger, 2, denitrogenation tower, 3, denitrogenation tower reboiler, 4, dehydrogenation tower, 5, dehydrogenation tower condenser, 6, dehydrogenation tower liquid separator, 7, washing tower, 8, denitrogenation tower condenser, 9, denitrogenation tower liquid separator, 10, subcooling heat exchanger, 11, nitrogen refrigeration compression system, 12, mixed refrigerant compression system,

[0043] L1, raw gas feed pipeline, L2, nitrogen-rich gas discharge pipeline, L3, LNG discharge pipeline, L4, hydrogen-rich gas discharge pipeline, L5, nitrogen refrigerant feed pipeline, L6, low-pressure nitrogen gas discharge pipeline, L7, gas-phase high-pressure refrigerant feed pipeline, L8, liquid-phase high-pressure refrigerant feed pipeline, L9, reflux refrigerant pipeline,

[0044] H1, first hot channel, H2, second hot channel, H3, third hot channel, H4, fourth hot channel, H5, fifth hot channel, C1, first cold channel, C2, second cold channel, C3, third cold channel, C4, fourth cold channel, C5, fifth cold channel, C6, sixth cold channel,

[0045] h1, first channel, h2, second channel, h3, third channel, c4, fourth channel, h5, fifth channel,

[0046] V1, first regulating valve, V2, second regulating valve, V3, third regulating valve, V4, fourth regulating valve, V5, fifth regulating valve, V6, sixth regulating valve, V7, seventh regulating valve, V8, eighth regulating valve, V9, ninth regulating valve, V10, tenth regulating valve. DETAILED DESCRIPTION

[0047] The technical scheme in the embodiments of the utility model will be clearly and completely described below in combination with the drawings of the embodiments of the utility model, and obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0048] In the description of the utility model, it is explained that, unless otherwise explicitly provided and limited, the terms "mounting", "provided with", "connection" and the like should be understood broadly, for example, "connection" can be fixed connection, can also be detachable connection, or integrally connected;It can be mechanical connection, it can be directly connected, it can be indirectly connected through intermediate medium, it can be the communication inside two elements.The terms "upper", "middle", "outer", "inner", "lower", "periphery", "left", "right", "front", "back", "top", "bottom" and the like indicate the orientation or position relationship, only for the convenience of describing the utility model and simplifying the description, and not indicate or imply that the indicated component or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it can not be understood as the limitation of the utility model.For the ordinary skilled person in the art, the specific meaning of the above-mentioned terms in the utility model can be understood according to the specific circumstances.

[0049] In the utility model, the raw material gas can be coke oven gas or synthesis gas after deacidification and dehydration, wherein CO2 content is < 50 ppm, H2S content is < 4 ppm, and H2O content is < 0.1 ppm.

[0050] As shown in Figure 1 The integrated device for co-production of hydrogen and nitrogen gas and liquefied natural gas in the utility model, comprising: a low-temperature rectification unit, a liquid nitrogen washing unit and a refrigerant circulation unit, the refrigerant circulation unit comprises a nitrogen refrigeration circulation unit and a mixed refrigerant refrigeration circulation unit, the cold quantity required for low-temperature rectification separation is provided by the nitrogen refrigeration circulation unit (i.e., the hydrogen removal column condenser 5, the washing tower 7 and the nitrogen removal column condenser 8 are supplied with nitrogen refrigerant by the nitrogen refrigeration circulation unit of the refrigerant circulation unit), and the cold quantity required for raw material gas liquefaction is provided by the mixed refrigerant refrigeration circulation unit;

[0051] The low-temperature rectification unit comprises a main heat exchanger 1, a denitrogenation tower 2, a denitrogenation tower reboiler 3, a dehydrogenation tower 4, a dehydrogenation tower condenser 5, a dehydrogenation tower liquid separator 6, a denitrogenation tower condenser 8, a denitrogenation tower liquid separator 9, and a subcooling heat exchanger 10. The raw material gas feeding pipeline L1 is connected to the first cold channel C1 inlet of the main heat exchanger 1. The first cold channel C1 outlet is connected to the inlet of the denitrogenation tower reboiler 3 through a pipeline. The outlet of the denitrogenation tower reboiler 3 is connected to the second cold channel C2 inlet of the main heat exchanger 1 through a pipeline. The second cold channel C2 outlet is connected to the inlet of the dehydrogenation tower 4 through a pipeline. The tower top outlet of the dehydrogenation tower 4 is connected to the tube side inlet of the dehydrogenation tower condenser 5 through a pipeline. The liquid phase tube side outlet of the dehydrogenation tower condenser 5 is connected to the inlet of the dehydrogenation tower liquid separator 6 through a pipeline. The bottom liquid phase outlet of the dehydrogenation tower liquid separator 6 is returned to the top of the dehydrogenation tower 4 through a pipeline. The tower kettle outlet of the dehydrogenation tower 4 is connected to the inlet (middle inlet) of the denitrogenation tower 2 through a pipeline. The tower top outlet of the denitrogenation tower 2 is connected to the tube side inlet of the denitrogenation tower condenser 8 through a pipeline. The bottom liquid phase tube side outlet of the denitrogenation tower condenser 8 is connected to the inlet of the denitrogenation tower liquid separator 9 through a pipeline. The bottom liquid phase outlet of the denitrogenation tower liquid separator 9 is returned to the top of the denitrogenation tower 2 through a pipeline. The top gas phase outlet of the denitrogenation tower liquid separator 9 is connected to the first channel h1 of the subcooling heat exchanger 10 and the first hot channel H1 of the main heat exchanger 1 in sequence through a pipeline. The first hot channel H1 outlet of the main heat exchanger 1 is connected to the nitrogen-rich gas discharge pipeline L2. The tower bottom outlet of the denitrogenation tower 2 is connected to the third cold channel C3 inlet of the main heat exchanger 1 through a pipeline. The third cold channel C3 outlet is connected to the LNG discharge pipeline L3.

[0052] The liquid nitrogen washing unit comprises a washing tower 7. The top outlet of the dehydrogenation tower liquid separator 6 is connected to the lower inlet of the washing tower 7 through a pipeline. The tower bottom outlet of the washing tower 7 is connected to the second channel h2 of the subcooling heat exchanger 10 and the second hot channel H2 of the main heat exchanger 1 in sequence through a pipeline. The second hot channel H2 outlet pipeline is connected to the nitrogen-rich gas discharge pipeline L2. The tower top outlet of the washing tower 7 is connected to the third channel h3 of the subcooling heat exchanger 10 and the third hot channel H3 of the main heat exchanger 1 in sequence through a pipeline. The third hot channel H3 outlet is connected to the hydrogen-rich gas discharge pipeline L4 through a pipeline.

[0053] In a preferred embodiment, the nitrogen refrigeration cycle unit comprises a nitrogen refrigeration compression system 11, a nitrogen refrigerant feed line L5 from the nitrogen refrigeration compression system 11 is connected to the fourth cold channel C4 of the main heat exchanger 1 and the fourth channel (which is a cold channel) c4 of the subcooling heat exchanger 10 in sequence, the fourth channel c4 outlet is divided into three paths by pipes, the first path is connected to the shell inlet of the dehydrogenation column condenser 5, the second path is connected to the shell inlet of the dehydrogenation column condenser 8, and the third path is connected to the overhead nitrogen refrigerant inlet of the scrubbing column 7, the top shell outlet pipe of the dehydrogenation column condenser 5 is merged with the top shell outlet pipe of the dehydrogenation column condenser 8, and then connected to the fifth channel (which is a hot channel) h5 of the subcooling heat exchanger 10 and the fourth hot channel H4 of the main heat exchanger 1 in sequence, the fourth hot channel H4 outlet is connected to the low-pressure nitrogen discharge line L6, and the other end of the low-pressure nitrogen discharge line L6 is connected to the inlet of the nitrogen refrigeration compression system 11;

[0054] The mixed refrigerant refrigeration cycle unit comprises a mixed refrigerant compression system 12, a gas-phase high-pressure refrigerant feed line L7 from the mixed refrigerant compression system 12 is connected to the fifth cold channel C5 inlet of the main heat exchanger 1, the fifth cold channel C5 outlet is returned to the fifth hot channel H5 of the main heat exchanger 1 after leaving the main heat exchanger 1 by a pipe, a liquid-phase high-pressure refrigerant feed line L8 is connected to the sixth cold channel C6 inlet of the main heat exchanger 1, the sixth cold channel C6 outlet is returned to the fifth hot channel H5 of the main heat exchanger 1 after leaving the main heat exchanger 1 by a pipe, and the fifth hot channel H5 outlet is connected to the inlet of the mixed refrigerant compression system 12 through a reflux refrigerant line L9.

[0055] In another preferred embodiment, a first regulating valve V1 is arranged on the outlet pipe of the dehydrogenation column 4, and the first regulating valve V1 is a pressure reducing valve;

[0056] A second regulating valve V2 is arranged on the outlet pipe of the first hot channel H1, and the second regulating valve V2 is a pressure reducing valve;

[0057] A third regulating valve V3 is arranged on the outlet pipe of the third cold channel C3, and the third regulating valve V3 is a throttle valve;

[0058] The outlet pipe of the second hot channel H2 is connected to the nitrogen-rich gas discharge line L2 downstream of the second regulating valve V2, and a fourth regulating valve V4 is arranged on the outlet pipe of the second hot channel H2, and the fourth regulating valve V4 is a pressure reducing valve;

[0059] A fifth regulating valve V5 is arranged on the outlet pipe of the third hot channel H3, and the fifth regulating valve V5 is a pressure reducing valve;

[0060] A sixth regulating valve V6 is arranged on the pipe between the fourth channel c4 outlet and the upper inlet of the dehydrogenation column condenser 5, and the sixth regulating valve V6 is a pressure reducing valve;

[0061] A seventh regulating valve V7 is arranged on the pipeline between the fourth passage c4 outlet and the upper inlet of the denitrification tower condenser 8, and the seventh regulating valve V7 is a pressure reducing valve;

[0062] An eighth regulating valve V8 is arranged on the pipeline between the fourth passage c4 outlet and the overhead inlet of the washing tower 7, and the eighth regulating valve V8 is a pressure reducing valve;

[0063] A ninth regulating valve V9 is arranged on the pipeline between the fifth cold passage C5 outlet and the fifth hot passage H5 inlet, and the ninth regulating valve V9 is a throttle valve;

[0064] A tenth regulating valve V10 is arranged on the pipeline between the sixth cold passage C6 outlet and the fifth hot passage H5 inlet, and the tenth regulating valve V10 is a throttle valve.

[0065] In another preferred embodiment, the denitrification tower reboiler 3 is arranged at the bottom of the denitrification tower 2.

[0066] In another embodiment, the fourth passage c4 of the subcooling heat exchanger 10 is still three-way through the pipeline, but the valve V8 is not opened, the first way is connected with the shell side inlet of the dehydrogenation tower condenser 5, the second way valve V8 is in the closed state, and the third way is connected with the shell side inlet of the denitrification tower condenser 8, which is suitable for the integrated device for co-producing hydrogen and nitrogen gas and liquefied natural gas from the raw material gas being synthesis gas.

[0067] The nitrogen refrigeration compression system 11 can adopt those known in the art, for example, can include a nitrogen compressor, a nitrogen inlet buffer tank, and a nitrogen outlet buffer tank.

[0068] The mixed refrigerant compression system 12 can adopt those known in the art, for example, can include a mixed refrigerant compressor, a refrigerant cooler, a refrigerant inlet distribution tank, a refrigerant outlet distribution tank, and a refrigerant regulating tank. Example 1

[0069] In this embodiment, the coke oven gas is used as the raw material gas, and the components are methane, hydrogen, nitrogen, and carbon monoxide, wherein the methane content is about 35%, the carbon monoxide content is about 6%, and the hydrogen content is about 50%.

[0070] The three-tower integrated device for co-producing hydrogen and nitrogen gas and liquefied natural gas in this embodiment co-produces hydrogen and nitrogen gas and liquefied natural gas according to the following process:

[0071] (1) Low-temperature rectification: the raw gas (35-45℃, 1.5-2.0 MPag, preferably 1.7-1.9 MPag) is extracted after being cooled by the first cold channel C1 of the main heat exchanger 1 (cooled to -120--100℃, preferably cooled to -110--102℃) through the raw gas feed line L1, and is used as the heat source for the denitrogenation column 2 auxiliary denitrogenation column reboiler 3, while heating the denitrogenation column 2 column bottom liquid, the raw gas is cooled (cooled to -145--120℃, preferably cooled to -140--130℃) and then enters the second cold channel C2 of the main heat exchanger 1 for further cooling (cooled to -165--160℃, preferably cooled to -164--161℃), and then enters the dehydrogenation column 4 (operating pressure 1.5-2.0 MPag, preferably 1.6-1.8 MPag), the overhead gas of the dehydrogenation column 4 (rich in hydrogen and carbon monoxide) is first cooled (cooled to -190--160℃, preferably cooled to -185--170℃) by the dehydrogenation column condenser 5, and then separated into gas and liquid phases by the dehydrogenation column liquid separator 6, the liquid phase is returned to the dehydrogenation column 4, and the gas phase is introduced into the washing column 7 (operating pressure 1.5-2.0 MPag, preferably 1.6-1.8 MPag), the dehydrogenation column 4 bottom liquid (rich in methane) is depressurized (depressurized to 0.3-0.6 MPag, preferably depressurized to 0.35-0.45 MPag) by the first regulating valve V1 (pressure reducing valve) and then enters the denitrogenation column 2 for rectification, the nitrogen and remaining carbon monoxide in the liquid stream are discharged from the top of the denitrogenation column 2 with the gas phase, first cooled (cooled to -190--160℃, preferably cooled to -185--170℃) by the denitrogenation column condenser 8, and then separated into gas and liquid phases by the denitrogenation column liquid separator 9, the liquid phase is returned to the denitrogenation column 2, and the gas phase (nitrogen-rich gas) discharged from the denitrogenation column liquid separator 9 is reheated (reheated to 30-40℃, preferably reheated to 32-38℃) by the first channel (which is a hot channel) h1 of the subcooling heat exchanger 10 and the first hot channel H1 of the main heat exchanger 1, depressurized to atmospheric pressure by the second regulating valve V2 (pressure reducing valve), and then sent out of the boundary area as a nitrogen-rich gas product through the nitrogen-rich gas discharge line L2, the denitrogenation column 2 column bottom liquid (LNG) is discharged from the bottom (temperature -145--130℃, preferably -140--135℃) and further cooled (cooled to -165--160℃, preferably cooled to -164--161℃) by the third cold channel C3 of the main heat exchanger 1, throttled by the third regulating valve V3 (throttle valve) and then sent out of the boundary, and the LNG product is output for storage through the LNG discharge line L3;

[0072] (2) Liquid nitrogen washing: the gas stream from the top of the dehydrogenation column 4 is contacted with liquid nitrogen from the top of the washing column 7 in a reverse direction, so that the carbon monoxide in the gas stream is absorbed by the liquid nitrogen, and the liquid phase at the bottom of the washing column 7 is vaporized and reheated (reheated to 30-40°C, preferably reheated to 32-38°C) through the second passage h2 of the subcooling heat exchanger 10 and the second hot passage H2 of the main heat exchanger 1, and then discharged to the outside through the fourth regulating valve V4 (a pressure reducing valve) after being reduced to atmospheric pressure, and then combined with the gas phase in the dehydrogenation column liquid separator tank that has been vaporized and reheated, and sent out as a nitrogen-rich gas product through the nitrogen-rich gas discharge pipeline L2;

[0073] The gas phase (hydrogen-rich gas with a carbon monoxide content of not higher than 20 ppm) at the top of the washing column 7 is discharged from the top, reheated (reheated to 30-40°C, preferably reheated to 32-38°C) through the third passage h3 of the subcooling heat exchanger 10 and the third hot passage H3 of the main heat exchanger 1, and then discharged as a hydrogen-rich gas product through the fifth regulating valve V5 (a pressure reducing valve) after being reduced to 1.4-1.8 MPag, preferably 1.5-1.6 MPag, and then through the hydrogen-rich gas discharge pipeline L4.

[0074] The refrigerant cycle in the integrated device for co-production of hydrogen and nitrogen gas and liquefied natural gas in the three-column embodiment comprises a nitrogen refrigeration cycle and a mixed refrigerant refrigeration cycle:

[0075] The cold energy required for cryogenic rectification separation is provided by the nitrogen refrigeration compression system 11, and the nitrogen refrigerant from the nitrogen refrigeration compression system 11 enters the fourth cold passage C4 of the main heat exchanger 1 and the fourth passage c4 of the subcooling heat exchanger 10 through the nitrogen refrigerant feed pipeline L5 (temperature 35-45°C, pressure 2.0-4.0 MPag, preferably 2.5-3.5 MPag) to be cooled to become liquid nitrogen (temperature -190 to -160°C, preferably -185 to -170°C), and then reduced in pressure (reduced to 0-1.0 MPag, preferably 0.2-0.5 MPag) through the sixth regulating valve V6 (a pressure reducing valve) and the seventh regulating valve V7 (a pressure reducing valve) to enter the dehydrogenation column condenser 5 and the dehydrogenation column condenser 8 to provide cold energy for the dehydrogenation column condenser 5 and the dehydrogenation column condenser 8, respectively; the nitrogen that has returned to the gas phase in the dehydrogenation column condenser 5 and the dehydrogenation column condenser 8 is reheated (reheated to 30-40°C, preferably 32-38°C) through the fifth passage h5 of the cold heat exchanger 10 and the fourth hot passage H4 of the main heat exchanger 1, and then returned to the nitrogen refrigeration compression system 11 as low-pressure nitrogen gas through the low-pressure nitrogen gas discharge pipeline L6; the liquid nitrogen is reduced in pressure (reduced to 1.5-2.0 MPag, preferably 1.6-1.8 MPag) through the eighth regulating valve V8 (a pressure reducing valve) to enter the washing column 7 to provide cold energy for the washing column 7;

[0076] The cold energy required for raw gas liquefaction is provided by the mixed refrigerant compression system 12 (the mixed refrigerant is a mixture of nitrogen, methane, ethylene, propane and isopentane), the gas-phase high-pressure refrigerant (temperature 35-45℃, pressure 2.0-4.0 MPag, preferably 2.5-3.5 MPag) from the mixed refrigerant compression system 12 enters the fifth cold channel C5 of the main heat exchanger 1 through the gas-phase high-pressure refrigerant feed line L7, is depressurized and cooled at different positions, after leaving the main heat exchanger, is throttled by the ninth regulating valve V9 (throttle valve) (depressurized to 0-1.0 MPag, preferably 0.2-0.5 MPag) to return to the fifth hot channel H5 of the main heat exchanger 1, the liquid-phase high-pressure refrigerant (temperature 35-45℃, pressure 2.0-4.0 MPag, preferably 2.5-3.5 MPag) enters the sixth cold channel C6 of the main heat exchanger 1 through the liquid-phase high-pressure refrigerant feed line L8, is depressurized and cooled at different positions, after leaving the main heat exchanger, is throttled by the tenth regulating valve V10 (throttle valve) (depressurized to 0-1.0 MPag, preferably 0.2-0.5 MPag) to return to the fifth hot channel H5 of the main heat exchanger 1, and the return flow refrigerant is reheated (reheated to 30-40℃, preferably 32-38℃) from the fifth hot channel H5 of the main heat exchanger 1 and then returned to the mixed refrigerant compression system 12 through the return flow refrigerant line L9 for recycling. Example 2

[0077] In this example, the raw gas is synthesis gas, and the components are methane, hydrogen and nitrogen, with the methane content being about 60% and the hydrogen content being about 30%.

[0078] Since there is no carbon monoxide in the synthesis gas, the liquid nitrogen does not need to be sent to the washing tower 7, and at this time, the eighth regulating valve V8 and the fourth regulating valve V4 in the integrated device for co-production of hydrogen, nitrogen and liquefied natural gas in Example 1 are closed, so that the integrated device in Example 1 can be used to co-produce hydrogen, nitrogen and liquefied natural gas with synthesis gas as the raw gas.

[0079] In summary, the integrated device for co-production of hydrogen, nitrogen and liquefied natural gas according to the present application can be applied to two kinds of raw gas, i.e. coke oven gas and synthesis gas, and the device can be flexibly switched between the two modes.

[0080] Obviously, the above examples are merely examples for clear illustration, and are not limitations on the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. An integrated plant for the co-production of hydrogen, nitrogen and liquefied natural gas with three columns, characterized in that, The application relates to a nitrogen-rich gas production system. The low-temperature rectification unit comprises a main heat exchanger (1), a denitrogenation tower (2), a denitrogenation tower reboiler (3), a dehydrogenation tower (4), a dehydrogenation tower condenser (5), a dehydrogenation tower liquid separator (6), a denitrogenation tower condenser (8), a denitrogenation tower liquid separator (9) and a subcooling heat exchanger (10); a raw gas feeding pipeline (L1) is connected with the inlet of a first cold channel (C1) of the main heat exchanger (1); the outlet of the first cold channel (C1) is connected with the inlet of the denitrogenation tower reboiler (3) through a pipeline; the outlet of the denitrogenation tower reboiler (3) is connected with the inlet of a second cold channel (C2) of the main heat exchanger (1) through a pipeline; the outlet of the second cold channel (C2) is connected with the inlet of the dehydrogenation tower (4) through a pipeline; the tower top outlet of the dehydrogenation tower (4) is connected with the tube side inlet of the dehydrogenation tower condenser (5) through a pipeline; the tube side outlet of the dehydrogenation tower condenser (5) is connected with the inlet of the dehydrogenation tower liquid separator (6) through a pipeline; the bottom liquid phase outlet of the dehydrogenation tower liquid separator (6) is returned to the top of the dehydrogenation tower (4) through a pipeline; the tower kettle outlet of the dehydrogenation tower (4) is connected with the inlet of the denitrogenation tower (2) through a pipeline; the tower top outlet of the denitrogenation tower (2) is connected with the tube side inlet of the denitrogenation tower condenser (8) through a pipeline; the tube side outlet of the denitrogenation tower condenser (8) is connected with the inlet of the denitrogenation tower liquid separator (9) through a pipeline; the bottom liquid phase outlet of the denitrogenation tower liquid separator (9) is returned to the top of the denitrogenation tower (2) through a pipeline; the top gas phase outlet of the denitrogenation tower liquid separator (9) is connected with the first channel (h1) of the subcooling heat exchanger (10) and the first hot channel (H1) of the main heat exchanger (1) in sequence through pipelines; the outlet of the first hot channel (H1) of the main heat exchanger (1) is connected with a nitrogen-rich gas discharge pipeline (L2); the tower bottom outlet of the denitrogenation tower (2) is connected with the inlet of a third cold channel (C3) of the main heat exchanger (1) through a pipeline; and the outlet of the third cold channel (C3) is connected with an LNG discharge pipeline (L3). The liquid nitrogen washing unit comprises a washing tower (7); the top outlet of the dehydrogenation tower liquid separator (6) is connected with the lower inlet of the washing tower (7) through a pipeline; the tower bottom outlet of the washing tower (7) is connected with the second channel (h2) of the subcooling heat exchanger (10) and the second hot channel (H2) of the main heat exchanger (1) in sequence through pipelines; the outlet pipeline of the second hot channel (H2) is connected with the nitrogen-rich gas discharge pipeline (L2); the tower top outlet of the washing tower (7) is connected with the third channel (h3) of the subcooling heat exchanger (10) and the third hot channel (H3) of the main heat exchanger (1) in sequence through pipelines; and the outlet pipeline of the third hot channel (H3) is connected with a hydrogen-rich gas discharge pipeline (L4). ​ 2. The integrated device of claim 1, wherein, The nitrogen refrigeration cycle unit comprises a nitrogen refrigeration compression system (11), a nitrogen refrigerant feeding pipeline (L5) from the nitrogen refrigeration compression system (11) is connected with a fourth cold channel (C4) of a main heat exchanger (1) and a fourth channel (c4) of a subcooling heat exchanger (10) in sequence, the fourth channel (c4) outlet is divided into three ways through a pipeline, the first way is connected with an inlet of a shell side of a dehydrogenation column condenser (5), the second way is connected with an inlet of a shell side of a dehydrogenation column condenser (8), the third way is connected with a top inlet of a washing column (7), a top shell side outlet pipeline of the dehydrogenation column condenser (5) is combined with a top shell side outlet pipeline of the dehydrogenation column condenser (8) and then connected with a fifth channel (h5) of the subcooling heat exchanger (10) and a fourth hot channel (H4) of the main heat exchanger (1) in sequence, the fourth hot channel (H4) outlet is connected with a low-pressure nitrogen outlet pipeline (L6), the other end of the low-pressure nitrogen outlet pipeline (L6) is connected with an inlet of the nitrogen refrigeration compression system (11); The mixed refrigerant refrigeration cycle unit comprises a mixed refrigerant compression system (12), a gaseous high-pressure refrigerant feeding pipeline (L7) from the mixed refrigerant compression system (12) is connected with an inlet of a fifth cold channel (C5) of the main heat exchanger (1), a fifth cold channel (C5) outlet is returned to a fifth hot channel (H5) of the main heat exchanger (1) through a pipeline after leaving the main heat exchanger (1), a liquid high-pressure refrigerant feeding pipeline (L8) is connected with an inlet of a sixth cold channel (C6) of the main heat exchanger (1), a sixth cold channel (C6) outlet is returned to the fifth hot channel (H5) of the main heat exchanger (1) through a pipeline after leaving the main heat exchanger (1), and a fifth hot channel (H5) outlet is connected with an inlet of the mixed refrigerant compression system (12) through a reflux refrigerant pipeline (L9).

3. The integrated device of claim 1 or 2, wherein, A first regulating valve (V1) is arranged on a column kettle outlet pipeline of the dehydrogenation column (4), and the first regulating valve (V1) is a pressure reducing valve; and / or, A second regulating valve (V2) is arranged on an outlet pipeline of the first hot channel (H1), and the second regulating valve (V2) is a pressure reducing valve; and / or, A fourth regulating valve (V4) is arranged on the second hot channel (H2) outlet pipeline downstream of the second regulating valve (V2), and the fourth regulating valve (V4) is a pressure reducing valve; and / or, A fifth regulating valve (V5) is arranged on the third hot channel (H3) outlet pipeline, and the fifth regulating valve (V5) is a pressure reducing valve.

4. The integrated device of claim 3, wherein, A third regulating valve (V3) is arranged on the third cold channel (C3) outlet pipeline, and the third regulating valve (V3) is a throttle valve.

5. The integrated device of claim 4, wherein, A sixth regulating valve (V6) is arranged on a pipeline between the fourth channel (c4) outlet and an upper inlet of the dehydrogenation column condenser (5), and the sixth regulating valve (V6) is a pressure reducing valve; and / or, A seventh regulating valve (V7) is arranged on a pipeline between the fourth channel (c4) outlet and an upper inlet of the dehydrogenation column condenser (8), and the seventh regulating valve (V7) is a pressure reducing valve; and / or, An eighth regulating valve (V8) is arranged on a pipeline between the fourth channel (c4) outlet and a top inlet of the washing column (7), and the eighth regulating valve (V8) is a pressure reducing valve.

6. The integrated device of claim 5, wherein, A ninth regulating valve (V9) is arranged on the pipeline between the outlet of the fifth cold channel (C5) and the inlet of the fifth hot channel (H5), and the ninth regulating valve (V9) is a throttle valve.

7. The integrated device of claim 6, wherein A tenth regulating valve (V10) is arranged on the pipeline between the outlet of the sixth cold channel (C6) and the inlet of the fifth hot channel (H5), and the tenth regulating valve (V10) is a throttle valve.

8. The integrated device of claim 1 or 2, wherein, The denitrogenation tower reboiler (3) is arranged at the bottom of the denitrogenation tower (2).

9. The integrated device of claim 2, wherein, When the raw material gas is the synthesis gas, the synthesis gas is washed in the washing tower without washing, and the fourth channel of the subcooling heat exchanger is divided into three channels by a pipeline, the first channel is connected with the shell inlet of the dehydrogenation tower condenser, the valve of the second channel is in a closed state, and the third channel is connected with the shell inlet of the denitrogenation tower condenser.

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