Safe and efficient water methanol hydrogen production and hydrogen using unit coupling process
By coupling methanol conversion for heating and hydrogen purification units, and employing catalytic oxidation technology and tail gas recycling, the problems of insufficient tail gas utilization and inadequate safety in methanol-to-hydrogen production have been solved, achieving safe and efficient hydrogen production.
Patent Information
- Application Number
- CN202511600758.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-04
- Publication Date
- 2026-01-20
AI Technical Summary
Existing methanol-to-hydrogen technologies do not effectively recover and utilize the tail gas from hydrogen purification, the high-temperature heat source is not fully utilized, and there is a risk of combustion and explosion of oxygen and flammable gas mixtures such as methanol and hydrogen in the system, resulting in insufficient safety.
The heating from methanol conversion is coupled with the subsequent hydrogen purification and hydrogen utilization unit. The system is heated by catalytic oxidation technology, and energy is recovered by recycling hydrogen-containing tail gas. Hydrogen is added in stages and the concentration is controlled within the lower explosive limit. Waste heat recovery from tail gas and circulating fans are set up to reduce emissions and energy consumption.
It improves system safety and energy efficiency, reduces hydrogen consumption by 15%, reduces emissions, and is suitable for miniaturized and integrated applications.
Smart Images
Figure CN121361766A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of methanol hydrogen production and hydrogen energy, and particularly relates to a safe and efficient water-methanol hydrogen production and hydrogen use unit coupled process. BACKGROUND
[0002] Methanol is an important hydrogen carrier and has the advantages of easy availability, convenient transportation, short hydrogen production process steps, mild reaction conditions, low overall investment in equipment and devices, etc. Methanol hydrogen production has great advantages in small-scale hydrogen supply scenarios. However, the existing technology has technical problems such as ineffective recycling of hydrogen gas purification tail gas, insufficient use of high-level heat sources, and insufficient coupling of hydrogen use systems (such as hydrogen fuel cells). At the same time, due to the presence of mixtures of oxygen and combustible gases such as methanol and hydrogen in the system, there is a high risk of combustion and explosion, and the safety of the production process is particularly important. SUMMARY
[0003] The purpose of the present application is to provide a safe and efficient water-methanol hydrogen production and hydrogen use unit coupled process to solve the problems in the prior art. The process couples the heat supply of methanol conversion and the subsequent hydrogen purification and hydrogen use unit, recycles the hydrogen-containing tail gas generated in the subsequent unit to the catalytic oxidation system for energy recovery and removes a small amount of hydrocarbons, alcohols, etc. in the tail gas, thereby saving energy and reducing emissions. The use of the process can greatly improve the safety and energy saving of the production process.
[0004] In order to achieve the above purposes, the specific technical solutions of the present application are as follows: A safe and efficient water-methanol hydrogen production and hydrogen use unit coupled process, which is composed of a water-methanol reforming unit, a hydrogen purification and use unit, and a catalytic combustion heat supply unit. The water-methanol reforming unit has heat recovery, vaporization and superheating, reforming reaction, cooling, and gas-liquid separation steps. The catalytic oxidation heat supply unit has catalytic oxidation reaction, start-up heating, circulating fan pressurization, fuel preheating, air preheating, and air supplementing steps. The hydrogen purification part of the hydrogen purification and use unit can use PSA or other hydrogen purification technologies. The qualified hydrogen gas generated is supplied to the hydrogen fuel cell group, and the purified desorption gas and the hydrogen-containing tail gas of the fuel cell group are introduced into the catalytic oxidation heat supply system for heat value recovery and emission reduction.
[0005] Further, in the above coupled process, there are also methanol and circulating liquid tanks, raw material and fuel methanol pumps, vaporizers, reforming reactors, heat exchangers, coolers, gas-liquid separators, catalytic oxidation reactors, tail gas waste heat recoveries, circulating fans, air supplementing fans, and hydrogen purification systems. The above steps are used to produce qualified hydrogen gas.
[0006] Further, in the water-methanol reforming unit of the coupling process, the vaporization superheating and reforming reaction steps use heat carrier gas (circulating gas) for heating; to ensure that the reforming reaction temperature is not too high, the heat carrier gas first passes through the vaporization superheating and then enters the reforming reactor in the water-methanol reforming unit.
[0007] Further, in the coupling process, the hydrogen extraction tail gas generated by the hydrogen purification and use unit is used to heat the fuel gas in the catalytic combustion heating unit to produce heat through low-temperature catalytic oxidation (no open flame); coupled with the hydrogen link, the energy is saved by recycling the tail gas, and the CO, hydrocarbons, and organic matter in the tail gas are combusted to achieve the effect of emission reduction.
[0008] Further, in the coupling process, the fuel gas is added to the catalytic oxidation reactor in stages to ensure that the hydrogen concentration in the mixed gas is far below the lower explosive limit, ensuring system safety.
[0009] Further, in the coupling process, a makeup air fan and a circulating fan are provided, the makeup air fan is used to supply air to the catalytic oxidation system, and the circulating fan provides heat carrier gas for the system, thereby reducing the amount of hot tail gas emissions. The makeup air and the small amount of emissions only meet the oxygen required for the reaction, and the heat carrier gas (also known as circulating gas) is not cooled after being circulated, the temperature of the heat carrier gas (also known as circulating gas) out of the catalytic oxidation reactor is 450-550℃, and the temperature after heating is 230-280℃, which greatly reduces heat loss and achieves the purpose of energy saving and emission reduction.
[0010] The catalytic combustion heating unit is provided with a tail gas waste heat recovery device, (the heat carrier gas is divided into two parts after being used to heat the methanol reforming system, most of which is recycled, and a small part is discharged after recovering waste heat through heat exchange) the exhaust gas (heat carrier gas) is heat exchanged with fresh air and fuel gas, waste heat is recovered, the temperature of the exhaust gas is reduced, and energy saving is achieved.
[0011] Methanol and desorbed tail gas, as well as fuel cell tail gas, are used as fuel and combustion air to undergo low-temperature oxidation reaction under the action of a catalyst to release heat, and the temperature of the gas after the reaction is 450-550℃, which is used as a heat source to heat the raw material vaporization and reforming reaction of methanol reforming.
[0012] Further, in the coupling process, since the hydrogen extraction desorption gas (generated after hydrogen purification) and the fuel cell tail gas both contain hydrogen, in order to ensure safety, the hydrogen content needs to be controlled within 50% of the lower explosive limit, i.e. 2% (V / V). This process uses segmented addition of hydrogen-containing gas, thereby greatly reducing the amount of gas used for dilution, and further reducing the amount of circulating hot air, while ensuring safety, the energy consumption is greatly reduced.
[0013] Further, in the coupling process, the tail gas waste heat recovery gas is provided to exchange heat with the combustion-supporting air intake and the recovered hydrogen-containing fuel gas after conversion heat supply, so as to achieve the effect of energy saving.
[0014] Further, in the coupling process, the hydrogen inlet online concentration automatic detection is provided, when the hydrogen concentration is too high, the air is supplemented, and when the hydrogen concentration is too high, the addition of the hydrogen-containing tail gas is cut off, so as to further improve the safety.
[0015] Further, in the coupling process, the fuel methanol pump and the methanol sprayer are provided to spray the liquid methanol into the circulating gas after atomization, so that the gas phase entering the catalytic oxidation reactor is uniform and beneficial to the reaction.
[0016] Further, in the coupling process, the methanol reforming system is provided with reaction outlet high-temperature gas and raw material heat exchange, and is provided with reaction gas water washing to recover energy and methanol in the reaction gas.
[0017] Further, in the coupling process, the hydrogen-containing tail gas flow regulating valve is provided to stabilize the flow and pressure, so that the system runs stably.
[0018] Further, in the coupling process, the water washing and gas-liquid separation tank two-in-one form is adopted, and desalted water raw material is used as the absorbent, so that the methanol content in the cracking gas is reduced, the effect of gas-liquid separation is reduced, and the number of equipment is reduced.
[0019] Further, in the coupling process, the cracking gas after cooling, condensation, water washing and separation enters the hydrogen purification system, and PSA or membrane separation purification technology can be used to purify the qualified hydrogen (the purity can be adjusted according to the subsequent fuel cell group hydrogen requirement) to enter the fuel cell group to supply hydrogen. The hydrogen purification and hydrogen-containing tail gas of the fuel cell group enter the catalytic oxidation after pressure stabilization, the hydrogen and a small amount of combustible materials such as hydrocarbons and alcohols in the catalytic oxidation are oxidized and released heat, so that the heat is recovered and the emission of organic components is reduced, and the purpose of energy saving and emission reduction is achieved. The combination of the above steps greatly improves the safety of the system, and the methanol consumption per standard cubic meter of hydrogen can be controlled to be ≤0.64 kg, which is reduced by about 15% compared with the conventional process.
[0020] A safe and efficient water-methanol hydrogen production and hydrogen utilization unit coupling process, specifically comprising the following steps: Step 1): Water-methanol reforming system feed, heat exchange, vaporization and superheating.
[0021] The methanol raw material enters the methanol and circulating liquid tank, mixes with the circulating liquid (containing methanol and water) returned, and then enters the heat exchanger after being pressurized to exchange heat with the reforming reaction gas to recover heat, and then enters the vaporization and superheating device to be completely vaporized and superheated to the reforming reaction temperature by the circulating heat carrier gas.
[0022] In this step, the water-methanol ratio is controlled to adjust the water addition amount of water washing and gas-liquid separation tank, w / w = 1:1. After mixing, the pressure is increased to 1.0 MPaG~2.8 MPaG; the reforming reaction temperature is 240℃~280℃.
[0023] Step 2): Water-methanol reforming reaction, reaction gas heat recovery, cooling, water washing and separation.
[0024] The raw material mixed gas heated to the reforming reaction temperature of 240℃~280℃ enters the reforming reactor for reaction; The reforming reaction equation is CH3OH + H2O = CO2 + 3H2; and the main side reaction is CH3OH = 2H2 + CO.
[0025] After reaction, the mixed gas mainly contains H2, CO2, CO and unreacted H2O and methanol, which then enter the heat exchanger of the heat recovery unit together to recover heat from the raw materials.
[0026] After heat exchange in the heat recovery heat exchanger, the reaction gas enters the cooler for cooling with circulating water, refrigerant or cold dry equipment; The temperature of the cooled reaction gas is 20~40℃.
[0027] The cooled reaction gas enters the water washing and separation tank for water washing with desalted water to further absorb the residual methanol in the reaction gas phase. The gas phase (typical composition in volume percentage is H2~74.5%, CO2~24%, CO~0.5%, and the rest is H2O, CH4, methanol and other trace impurities) after water washing and separation is sent to the subsequent hydrogen purification step after pressure stabilization. The bottom liquid phase of the water washing and separation tank is stored in the circulating liquid tank and then pressurized together with the feed methanol to form a mixed raw material.
[0028] Step 3): Hydrogen purification and hydrogen fuel cell The reaction gas after cooling, water washing and separation mainly contains H2, CO, CO2 and a small amount of other impurities. The hydrogen gas is purified by pressure swing adsorption or other methods, and the purified hydrogen gas is supplied to the hydrogen fuel cell for power generation or other uses. After supplying the hydrogen fuel cell for power generation, hydrogen-containing tail gas is produced together with the tail gas remaining after purification and is sent to the next step-catalytic oxidation for heat supply after pressure stabilization.
[0029] Step 4): Catalytic oxidation for heat supply The hydrogen-containing tail gas from the previous step enters the tail gas waste heat recovery device as a heat supply material and exchanges heat with the exhaust gas, and then is divided into two or more streams and added into the catalytic oxidation reactor. At the same time, the system needs air to supply oxygen, and the amount of fresh air supplement is adjusted by the air supplement fan. The fresh air exchanges heat with the exhaust gas with waste heat in the tail gas waste heat recovery device, and then is mixed with the hydrogen-containing tail gas. At the same time, if the heat of the exhaust gas oxidation is not enough, the process is provided with a methanol atomization supplement process. The methanol from the methanol raw material tank is pressurized by a fuel methanol pump and atomized by a methanol injector and then sprayed into the mixed gas. The mixed gas composed of air, hydrogen-containing tail gas and methanol is adjusted by the circulating fan to ensure that the H2concentration in the mixed gas is 1-2% for safety. The mixed gas enters the catalytic oxidation reactor to produce heat and remove a small amount of combustible substances such as hydrocarbons and alcohols in the tail gas. The outlet temperature can be adjusted by adjusting the amount of methanol added and the amount of air supplemented, and the temperature can be adjusted between 450-550°C. The initial start-up needs to start the reaction, and an electric heater is provided for start-up.
[0030] The high-temperature heat-carrying gas from the catalytic oxidation reactor first enters the raw material vaporization superheater to vaporize and superheat the raw material, and then enters the reforming reactor to provide heat for the reaction. A small part of the mixed gas after heat removal exchanges heat with the hydrogen-containing tail gas and fresh air to recover heat and meet the emission standards, and most of it returns to the inlet of the circulating fan as a heat-carrying gas circulation.
[0031] A safe and efficient water-methanol hydrogen production and hydrogen utilization unit coupling device, comprising a raw material refined methanol input device, a methanol and circulating liquid tank, a water washing and separation tank, a raw material methanol pump, a heat exchanger, a vaporization superheater (vaporizer), a reforming reactor, a fuel methanol pump, a circulating fan, a methanol injector, a start-up heater, a catalytic oxidation reactor, a circulating water cooler, an air supplement fan, a hydrogen purification system, and a fuel cell group; wherein, The raw material refined methanol and the water washing and separation tank are connected to the methanol and circulating liquid tank buffer; the circulating liquid tank buffer is connected to the raw material methanol pump, the heat exchanger, and the vaporization superheater in turn, and then connected to the reforming reactor; the heat exchanger is connected to the circulating water cooler, and then connected to the water washing and separation tank.
[0032] The methanol and circulating liquid tank is connected to the fuel methanol pump and the methanol injector in turn, one end of the methanol injector is connected to the pipeline from the reforming reactor through the circulating fan, and then connected to the tail gas waste heat recovery device; the other end of the methanol injector is connected to the catalytic oxidation reactor through the start-up heater.
[0033] The catalytic oxidation reactor is connected to the vaporization superheater.
[0034] The tail gas waste heat recovery device is connected to the exhaust gas pipeline, and the outlet pipeline of the tail gas waste heat recovery device is divided into two streams. The first stream is connected to the methanol injector, and the second stream is connected to the middle part of the catalytic oxidation reactor.
[0035] Fresh air is connected with the tail gas waste heat recovery device through a make-up air blower.
[0036] The tail gas waste heat recovery device is connected with a methanol injector and a circulating air blower through pipelines. The reforming reactor is connected with a heat exchanger. Fresh desalted water is connected with a water washing and separation tank. The water washing and separation tank is connected with a hydrogen purification system, and the hydrogen purification system is connected with a fuel cell group; both the hydrogen purification system and the fuel cell group are connected with the tail gas waste heat recovery device.
[0037] Compared with the prior art, the present application has the following beneficial effects: (1) The present application couples the heat supply of methanol conversion and the subsequent hydrogen purification and use unit, recycles the hydrogen-containing tail gas generated by the subsequent unit to the catalytic oxidation system for energy recovery, and removes a small amount of hydrocarbons, alcohols and the like in the tail gas, thereby saving energy and reducing emissions.
[0038] (2) The present application uses catalytic oxidation technology to supply heat to the system, and eliminates open flames. At the same time, the hydrogen-containing tail gas is added in sections, and the hydrogen content in the mixed gas is strictly controlled to be less than 50% of the lower explosive limit, i.e. 2% (v / v), which essentially eliminates the risk of combustion and explosion, greatly improves the safety of the system, and reduces the amount of dilution circulating gas, thereby greatly reducing the energy consumption of the circulating air blower. Compared with directly adding air to dilute to 2%, the amount of circulating gas can be reduced by 20% due to heat loss and blower power consumption caused by exhaust smoke.
[0039] (3) The heat-carrying gas circulation power of the present application comes from the circulating air blower, and fresh air is supplemented in a small amount to meet the catalytic oxidation, which corresponds to a large reduction in flue gas emission, and an exhaust flue gas and fuel gas and make-up air heat exchange process is provided to recover heat, which is beneficial to energy saving.
[0040] (4) The process of the present application does not have a traditional heat-conducting oil heating device, the number of devices is small, the form is simple, the process is short, and it is suitable for miniaturization, integration and skid-mounted manufacturing, and has high compatibility with hydrogen fuel cells and other scenes, and has a broad application prospect. BRIEF DESCRIPTION OF DRAWINGS
[0041] Figure 1 It is a kind of safe and efficient water-methanol hydrogen production and hydrogen use unit coupling process flow diagram described in embodiment 1 in the present application.
[0042] Figure 2 It is a connection relationship diagram of a safe and efficient water-methanol hydrogen production and hydrogen use unit coupling device. The methanol and circulating liquid tank V101, the water washing and separation tank V104, the raw material methanol pump P101, the heat exchanger E102, the vaporization superheater (vaporizer) E101, the reforming reactor R101, the fuel methanol pump P201, the circulating fan C202, the methanol ejector X201, the start-up heater E201, the catalytic oxidation reactor R201, the circulating water cooler E103, the air supply fan C201, the hydrogen purification system X301, and the fuel cell group X401. DETAILED DESCRIPTION
[0043] All features disclosed in this specification, and / or all steps of any methods or processes disclosed in this specification, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.
[0044] Any feature disclosed in this specification, unless stated otherwise, can be replaced by any equivalent or similar feature.
[0045] The features and properties of the present application will become further apparent to those of ordinary skill in the art upon consideration of the following detailed description of the application.
[0046] In this application, nothing is marked, which means volume percentage, that is, v / v%.
[0047] A safe and efficient water-methanol hydrogen production and hydrogen unit coupling device, comprising a raw material refined methanol input device, a methanol and circulating liquid tank V101, a water washing and separation tank V104, a raw material methanol pump P101, a heat exchanger E102, a vaporization superheater (vaporizer) E101, a reforming reactor R101, a fuel methanol pump P201, a circulating fan C202, a methanol ejector X201, a start-up heater E201, a catalytic oxidation reactor R201, a circulating water cooler E103, an air supply fan C201, a hydrogen purification system X301, and a fuel cell group X401. The raw material refined methanol and the water washing and separation tank V104 are connected with the methanol and circulating liquid tank buffer V101; the circulating liquid tank buffer V101 is connected with the raw material methanol pump P101, the heat exchanger E102, and the vaporization superheater E101 in sequence, and then connected with the reforming reactor R101; the heat exchanger E102 is connected with the circulating water cooler E103, and then connected with the water washing and separation tank V104.
[0048] Methanol and circulating liquid tank V101 in turn with fuel methanol pump P201, methanol injector X201 connected, methanol injector X201 one end through the circulating fan C202 and from the pipeline of the reforming reactor R101 communication after the tail gas waste heat recovery device E202 connection; the other end of the methanol injector X201 through the start-up heater E201 after the catalytic oxidation reactor R201 connection.
[0049] Catalytic oxidation reactor R201 and vaporization superheater E101 connection; Tail gas waste heat recovery device E202 and the flue gas duct connection, tail gas waste heat recovery device E202 outlet pipeline is divided into two, the first with methanol injector X201 connection, the second with catalytic oxidation reactor R201 middle connection; Fresh air through the air supply fan C201 and tail gas waste heat recovery device E202 connection; Tail gas waste heat recovery device E202 and methanol injector X201 and circulating fan C202 between the pipeline communication; Reforming reactor R101 and heat exchanger E102 connection; Fresh desalted water and water washing and separation tank V104 connection; Water washing and separation tank V104 and hydrogen purification system X301 connection, hydrogen purification system X301 and fuel cell group X401 connection; hydrogen purification system X301 and fuel cell group X401 are connected with tail gas waste heat recovery device E202.
[0050] Example 1: A safe and efficient water methanol hydrogen production and hydrogen unit coupling process, comprising the following steps: This example uses methanol and water (water methanol) as raw material to produce hydrogen containing mixed gas, the mixed gas is purified to high purity hydrogen after the fuel cell group for hydrogen, at the same time, the tail gas produced in the purification of hydrogen and the tail gas of fuel cell group are recovered as fuel for methanol reforming to supply hydrogen. The process is shown in Figure 1 .
[0051] 99.85w% of the raw material refined methanol into the methanol and circulating liquid tank buffer V101, methanol feed is 159kg / h, mixed with water methanol circulating liquid (containing methanol ~4.2w%, flow 173kg / h) from the water washing and separation tank V104, after mixing, the raw material liquid flow is 332kg / h (water: methanol w / w =1), the raw material liquid is pressurized to 1.8Mpa by raw material methanol pump P101, enters the heat exchanger E102 and exchanges heat with the reforming reaction gas, the raw material liquid is heated to ~180℃, then enters the vaporization superheater E101 and exchanges heat with the high temperature catalytic combustion gas, after vaporization and superheating, the temperature is ~250℃.
[0052] The water-methanol feed gas reaching the reaction temperature enters the reforming reactor R101, and the water-methanol is reformed to generate CO2 and hydrogen, with the reaction formula being CH3OH + H2O = CO2 + 3H2. Due to the influence of conversion rate, selectivity and other factors, the composition of the reformed gas is: methanol ~ 1.07%, water ~ 18.62%, CO ~ 0.6%, CO2 ~ 19.62%, hydrogen ~ 59.99%, and a small amount of methane and C2+ impurities. The hydrogen reforming reactor R101 is heated by catalytic combustion gas to control the temperature at 250-260°C. The reformed gas first enters the heat exchanger E102 to exchange heat with the feed liquid and is cooled to ~ 112°C to recover energy, and then is condensed to ~ 40°C in the cooler E103, enters the water washing and separation tank V104, and the desalted water feed is sprayed from the upper part of the tank to absorb the methanol in the gas phase. The liquid at the bottom is circulated to the methanol and circulating liquid tank V101 for temporary storage and recycling.
[0053] After condensation and water washing, the mixed gas is 437 Nm 3 / h, and the composition of the mixed gas is: methanol ~ 0.17%, water ~ 0.38%, CO ~ 0.74%, CO2 ~ 24.29%, and hydrogen ~ 74.29%. The mixed gas enters the hydrogen PSA hydrogen purification unit (prior art) to purify 99.999% high-purity hydrogen 260 Nm 3 / h, and the obtained desorption gas 177 Nm 3 / h is sent to the catalytic oxidation heating system as fuel. The high-purity hydrogen is supplied to the fuel cell for power generation, and the tail gas after power generation ~ 2.5 Nm 3 / h containing 98% hydrogen is also returned to the catalytic oxidation heating system as fuel.
[0054] The desorption gas from the PSA unit and the tail gas from the fuel cell stack are mixed and adjusted in flow rate, then enter the tail gas waste heat recovery device E202 to exchange heat with the flue gas, and are divided into two after adjustment. The first one is mixed with the circulating heat carrier gas and fuel methanol to form a mixed gas 1684 Nm 3 / h as the feed of the catalytic oxidation reactor R201 (E201 electric heater is provided in the process for heating during the initial start-up), wherein the fuel methanol is atomized by the fuel methanol pump P201 and the methanol injector X201, and the amount of supplement is controlled by the temperature at the outlet of R201 (in this case, the heat provided by the combustion of the recovered gas is sufficient, and no fuel methanol is supplemented). After the first bed layer in the catalytic oxidation reactor R201, the hydrogen in the fuel gas is consumed, and then the second one is added from the middle of the catalytic oxidation reactor R201. At this time, the hydrogen concentration in the mixed gas is 1.92%, which is lower than the set value of 2%. After two-stage heating, the temperature of the heat carrier gas out of R201 is 530°C, and the gas amount is 1739 Nm 3 / h. The heat carrier gas enters the vaporizer E101, the reforming reactor R101 for heating in turn, and the temperature drops to 255°C. A part of the heat carrier gas is 330 Nm 3 / h into the tail gas waste heat recovery device E202 and the supplementary fresh air and fuel gas heat exchange to reduce the exhaust temperature, recover the heat, and the remaining part 1408Nm 3 / h by the circulating fan C202 to increase 3kpa after circulation, to reduce the exhaust fume as much as possible.
[0055] In summary, the application combines water-methanol reforming and hydrogen fuel cell together, and uses the desorption gas and fuel cell tail gas as fuel to catalytically oxidize without flame, and adds hydrogen-containing gas into the catalytic oxidizer in sections to reduce the gas amount and the exhaust emission as much as possible under the premise of safety, and most of the heat-carrying gas is circulated to reduce the exhaust emission, which greatly improves the safety of the process, and achieves the effect of energy saving and emission reduction. In addition, methanol is easy to transport and obtain, which provides a new idea for hydrogen fuel cell and other gas sources, and has a wide application prospect.
[0056] The above-mentioned embodiments only express the specific implementation of the present application, and the description is more specific and detailed, but it cannot be understood as the limitation of the protection scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the technical scheme concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application.
[0057] This background section is provided to generally present the context of the application, the work of the current named inventors, the work described in this background section to the extent that it is described, and the aspects described in this section at the time of filing, neither expressly nor implicitly, are recognized as prior art of the present application.
Claims
1. A safe and efficient process for hydrogen production from water-methanol coupled with a hydrogen-consuming unit, characterized by: The process comprises a water-methanol reforming unit, a hydrogen purification and use unit, and a catalytic combustion heat supply unit; wherein the water-methanol reforming unit is provided with heat recovery, vaporization superheating, reforming reaction, cooling, and gas-liquid separation steps; the catalytic combustion heat supply unit is provided with catalytic oxidation reaction, start-up heating, circulating fan pressurization, fuel preheating, air preheating, and air make-up steps; the hydrogen purification and use unit selects a hydrogen purification system, so that the qualified hydrogen generated is used to supply hydrogen to a hydrogen fuel cell group, and the purified desorbed gas and the hydrogen-containing tail gas of the fuel cell group are introduced into the catalytic oxidation heat supply unit to recover heat values and reduce emissions.
2. A safe and efficient process of hydrogen production from water-methanol and coupling with hydrogen utilization unit as claimed in claim 1, wherein: The vaporization superheating and reforming reaction steps in the water-methanol reforming unit adopt heat supply by carrier gas; in order to ensure that the reforming reaction temperature is not too high, the carrier gas first passes through vaporization superheating and then enters the reforming reactor in the water-methanol reforming unit.
3. A safe and efficient process of hydrogen production from water-methanol and coupling with hydrogen utilization unit as claimed in claim 1, wherein: The hydrogen purification and use unit produces hydrogen extraction tail gas, which is used for low-temperature catalytic oxidation heat supply of the fuel gas in the catalytic combustion heat supply unit; and is coupled with the hydrogen use link.
4. A safe and efficient process of hydrogen production from water-methanol and coupling with hydrogen utilization unit as claimed in claim 1, wherein: The fuel gas is added into the catalytic oxidation reactor in sections, so as to ensure that the hydrogen concentration in the mixed gas is far below the lower explosive limit, and to ensure system safety.
5. A safe and efficient process of hydrogen production from water-methanol and coupling with hydrogen utilization unit as claimed in claim 1, wherein: The air make-up and discharge amount is small, and only the oxygen required for the reaction is sufficient, a carrier gas non-cooling circulation is provided, the carrier gas temperature out of the catalytic oxidation reactor is 450-550 DEG C, and after heat supply, the temperature is 230-280 DEG C, so that the purpose of energy saving and emission reduction is achieved.
6. A safe and efficient process of hydrogen production from water-methanol and coupling with hydrogen utilization unit as claimed in claim 1, wherein: The catalytic combustion heat supply unit is provided with a tail gas waste heat recovery device, the discharge gas is heat-exchanged with fresh air and fuel gas, waste heat is recovered, the discharge gas temperature is reduced, and energy saving is achieved.
7. A safe and efficient process of hydrogen production from water-methanol and coupling with hydrogen utilization unit as claimed in claim 1, wherein The process comprises the following specific steps: Step 1) water-methanol reforming system feed, heat exchange, vaporization superheating: methanol raw material enters a methanol and circulating liquid tank, is mixed with circulating liquid containing methanol and water, is pressurized, enters a heat exchanger to exchange heat with reforming reaction gas to recover heat, then enters a vaporization superheater to be heated by circulating carrier gas to completely vaporize and superheat to a reforming reaction temperature; Step 2) water-methanol reforming reaction, reaction gas heat recovery, cooling, water washing and separation: the raw material mixed gas superheated to the reforming reaction temperature enters a reforming reactor to undergo reforming reaction, the mixed gas after the reforming reaction mainly comprises H2, CO2, CO, and unreacted H2O and methanol, and the substances after the reforming reaction enter a heat recovery unit heat exchanger and raw material to exchange heat and recover heat; after heat exchange in the heat recovery heat exchanger, the reaction gas enters a cooler to be cooled, the cooled reaction gas enters a water washing and separation tank to be washed with feed desalinated water to further absorb residual methanol in the reaction gas phase, the gas phase after water washing and separation is sent to a subsequent hydrogen purification step after being stabilized; the liquid phase at the bottom of the water washing and separation tank is stored in a circulating liquid tank, and is pressurized together with the feed methanol to form mixed raw material; Step 3) hydrogen purification and hydrogen fuel cell: the reaction gas after cooling, water washing, and separation is purified to obtain hydrogen, and the purified hydrogen is supplied to a hydrogen fuel cell for power generation or other uses; after the hydrogen fuel cell is supplied with power, hydrogen-containing tail gas is generated, which is sent to the next step-catalytic oxidation heat supply after being stabilized together with the tail gas remaining after purification; Step 4) catalytic oxidation heat supply: The hydrogen-containing tail gas from the previous step enters the tail gas waste heat recovery device as a heat supply material to exchange heat with the exhaust gas, and then is divided into two or more sub-sections and added to the catalytic oxidation reactor. At the same time, the system needs air to supply oxygen, and the amount of fresh air supplement is adjusted by the air supplement fan. The fresh air exchanges heat with the exhaust gas with waste heat in the tail gas waste heat recovery device, and then is mixed with the hydrogen-containing tail gas. At the same time, if the heat of the tail gas oxidation is not enough, a methanol atomization supplement process is provided. The methanol from the methanol raw material tank is pressurized by a fuel methanol pump and atomized by a methanol atomizer and then sprayed into the mixed gas. The mixed gas composed of air, hydrogen-containing tail gas and methanol enters the catalytic oxidation reactor to produce heat and remove a small amount of combustible substances in the tail gas. The outlet temperature is adjusted by adjusting the amount of methanol added and the amount of air supplemented, and the temperature can be adjusted between 450-550°C. An electric heater is provided for starting the reaction at the initial stage of starting the system. The high-temperature heat-carrying gas from the catalytic oxidation reactor first enters the raw material vaporization superheater to vaporize and superheat the raw material, and then enters the reforming reactor to supply heat for the reaction. A small part of the mixed gas after heat removal exchanges heat with the hydrogen-containing tail gas and fresh air to recover heat and meet the emission standards, and most of it returns to the inlet of the circulating fan as a heat-carrying gas.
8. A safe and efficient process of hydrogen production from water-methanol and coupling with hydrogen utilization unit as claimed in claim 1, wherein In step 1), The methanol raw material enters the methanol and circulating liquid tank and is mixed with the circulating liquid containing methanol and water. The water to alcohol ratio is controlled by adjusting the amount of water added to the water washing and gas-liquid separation tank, and the w / w is 1:
1. After mixing, the pressure is increased to 1.0 MpaG-2.8 MpaG, and the superheating temperature is increased to 240-280°C.
9. A safe and efficient process of hydrogen production from water-methanol and coupling with hydrogen utilization unit as claimed in claim 1, wherein In step 2), the reaction formula of the reforming reaction is CH3OH+H2O=CO2+3H2, and the main side reaction in the reforming reaction is CH3OH =2H2+CO. The temperature is cooled to 20-40°C by circulating water, refrigerant or cold dry equipment. After water washing and separation, the typical composition of the gas phase is H2 74.5%, CO2 24%, CO 0.5%, and the rest is trace impurities.
10. A safe and efficient process of hydrogen production from water-methanol and coupling with hydrogen utilization unit as claimed in claim 1, wherein In step 3), the hydrogen purification is carried out by pressure swing adsorption. In step 4), the H2 concentration in the mixed gas is controlled to be 1-2%, and the outlet temperature is adjusted by adjusting the amount of methanol added and the amount of air supplemented, and the temperature is adjusted between 450-550°C.