Methanol-to-hydrogen process

Abstract

The invention relates to the technical field of methanol-to-hydrogen, and discloses a methanol-to-hydrogen process which comprises the following steps: S1, dehydrating methanol in a raw material pretreatment stage, S101, reheating the raw material, and S2, enabling a pretreated methanol-water mixed solution to pass through a composite purification column filled with an adsorbent and ion exchange resin, the method comprises the following steps: S1, carrying out catalytic reaction on methanol and water vapor under the action of a copper-based catalyst, S3, carrying out reforming reaction on methanol and water vapor under the action of a copper-based catalyst, S4, carrying out reaction strengthening in a catalytic reaction process, S5, carrying out real-time separation on hydrogen from a reaction product by utilizing a high-selectivity hydrogen film in a hydrogen separation stage, and S6, recovering hydrogen and heat in the reaction process through a high-efficiency heat exchanger in a waste heat recovery stage. And S7, applying an intelligent control system in an intelligent control stage. By adopting the nano Cu-Zn-Al-O catalyst, the high activity is kept for a long time in an environment containing 50 ppm of sulfur and 30 ppm of chlorine, and the effects of improving the stability of the catalyst and prolonging the service life are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of methanol-to-hydrogen production, and particularly to a methanol-to-hydrogen production process. Background Art

[0002] Methanol reforming to hydrogen production technology has been widely used in fields such as fuel cells and hydrogen energy supply due to its relatively low reaction temperature and high hydrogen production rate. Copper-based catalysts (such as Cu-Zn-Al-O) have become the core of this technology due to their excellent methanol conversion activity and selectivity. However, during industrial applications, the stability and anti-poisoning ability of the catalyst directly affect the long-term stable operation of the system.

[0003] During long-term operation, traditional copper-based catalysts are easily contaminated by sulfides (such as H2S) and chlorides (such as HCl), resulting in the inactivation of active sites, a decrease in the redox performance on the catalyst surface, and thus affecting the methanol conversion efficiency. In addition, the catalyst particles are prone to sintering, leading to a reduction in specific surface area and a gradual decrease in activity. These problems not only shorten the catalyst life but also increase the maintenance cost and downtime, affecting the economy of industrial production. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a methanol-to-hydrogen production process to solve the problems that traditional catalysts are prone to inactivation in an environment with a sulfur content > 10 ppm or a chlorine content > 5 ppm, which limits their application in complex working conditions. Under high-temperature conditions, metal particles on the catalyst surface are prone to aggregation, resulting in a decrease in specific surface area and a decline in catalytic activity. During long-term operation, the catalyst inactivation rate is relatively fast, and it needs to be frequently replaced, increasing the production cost.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A methanol-to-hydrogen production process includes the following steps: S1. Raw material pretreatment stage: First, dehydrate methanol, use molecular sieve adsorption technology to remove trace moisture in methanol, remove particulate matter and impurities in methanol through an efficient filtration system, mix the raw material methanol with water, and then heat and mix evenly; S101. Raw material reheating: The gas after gasification of the hot methanol and water mixture passes through a special heat exchanger in the reaction tank to raise the gas temperature to the working temperature; S2. Impurity deep purification step: Pass the pretreated methanol-water mixture through a composite purification column equipped with adsorbent and ion exchange resin. The adsorbent selectively adsorbs residual organic impurities in methanol, and the ion exchange resin removes metal ions; S3. Catalytic reaction stage: The reforming reaction occurs between methanol and water vapor under the action of a copper-based catalyst. The autothermal reforming technology is adopted to maintain the reaction temperature, and the catalyst is a composite catalyst that uses nanotechnology to optimize the surface activity and has sulfur and chlorine resistance capabilities. S4. Reaction intensification step: During the catalytic reaction process, a method combining ultrasonic-assisted technology and a microchannel reactor is introduced. Utilizing the cavitation effect of ultrasonic waves and the high specific surface area of the microchannel reactor, the reaction is promoted. S5. Hydrogen separation stage: The membrane separation technology is adopted. Using a highly selective hydrogen membrane, hydrogen is separated from the reaction products in real time, promoting the reaction equilibrium to shift towards the hydrogen production direction and reducing the contents of carbon monoxide and carbon dioxide. S6. Waste heat recovery stage: The hydrogen and heat in the reaction process are recovered through an efficient heat exchanger, used to preheat the raw materials or generate steam, and part of the waste heat is converted into heat energy through combustion. S7. Intelligent control stage: An intelligent control system is applied. Through the Internet of Things and artificial intelligence algorithms, the system is monitored and adjusted in real time, key parameters are automatically adjusted, the activity and usage of the catalyst are monitored in real time, and the maintenance time is automatically predicted and prompted.

[0006] Preferably, in S1, the molecular sieve used is a 3A molecular sieve, the trace moisture in methanol after removing moisture is <1%, the high-efficiency filtration system adopts a multi-layer filter screen structure, the mesh numbers of the filter screens are 100 mesh, 200 mesh, and 500 respectively, the mixing ratio is 1:1 or 1:5, the heating temperature is 200 - 300 °C, the temperature fluctuation range is controlled within ±2 °C, the mixing uses a multi-channel high-efficiency mixer, the mixing time is 30 - 60, and the mixing ratio of formaldehyde and water is 90 - 100% formaldehyde: 0 - 10% water.

[0007] Preferably, in S101, the working temperature is 220 - 300 °C, which is used to increase the working temperature to improve the hydrogen concentration obtained after the reaction.

[0008] Preferably, in S2, the special adsorbent and ion exchange resin in the composite purification column are loaded in layers, the proportion of the layered loading is 3:2, the flow rate of the methanol-water mixture through the composite purification column is 0.5 - 1.5 m³ / h, the adsorbent and ion exchange resin are regenerated regularly, the regeneration treatment adopts high-temperature roasting and acid-base elution, and the service life of the adsorbent and ion exchange resin is 1000 hours or they are replaced after treating 500 m³ of the methanol-water mixture.

[0009] Preferably, in S3, the elements in the copper-based catalyst include Cu-Zn-Al-O with a molar ratio of 2:1:1:4. The autothermal reforming technology monitors the reaction temperature in real time and adjusts the feed rate according to the temperature feedback. The reaction temperature is maintained at 250-280 °C with a temperature control accuracy of ±3 °C. The composite catalyst is prepared by nanotechnology, and the average particle size of its nanoparticles is 30-50 nm. The number of surface active sites detected by X-ray photoelectron spectroscopy and scanning electron microscopy reaches 1.5×10¹ 5 sites / cm². The sulfur resistance performance shows that in an environment with a sulfur content of 50 ppm, the catalyst activity decreases by no more than 10% within 500 hours. The chlorine resistance performance shows that in an environment with a chlorine content of 30 ppm, the catalyst activity decreases by no more than 12% within 400 hours. The equation of the reforming reaction is 2CH3OH + 3H2O = 6H2 + 2CO2 or H4 + co.

[0010] Preferably, in S4, the power adjustment range of the ultrasonic assistance technology is 50-200 W, and the frequency adjustment range is 20-100 kHz. The inner diameter of the channels of the microchannel reactor is between 0.1-1 mm. The inner diameter of 0.5 mm is selected, and the length is 10-100 cm, and the length of 30-35 cm is selected.

[0011] Preferably, in S5, the material of the highly selective hydrogen membrane includes a polyimide-silica composite membrane. The thickness of the membrane is 50 μm, the porosity of the membrane is 30-35%, the pore size distribution is 0.5-2 nm, and the hydrogen permeation rate is 5×10⁻ 7 mol / m²·s·Pa, the operating pressure is 2-3 MPa, and the temperature is 50-60 °C.

[0012] Preferably, in S6, the high-efficiency heat exchanger adopts the countercurrent heat exchange principle. The heat exchanger includes stainless steel 316L. The inside of the heat exchanger adopts a spiral tube structure with a spiral diameter of 10 cm and a tube pitch of 2 cm. The spiral tube is used to improve the heat exchange efficiency and transfer the heat in the reaction waste gas to the raw material or water. The preheating temperature of the raw material is 150 °C, the pressure of the generated steam is less than 1 MPa, and the temperature is 190 °C. The thermoelectric conversion material includes bismuth telluride, and the electrode adopts an interdigital electrode with an electrode spacing of 0.5 mm.

[0013] Preferably, in S7, the key parameters include the feeding rate, steam / methanol ratio, temperature, and pressure. The sensors of the intelligent control system distributed at each key part include temperature sensors, pressure sensors, flow sensors, and activity detection probes for detecting the activity of the catalyst. The Internet of Things uses the MQTT protocol for data transmission. The artificial intelligence algorithm uses a long short-term memory network algorithm based on deep learning to analyze and process the collected data. According to the preset optimization objectives including maximizing the hydrogen production rate and optimizing the purity, the operating parameters of relevant equipment are adjusted. The adjustment of the operating parameters includes the feeding rate ±0.1 m³ / h, steam / methanol ratio ±0.05, temperature ±1 °C, and pressure ±0.02 MPa. The automatic prediction uses a prediction model based on LSTM to predict the service life and maintenance time of the catalyst, and the prediction error is ±5%.

[0014] Preferably, the following steps are carried out after step S7: S701. When the methanol purity reaches more than 99.9%, it is directly evaporated and enters the catalyst reaction zone to produce hydrogen and carbon monoxide or hydrogen and carbon dioxide. If it can be directly used, there is no need to purify the hydrogen purity.

[0015] The present invention provides a methanol-to-hydrogen process, which has the following beneficial effects: 1. By using a nano Cu-Zn-Al-O catalyst and optimizing the surface active site structure in the present invention, the high activity can be maintained for a long time in an environment containing 50 ppm of sulfur and 30 ppm of chlorine, resulting in improved catalyst stability and extended service life.

[0016] 2. By using a polyimide-silica composite membrane and optimizing the pore size distribution and membrane thickness in the present invention, the efficient permeation of hydrogen and the blocking of impurities are achieved, resulting in the separation of high-purity hydrogen and improved system separation efficiency.

[0017] 3. By using a spiral tube countercurrent heat exchanger and integrating bismuth telluride thermoelectric materials in the present invention, the efficient recovery of reaction waste heat and the conversion of part of the thermal energy into electrical energy are achieved, resulting in the effects of reducing energy consumption and improving energy utilization rate. At the same time, by deploying various sensors such as temperature, pressure, and flow, and combining with a deep learning algorithm based on LSTM, the real-time monitoring and adaptive control of the production process are realized, resulting in the effects of maximizing the hydrogen production rate and optimizing the purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a process flow chart of a methanol-to-hydrogen process of the present invention; Figure 2 It is a process architecture schematic diagram of a methanol-to-hydrogen process of the present invention; Figure 3 It is a process exhaust architecture flow chart of a methanol-to-hydrogen process of the present invention. Detailed implementation manners

[0019] The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work fall within the scope of protection of the present invention.

[0020] Please refer to the attached Figure 1 , the embodiment of the present invention provides a methanol-to-hydrogen process, including the following steps: S1. Raw material pretreatment stage: First, dehydrate methanol, use molecular sieve adsorption technology to remove trace moisture in methanol, remove particulate matter and impurities in methanol through an efficient filtration system, mix the raw material methanol with water, then heat it, and mix it evenly; S101. Raw material reheating: The gas after gasifying the methanol-water mixture is passed through a special heat exchanger in the reaction tank to raise the gas temperature to the working temperature.

[0021] S2. Impurity deep purification step: Pass the pretreated methanol-water mixture through a composite purification column equipped with adsorbent and ion exchange resin. The adsorbent selectively adsorbs residual organic impurities in methanol, and the ion exchange resin removes metal ions; S3. Catalytic reaction stage: Methanol and water vapor undergo a reforming reaction under the action of a copper-based catalyst. The autothermal reforming technology is used to maintain the reaction temperature, and the catalyst is a composite catalyst that uses nanotechnology to optimize the surface activity and has sulfur and chlorine resistance; S4. Reaction intensification step: In the catalytic reaction process, a method combining ultrasonic-assisted technology and a microchannel reactor is introduced. Utilize the cavitation effect of ultrasonic waves and the high specific surface area of the microchannel reactor to promote the reaction; S5. Hydrogen separation stage: Adopt membrane separation technology, use a highly selective hydrogen membrane to separate hydrogen from the reaction products in real time, promote the reaction equilibrium to shift towards the hydrogen production direction, and reduce the contents of carbon monoxide and carbon dioxide; S6. Waste heat recovery stage: Recover hydrogen and heat in the reaction process through an efficient heat exchanger for preheating raw materials or generating steam, and part of the waste heat is converted into heat energy through combustion; S7. Intelligent control stage: Apply an intelligent control system to monitor and adjust the system in real time through the Internet of Things and artificial intelligence algorithms, automatically adjust key parameters, and monitor the activity and usage of the catalyst in real time and automatically predict and prompt the maintenance time.

[0022] In S1, 3A molecular sieve is used, and the trace moisture in methanol after removing moisture is <1%. The high-efficiency filtration system adopts a multi-layer filter screen structure. The mesh numbers of the filter screens are 100 mesh, 200 mesh, and 500 mesh respectively, and the mixing ratio is 1:1 or 1:5. The heating temperature is 200 - 300 °C, and the temperature fluctuation range is controlled within ±2 °C. A multi-channel high-efficiency mixer is used for mixing, and the mixing time is 30 - 60. The mixing ratio of formaldehyde and water is 90 - 100% formaldehyde: 0 - 10% water.

[0023] Specifically, in terms of the high-efficiency filtration system, a multi-layer filter screen structure is adopted. The mesh numbers of the filter screens are set to 100 mesh, 200 mesh, and 500 mesh respectively, and are used for hierarchical filtration in sequence. The 100-mesh filter screen is mainly used to remove larger particle impurities, the 200-mesh filter screen further intercepts smaller particles, and the 500-mesh filter screen can effectively remove fine impurities, thus ensuring the purity of the final material. The material of the filter screen should preferably be high-strength corrosion-resistant stainless steel or polymer to ensure long-term stable operation. The filter screen needs to be replaced regularly or backwashed for cleaning to prevent blockage from affecting the filtration effect; For the material mixing process, to ensure uniform mixing, the mixing ratio can be selected as 1:1 or 1:5, and can be flexibly adjusted according to different process requirements. During the mixing process, to avoid local overheating or uneven mixing, a multi-channel high-efficiency mixer is used. Through the optimized design of multi-stage mixing chambers and fluid dynamics, rapid, efficient, and uniform mixing is achieved. The mixing time is controlled within 30 - 60 seconds to ensure sufficient contact between each component and improve the uniformity and stability of the final product; The heating process adopts precise temperature control technology. The heating temperature range is set to 200 - 300 °C, and the temperature fluctuation control within ±2 °C is achieved through an intelligent temperature control system to ensure the stability of the heating process. The temperature control system can adopt a PID adjustment algorithm to avoid side reactions or performance degradation caused by excessive temperature fluctuations. In addition, the heating device can adopt infrared heating or electric heating methods to improve heating efficiency and reduce energy consumption. During the heating process, the residence time of the material is appropriately controlled to ensure uniform temperature distribution and improve the reaction efficiency. Through technical means such as precise dehydration, high-efficiency filtration, uniform mixing, and precise temperature control, the process is ensured to be stable and reliable, and finally high-quality products are obtained.

[0024] In S101, the working temperature is 220 - 300 °C, which is used to increase the working temperature to improve the hydrogen concentration obtained after the reaction.

[0025] Specifically, the methanol steam reforming reaction provides a suitable environment to achieve the conversion of liquid raw materials into hydrogen-containing gaseous products, determining the hydrogen production and quality. Its performance affects subsequent unit operations and hydrogen quality. At 220 - 300 °C and a specific pressure, it can efficiently promote the reaction. Generally, the methanol conversion rate exceeds 90%, and the hydrogen volume fraction reaches 70% - 80%. It is filled with a specific catalyst inside, which activates gas molecules through physical and chemical adsorption, and the main reaction occurs while maintaining the temperature by heating, while suppressing side reactions. The gas distribution device ensures uniform reaction.

[0026] In S2, special adsorbents and ion exchange resins in the composite purification column are filled in layers, and the layering ratio is 3:2. The flow rate of the methanol-water mixture through the composite purification column is 0.5 - 1.5 m³ / h. The adsorbents and ion exchange resins are regularly regenerated. The regeneration treatment uses high-temperature calcination and acid-base elution. The service life of the adsorbents and ion exchange resins is 1000 hours or they are replaced after treating 500 m³ of the methanol-water mixture.

[0027] Specifically, special adsorbents and ion exchange resins are filled in layers in the composite purification column, with a ratio of 3:2. The special adsorbents are used to adsorb organic impurities and metal ions, and the ion exchange resins further remove ionic impurities to improve purity; The methanol-water mixture passes through the composite purification column at a flow rate of 0.5 - 1.5 m³ / h to ensure sufficient contact between the liquid and the purification medium and achieve the best treatment effect. Too fast a flow rate affects purification, and too low a flow rate reduces efficiency, which can be accurately controlled by a flow meter; To ensure the long-term stable operation of the purification column, the adsorbents and ion exchange resins need to be regularly regenerated. The regeneration uses high-temperature calcination (300 - 500 °C) and acid-base elution (dilute hydrochloric acid or sodium hydroxide solution) to remove adsorbed pollutants and restore the exchange capacity; The service life of the adsorbents and ion exchange resins is 1000 hours or they are replaced after treating 500 m³ of the methanol-water mixture. The replacement timing can be judged by an on-line water quality monitoring system to ensure the effluent quality. Those skilled in the art can optimize the materials and regeneration process according to requirements to improve the performance of the purification system.

[0028] In S3, each element in the copper-based catalyst includes Cu-Zn-Al-O, and the molar ratio is 2:1:1:4. The autothermal reforming technology monitors the reaction temperature in real time and adjusts the feed rate according to the temperature feedback. Among them, the reaction temperature is maintained at 250 - 280 °C, and the temperature control accuracy is ±3 °C. The composite catalyst is prepared by nanotechnology, and the average particle size of its nanoparticles is 30 - 50 nm. The number of surface active sites detected by X-ray photoelectron spectroscopy and scanning electron microscopy reaches 1.5×10¹ 5pieces / cm². The sulfur resistance ability is demonstrated by the fact that in an environment with a sulfur content of 50 ppm, the catalyst activity remains decreased by no more than 10% within 500 hours. The chlorine resistance ability is demonstrated by the fact that in an environment with a chlorine content of 30 ppm, the catalyst activity remains decreased by no more than 12% within 400 hours. The reforming reaction equation is 2CH3OH + 3H2O = 6H2 + 2CO2 or H4 + co.

[0029] Specifically, the copper-based catalyst is composed of Cu-Zn-Al-O with a molar ratio of 2:1:1:4. Through the autothermal reforming technology, the reaction temperature is monitored in real time and the feed rate is adjusted according to the temperature feedback to ensure that the reaction temperature is maintained between 250 - 280 °C with a temperature control accuracy of ±3 °C. The composite catalyst is prepared by nanotechnology, and the average particle size of the catalyst nanoparticles is 30 - 50 nm. Through X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) detection, the number of active sites on the catalyst surface reaches 1.5×10¹ 5 pieces / cm², significantly improving the catalytic effect; This catalyst exhibits excellent sulfur and chlorine resistance capabilities. In an environment with a sulfur content of 50 ppm, the activity of the catalyst decreases by no more than 10% within 500 hours. In an environment with a chlorine content of 30 ppm, the activity of the catalyst decreases by no more than 12% within 400 hours. The chemical equation of the reforming reaction is: 2CH3OH + 3H2O = 6H2 + 2CO2. By precisely controlling the reaction conditions, the high efficiency of the reaction and the long-term stability of the catalyst are ensured, thereby improving the hydrogen production efficiency of methanol reforming.

[0030] In S4, the power adjustment range of the ultrasonic-assisted technology is 50 - 200 W, the frequency adjustment range is 20 - 100 kHz, the inner diameter of the channels of the microchannel reactor is between 0.1 - 1 mm, the inner diameter of 0.5 mm is selected, the length is 10 - 100 cm, and the length of 30 - 35 cm is selected.

[0031] Specifically, the highly selective hydrogen membrane uses a polyimide-silica composite membrane material with a membrane thickness of 50 μm. The porosity of the membrane is controlled between 30 - 35%, and the pore size distribution is 0.5 - 2 nm to ensure the efficient permeation of hydrogen molecules while inhibiting the permeation of other gases. The permeation rate of hydrogen is 5×10⁻ 7 mol / m²·s·Pa, showing excellent performance of the membrane in hydrogen separation; During the operation of this membrane, the working pressure range is set to 2 - 3 MPa, and the temperature is controlled at 50 - 60 °C to achieve the best hydrogen permeation efficiency and selectivity. By precisely controlling the operating conditions, high-purity separation of hydrogen can be ensured, and the long-term stability and high efficiency of the membrane material can be maintained.

[0032] In S5, the material of the medium- and high-selectivity hydrogen membrane includes a polyimide-silica composite membrane. The thickness of the membrane is 50 μm, the porosity of the membrane is 30 - 35%, the pore size distribution is 0.5 - 2 nm, and the permeation rate of hydrogen is 5×10⁻ 7 mol / m²・s・Pa, the operating pressure is 2 - 3 MPa, and the temperature is 50 - 60 °C.

[0033] Specifically, the high-selectivity hydrogen membrane uses a polyimide-silica composite membrane material with a thickness of 50 μm, the porosity is controlled at 30 - 35%, and the pore size distribution is 0.5 - 2 nm. This structure ensures the efficient permeation of hydrogen molecules while effectively blocking other larger molecules, achieving high-selectivity separation; The permeation rate of hydrogen is 5×10⁻ 7 mol / m²·s·Pa, indicating that the membrane has excellent permeation performance and can achieve efficient separation even under a low pressure difference. The operating pressure is set at 2 - 3 MPa, which provides sufficient driving force in industrial applications while avoiding membrane structure damage caused by excessive pressure. The working temperature is controlled at 50 - 60 °C. This temperature range helps to maintain the stability of the membrane, while increasing the permeation rate of hydrogen, avoiding membrane material degradation or structural changes caused by too high temperature, which can further improve the hydrogen purity, reduce energy consumption, and improve the overall separation efficiency to meet the production requirements of different scales.

[0034] In S6, the medium- and high-efficiency heat exchanger adopts the countercurrent heat exchange principle. The heat exchanger includes 316L stainless steel. The inside of the heat exchanger adopts a spiral tube structure with a spiral diameter of 10 cm and a tube pitch of 2 cm. The spiral tube is used to improve the heat exchange efficiency and transfer the heat in the reaction waste gas to the raw material or water. The preheating temperature of the raw material is 150 °C, the pressure of the generated steam is less than 1 MPa, and the temperature is 190 °C. The thermoelectric conversion material includes bismuth telluride, and the electrodes adopt interdigital electrodes with an electrode pitch of 0.5 mm.

[0035] Specifically, the high-efficiency heat exchanger adopts the countercurrent heat exchange principle to maximize the heat recovery efficiency. The heat exchanger material is selected as 316L stainless steel with strong corrosion resistance, and a spiral tube structure with a spiral diameter of 10 cm and a tube pitch of 2 cm is adopted to increase the heat exchange area and fluid disturbance, thereby enhancing the heat exchange effect. The spiral tube structure can effectively reduce fluid retention, increase the heat exchange rate, and reduce the space occupied by the equipment; This heat exchanger is mainly used to recover the waste heat in the reaction exhaust gas and transfer it to the raw materials or water to improve the energy utilization efficiency of the system. This heat exchange system can be used to generate steam with a working pressure of less than 1 MPa and a temperature of up to 190 °C, meeting the high-temperature steam demand in industrial applications. To further improve the energy utilization rate, a thermoelectric conversion unit is integrated into the system, and bismuth telluride (Bi2Te3) is used as the thermoelectric material to achieve efficient conversion of thermal energy into electrical energy. Bismuth telluride materials have excellent thermoelectric properties and can generate a stable current output under the action of temperature difference. The electrodes are designed in a finger-like structure with an electrode spacing of 0.5 mm to optimize the current collection efficiency and improve the overall thermoelectric conversion performance. This not only improves the thermal energy utilization rate but also effectively reduces energy losses, achieving energy conservation and consumption reduction. It can also be combined with an intelligent control system to optimize the heat exchange process and improve the operation stability and economic benefits.

[0036] In S7, the key parameters include the feed rate, steam / methanol ratio, temperature, and pressure. The intelligent control system distributes sensors at each key part, including temperature sensors, pressure sensors, flow sensors, and activity detection probes for detecting the catalyst activity. The Internet of Things uses the MQTT protocol for data transmission, and the artificial intelligence algorithm uses the long short-term memory network algorithm based on deep learning to analyze and process the collected data. According to the preset optimization goals, including maximizing the hydrogen production rate and optimizing the purity, the operating parameters of relevant equipment are adjusted. The adjustment of operating parameters includes the feed rate ±0.1 m³ / h, steam / methanol ratio ±0.05, temperature ±1 °C, and pressure ±0.02 MPa. The automatic prediction uses a prediction model based on LSTM to predict the service life and maintenance time of the catalyst, with a prediction error of ±5%.

[0037] Specifically, through the real-time monitoring and optimized regulation of the key parameters (feed rate, steam / methanol ratio, temperature, pressure), the efficient and stable operation of the system is achieved. Sensors are deployed at each key part, including temperature sensors, pressure sensors, flow sensors, and catalyst activity detection probes, to ensure accurate data collection; The Internet of Things communication uses the lightweight Message Queuing Telemetry Transport protocol (MQTT) to achieve efficient and low-latency data transmission. The artificial intelligence algorithm uses the long short-term memory network (LSTM) algorithm based on deep learning to analyze and process the collected data and dynamically adjust the equipment operating parameters according to the optimization goals (maximizing the hydrogen production rate and optimizing the purity); The adjustment range of operating parameters includes: feed rate ±0.1 m³ / h to ensure stable supply of reactants, steam / methanol ratio ±0.05 to optimize the reforming reaction efficiency, reaction temperature ±1 °C to ensure efficient operation of the catalyst, system pressure ±0.02 MPa to maintain the optimal operating conditions. The service life and maintenance time of the catalyst are predicted based on the LSTM model, and the prediction error is controlled within ±5%. This intelligent maintenance strategy can effectively reduce downtime, improve equipment operation efficiency, and extend the service life of the catalyst, thereby reducing operating costs. Through data-driven optimization strategies, production efficiency is improved, precise control is achieved, and overall economic benefits are enhanced.

[0038] After step S7, the following steps are carried out: S701. When the methanol purity reaches over 99.9%, it is directly evaporated into the catalyst reaction zone to produce hydrogen and carbon monoxide or hydrogen and carbon dioxide. If it can be directly used, there is no need to purify the hydrogen purity.

[0039] Specifically, when the methanol purity reaches over 99.9%, it is directly evaporated into the catalyst reaction zone to produce hydrogen and carbon monoxide or hydrogen and carbon dioxide. If it can be directly used, there is no need to purify the hydrogen purity. High-purity methanol can quickly form a uniform gas-phase mixture during evaporation and rapidly undergo a reforming reaction with water vapor on the catalyst surface. Due to the purity of the raw material, no additional purification steps are required, which can significantly reduce the energy consumption and time loss brought by the pretreatment process. The catalyst in the reaction zone promotes the rapid progress of the reaction through physical adsorption and surface activation of gas-phase molecules. The generated hydrogen and by-products CO or CO2 have stable concentrations and controllable components. In specific application scenarios, such as fuel cells, heat treatment atmospheres, or small energy stations, the hydrogen at this purity is sufficient to meet the system requirements, so it can be directly used without additional purification treatment, thereby reducing the overall operating cost, improving the system energy efficiency, simplifying the system structure, facilitating modular and mobile deployment of equipment, and avoiding the pressure drop, energy consumption, and maintenance problems introduced by subsequent membrane separation or purification systems. It is particularly suitable for scenarios with low requirements for hydrogen purity but high stability requirements.

[0040] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A methanol-to-hydrogen production process, characterized in that, It includes the following steps: S1. Raw material pretreatment stage: First, dehydrate methanol. Use molecular sieve adsorption technology to remove trace moisture in methanol, and remove particulate matters and impurities in methanol through a high-efficiency filtration system. Mix the raw material methanol with water, then heat it and mix it evenly; S101. Raw material reheating: The gas after gasification of the methanol-water mixture is passed through a special heat exchanger in the reaction tank to raise the gas temperature to the working temperature; S2. Impurity deep purification step: Pass the pretreated methanol-water mixture through a composite purification column filled with adsorbent and ion exchange resin. Selectively adsorb the residual organic impurities in methanol by the adsorbent, and remove metal ions by the ion exchange resin; S3. Catalytic reaction stage: Methanol and water vapor undergo a reforming reaction under the action of a copper-based catalyst. Use autothermal reforming technology to maintain the reaction temperature, and the catalyst is a composite catalyst that uses nanotechnology to optimize the surface activity and has sulfur and chlorine resistance capabilities; S4. Reaction intensification step: During the catalytic reaction process, introduce a combination of ultrasonic-assisted technology and a microchannel reactor. Utilize the cavitation effect of ultrasonic waves and the high specific surface area of the microchannel reactor to promote the reaction; S5. Hydrogen separation stage: Adopt membrane separation technology. Use a highly selective hydrogen membrane to separate hydrogen from the reaction products in real time, promote the reaction equilibrium to shift towards the hydrogen production direction, and reduce the contents of carbon monoxide and carbon dioxide; S6. Waste heat recovery stage: Recover hydrogen and heat during the reaction process through a high-efficiency heat exchanger for preheating raw materials or generating steam, and convert part of the waste heat into heat energy through combustion; S7. Intelligent control stage: Apply an intelligent control system. Through the Internet of Things and artificial intelligence algorithms, conduct real-time monitoring and adjustment of the system, automatically adjust key parameters, and real-time monitor the activity and usage of the catalyst and automatically predict and prompt the maintenance time.

2. The methanol hydrogen production process according to claim 1, characterized in that: In S1, the molecular sieve uses 3A molecular sieve, the trace moisture in methanol after removing moisture <1%, the high-efficiency filtration system adopts a multi-layer filter screen structure, the filter screen mesh numbers are 100 mesh, 200 mesh and 500 respectively, the mixing ratio is 1:1 or 1:5, the heating temperature is 200 - 300°C, the temperature fluctuation range is controlled within ±2°C, the mixing uses a multi-channel high-efficiency mixer, the mixing time is 30 - 60, and the mixing ratio of formaldehyde and water is 90 - 100% formaldehyde: 0 - 10% water.

3. The methanol hydrogen production process according to claim 1, characterized in that: In S101, the working temperature is 220 - 300°C, and the working temperature is used to increase the hydrogen concentration obtained after the reaction.

4. The methanol hydrogen production process according to claim 1, wherein: In S2, the special adsorbent and ion exchange resin in the composite purification column are loaded in layers, the proportion of the layered loading is 3:2, the flow rate of the methanol-water mixture through the composite purification column is 0.5 - 1.5 m³ / h, the adsorbent and ion exchange resin are regenerated regularly, the regeneration treatment adopts high-temperature calcination and acid-base elution, and the service life of the adsorbent and ion exchange resin is 1000 hours or they are replaced after treating 500 m³ of methanol-water mixture.

5. A hydrogen production process from methanol according to claim 1, characterized in that: In S3, each element in the copper-based catalyst includes Cu-Zn-Al-O with a molar ratio of 2:1:1:

4. The autothermal reforming technology monitors the reaction temperature in real time and adjusts the feed rate according to the temperature feedback. The reaction temperature is maintained at 250-280 °C with a temperature control accuracy of ±3 °C. The composite catalyst is prepared by nanotechnology, and its average nanoparticle size is 30-50 nm. The number of surface active sites detected by X-ray photoelectron spectroscopy and scanning electron microscopy reaches 1.5×10¹ 5 sites / cm². The sulfur resistance performance shows that in an environment with a sulfur content of 50 ppm, the catalyst activity remains unchanged by no more than 10% within 500 hours. The chlorine resistance performance shows that in an environment with a chlorine content of 30 ppm, the catalyst activity remains unchanged by no more than 12% within 400 hours. The equation for the reforming reaction is 2CH3OH + 3H2O = 6H2 + 2CO2 or H4 + co.

6. The methanol hydrogen production process according to claim 1, characterized in that: In S4, the power adjustment range of the ultrasonic assistance technology is 50 - 200 W, and the frequency adjustment range is 20 - 100 kHz. The inner diameter of the channels of the microchannel reactor is between 0.1 - 1 mm. An inner diameter of 0.5 mm is selected, and the length is 10 - 100 cm. A length of 30 - 35 cm is selected.

7. A methanol-to-hydrogen production process according to claim 1, characterized in that: In S5, the material of the highly selective hydrogen membrane includes a polyimide-silica composite membrane. The thickness of the membrane is 50 μm, the porosity of the membrane is 30-35%, the pore size distribution is 0.5-2 nm, and the hydrogen permeation rate is 5×10⁻ 7 mol / m²・s・Pa, the operating pressure is 2-3 MPa, and the temperature is 50-60 °C.

8. A hydrogen production process from methanol according to claim 1, characterized in that: In S6, the high-efficiency heat exchanger adopts the countercurrent heat exchange principle. The heat exchanger includes 316L stainless steel. The interior of the heat exchanger adopts a spiral tube structure with a spiral diameter of 10 cm and a tube pitch of 2 cm. The spiral tube is used to improve the heat exchange efficiency and transfer the heat in the reaction waste gas to the raw material or water. The preheating temperature of the raw material is 150 °C, the pressure of the generated steam is less than 1 MPa, and the temperature is 190 °C. The thermoelectric conversion material includes bismuth telluride, and the electrodes adopt interdigitated electrodes with an electrode pitch of 0.5 mm.

9. A hydrogen production process from methanol according to claim 1, characterized in that: In S7, the key parameters include the feed rate, steam / methanol ratio, temperature, and pressure. The sensors of the intelligent control system distributed at each key part include temperature sensors, pressure sensors, flow sensors, and activity detection probes for detecting the activity of the catalyst. The Internet of Things uses the MQTT protocol for data transmission. The artificial intelligence algorithm adopts a long short-term memory network algorithm based on deep learning, which is used to analyze and process the collected data. According to the preset optimization objectives including maximizing the hydrogen production rate and optimizing the purity, the operating parameters of relevant equipment are adjusted. The adjustment of the operating parameters includes the feed rate ±0.1 m³ / h, steam / methanol ratio ±0.05, temperature ±1 °C, and pressure ±0.02 MPa. The automatic prediction adopts a prediction model based on LSTM to predict the service life and maintenance time of the catalyst, and the prediction error is ±5%.

Images