CN117490349A - Device and method for recycling natural gas and hydrogen by low-temperature method - Google Patents

Device and method for recycling natural gas and hydrogen by low-temperature method Download PDF

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Publication number
CN117490349A
CN117490349A CN202311758578.9A CN202311758578A CN117490349A CN 117490349 A CN117490349 A CN 117490349A CN 202311758578 A CN202311758578 A CN 202311758578A CN 117490349 A CN117490349 A CN 117490349A
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China
Prior art keywords
heat exchanger
gas
water
hydrogen
gas separator
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Application number
CN202311758578.9A
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Chinese (zh)
Inventor
王耀亮
李超凡
王传瑞
马海鸣
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Shanghai Yueshen Energy Technology Co ltd
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Shanghai Yueshen Energy Technology Co ltd
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Priority to CN202311758578.9A priority Critical patent/CN117490349A/en
Publication of CN117490349A publication Critical patent/CN117490349A/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/06—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation
    • F25J3/0605—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation characterised by the feed stream
    • F25J3/062—Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/06—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation
    • F25J3/063—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation characterised by the separated product stream
    • F25J3/0635—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation characterised by the separated product stream separation of CnHm with 1 carbon atom or more
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/06—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation
    • F25J3/063—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation characterised by the separated product stream
    • F25J3/064—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation characterised by the separated product stream separation of CnHm with 2 carbon atoms or more
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/06—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation
    • F25J3/063—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation characterised by the separated product stream
    • F25J3/0655—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation characterised by the separated product stream separation of hydrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/40—Processes or apparatus using other separation and/or other processing means using hybrid system, i.e. combining cryogenic and non-cryogenic separation techniques
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/60—Processes or apparatus using other separation and/or other processing means using adsorption on solid adsorbents, e.g. by temperature-swing adsorption [TSA] at the hot or cold end
    • F25J2205/64—Processes or apparatus using other separation and/or other processing means using adsorption on solid adsorbents, e.g. by temperature-swing adsorption [TSA] at the hot or cold end by pressure-swing adsorption [PSA] at the hot end
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2210/00—Processes characterised by the type or other details of the feed stream
    • F25J2210/12—Refinery or petrochemical off-gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2210/00—Processes characterised by the type or other details of the feed stream
    • F25J2210/42—Nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/90—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
    • F25J2270/904—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration by liquid or gaseous cryogen in an open loop

Abstract

The invention discloses a device and a method for recycling natural gas and hydrogen by a low-temperature method, which belong to the technical field of waste gas recycling, and comprise a compressor, a purification assembly, a cold box, a first heat exchanger, a first water-gas separator, a second heat exchanger, a second water-gas separator and a PSA pressure swing adsorption system; the first heat exchanger, the first water-gas separator, the second heat exchanger and the second water-gas separator are all positioned in the cold box; by adopting the mode, the method provided by the invention adopts the low-temperature method to recycle the natural gas and hydrogen in the methane waste gas, and has the following advantages compared with the traditional membrane separation method: the purity of the product gas is high; the hydrogen mixed gas can be further purified and recycled, so that waste can be avoided; the separation efficiency is high.

Description

Device and method for recycling natural gas and hydrogen by low-temperature method
Technical Field
The invention relates to the technical field of waste gas recovery, in particular to a device and a method for recovering natural gas and hydrogen by a low-temperature method.
Background
Methane is a colorless, odorless gas and is widely used as a fuel in the civil and industrial industries. In the methane production process, if other gas impurities are mixed into methane, the methane is contaminated, and if the methane is discharged as an exhaust gas, the methane consumption is increased, the production cost is high, and the like, so that the contaminated methane needs to be recovered and reused after purification.
The raw gas, that is, methane off-gas, generally contains hydrogen impurities and small amounts of impurities such as air, moisture, and carbon dioxide mixed in due to transportation.
The impurities in the waste gas can be separated by adopting a traditional membrane separation method and a low-temperature method;
the traditional membrane separation method is an exhaust gas treatment method for reducing pollutant emission by separating gas or liquid through a membrane, and has the problems that the purity of product gas, the separation efficiency, the purification effect of hydrogen mixed gas and the like are required to be further improved;
the low temperature method is an exhaust gas treatment method for realizing separation by utilizing the boiling point difference of different gases at low temperature, and how to better apply the method to methane exhaust gas treatment is a technical problem to be solved by the invention.
Based on the above, the present invention has devised an apparatus for recovering natural gas and hydrogen gas by a low temperature method and a method thereof to solve the above-mentioned problems.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, the present invention provides an apparatus for recovering natural gas and hydrogen gas by a low temperature process and a method thereof.
In order to achieve the above purpose, the invention is realized by the following technical scheme:
a device for recycling natural gas and hydrogen by a low-temperature method comprises a compressor, a purification assembly, a cold box, a first heat exchanger, a first water-gas separator, a second heat exchanger, a second water-gas separator and a PSA pressure swing adsorption system; the first heat exchanger, the first water-gas separator, the second heat exchanger and the second water-gas separator are all positioned in the cold box;
the discharge end of the compressor is connected with the feed end of the purification assembly, and the discharge end of the purification assembly is connected with the feed end of the first heat exchanger; the discharge end of the first heat exchanger is connected with the feed end of the first water-gas separator, the liquid outlet end of the first water-gas separator is connected with the liquid non-methane total hydrocarbon storage tank, the gas outlet end of the first water-gas separator is connected with the feed end of the second heat exchanger, the discharge end of the second heat exchanger is connected with the feed end of the second water-gas separator, the liquid outlet end of the second water-gas separator is connected with the liquid inlet end of the second heat exchanger, and the gas outlet end of the second heat exchanger is connected with the PSA pressure swing adsorption system.
Further, the purification component comprises a refrigerator, an activated carbon deoiler, a deaerator, a first adsorption tower and a second adsorption tower; the discharge end of the compressor is connected with the feed end of the refrigerator, the discharge end of the refrigerator is connected with the feed end of the activated carbon deoiler, the discharge end of the activated carbon deoiler is connected with the feed end of the deaerator, the discharge end of the deaerator is connected with the feed end of the first absorption tower and the second absorption tower which are connected in parallel, and the discharge end of the first absorption tower and the second absorption tower is connected with the feed end of the first heat exchanger.
Further, the other liquid inlet end of the second heat exchanger is connected with a liquid nitrogen storage tank.
Further, the deaerator is filled with palladium-carbon deoxidizer.
Further, the first adsorption tower and the second adsorption tower are filled with 13X molecular sieves.
Further, the temperature of the first heat exchanger is-110 ℃.
Further, the temperature of the second heat exchanger was-190 ℃.
Still further, the feed gas was pressurized to 22.5barg using a compressor.
The application method of the device for recycling the natural gas and the hydrogen by the low-temperature method comprises the following steps:
1. the pressurized raw material gas enters a refrigerator and an active carbon deoiler to realize deoiling;
2. the deoiled raw gas enters a deaerator to deoxidize, and hydrogen, methane and oxygen react to generate water and carbon dioxide under the action of a palladium-carbon deoxidizer;
3. the reacted raw material gas enters a first absorption tower or a second absorption tower, and water and carbon dioxide are removed through a 13X molecular sieve;
4. the raw material gas after removing carbon dioxide and water enters a first heat exchanger in a cold box, the temperature of the first heat exchanger is 110 ℃ below zero, and the first heat exchanger changes non-methane total hydrocarbon into liquid state due to different boiling points of components;
5. the liquid and the gas of the first heat exchanger enter a first water-gas separator, wherein the liquid non-methane total hydrocarbon is discharged through a liquid outlet end of the first water-gas separator;
6. the rest of gas in the first water-gas separator enters a second heat exchanger, the temperature of the second heat exchanger is 190 ℃ below zero, the pressure is 2 barg to 6barg by injecting a stream of liquid nitrogen, cold energy is provided for the second heat exchanger, heat exchange is carried out, and then nitrogen is discharged through the air outlet end of the second heat exchanger; the hydrogen and the nitrogen are discharged to the PSA pressure swing adsorption system through the second heat exchanger to realize separation; wherein methane becomes liquid due to its lower boiling point;
7. the liquid methane enters a second water-gas separator, is conveyed to a second heat exchanger through the second water-gas separator to carry out heat mass exchange, is changed into gaseous methane and is discharged.
Advantageous effects
The invention adopts a low-temperature method to recycle natural gas and hydrogen in methane waste gas, and the principle is as follows: after compressing and purifying the raw material gas, using a heat exchange mode to enable the components with low boiling points to be liquid; the purified feed gas is mainly a mixture of methane, hydrogen, nitrogen and non-methane total hydrocarbons; separating by utilizing the difference of boiling points of methane and hydrogen to obtain natural gas and hydrogen;
the process of the invention is that raw gas is pressurized to 22.5barg by a compressor, deoiled by a refrigerator and an active carbon deoiler, and deoxygenated by a deaerator; removing carbon dioxide and water through a first absorption tower or a second absorption tower, so that high-boiling impurities in the raw material gas are removed in advance, and the blockage of channels in equipment is avoided, so that the standard of entering a cold box is achieved; the separation is completed in a cold box by utilizing the difference of boiling points of hydrogen, methane and non-methane total hydrocarbons, the non-methane total hydrocarbons are changed into liquid state and discharged, the mixed gas of the hydrogen and the nitrogen enters a PSA pressure swing adsorption system for further separation, and the methane can be sent to a user pipeline;
compared with the traditional membrane separation method, the invention has the following advantages: 1. the purity of the product gas is high; 2. the hydrogen mixed gas can be further purified and recycled, so that waste can be avoided; 3. the separation efficiency is high.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is evident that the drawings in the following description are only some embodiments of the present invention and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.
FIG. 1 is a schematic diagram of an apparatus for recovering natural gas and hydrogen by cryogenic process according to the present invention.
Reference numerals in the drawings represent respectively:
1. compressor 2, refrigerator 3, active carbon deoiler 4, deaerator 5, first adsorption tower 6, cold box 7, first heat exchanger 8, first moisture separator 9, second heat exchanger 10, second moisture separator 11, second absorption tower 12, PSA pressure swing adsorption system.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It will be apparent that the described embodiments are some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention is further described below with reference to examples.
In some embodiments, referring to fig. 1 of the specification, an apparatus for recovering natural gas and hydrogen by a low temperature method includes a compressor 1, a refrigerator 2, an activated carbon deoiler 3, a deaerator 4, a first adsorption tower 5, a cold box 6, a first heat exchanger 7, a first moisture separator 8, a second heat exchanger 9, a second moisture separator 10, a second absorption tower 11, and a PSA pressure swing adsorption system 12;
the discharge end of the compressor 1 is connected with the feed end of the refrigerator 2, the discharge end of the refrigerator 2 is connected with the feed end of the activated carbon deoiler 3, the discharge end of the activated carbon deoiler 3 is connected with the feed end of the deaerator 4, the discharge end of the deaerator 4 is connected with the feed ends of the first adsorption tower 5 and the second adsorption tower 11 which are connected in parallel, the discharge ends of the first adsorption tower 5 and the second adsorption tower 11 are connected with the feed end of the first heat exchanger 7, and the first heat exchanger 7, the first water-gas separator 8, the second heat exchanger 9 and the second water-gas separator 10 are all positioned in the cold box 6;
the discharge end of the first heat exchanger 7 is connected with the feed end of the first water-gas separator 8, the liquid outlet end of the first water-gas separator 8 is connected with the liquid non-methane total hydrocarbon storage tank, the gas outlet end of the first water-gas separator 8 is connected with the feed end of the second heat exchanger 9, the discharge end of the second heat exchanger 9 is connected with the feed end of the second water-gas separator 10, the liquid outlet end of the second water-gas separator 10 is connected with the liquid inlet end of the second heat exchanger 9, and the gas outlet end of the second heat exchanger 9 is connected with the PSA pressure swing adsorption system 12; the other liquid inlet end of the second heat exchanger 9 is connected with a liquid nitrogen storage tank;
the deaerator 4 is filled with a palladium-carbon deoxidizer;
13X molecular sieves are filled in the first adsorption tower 5 and the second adsorption tower 11;
the temperature of the first heat exchanger 7 is-110 ℃;
the temperature of the second heat exchanger 9 is-190 ℃;
the application principle of the invention is as follows:
after the feed gas enters the compressor 1, the feed gas is pressurized to 22.5barg by the compressor 1;
the pressurized raw material gas enters a refrigerator 2 and an active carbon deoiler 3 to realize deoiling;
the deoiled raw gas enters a deaerator 4 to deoxidize, and hydrogen, methane and oxygen react to generate water and carbon dioxide under the action of a palladium-carbon deoxidizer;
the reacted raw material gas enters a first absorption tower 5 or a second absorption tower 11, and water and carbon dioxide are removed through a 13X molecular sieve; the first adsorption tower 5 or the second adsorption tower 11 is used alternatively, for example, the second adsorption tower 11 is regenerated by air or nitrogen while the first adsorption tower 5 is operated for adsorption;
the raw material gas after removing carbon dioxide and water enters a first heat exchanger 7 in a cold box 6, the temperature of the first heat exchanger 7 is-110 ℃, and the first heat exchanger 7 changes non-methane total hydrocarbon into liquid state due to different boiling points of components;
the liquid and the gas of the first heat exchanger 7 enter the first water-gas separator 8, wherein the liquid non-methane total hydrocarbon is discharged through the liquid outlet end of the first water-gas separator 8, so that the separation purpose is realized;
the rest of the gas in the first water-gas separator 8 enters the second heat exchanger 9, the temperature of the second heat exchanger 9 is 190 ℃ below zero, the pressure is 2 barg to 6barg by injecting a stream of liquid nitrogen, the cold energy is provided for the second heat exchanger 9, heat exchange is carried out, and then the nitrogen is discharged through the air outlet end of the second heat exchanger 9; wherein, the hydrogen and the nitrogen are discharged to the PSA pressure swing adsorption system 12 through the second heat exchanger 9 to realize separation; wherein methane becomes liquid due to its lower boiling point;
the liquid methane enters a second water-gas separator 10, is conveyed to a second heat exchanger 9 through the second water-gas separator 10 to perform heat and mass exchange, is changed into gaseous methane and is discharged;
the invention adopts a low-temperature method to recycle natural gas and hydrogen, and the principle is as follows: after compressing and purifying the raw material gas, using a heat exchange mode to enable the components with low boiling points to be liquid; the purified feed gas is mainly a mixture of methane, hydrogen, nitrogen and non-methane total hydrocarbons; separating by utilizing the difference of boiling points of methane and hydrogen to obtain natural gas and hydrogen;
the process of the invention is that raw gas is pressurized to 22.5barg through a compressor 1, deoiled through a refrigerator and an active carbon deoiler 3, and deoxidized through a deoxidizer 4; removing carbon dioxide and water through the first adsorption tower 5 or the second adsorption tower 11 to remove high boiling impurities in the raw material gas in advance, so as to avoid blocking the channels in the equipment and reach the standard of entering the cold box 6; the separation is completed in the cold box 6 by utilizing the difference of boiling points of hydrogen, methane and non-methane total hydrocarbons, the non-methane total hydrocarbons are changed into liquid state and discharged, the mixed gas of the hydrogen and the nitrogen enters the PSA pressure swing adsorption system 12 for further separation, and the methane can be sent to a user pipeline;
compared with the traditional membrane separation method, the invention has the following advantages: 1. the purity of the product gas is high; 2. the hydrogen mixed gas can be further purified and recycled, so that waste can be avoided; 3. the separation efficiency is high.
In some embodiments, a method of using the apparatus for recovering natural gas and hydrogen using a cryogenic process, comprises the steps of:
1. the pressurized raw material gas enters a refrigerator 2 and an active carbon deoiler 3 to realize deoiling;
2. the deoiled raw gas enters a deaerator 4 to deoxidize, and hydrogen, methane and oxygen react to generate water and carbon dioxide under the action of a palladium-carbon deoxidizer;
3. the reacted raw material gas enters a first absorption tower 5 or a second absorption tower 11, and water and carbon dioxide are removed through a 13X molecular sieve;
4. the raw material gas after removing carbon dioxide and water enters a first heat exchanger 7 in a cold box 6, the temperature of the first heat exchanger 7 is-110 ℃, and the first heat exchanger 7 changes non-methane total hydrocarbon into liquid state due to different boiling points of components;
5. the liquid and the gas of the first heat exchanger 7 enter a first water-gas separator 8, wherein the liquid non-methane total hydrocarbon is discharged through a liquid outlet end of the first water-gas separator 8;
6. the rest of the gas in the first water-gas separator 8 enters the second heat exchanger 9, the temperature of the second heat exchanger 9 is 190 ℃ below zero, the pressure is 2 barg to 6barg by injecting a stream of liquid nitrogen, the cold energy is provided for the second heat exchanger 9, heat exchange is carried out, and then the nitrogen is discharged through the air outlet end of the second heat exchanger 9; wherein, the hydrogen and the nitrogen are discharged to the PSA pressure swing adsorption system 12 through the second heat exchanger 9 to realize separation; wherein methane becomes liquid due to its lower boiling point;
7. the liquid methane enters the second water-gas separator 10, is conveyed to the second heat exchanger 9 through the second water-gas separator 10 for heat and mass exchange, is changed into gaseous methane and is discharged.
The above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (9)

1. The device for recycling the natural gas and the hydrogen by using the low-temperature method is characterized by comprising a compressor (1), a purification assembly, a cold box (6), a first heat exchanger (7), a first water-gas separator (8), a second heat exchanger (9), a second water-gas separator (10) and a PSA pressure swing adsorption system (12); the first heat exchanger (7), the first water-gas separator (8), the second heat exchanger (9) and the second water-gas separator (10) are all positioned in the cold box (6);
the discharge end of the compressor (1) is connected with the feed end of the purification assembly, and the discharge end of the purification assembly is connected with the feed end of the first heat exchanger (7); the discharging end of the first heat exchanger (7) is connected with the feeding end of the first water-gas separator (8), the liquid outlet end of the first water-gas separator (8) is connected with the liquid non-methane total hydrocarbon storage tank, the gas outlet end of the first water-gas separator (8) is connected with the feeding end of the second heat exchanger (9), the discharging end of the second heat exchanger (9) is connected with the feeding end of the second water-gas separator (10), the liquid outlet end of the second water-gas separator (10) is connected with the liquid inlet end of the second heat exchanger (9), and the gas outlet end of the second heat exchanger (9) is connected with the PSA pressure swing adsorption system (12).
2. The apparatus for recovering natural gas and hydrogen by cryogenic process according to claim 1, characterized in that the purification assembly comprises a refrigerator (2), an activated carbon deoiler (3), a deaerator (4), a first adsorption column (5) and a second adsorption column (11); the discharge end of compressor (1) is connected with the feed end of refrigerator (2), and the discharge end of refrigerator (2) is connected with the feed end of active carbon deoiler (3), and the discharge end of active carbon deoiler (3) is connected with the feed end of oxygen-eliminating device (4), and the discharge end of oxygen-eliminating device (4) is connected with the feed end of parallelly connected first adsorption tower (5) and second adsorption tower (11), and the discharge end of first adsorption tower (5) and second adsorption tower (11) is connected with the feed end of first heat exchanger (7).
3. The device for recovering natural gas and hydrogen by cryogenic process according to claim 2, characterized in that the other liquid inlet end of the second heat exchanger (9) is connected to a liquid nitrogen storage tank.
4. The apparatus for recovering natural gas and hydrogen by cryogenic process according to claim 3, characterized in that the deaerator (4) is filled with palladium carbon deoxidizer.
5. The apparatus for recovering natural gas and hydrogen by cryogenic process according to claim 4, wherein the first adsorption tower (5) and the second adsorption tower (11) are each packed with 13X molecular sieve.
6. The plant for the recovery of natural gas and hydrogen at low temperature according to claim 5, characterized in that the temperature of the first heat exchanger (7) is-110 ℃.
7. The plant for the recovery of natural gas and hydrogen at low temperature according to claim 6, characterized in that the temperature of the second heat exchanger (9) is-190 ℃.
8. The plant for the recovery of natural gas and hydrogen at low temperature according to claim 7, characterized in that the feed gas is pressurized to 22.5barg by means of a compressor (1).
9. A method of using the cryogenic natural gas and hydrogen recovery apparatus of claim 8, comprising the steps of:
1. the pressurized raw material gas enters a refrigerator (2) and an active carbon deoiling device (3) to realize deoiling;
2. the deoiled raw gas enters a deaerator (4) to deoxidize, and hydrogen, methane and oxygen react to generate water and carbon dioxide under the action of a palladium-carbon deoxidizer;
3. the reacted raw material gas enters a first adsorption tower (5) or a second adsorption tower (11), and water and carbon dioxide are removed through a 13X molecular sieve;
4. the raw material gas after removing carbon dioxide and water enters a first heat exchanger (7) in a cold box (6), the temperature of the first heat exchanger (7) is-110 ℃, and the first heat exchanger (7) changes non-methane total hydrocarbon into liquid state due to different boiling points of components;
5. the liquid and the gas of the first heat exchanger (7) enter a first water-gas separator (8), wherein the liquid non-methane total hydrocarbon is discharged through a liquid outlet end of the first water-gas separator (8);
6. the rest of gas in the first water-gas separator (8) enters a second heat exchanger (9), the temperature of the second heat exchanger (9) is 190 ℃ below zero, a stream of liquid nitrogen is injected, the pressure is 2 barg to 6barg, cold energy is provided for the second heat exchanger (9) for heat exchange, and then nitrogen is discharged through the air outlet end of the second heat exchanger (9); wherein, the hydrogen and the nitrogen are discharged to the PSA pressure swing adsorption system (12) through the second heat exchanger (9) to realize separation; wherein methane becomes liquid due to its lower boiling point;
7. the liquid methane enters a second water-gas separator (10), is conveyed to a second heat exchanger (9) through the second water-gas separator (10) to carry out heat mass exchange, is changed into gaseous methane, and is discharged.
CN202311758578.9A 2023-12-20 2023-12-20 Device and method for recycling natural gas and hydrogen by low-temperature method Pending CN117490349A (en)

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