Conversion system and conversion process for preparing methanol from coke oven gas

Abstract

The invention provides a conversion system and a conversion process for preparing methanol from coke oven gas, and relates to the technical field of processes for preparing methanol from coke oven gas. The conversion system for preparing methanol from coke oven gas comprises an oxygen supply module at least provided with an air separation oxygen supply unit and an oxygen supply compressor which are communicated with each other; a mixing module having at least a first mixing unit and a second mixing unit; and the conversion module is communicated with the first mixing unit and the second mixing unit. Wherein the oxygen supply compressor is further communicated with a liquid oxygen supply unit, and the liquid oxygen supply unit is used for supplementing supplied oxygen; the first mixing unit is communicated with the oxygen supply compressor, and the first mixing unit is communicated with a steam generator and carbon dioxide supply equipment; the second mixing unit is communicated with the steam generator and the coke-oven gas compressor; the first mixing unit is provided with a first heating device; and the second mixing unit is provided with a second heating device. The conversion rate of methanol synthesized from coke oven gas can be improved.

Description

Technical Field

[0001] This invention relates to the field of methanol production technology from coke oven gas, specifically to a methanol conversion system and process from coke oven gas. Background Technology

[0002] Methanol is a relatively simple saturated monohydric alcohol. At room temperature and pressure, it is a colorless, volatile, transparent liquid with a pungent odor. Coke oven gas is suitable as a feedstock for methanol production, which can improve the utilization rate of coke oven gas and has a low conversion cost. In the process of producing methanol from coke oven gas, the equipment needs to meet the following requirements: 1) Purify nitrogen and sulfur contaminants in the coke oven gas to avoid catalyst poisoning; 2) Reduce the temperature rise during the reaction process; 3) The methane contained in the coke oven gas needs to be further reacted to generate synthesis gas; 4) The ratio of carbon monoxide to hydrogen in the synthesis must meet the requirements; 5) Control the amount of reaction catalyst, reaction temperature, and pressure.

[0003] The general process for converting coke oven gas into methanol is as follows: Coke oven gas from the desulfurization unit has a pressure of approximately 2.3 MPa, a temperature of approximately 350°C, and a methane content of approximately 27.17%. This gas is mixed with steam from the boiler and enters a coke oven gas preheater, where it is heated to 660°C before entering the converter. Oxygen from the air separation unit, at a temperature of approximately 100°C and a pressure of approximately 2.5 MPa, is added with superheated steam and enters the converter. At the top of the converter, it mixes with the coke oven gas and steam. The oxygen in the mixture reacts with the combustible gas to generate heat, providing heat for the methane conversion reaction. After entering the bed, under the action of a catalyst, methane and a few high-carbon hydrocarbons are converted into carbon monoxide and hydrogen. The converted gas is drawn from the bottom of the converter at a temperature of 980°C-985°C, a pressure of approximately 2.2 MPa, and a methane content of approximately 0.69%. However, in the existing technology, due to the combined effects of various factors such as the carbon-hydrogen ratio in the reactants, the selection and consumption of catalysts, oxygen supply, and reaction temperature control, the existing coke oven gas to methanol conversion system has the problem of low methanol synthesis conversion rate. Summary of the Invention

[0004] This invention addresses the problem of low methanol synthesis conversion rate in existing coke oven gas-to-methanol conversion systems by providing a coke oven gas-to-methanol conversion system and process that improves the conversion process, optimizes the methanol conversion gas composition and carbon-hydrogen ratio, thereby increasing the conversion rate of coke oven gas to methanol.

[0005] The technical solution adopted in this invention is: A coke oven gas to methanol conversion system, comprising: The oxygen supply module has at least an air separation oxygen supply unit and an oxygen supply compressor that are interconnected. The mixing module includes at least a first mixing unit and a second mixing unit; the first mixing unit is connected to the oxygen supply compressor, and the first mixing unit is also connected to a steam generator and a carbon dioxide supply device; the second mixing unit is connected to the steam generator and a coke oven gas compressor. The conversion module is connected to both the first mixing unit and the second mixing unit; the conversion module is used to carry out the conversion reaction of coke oven gas. The oxygen compressor is also connected to a liquid oxygen supply unit, which is used to supplement oxygen supply; the first mixing unit is equipped with a first heating device; and the second mixing unit is equipped with a second heating device.

[0006] Furthermore, the first heating device can heat the mixed gas in the first mixing unit to 280~550°C; the second heating device can heat the mixed gas in the second mixing unit to 600~680°C.

[0007] Furthermore, the air separation oxygen supply unit has at least a centrifugal air compressor, a plate heat exchanger, a vertical radial flow adsorber, an expander, and a cryogenic distillation column connected in sequence; the cryogenic distillation column is connected to the air inlet of the oxygen supply compressor.

[0008] Furthermore, the oxygen outlet pipe of the cryogenic distillation column has at least two output ends, one output end is connected to the oxygen supply compressor, and the other output end is connected to an oxygen storage tank; and electromagnetic regulating valves are provided on both output ends of the oxygen outlet pipe of the cryogenic distillation column.

[0009] Furthermore, the liquid oxygen supply unit has at least a liquid oxygen storage tank and a vaporizer; the input ends of the liquid oxygen storage tank and the vaporizer are connected; the output end of the vaporizer is connected to the oxygen supply compressor.

[0010] Furthermore, a first branch line is provided on the connecting pipeline between the liquid oxygen storage tank and the vaporizer, and a liquid oxygen pump and an electromagnetic shut-off valve are provided on the first branch line; an electromagnetic shut-off valve is provided on the main pipeline section that branches off from the first branch line; a second branch line is provided on the connecting pipeline between the first branch line and the vaporizer, and a medium-pressure storage tank and an electromagnetic shut-off valve are provided on the second branch line; an electromagnetic shut-off valve is provided on the main pipeline section that branches off from the second branch line; when the air separation oxygen supply unit cannot meet the oxygen supply demand, the electromagnetic shut-off valves on the main pipeline section that branches off from the first branch line and the main pipeline section that branches off from the second branch line can be closed, and the electromagnetic shut-off valves on the first and second branch lines can be opened to supplement the oxygen supply.

[0011] Furthermore, the conversion module has at least a conversion reactor, and the furnace top of the conversion reactor is provided with a first air inlet and a second air inlet; the first air inlet is connected to the air outlet of the first mixing unit; the second air inlet is connected to the air outlet of the second mixing unit; and a central tube burner is provided inside the conversion reactor, and the central tube burner is connected to both the first air inlet and the second air inlet; the gas input from the first mixing unit and the second mixing unit can be mixed in the central tube burner.

[0012] Furthermore, the conversion reactor is equipped with a wire mesh inside, which is used to place the catalyst.

[0013] Furthermore, it also includes: The desulfurization module has at least a coarse desulfurization unit connected to the conversion module, and the output end of the coarse desulfurization unit is connected to a fine desulfurization unit; the desulfurization module is used to process the methanol synthesis gas output from the conversion module and reduce the sulfur content in the methanol synthesis gas.

[0014] A coke oven gas to methanol conversion process, using the coke oven gas to methanol conversion system as described above, the coke oven gas to methanol conversion process includes the following steps: S10. Oxygen is obtained through the air separation oxygen supply unit and the liquid oxygen supply unit; S20. The obtained oxygen is introduced into the first mixing unit, mixed with water vapor and carbon dioxide, and heated to 280~550°C; and water vapor and coke oven gas are introduced into the second mixing unit and heated to 600~680°C. S30. The heated mixed gas from the first mixing unit and the second mixing unit is introduced into the conversion module for conversion reaction to obtain methanol synthesis gas.

[0015] The beneficial effects of this invention are: 1. The conversion system of the present invention, by setting up an interconnected oxygen supply module, a mixing module, and a conversion module, relies on the simultaneous introduction of oxygen, water vapor, and carbon dioxide into the first mixing unit of the mixing module to facilitate the replenishment of carbon elements, adjust the carbon-hydrogen ratio, and solve the problem of excess hydrogen affecting the conversion reaction; by setting up multiple oxygen supply units, including an air separation oxygen supply unit and a liquid oxygen supply unit, the problem of insufficient oxygen limiting the reaction is solved; and by using the first and second heating devices in the mixing module to preheat the mixed gas, the reaction temperature in the conversion module is guaranteed. Combined with the unified adjustment and replenishment of water vapor and carbon dioxide by the first mixing unit, the two-stage conversion reaction in the conversion module is guaranteed to proceed fully in the forward direction, compensating for the insufficient catalytic capacity of the catalyst. As a result, the methane content of the methanol synthesis gas output from the conversion module is significantly reduced to approximately 0.2 vol.% - 0.3 vol.%, thereby improving the methanol synthesis conversion rate and solving the problem of low methanol synthesis conversion rate in existing coke oven gas-to-methanol conversion systems. 2. The conversion system of the present invention adds oxygen supply equipment in the oxygen generation stage, performs gas mixing and temperature regulation in two groups, and facilitates gas reaction conversion within the conversion module. In step S20, oxygen, water vapor, and carbon dioxide are simultaneously introduced into the first mixing unit of the mixing module to supplement carbon elements, adjust the carbon-hydrogen ratio, and solve the problem of excess hydrogen affecting the conversion reaction. In step S10, multiple oxygen supply units, including an air separation oxygen supply unit and a liquid oxygen supply unit, are set up in the oxygen supply module to solve the problem of insufficient oxygen limiting the reaction. Furthermore, the first and second heating devices in the mixing module preheat the mixed gas, ensuring the reaction temperature within the conversion module. Combined with the unified distribution and supplementation of water vapor and carbon dioxide by the first mixing unit, the two-stage conversion reaction in the conversion module is ensured to proceed fully in the forward direction, compensating for insufficient catalyst catalytic capacity. As a result, the methane content in the methanol synthesis gas output from the conversion module is significantly reduced to approximately 0.2 vol.% - 0.3 vol.%, thereby improving the methanol synthesis conversion rate and solving the problem of low methanol synthesis conversion rate in existing coke oven gas-to-methanol conversion systems. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the conversion system according to Embodiment 1 of the present invention; Figure 2This is a schematic diagram of the air separation oxygen supply unit according to Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the liquid oxygen supply unit according to Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the conversion reactor of Embodiment 1 of the present invention; Figure 5 This is a flowchart of the conversion process in Embodiment 2 of the present invention.

[0018] Reference numerals: 100-Oxygen supply module, 110-Air separation oxygen supply unit, 111-Centrifugal air compressor, 112-Plate heat exchanger, 113-Refrigerator, 114-Vertical radial flow adsorber, 115-Expander, 116-Cryogenic distillation column, 117-Oxygen storage tank, 120-Liquid oxygen supply unit, 121-Liquid oxygen storage tank, 122-Vaporizer, 123-Liquid oxygen pump, 124-Medium pressure storage tank, 125-First branch pipeline, 126-Second branch pipeline, 130-Oxygen supply compressor; 200 - Mixing module, 210 - First mixing unit, 212 - First heating device, 220 - Second mixing unit, 222 - Second heating device; 300-Conversion module, 310-Conversion reactor, 311-First air inlet, 312-Second air inlet, 313-Central tube burner, 314-Wire mesh, 315-Synthesis gas outlet pipe, 316-Tube heat exchanger; 400 - Desulfurization module, 410 - Coarse desulfurization unit, 420 - Fine desulfurization unit; 500-Steam generator; 600-Carbon Dioxide Supply Equipment; 700-coke oven gas compressor. Detailed Implementation

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention.

[0021] The embodiments of the invention will now be described in detail with reference to the accompanying drawings.

[0022] Example 1

[0023] In existing processes for producing methanol from coke oven gas, the methanol conversion system suffers from low methanol synthesis conversion rates due to the combined effects of various factors, including the carbon-hydrogen ratio in the reactants, catalyst selection and consumption, oxygen supply, and reaction temperature control.

[0024] To address the aforementioned problems in the prior art, this embodiment provides a coke oven gas to methanol conversion system. This system is used to perform a conversion process on coke oven gas, transforming it into methanol synthesis gas. The main components of the methanol synthesis gas are hydrogen, carbon monoxide, and carbon dioxide, facilitating subsequent methanol synthesis. This coke oven gas to methanol conversion system can improve the conversion process, optimize the composition and carbon-hydrogen ratio of the methanol synthesis gas, thereby increasing the conversion rate of coke oven gas to methanol. Please refer to [link to previous document]. Figure 1-Figure 4 The coke oven gas to methanol conversion system mainly includes: oxygen supply module 100, mixing module 200 and conversion module 300, etc.

[0025] The oxygen supply module 100 is used to provide the oxygen required for the first stage of combustion reaction in the coke oven gas conversion process. For example... Figure 1 As shown, the oxygen supply module 100 mainly includes an air separation oxygen supply unit 110 and an oxygen supply compressor 130. The air separation oxygen supply unit 110 separates oxygen from the air, and its output is connected to the input of the oxygen supply compressor 130, which pressurizes and supplies oxygen to the mixing module 200. Furthermore, the oxygen supply module 100 also includes a liquid oxygen supply unit 120, which is connected to the oxygen supply compressor 130. Since the conversion reactor 310 in this embodiment has a large oxygen demand, the liquid oxygen supply unit 120 can supplement the oxygen supply when the air separation oxygen supply unit 110 stops or the oxygen supply is insufficient.

[0026] The mixing module 200 is used to mix the oxygen, water vapor, and carbon dioxide required in the coke oven gas conversion reaction process, raise the temperature to the required level, and then supply it to the conversion module 300 for reaction. The mixing module 200 mainly includes a first mixing unit 210 and a second mixing unit 220, etc. The first mixing unit 210 is connected to the outlet of the oxygen supply compressor 130 of the oxygen supply module 100, and receives oxygen from the oxygen supply module 100; the first mixing unit 210 is also connected to a steam generator 500 and a carbon dioxide supply device 600, receiving water vapor from the steam generator 500 and carbon dioxide from the carbon dioxide supply device 600; and the first mixing unit 210 is equipped with a first heating device 212, which can heat the oxygen, water vapor, and carbon dioxide mixed in the first mixing unit 210 to 280~550℃. Meanwhile, the second mixing unit 220 is also connected to the steam generator 500, from which steam is input; the second mixing unit 220 is also connected to the coke oven gas compressor 700, from which pressurized coke oven gas is input; and the second mixing unit 220 is equipped with a second heating device 222, which can heat the steam and coke oven gas mixed in the second mixing unit 220 to 600~680℃.

[0027] The conversion module 300 is used to mix coke oven gas, oxygen, carbon dioxide, and water vapor to carry out a two-stage conversion reaction of the coke oven gas, generating methanol synthesis gas whose main components are carbon monoxide and hydrogen. The methanol synthesis gas is then transported to subsequent processes for methanol synthesis. The conversion module 300 mainly includes a conversion reactor 310, etc. The conversion reactor 310 is simultaneously connected to the first mixing unit 210 and the second mixing unit 220. By introducing water vapor at 600~680℃ and coke oven gas mixed in the second mixing unit 220, the auto-ignition point of the coke oven gas can be reached, accelerating the first-stage methane combustion reaction for heating, increasing the methane combustion consumption in the coke oven gas, and raising the furnace temperature. Simultaneously, the oxygen, water vapor, and carbon dioxide mixed at 280-550°C introduced into the first mixing unit 210 ensure sufficient oxygen, improving combustion efficiency. Furthermore, the mixing and blending of water vapor and carbon dioxide ensures an appropriate ratio of hydrogen to carbon monoxide in the methanol synthesis gas produced in the second stage, avoiding hydrogen excess and thus increasing the conversion rate of methanol synthesis gas to methanol in subsequent processes. On the other hand, the relatively low temperature of the oxygen, water vapor, and carbon dioxide mixed in the first mixing unit 210 controls the temperature inside the conversion reactor 310 to below 1700°C, preventing excessive wear and tear and shortened service life of the furnace lining and burners due to excessively high reaction temperatures, thus avoiding impacting the long-term stable operation of the conversion reactor 310. The second-stage conversion reaction within the conversion reactor 310 is as follows: Methane reacts with water vapor: CH4 + H2O ⇌ CO + 3H2 - 49.3kcal.

[0028] The reaction of methane with carbon dioxide: CH4 + 2CO2 ⇌ 3CO + H2 + H2O - 59.1kcal.

[0029] Both stages of the conversion reaction are endothermic reactions, using steam and carbon dioxide as raw materials. The appropriately increased reaction temperature in the furnace, combined with higher steam and carbon dioxide content, makes the second-stage reaction more complete, thereby compensating for the insufficient catalytic effect of the catalyst.

[0030] One specific working method of this embodiment is as follows: First, high-purity oxygen is separated from the air by the air separation oxygen supply unit 110 of the oxygen supply module 100, and combined with the oxygen produced by the liquid oxygen supply unit 120. The oxygen is then delivered to the first mixing unit 210 of the mixing module 200 via the oxygen supply compressor 130. Next, water vapor and carbon dioxide are simultaneously introduced into the first mixing unit 210, where the oxygen is mixed with the water vapor and carbon dioxide and heated to a lower temperature. Meanwhile, water vapor and coke oven gas are introduced into the second mixing unit 220, where they are mixed and heated to a higher temperature than the auto-ignition point of the coke oven gas. Then, the mixed gas from the first mixing unit 210 and the second mixing unit 220 is introduced into the conversion reactor 310 of the conversion module 300 for conversion reaction. During the reaction, a suitable high temperature can be maintained, and there is an abundance of carbon dioxide and water vapor, which is conducive to the forward progress of the conversion reaction, thereby improving the reaction efficiency and the conversion rate of methane.

[0031] The applicant's research revealed that the low methanol conversion rate in the process of producing methanol from coke oven gas is mainly due to the combined effects of three factors: First, there is an excess of hydrogen in the raw material gas used for methanol production from coke oven gas, resulting in a large amount of hydrogen being wasted and thus affecting the efficiency of the methanol synthesis reaction; second, the conversion catalysts currently used in the coke oven gas conversion process have problems such as insufficient conversion efficiency and limited catalyst life, which reduce the methanol conversion rate; third, insufficient oxygen supply in the conversion section limits the progress of the conversion reaction, and together with the excess hydrogen, this leads to a low methane conversion rate. In this embodiment, the coke oven gas to methanol conversion system is equipped with an interconnected oxygen supply module 100, a mixing module 200, and a conversion module 300. Oxygen, water vapor, and carbon dioxide are simultaneously introduced into the first mixing unit 210 of the mixing module 200 to replenish carbon, adjust the carbon-to-hydrogen ratio, and solve the problem of excess hydrogen affecting the conversion reaction. Multiple oxygen supply units, namely an air separation oxygen supply unit 110 and a liquid oxygen supply unit 120, within the oxygen supply module 100, solve the problem of insufficient oxygen limiting the reaction. Furthermore, the first heating device 212 and the second heating device 222 within the mixing module 200 preheat the mixed gas, ensuring the reaction temperature within the conversion module 300. Combined with the unified distribution and replenishment of water vapor and carbon dioxide by the first mixing unit 210, the system ensures the full forward progress of the two-stage conversion reaction in the conversion module 300, compensating for insufficient catalyst catalytic capacity. As a result, the methane content in the methanol synthesis gas output from the conversion module 300 is significantly reduced, reaching 0.2 vol.% - 0.3 vol.%. This improved the methanol synthesis conversion rate, solving the problem of low methanol synthesis conversion rate in existing coke oven gas-to-methanol conversion systems.

[0032] Furthermore, such as Figure 2As shown in the diagram, the oxygen supply module 100 of this embodiment includes an air separation oxygen supply unit 110, which mainly comprises a centrifugal air compressor 111, a plate heat exchanger 112, a refrigeration unit 113, a vertical radial flow adsorber 114, an expander 115, a cryogenic distillation column 116, and an oxygen storage tank 117. The centrifugal air compressor 111 is used to compress ambient air, increasing its pressure to provide sufficient pressure for subsequent pre-cooling, purification, and other processes. Plate heat exchanger 112 is connected to centrifugal air compressor 111, and refrigeration unit 113 is connected to plate heat exchanger 112. Plate heat exchanger 112 and refrigeration unit 113 work together to cool the high-temperature compressed air from the air compressor in stages, causing some of the water vapor in the air to condense into liquid water and be discharged from the system, preventing the water vapor from freezing in subsequent cryogenic equipment. At the same time, some of the heat in the compressed air is recovered to provide cooling capacity for the air separation process. Plate heat exchanger 112 cools the compressed air through the flow and heat exchange of hot and cold fluids on both sides of the plates. Refrigeration unit 113 cools the air through a tubular cryogenic cooler. In one or more other embodiments, refrigeration unit 113 may be omitted, and plate heat exchanger 112 may be used for single-stage cooling, but this may increase the temperature gradient and reduce the heat exchange efficiency. The vertical radial flow adsorber 114 is connected to the refrigeration unit 113. The adsorber 114 is filled with adsorbent to remove residual impurities such as water vapor, carbon dioxide, and acetylene remaining in the pre-cooled air, preventing these impurities from accumulating in the air separation tower and affecting the safe and stable operation of the air separation equipment, or even causing explosions. Simultaneously, the expander 115 is connected to the vertical radial flow adsorber 114. The expander 115 converts the internal energy of the gas into mechanical energy by expanding the high-pressure gas, thereby cooling the gas and providing sufficient cooling for the air separation process, allowing the air to liquefy for subsequent distillation separation. The cryogenic distillation column 116 is connected to the expander 115. The cryogenic distillation column 116 mainly consists of an upper column, a lower column, and a main condenser-evaporator. The cryogenic distillation column 116 utilizes the different boiling points of the components in the air to carry out multiple partial evaporations and partial condensations within the distillation column, gradually separating components such as oxygen and nitrogen from the air to produce high-purity oxygen and nitrogen. In the distillation column, liquid air flows from top to bottom. The column is equipped with trays or packing to provide a place for the contact and heat and mass transfer of the gas and liquid phases. Through multiple evaporation and condensation processes, the nitrogen concentration in the gas phase gradually increases, and the oxygen concentration in the liquid phase gradually increases, thereby achieving oxygen and nitrogen separation. Furthermore, the oxygen outlet pipe of the low-temperature distillation column 116 is equipped with two output ends. One output end is connected to the oxygen supply compressor 130, and the other output end is connected to the oxygen storage tank 117. Both output ends are equipped with electromagnetic regulating valves, so that oxygen can be directly supplied to the mixing module 200 through the oxygen supply compressor 130, or oxygen can be temporarily stored in the oxygen storage tank 117.

[0033] Furthermore, such as Figure 3 As shown in the diagram, in the oxygen supply module 100 of this embodiment, the liquid oxygen supply unit 120 mainly includes a liquid oxygen storage tank 121 and a vaporizer 122. The input ends of the liquid oxygen storage tank 121 and the vaporizer 122 are connected. The liquid oxygen storage tank 121 stores high-purity liquid oxygen (purity > 99.6%). The vaporizer 122 is a water bath type, mainly composed of a shell, coil, and nozzle. The liquid oxygen is stored in the coil, and hot water or steam is introduced into the cavity between the shell and the coil. Through convective heat exchange, the liquid oxygen is vaporized and converted into gaseous oxygen. In this embodiment, a first branch line 125 is also provided on the connecting pipeline between the liquid oxygen storage tank 121 and the vaporizer 122. A liquid oxygen pump 123 and an electromagnetic shut-off valve are installed on the first branch line 125. An electromagnetic shut-off valve is also installed on the main pipeline section that branches off from the first branch line 125. Furthermore, a second branch line 126 is provided on the connecting pipeline between the first branch line 125 and the vaporizer 122. A medium-pressure storage tank 124 and an electromagnetic shut-off valve are installed on the second branch line 126. The medium-pressure storage tank 124 is equipped with a self-pressurizing device to adjust the pressure to 2.3~2.6 liters per second. MPa ensures a stable oxygen supply; and electromagnetic shut-off valves are also installed on the main pipe section that branches off from the second branch pipeline 126. Thus, when the air separation oxygen supply unit 110 malfunctions or there is insufficient oxygen, the electromagnetic shut-off valves on the main pipe section that branches off from the first branch pipeline 125 and the main pipe section that branches off from the second branch pipeline 126 are closed, while the electromagnetic shut-off valves on the first branch pipeline 125 and the second branch pipeline 126 are opened. After the liquid oxygen pump 123 pressurizes the liquid oxygen, the pressure is then regulated by the medium-pressure storage tank 124, and the oxygen is directly output through the vaporizer 122, avoiding production interruption.

[0034] Furthermore, in the mixing module 200 of this embodiment, the first mixing unit 210 is provided with a mixed gas inlet and an internal partition plate; superheated steam (350~550℃) is mixed with oxygen and carbon dioxide in a ratio of (steam:oxygen:carbon dioxide = 6:6:1~3:3:1). The second mixing unit 220 is also provided with a mixed gas inlet and an internal partition plate; superheated steam (350~550℃) is mixed with coke oven gas in a ratio of (steam:coke oven gas = 8:1~5:4), with a steam to hydrocarbon carbon atom volume ratio of 1.3~3. This ensures that the flame temperature within the conversion module 300 is ≤1700℃. The mixed gas in the first mixing unit 210 is preheated to 280-550°C by the first heating device 212 (to avoid excessively affecting the temperature of the coke oven gas), and the mixed gas in the second mixing unit 220 is preheated to 600-680°C (above the auto-ignition point of the coke oven gas) by the second heating device 222, thereby eliminating the need for the start-up burner in the conversion module 300 and simplifying the start-up process. In this embodiment, the first heating device 212 and the second heating device 222 are tubular heat exchangers; in one or more other embodiments, other heating methods may also be used. Simultaneously, the partition plate is provided with a vent and a one-way valve to allow water vapor to be evenly incorporated into the oxygen flow or coke oven gas flow, improving mixing efficiency.

[0035] Furthermore, in the conversion module 300 of this embodiment, the conversion reactor 310 is a cylindrical conversion furnace with an external steel structure and an internal lining of corundum bricks. The furnace top is provided with a first air inlet 311 and a second air inlet 312. The first air inlet 311 is connected to the air outlet of the first mixing unit 210; the second air inlet 312 is connected to the air outlet of the second mixing unit 220. Furthermore, a central tube burner 313 is installed inside the furnace top of the conversion reactor 310. The central tube burner 313 is interconnected with the first air inlet 311 and the second air inlet 312. The gas input from the first mixing unit 210 and the second mixing unit 220 is mixed in the central tube burner 313. The coke oven gas and oxygen are burned at the burner outlet of the central tube burner 313, generating heat and raising the furnace temperature to 1500~1700℃ and the pressure to 2.0~3.5MPa. Water and carbon dioxide are produced, which undergo catalytic cracking reaction with the input steam, carbon dioxide and the remaining methane in the coke oven gas to generate methanol synthesis gas composed of H2, CO and other substances. Meanwhile, the furnace interior of the conversion reactor 310 is equipped with a wire mesh 314 for placing the catalyst. A syngas outlet pipe 315 is installed on the side wall of the conversion reactor 310, and the temperature of the methanol synthesis gas output from the syngas outlet pipe 315 is 1000~1300℃. A tubular heat exchanger 316 is installed on the syngas outlet pipe to recover the heat from the methanol synthesis gas. This recovered heat is used to preheat the raw material water, saving the heat required to generate steam and improving energy utilization by more than 20%. In one or more other embodiments, the tubular heat exchanger 316 can also be connected to the water-cooled wall in the external steel structure of the conversion reactor 310, simultaneously recovering the heat from the methanol synthesis gas and the furnace wall of the conversion reactor 310 for preheating the raw material water.

[0036] Furthermore, the coke oven gas to methanol conversion system of this embodiment is also equipped with a desulfurization module 400. The desulfurization module 400 is mainly used to process the methanol synthesis gas output from the conversion module 300 and reduce the sulfur content in the methanol synthesis gas. The desulfurization module 400 mainly includes a coarse desulfurization unit 410 and a fine desulfurization unit 420. The input end of the coarse desulfurization unit 410 is connected to the synthesis gas outlet pipe 315. The coarse desulfurization unit 410 mainly includes a wet desulfurization tower. The methanol synthesis gas first enters the wet desulfurization tower, where the desulfurization solution absorbs acidic gases such as hydrogen sulfide to achieve coarse desulfurization. The desulfurization solution can adopt various formulations, such as tannin desulfurization alcohol flotation oil solution. The desulfurization tower is equipped with nozzles, packing materials, and other components to ensure sufficient gas-liquid contact and reaction. After desulfurization, the hydrogen sulfide content in the gas can be reduced to below 200 mg / Nm³. Furthermore, the wet desulfurization tower is equipped with an electrostatic precipitator. After wet desulfurization, some impurities contained in the crude desulfurized gas can be removed by the electrostatic precipitator, further purifying the gas and preventing impurities from affecting subsequent equipment and processes. The input end of the fine desulfurization unit 420 is connected to the output end of the coarse desulfurization unit 410. The fine desulfurization unit 420 mainly includes two-stage dry desulfurization towers. The first tower is filled with iron oxide desulfurizing agent to remove most of the acidic gases such as hydrogen sulfide; the second tower is filled with zinc oxide desulfurizing agent to further remove trace amounts of sulfides, treating the total sulfur in the methanol synthesis gas to below 0.1 ppm. By setting up a two-stage desulfurization unit, the problem of excessive sulfur content in the methanol produced by subsequent processes, which would affect product quality, can be prevented.

[0037] Example 2

[0038] Based on the above embodiments, a coke oven gas to methanol conversion process using the coke oven gas to methanol conversion system is further proposed, and a second embodiment is provided below.

[0039] Please see Figure 5 The second embodiment of the coke oven gas to methanol conversion process is used to perform a conversion step of coke oven gas, converting coke oven gas into methanol synthesis gas. This coke oven gas to methanol conversion process can improve the conversion process, optimize the composition and carbon-hydrogen ratio of methanol synthesis gas, thereby increasing the conversion rate of coke oven gas to methanol. The coke oven gas to methanol conversion process mainly includes the following steps: S10. Oxygen is obtained through the air separation oxygen supply unit 110 and the liquid oxygen supply unit 120 of the oxygen supply module 100; S20. The obtained oxygen is delivered to the first mixing unit 210 of the mixing module 200 through the oxygen supply compressor 130, and water vapor and carbon dioxide are simultaneously introduced into the first mixing unit 210. The oxygen is mixed with water vapor and carbon dioxide and heated to a lower temperature. In the second mixing unit 220, water vapor and coke oven gas are introduced and mixed and heated to a higher temperature exceeding the auto-ignition point of coke oven gas. S30. The heated mixed gas in the first mixing unit 210 and the second mixing unit 220 is respectively introduced into the conversion reactor 310 of the conversion module 300 for conversion reaction to obtain methanol synthesis gas.

[0040] In this embodiment, the coke oven gas to methanol conversion process adds oxygen supply equipment during the oxygen generation stage, performs gas mixing and temperature regulation in two groups, and controls the gas reaction conversion within the conversion module 300. In step S20, oxygen, water vapor, and carbon dioxide are simultaneously introduced into the first mixing unit 210 of the mixing module 200 to supplement carbon, adjust the carbon-hydrogen ratio, and solve the problem of excess hydrogen affecting the conversion reaction. In step S10, multiple oxygen supply units, namely an air separation oxygen supply unit 110 and a liquid oxygen supply unit 120, are set up in the oxygen supply module 100 to solve the problem of insufficient oxygen limiting the reaction. Furthermore, the first heating device 212 and the second heating device 222 within the mixing module 200 preheat the mixed gas, ensuring the reaction temperature within the conversion module 300. Combined with the unified distribution and supplementation of water vapor and carbon dioxide by the first mixing unit 210, the two-stage conversion reaction in the conversion module 300 is ensured to proceed fully in the forward direction, compensating for insufficient catalyst catalytic capacity. As a result, the methane content in the methanol synthesis gas output from the conversion module 300 is significantly reduced, reaching 0.2 vol.% - The methanol conversion rate is around 0.3 vol.%, thereby improving the methanol synthesis conversion rate and solving the problem of low methanol synthesis conversion rate in existing coke oven gas to methanol conversion systems.

[0041] Furthermore, in step S20 of this embodiment, superheated steam (350~550℃) in the first mixing unit 210 is mixed with oxygen and carbon dioxide in a ratio of (steam:oxygen:carbon dioxide = 6:6:1~3:3:1). In addition, superheated steam (350~550℃) in the second mixing unit 220 is mixed with coke oven gas in a ratio of (steam:coke oven gas = 8:1~5:4), with a steam-to-hydrocarbon carbon atom volume ratio of 1.3~3. This ensures that the flame temperature in the conversion module 300 is ≤1700℃. The mixed gas in the first mixing unit 210 is preheated to 280~550℃ by the first heating device 212 (to avoid excessively affecting the coke oven gas temperature), and the mixed gas in the second mixing unit 220 is preheated to 600~680℃ (above the auto-ignition point of coke oven gas) by the second heating device 222, thereby eliminating the need for a start-up burner in the conversion module 300 and simplifying the start-up process.

[0042] Furthermore, the coke oven gas to methanol conversion process in this embodiment also includes: S40. The methanol synthesis gas obtained in S30 is desulfurized using the desulfurization module 400.

[0043] The desulfurization process includes two stages: wet coarse desulfurization and dry fine desulfurization. In the wet coarse desulfurization stage, methanol synthesis gas first enters the wet desulfurization tower, where the desulfurization solution absorbs acidic gases such as hydrogen sulfide, achieving coarse desulfurization. Various formulations of the desulfurization solution can be used, such as tannin-based alcohol flotation oil solutions. The desulfurization tower is equipped with nozzles, packing materials, and other components to ensure sufficient gas-liquid contact and reaction. After desulfurization, the hydrogen sulfide content in the gas can be reduced to below 200 mg / Nm³. Furthermore, the wet desulfurization tower is equipped with electrostatic precipitator (ESP). After wet desulfurization, some impurities in the crude desulfurized gas can be removed by the ESP, further purifying the gas and preventing impurities from affecting subsequent equipment and processes. In the dry fine desulfurization stage, a two-stage dry desulfurization tower is set up. The first tower is filled with iron oxide desulfurizing agent to remove most of the acidic gases such as hydrogen sulfide; the second tower is filled with zinc oxide desulfurizing agent to further remove trace amounts of sulfides, treating the total sulfur in the methanol synthesis gas to below 0.1 ppm. By setting up a two-stage desulfurization unit, the problem of excessive sulfur content in methanol produced in subsequent processes, which would affect product quality, can be prevented.

[0044] 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 to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A coke oven gas to methanol conversion system, characterized in that, Include: The oxygen supply module (100) has at least an air separation oxygen supply unit (110) and an oxygen supply compressor (130) that are interconnected. The mixing module (200) has at least a first mixing unit (210) and a second mixing unit (220); the first mixing unit (210) is connected to the oxygen supply compressor (130), and the first mixing unit (210) is connected to a steam generator (500) and a carbon dioxide supply device (600); the second mixing unit (220) is connected to the steam generator (500) and a coke oven gas compressor (700). The conversion module (300) is connected to both the first mixing unit (210) and the second mixing unit (220); the conversion module (300) is used to carry out the conversion reaction of coke oven gas; The oxygen compressor (130) is also connected to a liquid oxygen supply unit (120), which is used to supplement oxygen supply; the first mixing unit (210) is provided with a first heating device (212); the second mixing unit (220) is provided with a second heating device (222).

2. The coke oven gas to methanol conversion system as described in claim 1, characterized in that, The first heating device (212) can heat the mixed gas in the first mixing unit (210) to 280~550°C; the second heating device (222) can heat the mixed gas in the second mixing unit (220) to 600~680°C.

3. The coke oven gas to methanol conversion system as described in claim 2, characterized in that, The air separation oxygen supply unit (110) has at least a centrifugal air compressor (111), a plate heat exchanger (112), a vertical radial flow adsorber (114), an expander (115), and a cryogenic distillation column (116) connected in sequence; the cryogenic distillation column (116) is connected to the air inlet of the oxygen supply compressor (130).

4. The coke oven gas to methanol conversion system as described in claim 3, characterized in that, The oxygen outlet pipe of the cryogenic distillation column (116) has at least two output ends, one of which is connected to the oxygen supply compressor (130), and the other of which is connected to the oxygen storage tank (117); and electromagnetic regulating valves are provided on both output ends of the oxygen outlet pipe of the cryogenic distillation column (116).

5. The coke oven gas to methanol conversion system as described in claim 1, characterized in that, The liquid oxygen supply unit (120) has at least a liquid oxygen storage tank (121) and a vaporizer (122); the input ends of the liquid oxygen storage tank (121) and the vaporizer (122) are connected; the output end of the vaporizer (122) is connected to the oxygen supply compressor (130).

6. The coke oven gas to methanol conversion system as described in claim 5, characterized in that, A first branch line (125) is provided on the connecting pipeline between the liquid oxygen storage tank (121) and the vaporizer (122). A liquid oxygen pump (123) and an electromagnetic shut-off valve are provided on the first branch line (125). An electromagnetic shut-off valve is provided on the main pipeline section that branches off from the first branch line (125). A second branch line (126) is provided on the connecting pipeline between the first branch line (125) and the vaporizer (122). A medium-pressure storage tank is provided on the second branch line (126). (124) and electromagnetic shut-off valve; an electromagnetic shut-off valve is provided on the main section that is mutually diverted from the second branch pipeline (126); when the air separation oxygen supply unit (110) cannot meet the oxygen supply demand, it can supplement the oxygen supply by closing the electromagnetic shut-off valve on the main section that is mutually diverted from the first branch pipeline (125) and the electromagnetic shut-off valve on the main section that is mutually diverted from the second branch pipeline (126), and opening the electromagnetic shut-off valves on the first branch pipeline (125) and the second branch pipeline (126).

7. The coke oven gas to methanol conversion system as described in claim 1, characterized in that, The conversion module (300) has at least a conversion reactor (310), and the furnace top of the conversion reactor (310) is provided with a first air inlet (311) and a second air inlet (312); the first air inlet (311) is connected to the gas outlet of the first mixing unit (210); the second air inlet (312) is connected to the gas outlet of the second mixing unit (220); and a central tube burner (313) is provided inside the conversion reactor (310), and the central tube burner (313) is connected to both the first air inlet (311) and the second air inlet (312); the gas input from the first mixing unit (210) and the second mixing unit (220) can be mixed in the central tube burner (313).

8. The coke oven gas to methanol conversion system as described in claim 7, characterized in that, The conversion reactor (310) is equipped with a wire mesh (314) for placing the catalyst.

9. The coke oven gas to methanol conversion system as described in claim 1, characterized in that, Also includes: The desulfurization module (400) has at least a coarse desulfurization unit (410) connected to the conversion module (300), and the output end of the coarse desulfurization unit (410) is connected to a fine desulfurization unit (420); the desulfurization module (400) is used to process the methanol synthesis gas output by the conversion module (300) and reduce the sulfur content in the methanol synthesis gas.

10. A process for converting coke oven gas into methanol, characterized in that, Using the coke oven gas to methanol conversion system as described in any one of claims 1-9, the coke oven gas to methanol conversion process includes the following steps: S10. Oxygen is obtained through the air separation oxygen supply unit (110) and the liquid oxygen supply unit (120); S20. The obtained oxygen is introduced into the first mixing unit (210), mixed with water vapor and carbon dioxide and heated to 280~550°C; and water vapor and coke oven gas are introduced into the second mixing unit (220) and heated to 600~680°C; S30. The heated mixed gas from the first mixing unit (210) and the second mixing unit (220) is introduced into the conversion module (300) for conversion reaction to obtain methanol synthesis gas.

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