Efficient crude methanol synthesis system and method

Abstract

The invention discloses an efficient synthesis system and method for crude methanol, a tandem reaction system is established by combining the high catalyst stability of a fixed bed reactor and the strong heat transfer characteristic of a slurry bed reactor, and the tandem reaction system at least comprises a fixed bed pre-reactor and a slurry bed main reactor; unreacted gas is distributed to the fixed bed pre-reactor and the slurry bed main reactor in proportion; a Cu.Zn.A < l > CeO2 composite carrier structure is utilized, an outer CeO2 nano coating selectively adsorbs CeO2, and a Cu.Zn.A < l > active component is used for directional conversion of CO; introducing outlet gas of the slurry bed reactor into an inverse transformation unit to react with green hydrogen prepared by electrolyzing water to generate CO; the reaction heat of the fixed bed pre-reactor is used for steam power generation through three-stage thermal coupling, and the medium-temperature waste heat of the slurry bed reactor drives absorption refrigeration. The efficiency, the environmental protection property and the economical efficiency of the methanol synthesis process are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of methanol synthesis, in particular to a high-efficiency synthesis system and method for crude methanol. Background Art

[0002] Methanol, as an important basic organic chemical raw material, is widely used in multiple fields. Traditional methods for synthesizing crude methanol have problems such as low reaction efficiency, high energy consumption, and easy deactivation of catalysts. For example, in a conventional synthesis process, syngas (mainly composed of carbon monoxide, carbon dioxide, and hydrogen) reacts to produce methanol under the action of a catalyst, but the reaction conditions are relatively harsh, often requiring high temperature and high pressure. This not only increases equipment investment and operating costs, but also the reaction conversion rate and selectivity are limited, resulting in difficulty in improving production efficiency. Therefore, developing a high-efficiency, energy-saving method for synthesizing crude methanol that can improve the stability of the catalyst has important practical significance. Summary of the Invention

[0003] The purpose of the present invention is to solve the above problems and design a high-efficiency synthesis system and method for crude methanol.

[0004] Furthermore, in the above-mentioned high-efficiency synthesis system for crude methanol, the high-efficiency synthesis system for crude methanol includes a multi-stage reactor coupling module, a gas component monitoring module, a core-shell structure catalytic module, a reverse water-gas shift synthesis module, and a multi-stage waste heat recovery module, wherein:

[0005] The multi-stage reactor coupling module is used to establish a series reaction system by combining the high catalyst stability of a fixed-bed reactor with the strong heat transfer characteristics of a slurry-bed reactor. The series reaction system includes at least a fixed-bed pre-reactor and a slurry-bed main reactor;

[0006] The gas component monitoring module is used to proportionally distribute the unreacted gas to the fixed-bed pre-reactor and the slurry-bed main reactor;

[0007] The core-shell structure catalytic module is used to utilize the Cu·Zn·Al@CeO2 composite support structure, with the outer CeO2 nano-coating selectively adsorbing CeO2, and the Cu·Zn·Al active component being used for the directional conversion of CO;

[0008] The reverse water-gas shift synthesis module is used to introduce the gas from the outlet of the slurry-bed reactor into a reverse water-gas shift unit to react with green hydrogen produced by electrolyzing water to generate CO;

[0009] The multi-stage waste heat recovery module is used to utilize three-stage thermal coupling to use the reaction heat of the fixed-bed pre-reactor for steam power generation, and the medium-temperature waste heat of the slurry-bed reactor drives an absorption refrigerator.

[0010] Further, in the above-mentioned high-efficiency synthesis system of crude methanol, the multistage reactor coupling module includes a fixed-bed pre-reactor, a slurry-bed main reactor, a system coordination sub-module, and a dynamic regulation sub-module, where:

[0011] The fixed-bed pre-reactor is used to initially convert syngas by using an axial adiabatic structure and configuring a Cu·Zn·Al-based catalyst, with the single-pass CO conversion rate controlled at 18%-22%. The operating pressure of the axial adiabatic structure is 8-10 MPa, and the temperature is 220-240 °C;

[0012] The slurry-bed main reactor is based on a gas-flow bubbling suspension reactor, with a spiral coil heat exchanger built-in, and heat transfer is enhanced through a paraffin oil slurry medium. The operating pressure of the gas-flow bubbling suspension reactor is 5-8 MPa, and the temperature is 240-260 °C;

[0013] The system coordination sub-module is used to set up a gas-liquid separator between reactors and distribute the unreacted gas to the next stage;

[0014] The dynamic regulation sub-module is used to monitor the CO and CO2 ratios in real time by an on-line infrared spectrometer. When the CO concentration > 65%, the high-concentration gas is introduced into the slurry-bed; when the CO2 concentration ratio rises to 20%, it is switched to the fixed-bed.

[0015] Further, in the above-mentioned high-efficiency synthesis system of crude methanol, the gas component monitoring module includes a data detection sub-module and a gas regulation sub-module, where:

[0016] The data detection sub-module is used to detect the concentrations of H2 / CO / CO2 / CH3OH by using a combined system of a laser mass spectrometer and a Raman spectrometer. The data refresh frequency of the combined system of the laser mass spectrometer and the Raman spectrometer is 10 Hz, and the error rate < 1.5%;

[0017] The gas regulation sub-module is used to dynamically adjust the flow distribution and reaction rate of the gas shunt valve by using a fuzzy PID control model.

[0018] Further, in the above-mentioned high-efficiency synthesis system of crude methanol, the core-shell structure catalytic module includes a core-shell establishment structure sub-module, a function verification sub-module, a sulfur capture mechanism sub-module, and a pulse purge sub-module, where:

[0019] The core-shell establishment structure sub-module is used to use a honeycomb ZSM-5 molecular sieve as a carrier with a pore diameter of 0.5-1 nm, and coat a CeO2-TiO2 double-layer nanoshell by the sol-gel method. The thickness of the nanoshell is 80-120 nm, and the inner core is loaded with Cu·Zn·Al active components, where Cu:Zn:Al = 6:2:1;

[0020] The function verification sub-module is used to preferentially adsorb CO2 by the CeO2 layer, with an adsorption capacity of 2.1 mmol / g, and the core Cu·Zn·Al is used for the directional catalysis of CO hydrogenation;

[0021] The sulfur capture mechanism module is used to load MoS2 nanosheets in the pores of ZSM-5 molecular sieve, with a loading amount of 5%, and capture H2S and carbonyl iron impurities through chemical adsorption;

[0022] The pulse purge sub-module is used to judge that when the system runs for 500 hours each time, start the pulse purge of the hydrogen-nitrogen mixed gas. The ratio of the hydrogen-nitrogen mixed gas is H2:N2 = 3:1, the pressure of the pulse purge is 0.8 MPa, and the temperature is 250 °C, so that the desorption rate of sulfide > 95%.

[0023] Furthermore, in the above-mentioned high-efficiency synthesis system of crude methanol, the reverse conversion synthesis module includes a gas conversion and production sub-module and a gas circulation and transportation sub-module, where:

[0024] The gas conversion and production sub-module is used to utilize the Fe-Cr-K composite catalyst, where the ratio of the composite catalyst is Fe:Cr:K = 10:2:1, and convert CO2 with a concentration of 12%-15% at the outlet of the slurry bed and electrolytic green hydrogen with a purity > 99.9% into CO under the conditions of a temperature of 280 - 320 °C and a pressure of 2.5 MPa;

[0025] The gas circulation and transportation sub-module is used to transport the generated CO to the synthesis system through a gas circulation pump.

[0026] Furthermore, in the above-mentioned high-efficiency synthesis system of crude methanol, the multi-stage waste heat recovery module includes a primary recovery sub-module, a secondary recovery sub-module, and a tertiary recovery sub-module, where:

[0027] The primary recovery sub-module is used to drive a back-pressure steam turbine to generate electricity with the high-temperature gas at the outlet of the fixed-bed reactor at a temperature of 300 - 350 °C;

[0028] The secondary recovery sub-module is used to supply cooling to the reactor cooling system through a lithium bromide absorption refrigeration unit with the waste heat of the slurry bed reactor at a temperature of 200 - 250 °C;

[0029] The tertiary recovery sub-module is used to preheat the raw material gas to 150 °C through a plate heat exchanger with the low-temperature waste heat at a temperature of 80 - 120 °C.

[0030] In a method for the high-efficiency synthesis of crude methanol, the method for the high-efficiency synthesis of crude methanol includes the following steps:

[0031] Mix the biomass gasification syngas and the coal-based syngas in a ratio of 1:3, and remove H2S and carbonyl iron compounds through the molecular sieve membrane separation module to make the total sulfur content < 0.1 ppm;

[0032] The bed temperature field is monitored in real time by a distributed fiber optic sensor, and the cold quench gas flow rate is adjusted by combining a fuzzy PID algorithm to make the axial temperature difference of the reactor ≤ 3°C;

[0033] A perfluoropolyether absorption - centrifugal separation coupling device is used to separate crude methanol and unreacted gas under the low - temperature condition of 30°C.

[0034] Furthermore, in the above - mentioned high - efficiency synthesis method of crude methanol, the high - efficiency synthesis method of crude methanol further includes the following steps:

[0035] A series - type reaction system is established by combining the high catalyst stability of a fixed - bed reactor and the strong heat - transfer characteristics of a slurry - bed reactor. The series - type reaction system includes at least a fixed - bed pre - reactor and a slurry - bed main reactor;

[0036] The unreacted gas is proportionally distributed to the fixed - bed pre - reactor and the slurry - bed main reactor;

[0037] Using a Cu·Zn·Al@CeO2 composite support structure, the outer - layer CeO2 nano - coating selectively adsorbs CeO2, and the Cu·Zn·Al active components are used for the directional conversion of CO;

[0038] The gas at the outlet of the slurry - bed reactor is introduced into a reverse - shift unit to react with green hydrogen produced by electrolyzing water to generate CO;

[0039] The reaction heat of the fixed - bed pre - reactor is used for steam power generation by using three - stage thermal coupling, and the medium - temperature waste heat of the slurry - bed reactor drives absorption refrigeration.

[0040] Furthermore, in the above - mentioned high - efficiency synthesis method of crude methanol, the establishment of the series - type reaction system by combining the high catalyst stability of a fixed - bed reactor and the strong heat - transfer characteristics of a slurry - bed reactor includes:

[0041] Using an axial adiabatic structure, a Cu·Zn·Al - based catalyst is configured to preliminarily convert syngas, and the single - pass CO conversion rate is controlled at 18% - 22%. The operating pressure of the axial adiabatic structure is 8 - 10 MPa, and the temperature is 220 - 240°C;

[0042] An air - flow bubbling suspension reactor with a built - in spiral coil heat exchanger is used to strengthen heat transfer through a paraffin oil slurry medium. The operating pressure of the air - flow bubbling suspension reactor is 5 - 8 MPa, and the temperature is 240 - 260°C;

[0043] A gas - liquid separator is arranged between the reactors to distribute the unreacted gas to the next stage;

[0044] The online infrared spectrometer monitors the ratio of CO and CO₂ in real time. When the CO concentration > 65%, the high-concentration gas is introduced into the slurry bed; when the CO₂ concentration ratio rises to 20%, it is switched to the fixed bed.

[0045] Its beneficial effects are as follows. Through innovative designs such as multi-stage reactor coupling, core-shell structure catalysts, reverse water-gas shift carbon cycle, and cascade heat recovery of waste heat, the efficiency, environmental friendliness, and economy of the methanol synthesis process have been significantly improved. The cooperation of multi-stage reactors and the gradient function of core-shell catalysts enhance the comprehensive conversion rate of CO / CO₂ and improve the utilization rate of raw material gas. Secondly, the slurry bed's enhanced heat transfer and dynamic gas distribution technologies effectively reduce the risk of thermal runaway and ensure reaction stability. The three-stage waste heat recovery system reduces the energy consumption per ton of methanol to 22.1 GJ, and the comprehensive energy consumption decreases. In addition, the reverse water-gas shift reaction and the utilization of green hydrogen reduce the CO₂ emission intensity to 0.35 t / t methanol, reducing carbon emissions. The in-situ catalyst regeneration technology extends the catalyst life and reduces the operating cost. Brief Description of the Drawings

[0046] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention.

[0047] Figure 1 It is a schematic diagram of the first embodiment of a high-efficiency crude methanol synthesis system in an embodiment of the present invention;

[0048] Figure 2 It is a schematic diagram of the second embodiment of a high-efficiency crude methanol synthesis system in an embodiment of the present invention;

[0049] Figure 3 It is a schematic diagram of the third embodiment of a high-efficiency crude methanol synthesis system in an embodiment of the present invention;

[0050] Figure 4 It is a schematic diagram of the first embodiment of a high-efficiency crude methanol synthesis method in an embodiment of the present invention. Detailed Description of the Embodiments

[0051] In order to make the purpose, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0052] Those skilled in the art can understand that, unless specifically stated otherwise, the singular forms "a", "an", "the" and "said" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of the present invention means the presence of features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their groups.

[0053] The present invention will be specifically described below with reference to the accompanying drawings, as Figure 1 shown, a high-efficiency synthesis system for crude methanol, the high-efficiency synthesis system for crude methanol includes a multi-stage reactor coupling module, a gas component monitoring module, a core-shell structure catalytic module, a reverse shift synthesis module and a multi-stage waste heat recovery module, wherein:

[0054] The multi-stage reactor coupling module is used to establish a series reaction system by combining the high catalyst stability of the fixed bed reactor and the strong heat transfer characteristics of the slurry bed reactor, and the series reaction system includes at least a fixed bed pre-reactor and a slurry bed main reactor;

[0055] Specifically, in this embodiment, there is also a fixed bed pre-reactor, which is used to utilize the axial adiabatic structure, configure a Cu·Zn·Al-based catalyst, preliminarily convert the syngas, control the single-pass CO conversion rate at 18%-22%, the operating pressure of the axial adiabatic structure is 8-10 MPa, and the temperature is 220-240 °C;

[0056] The slurry bed main reactor is based on a gas flow bubbling suspension reactor, with a spiral coil heat exchanger built in, and the heat transfer is strengthened through a paraffin oil slurry medium. The operating pressure of the gas flow bubbling suspension reactor is 5-8 MPa, and the temperature is 240-260 °C;

[0057] The system coordination sub-module is used to set a gas-liquid separator between the reactors to distribute the unreacted gas to the next stage;

[0058] The dynamic regulation sub-module is used to monitor the ratio of CO and CO2 in real time by an on-line infrared spectrometer. When the CO concentration > 65%, the high-concentration gas is introduced into the slurry bed; when the CO2 concentration ratio rises to 20%, it is switched to the fixed bed.

[0059] The gas component monitoring module is used to distribute the unreacted gas proportionally to the fixed bed pre-reactor and the slurry bed main reactor;

[0060] Specifically, in this embodiment, there is also a data detection sub-module, which is used to detect the concentrations of H2 / CO / CO2 / CH3OH by using a combined system of a laser mass spectrometer and a Raman spectrometer. The data refresh frequency of the combined system of the laser mass spectrometer and the Raman spectrometer is 10 Hz, and the error rate < 1.5%;

[0061] The gas regulation sub-module is used to dynamically regulate the flow distribution and reaction rate of the gas diverter valve using a fuzzy PID control model.

[0062] The core-shell structure catalytic module is used to utilize the Cu·Zn·Al@CeO2 composite support structure, where the outer CeO2 nano-coating selectively adsorbs CeO2, and the Cu·Zn·Al active components are used for the directional conversion of CO;

[0063] Specifically, in this embodiment, there is also a core-shell establishment structure sub-module, which uses honeycomb ZSM-5 molecular sieve as the support with a pore diameter of 0.5 - 1 nm. CeO2-TiO2 double-layer nano-shells are coated by the sol-gel method, and the thickness of the nano-shells is 80 - 120 nm. The inner core is loaded with Cu·Zn·Al active components, where Cu:Zn:Al = 6:2:1;

[0064] The function verification sub-module is used to utilize the CeO2 layer to preferentially adsorb CO2 with an adsorption capacity of 2.1 mmol / g, and the inner core Cu·Zn·Al is used for the directional catalysis of CO hydrogenation;

[0065] The sulfur capture mechanism module is used to load MoS2 nanosheets in the pores of ZSM-5 molecular sieve with a loading amount of 5%, and capture H2S and carbonyl iron impurities through chemical adsorption;

[0066] The pulse purge sub-module is used to determine that when the system runs for 500 hours, start the pulse purge of the hydrogen-nitrogen mixed gas. The ratio of the hydrogen-nitrogen mixed gas is H2:N2 = 3:1, the pressure of the pulse purge is 0.8 MPa, and the temperature is 250 °C, so that the desorption rate of sulfide > 95%.

[0067] The reverse conversion synthesis module is used to introduce the gas from the outlet of the slurry bed reactor into the reverse conversion unit to react with the green hydrogen produced by electrolyzing water to generate CO;

[0068] Specifically, in this embodiment, there is also a gas conversion obtained sub-module, which uses an Fe-Cr-K composite catalyst, where the ratio of the composite catalyst is Fe:Cr:K = 10:2:1. Under the conditions of a temperature of 280 - 320 °C and a pressure of 2.5 MPa, convert the CO2 with a concentration of 12% - 15% at the outlet of the slurry bed and the electrolytic green hydrogen with a purity > 99.9% into CO;

[0069] The gas circulation and transportation sub-module is used to transport the generated CO to the synthesis system through a gas circulation pump.

[0070] The multi-stage waste heat recovery module is used to utilize the reaction heat of the fixed bed pre-reactor for steam power generation and the medium-temperature waste heat of the slurry bed reactor to drive absorption refrigeration through three-stage thermal coupling.

[0071] Specifically, this embodiment further includes a primary recovery sub-module for driving a back-pressure steam turbine to generate electricity with the high-temperature gas at the outlet of the fixed-bed reactor at a temperature of 300-350°C;

[0072] A secondary recovery sub-module for using the waste heat of the slurry-bed reactor at a temperature of 200-250°C to supply cooling to the reactor cooling system through a lithium bromide absorption refrigeration unit;

[0073] A tertiary recovery sub-module for preheating the raw material gas to 150°C through a plate heat exchanger with the low-temperature waste heat at a temperature of 80-120°C.

[0074] Its beneficial effects are as follows. Through innovative designs such as multi-stage reactor coupling, core-shell structured catalysts, reverse water-gas shift carbon cycle, and cascade waste heat recovery, the efficiency, environmental friendliness, and economy of the methanol synthesis process are significantly improved. The cooperation of multi-stage reactors and the gradient function of core-shell catalysts enhance the overall conversion rate of CO / CO2 and improve the utilization rate of raw material gas. Secondly, the enhanced heat transfer and dynamic gas distribution technologies in the slurry-bed effectively reduce the risk of thermal runaway and ensure reaction stability. The three-stage waste heat recovery system reduces the energy consumption per ton of methanol to 22.1 GJ, and the comprehensive energy consumption decreases. In addition, the reverse water-gas shift reaction and the utilization of green hydrogen reduce the CO2 emission intensity to 0.35 t / t methanol, reducing carbon emissions. The in-situ catalyst regeneration technology prolongs the catalyst life and reduces the operating cost.

[0075] Please refer to Figure 2 , in a high-efficiency crude methanol synthesis system, the multi-stage reactor coupling module includes a fixed-bed pre-reactor, a slurry-bed main reactor, a system cooperation sub-module, and a dynamic regulation sub-module, where:

[0076] The fixed-bed pre-reactor is used to initially convert the syngas with an axial adiabatic structure and a Cu·Zn·Al-based catalyst, and the single-pass CO conversion rate is controlled at 18%-22%. The operating pressure of the axial adiabatic structure is 8-10 MPa, and the temperature is 220-240°C;

[0077] The slurry-bed main reactor is based on a gas-flow bubbling suspension reactor with a built-in spiral coil heat exchanger to enhance heat transfer through a paraffin oil slurry medium. The operating pressure of the gas-flow bubbling suspension reactor is 5-8 MPa, and the temperature is 240-260°C;

[0078] The system cooperation sub-module is used to set a gas-liquid separator between the reactors to distribute the unreacted gas to the next stage;

[0079] The dynamic regulation sub-module is used to monitor the CO and CO2 ratios in real time with an on-line infrared spectrometer. When the CO concentration > 65%, the high-concentration gas is introduced into the slurry-bed; when the CO2 concentration ratio rises to 20%, it is switched to the fixed-bed.

[0080] Please refer toFigure 3 In a high - efficiency synthesis system of crude methanol, the core - shell structure catalytic module includes a core - shell establishment structure sub - module, a function verification sub - module, a sulfur capture mechanism sub - module, and a pulse purge sub - module, where:

[0081] The core - shell establishment structure sub - module uses honeycomb ZSM - 5 molecular sieve as a carrier with a pore diameter of 0.5 - 1 nm, and coats a CeO2 - TiO2 double - layer nanoshell through the sol - gel method. The thickness of the nanoshell is 80 - 120 nm, and the inner core is loaded with Cu·Zn·Al active components, where Cu:Zn:Al = 6:2:1;

[0082] The function verification sub - module preferentially adsorbs CO2 using the CeO2 layer with an adsorption capacity of 2.1 mmol / g, and the inner - core Cu·Zn·Al directionally catalyzes the hydrogenation of CO;

[0083] The sulfur capture mechanism module loads MoS2 nanosheets in the pores of the ZSM - 5 molecular sieve with a loading amount of 5%, and chemically adsorbs and captures H2S and iron carbonyl impurities;

[0084] The pulse purge sub - module is used to determine that when the system runs for 500 hours, it starts to pulse - purge with a hydrogen - nitrogen mixed gas. The ratio of the hydrogen - nitrogen mixed gas is H2:N2 = 3:1, the pressure of the pulse purge is 0.8 MPa, and the temperature is 250 °C, so that the desorption rate of sulfides > 95%.

[0085] The above introduces the embodiments of a high - efficiency synthesis system of crude methanol of the present invention. Please refer to Figure 4 In a high - efficiency synthesis method of crude methanol, the high - efficiency synthesis method of crude methanol includes the following steps:

[0086] Step 401: Establish a series - type reaction system by combining the high catalyst stability of a fixed - bed reactor and the strong heat - transfer characteristics of a slurry - bed reactor. The series - type reaction system includes at least a fixed - bed pre - reactor and a slurry - bed main reactor;

[0087] Step 402: Distribute the unreacted gas proportionally to the fixed - bed pre - reactor and the slurry - bed main reactor;

[0088] Step 403: Use the Cu·Zn·Al@CeO2 composite carrier structure, and the outer - layer CeO2 nano - coating selectively adsorbs CeO2, and the Cu·Zn·Al active components are used for the directional conversion of CO;

[0089] Step 404: Introduce the gas from the outlet of the slurry - bed reactor into the reverse - shift unit to react with the green hydrogen produced by electrolyzing water to generate CO;

[0090] Step 405: Use the reaction heat of the fixed - bed pre - reactor for steam power generation through three - stage thermal coupling, and use the medium - temperature waste heat of the slurry - bed reactor to drive absorption refrigeration.

[0091] Specifically, the present invention can also be implemented through the following steps:

[0092] I. Multi-stage reactor coupling module

[0093] Technical architecture and parameter optimization

[0094] 1. Series reaction system design

[0095] Fixed bed pre-reactor: Adopting an axial adiabatic structure (operating pressure 8 - 10 MPa, temperature 220 - 240 °C), equipped with a Cu-Zn-Al-based catalyst, using its high mechanical stability to achieve the preliminary conversion of syngas (CO / CO2 / H2), and the single-pass CO conversion rate is controlled at 18% - 22%.

[0096] Slurry bed main reactor: Selecting a gas flow bubbling suspension reactor (operating pressure 5 - 8 MPa, temperature 240 - 260 °C), with a spiral coil heat exchanger built-in, strengthening heat transfer through a paraffin oil slurry medium, and the single-pass CO conversion rate is increased to 36% - 40%.

[0097] System coordination: A gas-liquid separator is set between the two-stage reactors to separate the unreacted gas and dynamically distribute it to the next stage. At the same time, the risk of thermal runaway is reduced through a multi-stage adiabatic series design.

[0098] 2. Dynamic regulation mechanism

[0099] Gas distribution strategy: Based on the real-time monitoring of the CO / CO2 ratio by an on-line infrared spectrometer (accuracy ±0.5%), when the CO concentration > 65%, the high-concentration gas is preferentially introduced into the slurry bed; when the CO2 ratio rises to 20%, it is switched to the fixed bed to utilize its stability advantage.

[0100] II. Gas component monitoring module

[0101] Multi-parameter on-line analysis

[0102] Core equipment: Adopting a combined system of a laser mass spectrometer and a Raman spectrometer to synchronously detect the concentrations of H2 / CO / CO2 / CH3OH, with a data refresh frequency of 10 Hz and an error rate < 1.5%.

[0103] Adaptive algorithm: Based on a fuzzy PID control model, dynamically adjust the opening of the gas shunt valve (adjustment accuracy 0.1%) to achieve the matching of flow distribution and reaction rate.

[0104] III. Core-shell structure catalytic module

[0105] Catalyst design and preparation

[0106] Core-shell structure: Using honeycomb ZSM-5 molecular sieve as the carrier (pore size 0.5 - 1 nm), a double-layer CeO2-TiO2 nanoshell (thickness 80 - 120 nm) is coated by the sol-gel method, and the inner core is loaded with Cu-Zn-Al active components (Cu:Zn:Al = 6:2:1) to form a gradient adsorption-catalysis function.

[0107] Function verification: The CeO2 layer preferentially adsorbs CO2 (adsorption capacity 2.1 mmol / g), and the inner core Cu-Zn-Al directionally catalyzes the hydrogenation of CO, increasing the comprehensive conversion rate of CO / CO2 to 39.5%.

[0108] In-situ regeneration technology

[0109] Sulfur capture mechanism: MoS2 nanosheets (loading amount 5%) are loaded in the pores of ZSM-5 molecular sieve, and H2S and iron carbonyl impurities are captured by chemical adsorption.

[0110] Regeneration process: Every 500 hours of operation, a hydrogen-nitrogen mixed gas (H2:N2 = 3:1) pulse purge (pressure 0.8 MPa, temperature 250 °C) is started, and the desorption rate of sulfides > 95%.

[0111] IV. Reverse transformation synthesis module

[0112] Reverse transformation reaction unit

[0113] Catalyst system: An Fe-Cr-K composite catalyst (Fe:Cr:K = 10:2:1) is used. Under the conditions of temperature 280 - 320 °C and pressure 2.5 MPa, the CO2 (concentration 12% - 15%) at the outlet of the slurry bed and electrolytic green hydrogen (purity > 99.9%) are converted into CO, and the single-pass conversion rate ≥ 85%.

[0114] Carbon cycle efficiency: The generated CO is returned to the synthesis system through a gas circulation pump, and the comprehensive carbon utilization rate is increased from 75% of the traditional process to 98%.

[0115] V. Multi-stage waste heat recovery module

[0116] Thermodynamic cycle integration

[0117] Primary recovery (high temperature): The high-temperature gas (300 - 350 °C) at the outlet of the fixed-bed reactor drives a back-pressure steam turbine to generate electricity, with a power generation efficiency of 27.5% and an annual power generation of 1.2×10^7 kWh (calculated based on an annual production capacity of 600,000 tons).

[0118] Secondary recovery (medium temperature): The waste heat (200 - 250 °C) of the slurry bed reactor is used by a lithium bromide absorption refrigeration unit (COP = 1.3) to supply cooling for the reactor cooling system, replacing 30% of the traditional electric refrigeration energy consumption.

[0119] Tertiary recovery (low temperature): The low-temperature waste heat (80 - 120 °C) preheats the raw gas to 150 °C through a plate heat exchanger, reducing the steam heating load and resulting in a 24% decrease in the comprehensive energy consumption.

[0120] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all such changes and improvements fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. An efficient synthesis system for crude methanol, characterized in that, The high-efficiency synthesis system for crude methanol includes a multi-stage reactor coupling module, a gas component monitoring module, a core-shell structure catalytic module, a reverse water-gas shift synthesis module, and a multi-stage waste heat recovery module, where: The multi-stage reactor coupling module is used to establish a series reaction system by combining the high catalyst stability of a fixed-bed reactor and the strong heat transfer characteristics of a slurry-bed reactor. The series reaction system includes at least a fixed-bed pre-reactor and a slurry-bed main reactor; The gas component monitoring module is used to proportionally distribute the unreacted gas to the fixed-bed pre-reactor and the slurry-bed main reactor; The core-shell structure catalytic module is used to utilize the Cu·Zn·Al@CeO2 composite support structure, where the outer CeO2 nano-coating selectively adsorbs CeO2, and the Cu·Zn·Al active component is used for the directional conversion of CO; The reverse water-gas shift synthesis module is used to introduce the gas from the outlet of the slurry-bed reactor into the reverse water-gas shift unit to react with green hydrogen produced by electrolyzing water to generate CO; The multi-stage waste heat recovery module is used to utilize three-stage thermal coupling to use the reaction heat of the fixed-bed pre-reactor for steam power generation, and the medium-temperature waste heat of the slurry-bed reactor drives absorption refrigeration.

2. An efficient synthesis system for crude methanol, characterized in that, The multi-stage reactor coupling module includes a fixed-bed pre-reactor, a slurry-bed main reactor, a system coordination sub-module, and a dynamic regulation sub-module, where: The fixed-bed pre-reactor is used to utilize an axial adiabatic structure, configure a Cu·Zn·Al-based catalyst, preliminarily convert syngas, and control the single-pass CO conversion rate at 18%-22%. The operating pressure of the axial adiabatic structure is 8-10 MPa, and the temperature is 220-240 °C; The slurry-bed main reactor is based on a gas-liquid bubbling suspension reactor, with a spiral coil heat exchanger built-in, and strengthens heat transfer through a paraffin oil slurry medium. The operating pressure of the gas-liquid bubbling suspension reactor is 5-8 MPa, and the temperature is 240-260 °C; The system coordination sub-module is used to set a gas-liquid separator between the reactors to distribute the unreacted gas to the next stage; The dynamic regulation sub-module is used to monitor the CO and CO2 ratios in real time with an on-line infrared spectrometer. When the CO concentration > 65%, the high-concentration gas is introduced into the slurry-bed; when the CO2 concentration ratio rises to 20%, it is switched to the fixed-bed.

3. A high-efficiency synthesis system for crude methanol, characterized in that, The gas component monitoring module includes a data detection sub-module and a gas regulation sub-module, where: The data detection sub-module is used to detect the concentrations of H2 / CO / CO2 / CH3OH using a combined system of a laser mass spectrometer and a Raman spectrometer. The data refresh frequency of the combined system of the laser mass spectrometer and the Raman spectrometer is 10 Hz, and the error rate < 1.5%; The gas regulation sub-module is used to dynamically adjust the flow distribution and reaction rate of the gas shunt valve using a fuzzy PID control model.

4. A high-efficiency synthesis system for crude methanol, characterized in that, The core-shell structure catalytic module includes a core-shell establishment structure sub-module, a function verification sub-module, a sulfur capture mechanism sub-module, and a pulse purge sub-module, where: Core-shell structure building sub-module, which uses honeycomb ZSM-5 molecular sieve as the carrier with a pore diameter of 0.5-1 nm, and coats a CeO2-TiO2 double-layer nanoshell through the sol-gel method. The thickness of the nanoshell is 80-120 nm, and the inner core is loaded with Cu·Zn·Al active components, where Cu:Zn:Al = 6:2:1; Function verification sub-module, which uses the CeO2 layer to preferentially adsorb CO2 with an adsorption capacity of 2.1 mmol / g, and the inner core Cu·Zn·Al directionally catalyzes the hydrogenation of CO; Sulfur capture mechanism module, which loads MoS2 nanosheets in the pores of ZSM-5 molecular sieve with a loading amount of 5%, and chemically adsorbs and captures H2S and carbonyl iron impurities; Pulse purge sub-module, which is used to judge that when the system runs for 500 hours each time, start the pulse purge of the hydrogen-nitrogen mixed gas. The ratio of the hydrogen-nitrogen mixed gas is H2:N2 = 3:1, the pressure of the pulse purge is 0.8 MPa, and the temperature is 250 °C, so that the desorption rate of sulfide > 95%.

5. A high-efficiency synthesis system for crude methanol, characterized in that, The reverse conversion synthesis module includes a gas conversion and obtaining sub-module and a gas circulation and transportation sub-module, where: Gas conversion and obtaining sub-module, which uses an Fe-Cr-K composite catalyst, where the ratio of the composite catalyst is Fe:Cr:K = 10:2:1, and under the conditions of a temperature of 280-320 °C and a pressure of 2.5 MPa, converts CO2 with a concentration of 12%-15% at the outlet of the slurry bed and electrolytic green hydrogen with a purity > 99.9% into CO; Gas circulation and transportation sub-module, which is used to transport the generated CO to the synthesis system through a gas circulation pump.

6. A high-efficiency synthesis system for crude methanol, characterized in that, The multi-stage waste heat recovery module includes a primary recovery sub-module, a secondary recovery sub-module and a tertiary recovery sub-module, where: Primary recovery sub-module, which is used to drive a back-pressure steam turbine to generate electricity with the high-temperature gas at the outlet of the fixed-bed reactor at a temperature of 300-350 °C; Secondary recovery sub-module, which is used to supply cooling to the reactor cooling system through a lithium bromide absorption refrigeration unit with the waste heat of the slurry bed reactor at a temperature of 200-250 °C; Tertiary recovery sub-module, which is used to preheat the raw material gas to 150 °C through a plate heat exchanger with the low-temperature waste heat at a temperature of 80-120 °C.

7. A method for efficient synthesis of crude methanol, characterized in that, The high-efficiency synthesis method of crude methanol includes the following steps: Mix the biomass gasification syngas and the coal-based syngas in a ratio of 1:3, and remove H2S and carbonyl iron compounds through the molecular sieve membrane separation module to make the total sulfur content < 0.1 ppm; Real-time monitor the bed temperature field through a distributed optical fiber sensor, and adjust the cold gas flow rate in combination with the fuzzy PID algorithm to make the axial temperature difference of the reactor ≤ 3 °C; Use a perfluoropolyether absorption-centrifugal separation coupling device to separate the crude methanol and the unreacted gas at a low temperature of 30 °C.

8. A method for highly efficient synthesis of crude methanol according to claim 7, characterized in that, The high-efficiency synthesis method of crude methanol also includes the following steps: Establish a series reaction system by combining the high catalyst stability of the fixed-bed reactor and the strong heat transfer characteristics of the slurry bed reactor. The series reaction system includes at least a fixed-bed pre-reactor and a slurry bed main reactor; Distribute the unreacted gas proportionally to the fixed-bed pre-reactor and the slurry bed main reactor; Utilize the Cu·Zn·Al@CeO2 composite support structure, with the outer layer of CeO2 nano-coating selectively adsorbing CeO2, and the Cu·Zn·Al active components being used for the directional conversion of CO; Introduce the outlet gas of the slurry bed reactor into the reverse shift unit to react with the green hydrogen produced by electrolyzing water to generate CO; Utilize three-stage thermal coupling to use the reaction heat of the fixed bed pre-reactor for steam power generation, and the medium-temperature waste heat of the slurry bed reactor to drive absorption refrigeration.

9. The high-efficiency synthesis method of crude methanol according to claim 8, characterized in that, Establish a series reaction system by combining the high catalyst stability of the fixed bed reactor and the strong heat transfer characteristics of the slurry bed reactor, including: Utilize the axial adiabatic structure, configure the Cu·Zn·Al-based catalyst, preliminarily convert the syngas, and control the single-pass CO conversion rate within 18%-22%. The operating pressure of the axial adiabatic structure is 8-10 MPa, and the temperature is 220-240 °C; An air flow bubbling suspension reactor with a spiral coil heat exchanger inside, and strengthen heat transfer through the paraffin oil slurry medium. The operating pressure of the air flow bubbling suspension reactor is 5-8 MPa, and the temperature is 240-260 °C; Install a gas-liquid separator between the reactors to combine the unreacted gas and distribute it to the next stage; Use an on-line infrared spectrometer to monitor the ratio of CO and CO2 in real time. When the CO concentration > 65%, introduce the high-concentration gas into the slurry bed; when the CO2 concentration ratio rises to 20%, switch to the fixed bed.

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