Method for efficiently recovering hydrogen by using raw gas in coal chemical industry

Abstract

The invention relates to the field of hydrogen recovery, and discloses a method for efficiently recovering hydrogen by using raw gas in coal chemical industry, which comprises the following steps: pretreating the raw gas to remove sulfides, particulate matters and tar in the raw gas; carbon dioxide in coal gas is removed through chemical absorption, and moisture is removed through a condensation technology; high-purity hydrogen is separated under different pressure conditions through a pressure swing adsorption technology, impurities in raw gas are selectively adsorbed through activated carbon through the PSA technology, the hydrogen is recycled in the desorption process, and the hydrogen is separated through the permeation rate difference of the membrane to different gases through a selective permeable membrane; and the recovered high-purity hydrogen is compressed, and the hydrogen is stored by using the high-pressure storage tank, so that the method has the advantages of improving economic benefits and sustainability.

Description

Technical Field

[0001] The invention relates to the field of hydrogen recovery, and in particular to a method for efficiently recovering hydrogen by utilizing waste gas from coal chemical industry. Background Art

[0002] At present, the method of using coal chemical waste gas for efficient hydrogen recovery usually adopts pressure swing adsorption (PSA) technology. PSA technology separates high-purity hydrogen from waste gas by adsorbing and desorbing specific gas components at different pressures. In the specific operation process, the waste gas first enters the adsorption tower, which is filled with an adsorbent with selective adsorption capacity. Under high pressure, the adsorbent preferentially adsorbs the impurity gases (such as carbon dioxide, methane, etc.) in the waste gas, while hydrogen is not adsorbed and discharged as product gas. When the adsorbent reaches saturation, it is desorbed by reducing the pressure and regenerated to continue the next round of adsorption process. However, this method also has some challenges, such as the selection of adsorbents and the efficiency of the regeneration process. In addition, when the PSA system is used to process large-scale waste gas, it requires fine control and maintenance to ensure the stable operation of the system and the high efficiency of hydrogen recovery. Therefore, it is necessary to design a method for efficient hydrogen recovery using coal chemical waste gas to improve economic benefits and sustainability. Summary of the invention

[0003] 1. Technical issues to be solved

[0004] In view of the deficiencies in the prior art, the present invention provides a method for efficiently recovering hydrogen using coal chemical waste gas, which has the advantages of improving economic benefits and sustainability, and solves the problems in the above-mentioned background technology.

[0005] (II) Technical solution

[0006] In order to achieve the above-mentioned purpose of improving economic benefits and sustainability, the present invention provides the following technical solution: a method for efficiently recovering hydrogen using coal chemical waste gas, comprising the following steps:

[0007] S1: Pre-treat the raw gas to remove sulfides, particulate matter and tar in the raw gas;

[0008] S2: Use chemical absorption to remove carbon dioxide from coal gas and condensation technology to remove water;

[0009] S3: Through pressure swing adsorption technology, high-purity hydrogen is separated under different pressure conditions. PSA technology uses activated carbon to selectively adsorb impurities in raw coal gas, so that hydrogen can be recovered during the desorption process. It uses selective permeation membranes to separate hydrogen through the difference in permeation rates of different gases.

[0010] S4: compress the recovered high-purity hydrogen and store it in a high-pressure storage tank.

[0011] According to the above technical scheme, S1 further includes using an absorption liquid to contact the raw gas through a spray or absorption tower to absorb sulfides in the gas, using a solid adsorbent to adsorb sulfides in a fixed bed reactor, and using an electrostatic field to charge the particles in the raw gas and deposit them on a dust collecting plate to treat a large flow of raw gas, using a bag to filter the particles in the raw gas to capture small particles, and using a rotating airflow to separate the particles under the action of centrifugal force to remove large particles, cooling the raw gas to a low temperature to condense and separate tar and water vapor, spraying the raw gas with a coolant in a spray tower to dissolve or condense the tar and take it out, and using activated carbon and silica gel to adsorb the tar.

[0012] According to the above technical scheme, S2 further includes installing an absorption tower, filling fillers, configuring absorbent solution as needed, and storing it in an absorbent storage tank, passing coal gas into the bottom of the absorption tower, and evenly distributing it through a gas distribution device, spraying the absorbent solution from the top of the tower, countercurrently contacting with the rising coal gas, absorbing carbon dioxide, and carbon dioxide reacts chemically with the absorbent to generate carbonate or bicarbonate, and the absorption liquid that absorbs carbon dioxide is discharged from the bottom of the tower and sent to a regeneration tower for regeneration. The regeneration tower is a distillation tower, and the carbon dioxide in the absorption liquid is released by heating. The regenerated absorbent returns to the absorption tower for recycling, and the released high-purity carbon dioxide can be further compressed and stored; cold water and ethylene glycol solution are used to pre-cool the coal gas through a heat exchanger to reduce its temperature, and the pre-cooled coal gas is passed into a condenser to further reduce its temperature to below the dew point, and the water vapor condenses into liquid water. The condensed water is discharged through a drain pipe at the bottom of the condenser and collected in a water collecting tank, and the condensed water and gas are further separated by a gas-liquid separation device, and the collected condensed water is treated and discharged as needed.

[0013] According to the above technical solution, S3 further includes using multiple adsorption towers to pre-treat the raw gas, pressurizing the raw gas to the operating pressure required by the PSA system through a compressor, passing the pressurized raw gas into the adsorption tower, and the adsorbent selectively adsorbs impurities under high pressure to enrich hydrogen in the adsorption tower, collecting hydrogen-rich gas from the top of the adsorption tower, reducing the pressure of the adsorption tower, allowing the adsorbent to release the adsorbed impurity gas, and further removing residual impurities in the adsorbent by purging gas or vacuum suction to restore the adsorption capacity of the adsorbent. Each adsorption tower alternately performs adsorption and desorption processes to achieve Continuously produce high-purity hydrogen, select permeable membrane materials, membrane components use hollow fiber membranes, flat membranes or spiral wound membrane modules, optimize gas flow path and permeation efficiency, ensure that the gas entering the membrane system has been preliminarily purified, remove particulate matter and liquid impurities, and pressurize the gas to the operating pressure of the membrane system through a compressor. The pressurized gas is passed into the membrane component. Due to the small molecular volume and high permeation rate of hydrogen, it permeates through the membrane to the low-pressure side, and the impurity gas is retained on the high-pressure side. High-purity hydrogen is collected from the low-pressure side of the membrane component, and the impurity gas retained on the high-pressure side is used as fuel gas or for pre-emission treatment.

[0014] According to the above technical scheme, S4 further includes selecting a duplex compressor, the material of the compressor should be resistant to hydrogen corrosion and have good sealing performance, multi-stage compression is adopted, and intermediate cooling is performed after each stage of compression to reduce the gas temperature. An intermediate cooler is arranged between each stage of compression, and the gas temperature is reduced by cooling water or other cooling media to reduce the load of the compressor. An automatic control system is used to accurately control the compression pressure of each stage, and the gas temperature of each stage during the compression process is monitored in real time. The storage tank should be arranged in a well-ventilated, fire-proof and explosion-proof area, and away from open flames and heat sources. The compressed hydrogen is filled into the storage tank through a high-pressure pipeline and valve system, and the filling equipment should be It should have pressure regulation and safety protection functions, monitor the pressure and temperature during the filling process in real time, and the filling speed should be controlled to prevent a sharp rise in temperature due to excessive filling. The storage tank should be equipped with a pressure gauge and a safety valve to monitor the internal pressure of the storage tank in real time, regularly check the sealing of the storage tank and pipeline system, use a hydrogen leak detector for detection, and promptly discover and deal with leaks. Use a high-pressure pipeline to transport hydrogen from the storage tank to the point of use or other storage facilities. The pipeline should be made of hydrogen corrosion-resistant materials and have good sealing properties. A pressure reducing device should be installed at the point of use to reduce the high-pressure hydrogen to the required use pressure. The pressure reducing device should have pressure regulation and safety protection functions.

[0015] (III) Beneficial effects

[0016] Compared with the prior art, the present invention provides a method for efficiently recovering hydrogen using coal chemical waste gas, which has the following beneficial effects:

[0017] The method for efficiently recovering hydrogen from raw coal gas from coal chemical industry uses pressure swing adsorption technology to separate high-purity hydrogen under different pressure conditions. The PSA technology uses activated carbon to selectively adsorb impurities in the raw coal gas, so that the hydrogen can be recovered during the desorption process. The selective permeation membrane is used to separate hydrogen through the difference in permeation rates of different gases to the membrane. The hydrogen in the raw coal gas from coal chemical industry can be efficiently recovered, thereby improving economic benefits and sustainability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figure 1

[0021] The present invention provides a technical solution: a method for efficiently recovering hydrogen using coal chemical waste gas, comprising the following steps:

[0022] S1: Pre-treat the raw gas to remove sulfides, particulate matter and tar in the raw gas;

[0023] S2: Use chemical absorption to remove carbon dioxide from coal gas and condensation technology to remove water;

[0024] S3: Through pressure swing adsorption technology, high-purity hydrogen is separated under different pressure conditions. PSA technology uses activated carbon to selectively adsorb impurities in raw coal gas, so that hydrogen can be recovered during the desorption process. It uses selective permeation membranes to separate hydrogen through the difference in permeation rates of different gases.

[0025] S4: compress the recovered high-purity hydrogen and store it in a high-pressure storage tank.

[0026] S1 further includes using an absorption liquid to contact the raw gas through spraying or an absorption tower to absorb sulfides in the gas, using a solid adsorbent to adsorb sulfides in a fixed bed reactor, using an electrostatic field to charge particulate matter in the raw gas and deposit it on a dust collecting plate, which is used to treat a large flow of raw gas, using a bag to filter particulate matter in the raw gas to capture small particulate matter, using a rotating airflow to separate the particulate matter under the action of centrifugal force to remove large particulate matter, cooling the raw gas to a low temperature to condense and separate tar and water vapor, spraying the raw gas with a coolant in a spray tower to dissolve or condense the tar and bring it out, and using activated carbon and silica gel to adsorb the tar.

[0027] S2 further includes installing an absorption tower, filling fillers, preparing absorbent solution as needed, and storing it in an absorbent storage tank, passing coal gas into the bottom of the absorption tower, and evenly distributing it through a gas distribution device, and the absorbent solution is sprayed from the top of the tower, countercurrently contacts with the rising coal gas, absorbs carbon dioxide, and the carbon dioxide reacts chemically with the absorbent to generate carbonate or bicarbonate, and the absorption liquid that has absorbed carbon dioxide is discharged from the bottom of the tower and sent to a regeneration tower for regeneration. The regeneration tower is a distillation tower, and the carbon dioxide in the absorption liquid is released by heating. The regenerated absorbent is returned to the absorption tower for recycling, and the released high-purity carbon dioxide can be further compressed and stored; cold water and ethylene glycol solution are used to pre-cool the coal gas through a heat exchanger to reduce its temperature, and the pre-cooled coal gas is passed into a condenser to further reduce its temperature to below the dew point, and the water vapor condenses into liquid water. The condensed water is discharged through a drain pipe at the bottom of the condenser and collected in a water collecting tank, and the condensed water and gas are further separated by a gas-liquid separation device, and the collected condensed water is treated and discharged as needed.

[0028] S3 further includes using multiple adsorption towers to pre-treat the raw gas, pressurizing the raw gas to the operating pressure required by the PSA system through a compressor, passing the pressurized raw gas into the adsorption tower, and the adsorbent selectively adsorbs impurities under high pressure to enrich hydrogen in the adsorption tower, collecting hydrogen-rich gas from the top of the adsorption tower, reducing the pressure of the adsorption tower to release the adsorbed impurity gas, further removing residual impurities in the adsorbent by purging gas or vacuum suction, and restoring the adsorption capacity of the adsorbent. Each adsorption tower alternately performs adsorption and desorption processes to achieve continuous production of high Pure hydrogen, selective permeation membrane materials, membrane components using hollow fiber membranes, flat membranes or spiral wound membrane modules, optimize gas flow path and permeation efficiency, ensure that the gas entering the membrane system has been preliminarily purified to remove particulate matter and liquid impurities, the gas is pressurized to the operating pressure of the membrane system by a compressor, the pressurized gas is passed into the membrane component, hydrogen has a small molecular volume and a high permeation rate, it permeates through the membrane to the low-pressure side, the impurity gas is retained on the high-pressure side, high-purity hydrogen is collected from the low-pressure side of the membrane component, the impurity gas retained on the high-pressure side is used as fuel gas or for pre-emission treatment.

[0029] S4 further includes selecting a duplex compressor, the material of which should be resistant to hydrogen corrosion and have good sealing performance, adopting multi-stage compression, performing intermediate cooling after each stage of compression to reduce the gas temperature, setting an intermediate cooler between each stage of compression, reducing the gas temperature through cooling water or other cooling media, reducing the load of the compressor, using an automatic control system to accurately control the compression pressure of each stage, and monitoring the gas temperature of each stage during the compression process in real time. The storage tank should be arranged in a well-ventilated, fire-proof and explosion-proof area, away from open flames and heat sources, and the compressed hydrogen is filled into the storage tank through a high-pressure pipeline and valve system. The filling equipment should have a pressure regulating The filling speed should be controlled to prevent the temperature from rising sharply due to excessive filling. The storage tank should be equipped with a pressure gauge and a safety valve to monitor the internal pressure of the storage tank in real time. The sealing of the storage tank and the piping system should be checked regularly. A hydrogen leak detector should be used for detection to promptly discover and deal with leaks. High-pressure pipelines should be used to transport hydrogen from the storage tank to the point of use or other storage facilities. The pipelines should be made of hydrogen corrosion-resistant materials and have good sealing properties. A pressure reducing device should be installed at the point of use to reduce the high-pressure hydrogen to the required operating pressure. The pressure reducing device should have pressure regulation and safety protection functions.

[0030] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0031] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for efficiently recovering hydrogen using coal chemical waste gas. It is characterized in that The following steps are involved: S1: Pre-treat the raw gas to remove sulfides, particulate matter and tar in the raw gas; S2: Use chemical absorption to remove carbon dioxide from coal gas and condensation technology to remove water; S3: Through pressure swing adsorption technology, high-purity hydrogen is separated under different pressure conditions. PSA technology uses activated carbon to selectively adsorb impurities in raw coal gas, so that hydrogen can be recovered during the desorption process. It uses selective permeation membranes to separate hydrogen through the difference in permeation rates of different gases. S4: compress the recovered high-purity hydrogen and store it in a high-pressure storage tank.

2. The method for efficiently recovering hydrogen using coal chemical waste gas according to claim 1, It is characterized in that The S1 further comprises: Absorbent liquid is used to contact with raw gas through spraying or absorption tower to absorb sulfide in the gas; solid adsorbent is used to adsorb sulfide in a fixed bed reactor; particles in the raw gas are charged by electrostatic field and deposited on dust collecting plates to treat large flow of raw gas; bags are used to filter particles in the raw gas to capture small particles; particles are separated by centrifugal force through rotating airflow to remove large particles; the raw gas is cooled to low temperature to condense and separate tar and water vapor; coolant is used to spray the raw gas in the spray tower to dissolve or condense the tar and take it out; activated carbon and silica gel are used to adsorb the tar.

3. The method for efficiently recovering hydrogen using coal chemical waste gas according to claim 1, It is characterized in that The S2 further comprises: The absorption tower is installed, filled with fillers, and absorbent solution is prepared as needed and stored in an absorbent storage tank. The coal gas is introduced into the bottom of the absorption tower and evenly distributed through the gas distribution device. The absorbent solution is sprayed from the top of the tower and contacts the rising coal gas in countercurrent to absorb carbon dioxide. The carbon dioxide reacts chemically with the absorbent to generate carbonate or bicarbonate. The absorption liquid that has absorbed carbon dioxide is discharged from the bottom of the tower and sent to the regeneration tower for regeneration. The regeneration tower is a distillation tower. The carbon dioxide in the absorption liquid is released by heating. The regenerated absorbent is returned to the absorption tower for recycling. The released high-purity carbon dioxide can be further compressed and stored. Cold water and ethylene glycol solution are used to pre-cool the coal gas through a heat exchanger to reduce its temperature. The pre-cooled coal gas is introduced into a condenser to further reduce its temperature to below the dew point. The water vapor condenses into liquid water. The condensed water is discharged through the drain pipe at the bottom of the condenser and collected in a water collecting tank. The condensed water and gas are further separated by a gas-liquid separation device. The collected condensed water is treated and discharged as needed.

4. The method for efficiently recovering hydrogen from coal chemical industry waste gas according to claim 1, It is characterized in that The S3 further comprises: Use multiple adsorption towers to pre-treat the raw gas, pressurize the raw gas to the operating pressure required by the PSA system through a compressor, pass the pressurized raw gas into the adsorption tower, and the adsorbent selectively adsorbs impurities under high pressure to enrich hydrogen in the adsorption tower. Collect hydrogen-rich gas from the top of the adsorption tower, reduce the pressure of the adsorption tower, and release the adsorbed impurity gas from the adsorbent. Use purge gas or vacuum suction to further remove residual impurities in the adsorbent and restore the adsorption capacity of the adsorbent. Each adsorption tower alternates between adsorption and desorption processes to achieve continuous production of high-purity hydrogen. , select the permeable membrane material, the membrane component adopts hollow fiber membrane, flat membrane or spiral wound membrane module, optimizes the gas flow path and permeation efficiency, ensures that the gas entering the membrane system has been preliminarily purified, removes particulate matter and liquid impurities, and pressurizes the gas to the operating pressure of the membrane system through a compressor, and passes the pressurized gas into the membrane component. Hydrogen has a small molecular volume and a high permeation rate, and permeates through the membrane to the low-pressure side. The impurity gas is retained on the high-pressure side. High-purity hydrogen is collected from the low-pressure side of the membrane component, and the impurity gas retained on the high-pressure side is used as fuel gas or pre-emission treatment.

5. The method for efficiently recovering hydrogen using coal chemical waste gas according to claim 1, It is characterized in that The S4 further comprises: Choose a duplex compressor. The material of the compressor should be resistant to hydrogen corrosion and have good sealing performance. Use multi-stage compression. Perform intermediate cooling after each stage of compression to reduce the gas temperature. Set an intermediate cooler between each stage of compression to reduce the gas temperature through cooling water or other cooling media to reduce the load of the compressor. Use an automatic control system to accurately control the compression pressure of each stage, and monitor the gas temperature of each stage during the compression process in real time. The storage tank should be arranged in a well-ventilated, fire-proof and explosion-proof area, away from open flames and heat sources. The compressed hydrogen is filled into the storage tank through a high-pressure pipeline and valve system. The filling equipment should have pressure regulation and safety Protection function, real-time monitoring of pressure and temperature during the filling process, the filling speed should be controlled to prevent a sharp rise in temperature due to excessive filling, the storage tank should be equipped with a pressure gauge and a safety valve, real-time monitoring of the internal pressure of the storage tank, regular inspection of the sealing of the storage tank and pipeline system, use of hydrogen leak detector for detection, timely discovery and treatment of leaks, use of high-pressure pipelines to transport hydrogen from the storage tank to the point of use or other storage facilities, the pipeline is made of hydrogen corrosion-resistant materials and has good sealing performance, a pressure reducing device is set at the point of use to reduce the high-pressure hydrogen to the required use pressure, the pressure reducing device should have pressure regulation and safety protection functions.

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