CN113430024A - Method for preparing SNG and hydrogen by coke oven gas conversion and pressure swing adsorption - Google Patents

Method for preparing SNG and hydrogen by coke oven gas conversion and pressure swing adsorption Download PDF

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CN113430024A
CN113430024A CN202110878763.6A CN202110878763A CN113430024A CN 113430024 A CN113430024 A CN 113430024A CN 202110878763 A CN202110878763 A CN 202110878763A CN 113430024 A CN113430024 A CN 113430024A
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gas
hydrogen
unit
psa
coke oven
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冉世红
杨先忠
龙雨谦
孙炳
赵洪法
刘艳艳
肖云山
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Southwest Research and Desigin Institute of Chemical Industry
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
    • C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
    • C10L3/10—Working-up natural gas or synthetic natural gas
    • C10L3/101—Removal of contaminants
    • C10L3/102—Removal of contaminants of acid contaminants
    • C10L3/103—Sulfur containing contaminants
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
    • C01B3/06—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents
    • C01B3/12—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents by reaction of water vapour with carbon monoxide
    • C01B3/16—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents by reaction of water vapour with carbon monoxide using catalysts
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/50—Separation of hydrogen or hydrogen containing gases from gaseous mixtures, e.g. purification
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
    • C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
    • C10L3/08—Production of synthetic natural gas
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/02—Processes for making hydrogen or synthesis gas
    • C01B2203/0283—Processes for making hydrogen or synthesis gas containing a CO-shift step, i.e. a water gas shift step
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
    • C01B2203/0465—Composition of the impurity
    • C01B2203/0475—Composition of the impurity the impurity being carbon dioxide
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/04—Integrated processes for the production of hydrogen or synthesis gas containing a purification step for the hydrogen or the synthesis gas
    • C01B2203/0465—Composition of the impurity
    • C01B2203/048—Composition of the impurity the impurity being an organic compound
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/06—Integration with other chemical processes
    • C01B2203/062—Hydrocarbon production, e.g. Fischer-Tropsch process

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Abstract

The invention provides a method for preparing SNG and hydrogen by coke oven gas conversion and pressure swing adsorption, belonging to the technical field of preparing SNG and hydrogen by coke oven gas2the/R decarbonization unit obtains decarbonized desorption gas, and the rest gas enters PSA-CH in sequence4Methane and PSA-H by methane extraction unit2Hydrogen is obtained by the hydrogen extracting unit; from PSA-CH4Methane output from the unit passes through a methane gas compression unit to obtain the SNG synthetic natural gas. The invention obtains decarbonization desorption gas, methane gas (SNG synthetic natural gas after compression) and hydrogenIt can be used as fuel for coke oven, city gas and raw material for producing other chemical products. The method has simple operation, low cost, CO and CH4The separation efficiency of (2) is high.

Description

Method for preparing SNG and hydrogen by coke oven gas conversion and pressure swing adsorption
Technical Field
The invention belongs to the technical field of preparing SNG (synthetic natural gas) and hydrogen from coke oven gas, and particularly relates to a method for preparing SNG and hydrogen by coke oven gas conversion and pressure swing adsorption.
Background
When a general coking enterprise produces metallurgical coke, the typical composition of coke oven gas is as follows:
Figure BDA0003191214100000011
the impurity content is as follows:
Figure BDA0003191214100000012
it can be seen from the above table that the coke oven gas contains a large amount of CH4And H2Can be separated out to be used as city gas and produce other chemical products, but CO and CH in coke oven gas4The separation of (2) is difficult.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for preparing SNG and hydrogen by coke oven gas shift and pressure swing adsorption, which is used for shifting CO in coke oven gas into CO2While generating H2Simple operation, low cost, CO and CH4Has high separation efficiency and improves H2The yield of (2) is beneficial to the removal of sulfide.
The invention discloses a method for preparing SNG and hydrogen by coke oven gas shift and pressure swing adsorption, which solves the technical problems and is characterized in that: the coke-oven gas sequentially passes through a coke-oven gas compression unit and PSA-CO2the/R decarbonization unit obtains decarbonization desorption gas, and the rest gas enters into the decarbonization desorption gasInto PSA-CH4Methane extraction unit to obtain methane and PSA-H2The hydrogen extracting unit obtains hydrogen; from PSA-CH4And (4) compressing the methane gas output from the unit to obtain the SNG synthetic natural gas.
In the optimized scheme, the coke-oven gas sequentially passes through a coke-oven gas pretreatment unit, a coke-oven gas compression unit, a coke-oven gas deoiling and decalcification unit, a coke-oven gas sulfur-tolerant shift unit, a shift gas desulfurization unit and a PSA-CO2the/R decarbonization unit obtains decarbonized desorption gas, and the rest gas enters PSA-CH in sequence4Methane extraction unit to obtain methane and PSA-H2The hydrogen extracting unit obtains hydrogen; from PSA-CH4And (4) compressing the methane gas output from the unit to obtain the SNG synthetic natural gas.
By PSA-CO in the present invention2Decarbonization of/R, PSA-CH4Methane and PSA-H extraction2And extracting hydrogen to obtain two products of methane and hydrogen.
The coke oven gas produced in the metallurgical coke production of coking enterprises in the invention is pretreated, compressed, deoiled and decalcified by the coke oven gas, and then is subjected to sulfur-tolerant shift, shift gas desulfurization and three sets of PSA devices (PSA-CO)2Decarbonization of/R, PSA-CH4Extracting methane and PSA-H2Hydrogen extraction) of coke oven gas, first converting CO in the coke oven gas into CO2(Simultaneous production of H2) (ii) a Removing PSA-CO after fine desulfurization and cooling to normal temperature2Decarbonization of/R, PSA-CH4Extracting methane and PSA-H2And (3) separating by three pressure swing adsorption separation devices for hydrogen extraction to respectively obtain decarbonized desorption gas, methane gas (SNG synthetic natural gas after compression) and hydrogen.
In an optimized scheme, the PSA-H2The hydrogen extracted gas in the hydrogen extraction unit is returned as regenerated flushing gas to the PSA-CO2/R decarbonization unit to be used as regenerated flushing gas so as to recover more methane and hydrogen.
In the invention, the Pressure Swing Adsorption (PSA) technology is utilized to remove H from the gas after methane extraction2The other components are adsorbed by the adsorbent and then pass through a series of adsorption steps, the adsorbed impurities are desorbed by reverse discharge and evacuation, and the extracted hydrogen gas is returned to PSA-CO2the/R decarbonization unit is used as regeneration flushing gas; the unadsorbed passing gas is hydrogenAnd the product is sent to a hydrogen user to produce other chemical products. PSA-CO2Decarbonization of/R, PSA-CH4Extracting methane and PSA-H2The hydrogen extraction unit is a pressure swing adsorption unit consisting of N adsorbers and a series of program control valves, and adsorbents are arranged in the adsorbers.
The coke oven gas pretreatment unit adopts a carbon-based adsorbent to primarily remove tar and naphthalene in the coke oven gas and adopts steam for regeneration.
The carbon-based adsorbent with strong adsorption capacity to tar and naphthalene in coke oven gas is at least two, such as the combination of coke and active carbon (the active carbon can be divided into a plurality of types according to different pore diameters), and is selected for use according to the properties of the carbon-based adsorbent. After adsorbing tar and naphthalene in the coke-oven gas, purging and regenerating once by steam at intervals, and removing coking treatment of the regenerated wastewater. The unit is characterized in that the adsorbent has high tar and naphthalene removal rate and mild adsorption conditions (performed at normal temperature and normal pressure).
The regeneration is carried out once by steam blowing at intervals, the decoking treatment of the regeneration wastewater is carried out, and the decoking and treatment mode of the decoking and the naphthalene are the conventional technology.
The coke oven gas compression unit can be compressed by adopting a reciprocating compressor or a combination of a screw compressor and a centrifugal compressor, and the pressure of the compressed coke oven gas is 0.5-3.0 MPa.
The coke oven gas deoiling and decalcification unit further removes impurities such as naphthalene, oil, water and the like in the coke oven gas by adopting reagents such as a carbon-based complexing agent, a silicate complexing agent and the like, and adopts steam for regeneration. Deoiling and decalcifying coke oven gas by using a deoiling and decalcifying tank filled with carbon-based complexing agent, silicate complexing agent and other reagents.
The gas compressed by the coke oven gas compressor still contains a small amount of naphthalene, oil, water and other impurities, and is further removed by adopting a carbon-based complexing agent, a silicate complexing agent and the like so as to reduce the influence on subsequent units. Carbon-based complexing agent and silicate complexing agent after adsorbing oil and naphthalene, and the like, according to the operation working condition, the regeneration is carried out by blowing steam at intervals, and the regenerated wastewater is subjected to coking treatment.
The coke oven gas is resistantA sulfur conversion unit, heating the coke oven gas after compression, deoiling and decalcification to 220 ℃, mixing the coke oven gas with supplemented water vapor, then entering the upper layer of a conversion reactor, removing harmful impurities such as oxygen, olefin and the like in the coke oven gas, simultaneously raising the temperature of the coke oven gas to 310 ℃, spraying water, cooling to 210 ℃, then entering the lower layer of the conversion reactor, and carrying out conversion reaction on most CO in the coke oven gas to generate CO under the action of a sulfur-resistant conversion catalyst2And H2The CO dry basis concentration was reduced to 0.6% v.
The water vapor accounting for 12 percent of the total amount of the coke oven gas is supplemented, and has a certain relation with the content of CO in the coke oven gas.
The shift reaction is exothermic reaction, proper measures (intermediate heat exchange and/or cold shock) are taken in the reactor, the temperature of the catalyst bed layer is well controlled, and accidents such as sintering inactivation and even equipment damage caused by overheating of the catalyst are prevented.
The maximum temperature of the catalyst bed in the first-stage shift reaction is about 310 ℃, the maximum temperature of the catalyst bed in the second-stage shift reaction is about 260 ℃, and the normal service life of the catalyst is about 3 years. The outlet temperature is reduced to be less than or equal to 40 ℃ and enters PSA-CO2an/R decarbonization unit for heat recovery and utilization.
The shift gas desulfurization unit is used for removing H from the shift gas by a solid desulfurizer at the temperature of the shift gas outlet2S is removed to less than or equal to 1ppm to make PSA-CO2The sulfur content of the desorbed gas of the/R decarburization unit can reach the standard and be discharged after the return combustion. Converting H from organic sulfur in the conversion process2And S, removing the sulfur by a solid desulfurizing agent under the condition of the temperature of a shift gas outlet.
The shift gas desulfurization unit is operated conventionally, but the connection position of the invention is favorable for the standard of sulfur content after the decarburization desorption gas is combusted, and the service life of the three sets of pressure swing adsorption unit adsorbents behind the shift gas desulfurization unit is prolonged.
The PSA-CO2the/R decarbonization unit is used for making CO in the conversion gas mainly be CO by utilizing Pressure Swing Adsorption (PSA) technology2Adsorbed by the adsorbent, and then passes through a series of adsorption steps to adsorb the CO2The desorption gas is obtained by flushing, and the desorption gas is sent to a coking device for re-melting after pressure stabilizationA fuel; the non-adsorbed passing gas is decarbonized gas and enters the next PSA unit to extract methane.
PSA-CO2the/R decarburization comprises a pressure swing adsorption unit consisting of N adsorbers and a series of program control valves, wherein an adsorbent is arranged in each adsorber. Each adsorber undergoes, in sequence, adsorption (a), equalization pressure drop (EiD), forward pressure release (PP), flushing (P), equalization pressure rise (EiR) and final pressure rise (FR) steps at different times.
The PSA-CH4The methane extracting unit consists of M adsorbers and a series of program control valves, and utilizes the Pressure Swing Adsorption (PSA) technology to make decarbonized gas mainly contain CH4Adsorbed by the adsorbent and then passed through a series of adsorption steps to adsorb the CH4Desorption is obtained through reverse discharge and evacuation, most of gas in the reverse discharge and evacuation is used as a product, and the methane gas is removed from the compression unit after pressure stabilization; the unadsorbed pass gas is crude hydrogen and enters the next PSA unit to extract hydrogen. Each adsorber undergoes the steps of adsorption (a), pressure equalization drop (EiD), displacement (RP), reverse pressure release (D), vacuum (V), pressure equalization rise (EiR) and final pressure rise (FR) in sequence at different times.
The PSA-H2The hydrogen extracting unit consists of K adsorbers and a series of program control valves, the Pressure Swing Adsorption (PSA) technology is utilized to make other components except H2 in the methane extracted gas adsorbed by the adsorbent, then a series of adsorption steps are carried out, the adsorbed impurities are desorbed by reverse release and evacuation, the hydrogen extracted and desorbed gas is returned to PSA-CO2the/R decarbonization unit is used as regeneration flushing gas; the unadsorbed passing gas is the hydrogen product and is sent to hydrogen users to produce other chemical products. Each adsorber undergoes adsorption (a), equalization pressure drop (EiD), reverse pressure release (D), evacuation (V), equalization pressure rise (EiR) and final pressure rise (FR) in sequence at different times.
The methane gas compression unit is prepared by compressing PSA-CH4The pressure of the methane gas extracted by the methane extraction unit is 0.02MPa, the methane gas is pressurized to 1.0-4.0 MPa by a methane gas compressor, and the methane gas is conveyed to an urban gas pipe network for use.
The invention removes PSA-CO after fine desulfurization and cooling to normal temperature2[ PSA-C ] decarbonizationH4Methane and PSA-H extraction2The three sets of pressure swing adsorption separation devices for extracting hydrogen are used for separation to respectively obtain decarbonization desorption gas, methane gas and hydrogen, the methane gas is compressed to form SNG synthetic natural gas, and the three gases can be respectively used as fuel of a coke oven, urban fuel gas and raw materials for producing other chemical products.
In the present invention, CO is converted into H2And CO2To make it and CH4Is easier to separate and increases CH4Yield of (A) and CH4The yield and the product quality. Conversion of CO to H2And CO2Can increase H2In addition, in the conversion process, the organic sulfur in the coke oven gas is mostly converted into H2S is beneficial to the removal of sulfide.
Drawings
The invention will be described in further detail with reference to the following drawings and detailed description:
FIG. 1 is a process flow diagram of the present invention
Detailed Description
The invention will be further illustrated with reference to specific embodiments:
example 1
A method for preparing SNG and hydrogen by coke oven gas conversion and pressure swing adsorption is characterized in that coke oven gas sequentially passes through a coke oven gas pretreatment unit, a coke oven gas compression unit, a coke oven gas deoiling and decalcification unit, a coke oven gas sulfur-tolerant conversion unit, a conversion gas desulfurization unit and PSA-CO2the/R decarbonization unit obtains decarbonized desorption gas, and the rest gas enters PSA-CH in sequence4Methane and PSA-H by methane extraction unit2Hydrogen is obtained by the hydrogen extracting unit; from PSA-CH4And (4) compressing the methane gas output from the unit to obtain the SNG synthetic natural gas.
Removing H from the gas after methane extraction by Pressure Swing Adsorption (PSA) technology2The other components are adsorbed by the adsorbent and then pass through a series of adsorption steps, the adsorbed impurities are desorbed by reverse discharge and evacuation, and the extracted hydrogen gas is returned to PSA-CO2the/R decarbonization unit is used as regeneration flushing gas; passing gas which is not adsorbed is hydrogen product and is sent to hydrogenUsers produce other chemical products. PSA-CO2Decarbonization of/R, PSA-CH4Extracting methane and PSA-H2The hydrogen extraction unit is a pressure swing adsorption unit consisting of N adsorbers and a series of program control valves, and adsorbents are arranged in the adsorbers.
The coke oven gas pretreatment unit adopts a carbon-based adsorbent to primarily remove tar and naphthalene in the coke oven gas and adopts steam for regeneration.
The coke oven gas tar and naphthalene are adsorbed by a carbon-based adsorbent with strong adsorption capacity, and then the coke oven gas tar and naphthalene are swept and regenerated once by steam at intervals, and the regenerated wastewater is subjected to coking treatment. The unit is characterized in that the adsorbent has high tar and naphthalene removal rate and mild adsorption conditions (performed at normal temperature and normal pressure).
The coke oven gas compression unit can be compressed by adopting a reciprocating compressor or a combination of a screw compressor and a centrifugal compressor, and the pressure of the compressed coke oven gas is 0.5-3.0 MPa.
The coke oven gas deoiling and decalcification unit further removes naphthalene, oil, water and other impurities in the coke oven gas by adopting reagents such as a carbon-based complexing agent, a silicate complexing agent and the like, and adopts steam for regeneration. The gas compressed by the coke oven gas compressor still contains a small amount of naphthalene, oil, water and other impurities, and is further removed by adopting a carbon-based complexing agent, a silicate complexing agent and the like so as to reduce the influence on subsequent units. Carbon-based complexing agent and silicate complexing agent after adsorbing oil and naphthalene, and the like, according to the operation working condition, the regeneration is carried out by blowing steam at intervals, and the regenerated wastewater is subjected to coking treatment.
A sulfur-resistant conversion unit of coke oven gas is prepared through heating coke oven gas after compression, deoiling and decalcification to 220 deg.C, mixing it with supplemented water vapor, introducing it to upper layer of conversion reactor, removing oxygen and olefin from coke oven gas, raising temp of coke oven gas, spraying water, cooling to 210 deg.C, introducing it to lower layer of conversion reactor, and converting most of CO in coke oven gas to CO under the action of sulfur-resistant conversion catalyst2And H2The CO dry basis concentration was reduced to 0.6% v.
The shift reaction is exothermic reaction, proper measures (intermediate heat exchange and/or cold shock) are taken in the reactor, the temperature of the catalyst bed layer is well controlled, and accidents such as sintering inactivation and even equipment damage caused by overheating of the catalyst are prevented.
The shift gas desulfurization unit is used for removing H from shift gas by a solid desulfurizer at the temperature of the shift gas outlet2S is removed to less than or equal to 1ppm to make PSA-CO2The sulfur content of the desorbed gas of the/R decarburization unit can reach the standard and be discharged after the return combustion. Converting H from organic sulfur in the conversion process2And S, removing the sulfur by a solid desulfurizing agent under the condition of the temperature of a shift gas outlet.
PSA-CO2the/R decarbonization unit is used for making CO in the conversion gas mainly be CO by utilizing Pressure Swing Adsorption (PSA) technology2Adsorbed by the adsorbent, and then passes through a series of adsorption steps to adsorb the CO2The desorption is obtained by flushing, and the desorbed gas is sent to a coking device to be returned as fuel after being subjected to pressure stabilization; the non-adsorbed passing gas is decarbonized gas and enters the next PSA unit to extract methane. PSA-CO2the/R decarburization comprises a pressure swing adsorption unit consisting of N adsorbers and a series of program control valves, wherein an adsorbent is arranged in each adsorber. Each adsorber undergoes, in sequence, adsorption (a), equalization pressure drop (EiD), forward pressure release (PP), flushing (P), equalization pressure rise (EiR) and final pressure rise (FR) steps at different times.
PSA-CH4The methane extraction unit mainly uses CH in decarbonized gas by utilizing Pressure Swing Adsorption (PSA) technology4Adsorbed by the adsorbent and then passed through a series of adsorption steps, each of which undergoes adsorption (a), equilibrium pressure drop (EiD), displacement (RP), reverse pressure release (D), evacuation (V), equilibrium pressure rise (EiR) and final pressure rise (FR) at different times in sequence. Adsorbed CH4Desorption is obtained through reverse discharge and evacuation, most of gas in the reverse discharge and evacuation is used as a product, and the methane gas is removed from the compression unit after pressure stabilization; the unadsorbed pass gas is crude hydrogen and enters the next PSA unit to extract hydrogen.
PSA-H2Each adsorber in the hydrogen extraction unit sequentially undergoes adsorption (A), pressure Equalization (EiD), reverse pressure release (D), vacuum pumping (V), pressure Equalization (EiR) and final pressure increase (FR) at different time.
Methane gas compression unit, namely PSA-CH4The pressure of the methane gas extracted by the methane extraction unit is 0.02MPa, the methane gas is pressurized to 1.0-4.0 MPa by a methane gas compressor, and the methane gas is conveyed to an urban gas pipe network for use.
Example 2
The flow of the method for preparing SNG and hydrogen through coke oven gas shift and pressure swing adsorption in the embodiment is as follows:
at 40000Nm3For example, the device for preparing SNG and hydrogen from/h coke oven gas is used, wherein the pressure of the coke oven gas is 6-7 kPa and the coke oven gas at normal temperature is 40000Nm3Composition is shown in the following table:
Figure BDA0003191214100000061
the impurity levels are shown in the following table:
Figure BDA0003191214100000062
firstly, a coke oven gas pretreatment unit is adopted to adsorb tar and naphthalene in the coke oven gas by using a carbon-based adsorbent, and the coke oven gas after pretreatment comprises the following steps: tar plus dust less than or equal to 10mg/Nm3Naphthalene is less than or equal to 20mg/Nm3。
Then, two reciprocating compressors are adopted for three-stage compression, and the pretreated coke oven gas is compressed to 1.2 MPa. And then, adopting a carbon-based adsorbent and a molecular sieve to carry out further deoiling and decalcification, wherein in the coke oven gas after the deoiling and decalcification: tar plus dust less than or equal to 1mg/Nm3Naphthalene is less than or equal to 2mg/Nm3。
The deoiled and naphthalene-removed coke-oven gas is subjected to sulfur-tolerant shift, the coke-oven gas is firstly heated to 220 ℃ by hot shift gas, is mixed with supplemented water vapor and then enters an upper layer of a shift reactor to remove harmful impurities such as oxygen, olefin and the like in the coke-oven gas, the oxygen, the olefin and the hydrogen react to release a large amount of heat, the coke-oven gas is heated to 310 ℃, enters a water spray cooler to spray water and cool to 210 ℃, then enters a lower layer of the shift reactor, and CO in the coke-oven gas is subjected to shift reaction to generate CO2And H2The CO concentration was reduced to 0.6% v/v on a dry basisThe temperature is 260 ℃. At the temperature, the shift gas enters a fine desulfurization tank, and H in the shift gas is removed by a solid desulfurizing agent2S is less than or equal to 1ppm, then the raw material coke oven gas is heated to be cooled down, finally the coke oven gas enters a water cooler to be cooled to be less than or equal to 40 ℃, condensed water is separated out and then the condensed water is sent to PSA-CO2an/R decarbonization unit.
The transformed gas consists of:
Figure BDA0003191214100000071
the variable gas volume is: 42303Nm3/h。
The desulfurized and cooled shift gas enters PSA-CO2an/R decarbonization unit. At the moment, the pressure of the conversion gas is 1.0MPa, the water is separated again by a gas-liquid separator, and then the water enters a pressure swing adsorption unit which consists of 8 adsorbers (connected in parallel, each adsorber is in different stages of time sequence, such as that a tower A adsorbs for 3 minutes, a tower B starts to adsorb, A enters regeneration, the tower B still adsorbs, but in the forward pressure release and flushing stage, two towers are partially connected in series) and a series of program control valves. At any moment, all adsorbers are in different stages of the adsorption step, raw materials are introduced from the inlet end, decarburization gas with the pressure of 0.95MPa is obtained at the outlet end, and each adsorber sequentially undergoes adsorption (A), pressure equalization drop (EiD), forward pressure relief (PP), flushing (P), pressure equalization rise (EiR) and final pressure rise (FR) at different times. Adsorbed CO2The desorption is obtained by flushing, and the desorbed gas is sent to a coking device to be returned as fuel after being subjected to pressure stabilization.
The stripping gas composition was as follows:
Figure BDA0003191214100000072
the desorption gas amount is: 10306Nm3/h。
The decarbonized gas with the pressure of 0.95MPa enters PSA-CH4And a methane extraction unit. The pressure swing adsorption unit comprises 8 adsorbers (connected in parallel, each adsorber is in different stages of time sequence, if tower A adsorbs 3 minutes, tower B starts to adsorb, and tower A enters into the adsorption tower againThe raw tower B still adsorbs; but in the displacement and reverse pressure release stages, two towers are partially connected in series) and a series of program control valves. In the unit, at any moment, the adsorbers are always in different stages of the adsorption step, feed gas is introduced from the inlet end, and the adsorbed passing gas obtained from the outlet end enters PSA-H as crude hydrogen2A hydrogen extraction unit; each adsorber undergoes adsorption (a), pressure Equalization (EiD), displacement (RP), reverse pressure release (D), evacuation (V), pressure Equalization (EiR) and final pressure increase (FR) in sequence at different times. Adsorbed CH4Desorption was obtained by reverse discharge and evacuation. Most of the reverse-discharge and evacuation gas is used as a product, the pressure is stabilized at 0.02MPa, the pressure is increased to 1.0MPa through a methane gas compressor, and the gas is transmitted to an urban gas pipe network for use.
The methane gas composition was as follows:
Figure BDA0003191214100000073
Figure BDA0003191214100000081
the methane gas quantity is: 9550Nm3/h。
From PSA-CH4Crude hydrogen from a methane extraction unit is fed to PSA-H2A hydrogen extraction unit. The pressure swing adsorption unit consists of 8 adsorbers (connected in parallel, each adsorber is in different stages of time sequence, for example, when the A tower adsorbs 3 minutes, the B tower starts to adsorb, the A tower enters regeneration, the B tower still adsorbs, but in the reverse pressure release stage, two towers are partially connected in series) and a series of program control valves. In the unit, at any moment, an adsorber is always in different stages of the adsorption step, feed gas is introduced from an inlet end, and product hydrogen obtained from an outlet end is sent to a hydrogen user; each adsorber undergoes adsorption (a), equalization pressure drop (EiD), reverse pressure release (D), evacuation (V), equalization pressure rise (EiR) and final pressure rise (FR) in sequence at different times. Desorbing the adsorbed impurities by reverse discharge and evacuation, and returning the extracted hydrogen gas to PSA-CO2the/R decarbonization unit is used as regeneration flushing gas。
The hydrogen composition was as follows:
Figure BDA0003191214100000082
the hydrogen gas amount is: 22447Nm3/h。
While the foregoing shows and describes the fundamental principles and principal features of the invention, together with the advantages thereof, the foregoing embodiments and description are illustrative only of the principles of the invention, and various changes and modifications can be made therein without departing from the spirit and scope of the invention, which will fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (10)

1. A method for preparing SNG and hydrogen by coke oven gas shift and pressure swing adsorption is characterized in that: the coke-oven gas sequentially passes through a coke-oven gas compression unit and PSA-CO2the/R decarbonization unit obtains decarbonized desorption gas, and the rest gas enters PSA-CH in sequence4Methane extraction unit to obtain methane and PSA-H2The hydrogen extracting unit obtains hydrogen; from PSA-CH4And (4) compressing the methane gas output from the unit to obtain the SNG synthetic natural gas.
2. The method for preparing SNG and hydrogen by coke oven gas shift and pressure swing adsorption according to claim 1, which is characterized in that: the coke-oven gas sequentially passes through a coke-oven gas pretreatment unit, a coke-oven gas compression unit, a coke-oven gas deoiling and decalcification unit, a coke-oven gas sulfur-tolerant conversion unit, a conversion gas desulfurization unit and a PSA-CO2the/R decarbonization unit obtains decarbonized desorption gas, and the rest gas enters PSA-CH in sequence4Methane and PSA-H by methane extraction unit2Hydrogen is obtained by the hydrogen extracting unit; from PSA-CH4Methane output from the unit passes through a methane gas compression unit to obtain the SNG synthetic natural gas.
3. The method for preparing SNG and hydrogen by coke oven gas shift and pressure swing adsorption according to claim 1The method is characterized in that: the PSA-H2The hydrogen extracted and desorbed gas in the hydrogen extracting unit is returned as regenerated flushing gas to PSA-CO2the/R decarbonization unit is used as regeneration flushing gas.
4. The method for preparing SNG and hydrogen by coke oven gas shift and pressure swing adsorption according to claim 1, which is characterized in that: the pressure of the coke oven gas compressed in the coke oven gas compression unit is 0.5-3.0 MPa.
5. The method for preparing SNG and hydrogen by coke oven gas shift and pressure swing adsorption according to claim 1, which is characterized in that: the tar and naphthalene removing unit for the coke oven gas further removes naphthalene, oil and water impurities in the coke oven gas by adopting a carbon-based complexing agent and a silicate complexing agent, and adopts steam for regeneration.
6. The method for producing SNG and hydrogen through coke oven gas shift and pressure swing adsorption according to any one of claims 1-3, wherein the coke oven gas sulfur-tolerant shift unit is characterized in that the coke oven gas after compression, deoiling and decalcification is heated to 220 ℃ and mixed with supplemented water vapor and then enters the upper layer of a shift reactor to remove harmful impurities, meanwhile, the temperature of the coke oven gas is increased to 310 ℃, and then is cooled to 210 ℃ and then enters the lower layer of the shift reactor, and CO in the coke oven gas is subjected to shift reaction to generate CO2And H2The CO concentration was reduced to 0.6% v on a dry basis.
7. The method for producing SNG and hydrogen through coke oven gas shift and pressure swing adsorption (PSA-CO) according to claim 1, wherein the PSA-CO is2the/R decarbonization unit consists of N adsorbers and a series of program control valves, wherein each adsorber sequentially undergoes the steps of adsorption, pressure equalization, forward pressure release, flushing, pressure equalization and final pressure increase at different time, and adsorbed CO is obtained2The desorption is obtained by flushing, and the desorbed gas is sent to a coking device to be returned as fuel after being subjected to pressure stabilization; the non-adsorbed passing gas is decarbonized gas and enters the next PSA unit to extract methane.
8. According to the claimsThe method for preparing SNG and hydrogen through coke oven gas shift and pressure swing adsorption (PSA-CH) solution 1 is characterized in that4The methane extracting unit consists of M adsorbers and a series of program control valves, each adsorber sequentially undergoes the steps of adsorption, pressure equalizing drop, replacement, reverse pressure release, vacuum pumping, pressure equalizing rise and final pressure rise at different time, and adsorbed CH4Desorption is obtained through reverse discharge and evacuation, most of gas in the reverse discharge and evacuation is used as a product, and the methane gas is removed from the compression unit after pressure stabilization; the unadsorbed pass gas is crude hydrogen and enters the next PSA unit to extract hydrogen.
9. The method for producing SNG and hydrogen by coke oven gas shift and pressure swing adsorption according to claim 1, wherein the PSA-H2The hydrogen extraction unit consists of K adsorbers and a series of program control valves, and H is removed from the gas after methane extraction2All the adsorbers are sequentially subjected to adsorption, pressure equalizing and reducing, reverse pressure releasing, vacuumizing, pressure equalizing and increasing and finally boosting at different time, the adsorbed impurities are desorbed by reverse pressure releasing and vacuumizing, the hydrogen extracted and absorbed gas is returned to PSA-CO2the/R decarbonization unit is used as regeneration flushing gas; the unadsorbed passing gas is the hydrogen product and is sent to hydrogen users to produce other chemical products.
10. The method for producing SNG and hydrogen through coke oven gas shift and pressure swing adsorption according to any one of claims 1-9, wherein the methane gas compression unit is formed by compressing PSA-CH4The pressure of the methane gas extracted by the methane extraction unit is 0.02MPa, the methane gas is pressurized to 1.0-4.0 MPa by a methane gas compressor, and the methane gas is conveyed to an urban gas pipe network for use.
CN202110878763.6A 2021-08-02 2021-08-02 Method for preparing SNG and hydrogen by coke oven gas conversion and pressure swing adsorption Pending CN113430024A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115448255A (en) * 2022-10-13 2022-12-09 瑞必科净化设备（上海）有限公司 Method for improving hydrogen recovery rate and recovering methane in coke oven tail gas
CN115888313A (en) * 2022-11-11 2023-04-04 西南化工研究设计院有限公司 Productivity adjusting process for producing fuel cell hydrogen and pipeline natural gas by coke oven gas

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115448255A (en) * 2022-10-13 2022-12-09 瑞必科净化设备（上海）有限公司 Method for improving hydrogen recovery rate and recovering methane in coke oven tail gas
CN115888313A (en) * 2022-11-11 2023-04-04 西南化工研究设计院有限公司 Productivity adjusting process for producing fuel cell hydrogen and pipeline natural gas by coke oven gas
CN115888313B (en) * 2022-11-11 2024-05-31 西南化工研究设计院有限公司 Energy production regulating process for preparing fuel cell hydrogen and pipeline natural gas from coke oven gas

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