Hydrogen preparation and purification system

Abstract

The utility model provides a hydrogen preparation and purification system, relates to the technical field of hydrogen preparation, and solves the technical problem that the pressure swing adsorption load is relatively high when an existing hydrogen preparation system adopts a pressure swing adsorption process to extract hydrogen. The system comprises a desulfurization system for desulfurizing natural gas and a conversion system for converting to generate hydrogen, and further comprises a decarburization system for removing carbon dioxide in converted gas, and the decarburization system comprises a decarburization tower for absorbing carbon dioxide through absorption liquid and a regeneration tower for regenerating the absorption liquid; the conversion system comprises a conversion furnace for generating hydrogen and a chimney which is communicated with the conversion furnace and is used for discharging waste gas. According to the utility model, through conversion, conversion reaction, decarbonization and multi-stage purification, the yield and the purity of hydrogen are improved, the amount of required conversion gas is less, and the comprehensive energy consumption is lower; by recycling waste heat in converted gas and waste heat of regenerated barren liquor, steam is generated, boiler water, desalted water and the like are preheated, and the energy utilization efficiency is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to hydrogen preparation technical field, specifically, relate to a hydrogen preparation purification system. BACKGROUND

[0002] Hydrogen is an important industrial raw material, widely used in synthetic ammonia, synthetic methanol, petroleum chemical industry and metallurgical industry. With light hydrocarbon (natural gas, decarburization biogas, light naphtha and dry gas) as raw material, industrial hydrogen is prepared, and there are steam conversion process and self-heating conversion process.

[0003] The steam conversion process is a chemical reaction process in which methane in natural gas is converted into hydrogen and carbon monoxide under the action of water vapor and catalyst at high temperature. After compression and desulfurization, natural gas is mixed with water vapor, and steam reforming reaction is carried out under the action of catalyst, and the conversion gas generated contains hydrogen, carbon monoxide and carbon dioxide. Subsequently, the conversion gas is converted into more hydrogen by shift reaction, and finally high-purity hydrogen is obtained by purification process such as pressure swing adsorption (PSA).

[0004] A system for preparing hydrogen from natural gas is disclosed in patent CN217264847U, which generates CO2 and H2 by setting two converters to reduce the temperature of the conversion gas, further improves the proportion of hydrogen in the conversion gas, and produces hydrogen with a purity of 99.9%. The system has short process flow, almost no toxicity, less investment in equipment and facilities, small land occupation, and easy and safe and stable production. However, the existing process usually removes sulfur from the raw gas natural gas, purifies hydrogen from the conversion gas by pressure swing adsorption process, and uses the by-product PSA desorption gas as fuel for the conversion furnace. The carbon dioxide in the conversion gas is not removed separately, which increases the load of pressure swing adsorption, so that multiple parallel adsorption towers are needed for pressure swing adsorption to consume more raw gas to obtain hydrogen with high concentration, and the final desorption gas has high carbon dioxide content, which is not conducive to the reuse as fuel gas. UTILITY MODEL CONTENT

[0005] The utility model aims at providing a hydrogen preparation and purification system to solve the technical problem of high load of pressure swing adsorption in the existing hydrogen preparation system.

[0006] The embodiments of the utility model are realized by the following technical solutions:

[0007] A hydrogen production and purification system, comprising a desulfurization system for desulfurizing natural gas and a conversion system for converting to produce hydrogen, further comprising a decarbonization system for removing carbon dioxide from the converted gas, the decarbonization system comprising a decarbonization tower for absorbing carbon dioxide by an absorbent liquid and a regenerator for regenerating the absorbent liquid, the conversion system comprising a conversion furnace for producing hydrogen and a chimney for discharging exhaust gas from the conversion furnace.

[0008] Preferably, further comprising a waste heat recovery and conversion system for recovering waste heat from the converted gas and converting to produce hydrogen, the waste heat recovery and conversion system comprising a converted gas steam generator for recovering heat from the converted gas, a shift reactor for converting carbon monoxide to carbon dioxide and hydrogen, a boiler feed water preheater for recovering waste heat, a shift gas water cooler for cooling the shifted gas, and a shift gas water knockout drum for separating liquid from the cooled shifted gas, the shift gas water knockout drum being connected to the decarbonization tower, the converted gas steam generator being connected to the chimney and the conversion furnace for providing steam.

[0009] Preferably, the waste heat recovery and conversion system further comprises a reboiler for recovering waste heat for regenerating the absorbent liquid and a desalted water preheater for preheating desalted water, the reboiler being connected to the upper and lower ends of the regenerator, respectively.

[0010] Preferably, the decarbonization system further comprises a decarbonizer cooler for cooling the decarbonized converted gas and a decarbonizer knockout drum for separating liquid from the cooled decarbonized converted gas, the decarbonizer knockout drum being connected to the regenerator for recycling the separated absorbent liquid.

[0011] Preferably, further comprising a pressure swing adsorption system for purifying the decarbonized converted gas, the pressure swing adsorption system comprising a plurality of adsorption towers connected in series to the decarbonizer knockout drum.

[0012] Preferably, the decarbonization system further comprises a lean / rich liquid heat exchanger for recovering heat from the regenerated lean liquid, a lean liquid cooler for cooling the regenerated lean liquid, and a mechanical filter for filtering solid impurities from the lean liquid, the lean / rich liquid heat exchanger being connected to the regenerator and the decarbonization tower at the hot source outlet and the cold source inlet, respectively.

[0013] Preferably, the decarbonization system further comprises a carbon dioxide cooler for cooling the regenerated carbon dioxide separated from the regenerator and a carbon dioxide knockout drum for separating liquid from the carbon dioxide.

[0014] Preferably, the desulfurization system comprises a compressor for compressing the raw material gas, a hydrodesulfurization tank for converting organic sulfur to inorganic sulfur, and a zinc oxide desulfurization tank for removing inorganic sulfur, the zinc oxide desulfurization tank being connected to the conversion furnace.

[0015] By removing sulfides through the hydrogen desulfurization tank and zinc oxide desulfurization tank, catalyst poisoning can be prevented, and the service life of the catalyst in the reformer can be extended. Reducing the content of sulfides can reduce the emission of sulfur dioxide (SO2) during combustion, reducing air pollution. Ensure the quality of the gas in the subsequent process and improve the purity of the final product. Efficiently generate hydrogen through steam reforming reactions to increase hydrogen production. By discharging treated exhaust gas through the chimney, the impact on the environment is reduced.

[0016] The high-temperature exhaust gas generated by the reformer can be reused through the waste heat recovery system, improving energy efficiency. Recovering waste heat from the reforming gas produces steam. Carbon monoxide (CO) is converted to carbon dioxide (CO2) and more hydrogen (H2) through the water-gas shift reaction (WGS). Preheat the boiler feed water to improve thermal efficiency. Used to regenerate the absorption liquid to provide heat. By recovering waste heat from the reforming gas, steam is generated, improving energy utilization efficiency. Through the shift reaction, the hydrogen production is further increased. Preheat the boiler feed water and desalinated water to reduce the energy required for heating, saving energy.

[0017] The decarbonization tower absorbs carbon dioxide (CO2) through an absorption liquid such as MDEA. The regeneration tower regenerates the absorption liquid to restore its absorption capacity. By removing carbon dioxide, the purity of hydrogen is improved. Regenerate the absorption liquid to achieve cyclic use and reduce costs. Recover heat through the lean-rich liquid heat exchanger to improve energy utilization efficiency. Separate and treat carbon dioxide to reduce greenhouse gas emissions.

[0018] Further purify hydrogen through multi-stage adsorption towers to remove trace impurities. By using multi-stage adsorption towers, hydrogen is further purified to meet high-purity requirements. Compared to other purification methods, decarbonization followed by pressure swing adsorption greatly reduces the load on the pressure swing adsorption system, and after separating carbon dioxide, the utilization rate of hydrogen purification from reforming gas is higher. To purify the same concentration and amount of hydrogen, less reforming gas is required and the overall energy consumption is lower.

[0019] Through conversion, shift reaction, decarbonization, and multi-stage purification, the yield and purity of hydrogen are improved. Energy recovery and energy saving: Through waste heat recovery and heat exchange equipment, energy utilization efficiency is improved, and energy consumption is reduced. Prolong the service life of the equipment: By removing harmful substances through pretreatment steps such as desulfurization, the corrosion of the equipment is reduced, and the service life of the equipment is extended. Reducing the emission of sulfides and carbon dioxide reduces environmental pollution.

[0020] The technical scheme of the utility model embodiment has at least the following advantages and beneficial effects:

[0021] 1、 The utility model discloses a method for purifying hydrogen by conversion, shift reaction, decarbonization and multi-stage purification, which improves the yield and purity of hydrogen, and requires less reforming gas and has lower overall energy consumption to purify the same concentration and amount of hydrogen.

[0022] 2. The utility model discloses a waste heat in the recovery conversion gas, the waste heat of lean liquid after regeneration, produce steam, preheat boiler water desalted water etc., improve energy utilization efficiency.

[0023] 3. The utility model discloses reduce the emission of sulfide and carbon dioxide, alleviate the pollution to the environment. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical scheme of the embodiments of the utility model, the following will be to the embodiment needed to use the drawing of the utility model briefly introduce, should understand, the following drawing only shows some embodiments of the utility model, therefore should not be seen as the limitation to the range, for the ordinary skilled person in the art comes, under the premise of not making the creative labor, can also obtain other related drawings according to these drawings.

[0025] Figure 1 The system structure schematic diagram of a hydrogen production purification system for the embodiment 1 of the utility model provides;

[0026] Figure: 1, desulfurization system;2, conversion system;3, waste heat recovery conversion system;4, decarburization system;5, pressure swing adsorption system;11, compressor;12, hydrogenation desulfurization groove;13, zinc oxide desulfurization groove;21, conversion furnace;22, chimney;31, conversion gas steam generator;32, shift reactor;33, boiler feed water preheater;34, reboiler;35, shift gas water cooler;36, shift gas water separator;37, desalted water preheater;41, decarburization tower;42, regeneration tower;43, decarburizer cooler;44, decarburizer liquid separator;45, carbon dioxide cooler;46, carbon dioxide liquid separator;47, lean rich liquid heat exchanger;48, lean liquid cooler;49, mechanical filter;51, adsorption tower. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantage of the embodiments of the utility model more clear, the following will be to the technical scheme in the embodiment of the utility model in the drawing of the utility model embodiment, clear, complete description, obviously, the described embodiment is the part of the embodiment of the utility model, rather than all the embodiment. The components of the embodiment of the utility model described and shown in the drawing here can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiment of the utility model provided in the drawing is not intended to limit the scope of the claimed utility model, but only represents the selected embodiment of the utility model. Based on the embodiment in the utility model, all other embodiments obtained by the ordinary skilled person in the art without making the creative labor belong to the scope of the utility model protection.

[0029] It should be noted that like numerals and letters refer to like items throughout the several views, and once an item is defined in one view, it should not require further defining and explaining in subsequent views.

[0030] In the description of the utility model, it needs to be explained that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, or the orientation or position relationship of the product of the application in usual use, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, therefore, it cannot be understood as a limitation on the utility model.

[0031] In the description of the utility model, it also needs to be explained that, unless otherwise explicitly specified and limited, if the terms "set", "mount", "connect", "connect" appear, it should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or indirectly connected through an intermediate medium, it can be the communication between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0032] Embodiment 1

[0033] A hydrogen production and purification system, comprising a desulfurization system 1 for desulfurizing natural gas and a conversion system 2 for converting hydrogen, further comprising a decarbonization system 4 for removing carbon dioxide in the converted gas, the decarbonization system 4 comprising a decarbonization tower 41 for absorbing carbon dioxide by absorbing liquid and a regeneration tower 42 for regenerating absorbing liquid, and the conversion system 2 comprising a conversion furnace 21 for generating hydrogen and a chimney 22 connected to the conversion furnace 21 for discharging waste gas.

[0034] In the embodiment, a waste heat recovery and conversion system 3 for recovering waste heat of the converted gas and generating hydrogen by secondary conversion is further included, the waste heat recovery and conversion system 3 comprising a converted gas steam generator 31 for recovering heat of the converted gas, a shift reactor 32 for converting carbon monoxide into carbon dioxide and hydrogen, a boiler feed water preheater 33 for recovering waste heat again, a shift gas water cooler 35 for cooling the shift gas, and a shift gas water separator 36 for separating liquid in the cooled shift gas, the shift reactor water separator being connected to the decarbonization tower 41, and the converted gas steam generator 31 being connected to the chimney 22 and providing steam to the conversion furnace 21.

[0035] In this embodiment, the waste heat recovery conversion system 3 also includes a reboiler 34 to recover waste heat for regenerating absorption liquid and a desalted water preheater 37 to preheat desalted water, the reboiler 34 being connected to the upper and lower ends of the regeneration column 42, respectively.

[0036] In this embodiment, the decarbonization system 4 also includes a decarbonizer cooler 43 connected to the decarbonization column 41 to cool the converted gas after decarbonization and a decarbonizer knock-out drum 44 to separate liquid from the converted gas after cooling, the decarbonizer knock-out drum 44 being connected to the regeneration column 42 to return the separated absorption liquid.

[0037] In this embodiment, a pressure swing adsorption system 5 is also included to purify the converted gas after decarbonization, the pressure swing adsorption system 5 including a plurality of adsorption columns 51 connected in series to the decarbonizer knock-out drum 44.

[0038] In this embodiment, the decarbonization system 4 also includes a lean-rich liquid heat exchanger 47 to recover heat from the lean liquid after regeneration, a lean liquid cooler 48 to cool the lean liquid after regeneration, and a mechanical filter 49 to filter solid impurities in the lean liquid, the lean-rich liquid heat exchanger 47 being connected to the regeneration column 42 and the decarbonization column 41 at the hot source outlet and the cold source inlet, respectively.

[0039] In this embodiment, the decarbonization system 4 also includes a carbon dioxide cooler 45 connected to the regeneration column 42 to cool the carbon dioxide separated by regeneration and a carbon dioxide knock-out drum 46 to separate liquid from the carbon dioxide.

[0040] In this embodiment, the desulfurization system 1 includes a compressor 11 to compress the raw material gas, a hydrodesulfurization tank 12 to convert organic sulfur into inorganic sulfur, and a zinc oxide desulfurization tank 13 to remove inorganic sulfur, the zinc oxide desulfurization tank 13 being connected to the conversion furnace 21.

[0041] Working principle and method of use:

[0042] Through the hydrodesulfurization tank 12 and the zinc oxide desulfurization tank 13, sulfides are removed, and the treated exhaust gas is discharged through the chimney 22, reducing the impact on the environment.

[0043] The high-temperature exhaust gas generated by the conversion furnace 21 can be reused through the waste heat recovery system, improving energy efficiency. The waste heat in the converted gas is recovered to generate steam. Carbon monoxide (CO) is converted to carbon dioxide (CO2) and more hydrogen (H2) through the water-gas shift reaction (WGS). Preheat the boiler feed water to improve thermal efficiency. It is used to regenerate absorption liquid and provides heat. By recovering waste heat from the converted gas, steam is generated, improving energy utilization efficiency. Through the shift reaction, the production of hydrogen is further increased. Preheat the boiler feed water and desalted water to reduce the energy required for heating and save energy.

[0044] The decarburization tower 41 absorbs carbon dioxide (CO2) by absorbing liquid (MDEA). The regeneration tower 42 regenerates the absorbing liquid to restore its absorption capacity. By removing carbon dioxide, the purity of hydrogen is improved. Regenerating the absorbing liquid achieves recycling use and reduces costs. Heat is recovered through the lean-rich liquid heat exchanger 47 to improve energy utilization efficiency.

[0045] The hydrogen is further purified by the multi-stage adsorption tower 51 to remove trace impurities. By the multi-stage adsorption tower 51, the hydrogen is further purified to meet the high-purity requirements.

[0046] The above is only the preferred embodiment of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A hydrogen production and purification system comprising a desulfurization system (1) for desulfurizing natural gas and a reforming system (2) for producing hydrogen by reforming, characterized in that: The system further comprises a decarbonization system (4) for removing carbon dioxide from the converted gas, and a waste heat recovery conversion system (3) for recovering waste heat from the converted gas and generating hydrogen from the secondary conversion, the decarbonization system (4) comprising a decarbonization tower (41) for absorbing carbon dioxide by an absorbent liquid and a regenerator (42) for regenerating the absorbent liquid, the conversion system (2) comprising a conversion furnace (21) for generating hydrogen and a chimney (22) for discharging exhaust gas from the conversion furnace (21), and the waste heat recovery conversion system (3) comprising a converted gas steam generator (31) for recovering heat from the converted gas, a shift reactor (32) for converting carbon monoxide into carbon dioxide and hydrogen, a boiler feed water preheater (33) for recovering waste heat again, a shift gas water cooler (35) for cooling the shift gas, and a shift gas water knockout drum (36) for separating liquid from the cooled shift gas, the shift gas water knockout drum (36) being connected to the decarbonization tower (41), and the converted gas steam generator (31) being connected to the chimney (22) and the conversion furnace (21) for providing steam.

2. The hydrogen production and purification system of claim 1, wherein: The waste heat recovery conversion system (3) further comprises a reboiler (34) for recovering waste heat for regenerating the absorbent liquid and a desalted water preheater (37) for preheating desalted water, the reboiler (34) being connected to the regenerator (42) at the top and the bottom, respectively.

3. The hydrogen production and purification system according to claim 1 or 2, characterized in that: The decarbonization system (4) further comprises a decarbonizer cooler (43) for cooling the converted gas after decarbonization and a decarbonizer knockout drum (44) for separating liquid from the cooled converted gas, the decarbonizer knockout drum (44) being connected to the decarbonization tower (41) and the regenerator (42) for returning the separated absorbent liquid.

4. The hydrogen production and purification system of claim 3, wherein: The system further comprises a pressure swing adsorption system (5) for purifying the converted gas after decarbonization, the pressure swing adsorption system (5) comprising a plurality of adsorption towers (51) connected in series to the decarbonizer knockout drum (44).

5. The hydrogen production and purification system of claim 1 or 2, wherein: The decarbonization system (4) further comprises a lean-rich liquid heat exchanger (47) for recovering heat from the lean liquid after regeneration, a lean liquid cooler (48) for cooling the lean liquid after regeneration, and a mechanical filter (49) for filtering solid impurities from the lean liquid, the lean-rich liquid heat exchanger (47) being connected to the regenerator (42) at the hot source outlet and to the decarbonization tower (41) at the cold source outlet.

6. The hydrogen production and purification system of claim 1 or 2, wherein: The decarbonization system (4) further comprises a carbon dioxide cooler (45) for cooling the carbon dioxide separated from the regenerator (42) and a carbon dioxide knockout drum (46) for separating liquid from the carbon dioxide.

7. The hydrogen production and purification system of claim 1 or 2, wherein: The desulfurization system (1) comprises a compressor (11) for compressing the raw material gas, a hydrodesulfurization tank (12) for converting organic sulfur into inorganic sulfur, and a zinc oxide desulfurization tank (13) for removing inorganic sulfur, the zinc oxide desulfurization tank (13) being connected to the conversion furnace (21).

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