Methanol synthesis system

Abstract

The utility model relates to the technical field of methanol synthesis, and discloses a methanol synthesis system which comprises an induced draft fan, a compressor, a methanol synthesis tower and a gas-liquid separator, and a gas inlet of the compressor communicates with a gas outlet of the induced draft fan through a first pipeline; a gas inlet of the methanol synthesis tower is communicated with a gas outlet of the compressor through a second pipeline; a gas inlet of the gas-liquid separator is communicated with a gas outlet of the methanol synthesis tower through a third pipeline; wherein an exhaust port of the gas-liquid separator is communicated with a gas inlet of the induced draft fan through a fourth pipeline, and the methanol synthesis system further comprises a pressure reducing device which is arranged on the fourth pipeline. The technical problems that raw material gas and backflow gas are compressed through two compressors respectively, the manufacturing cost is high, and the use consumption is large are solved.

Description

Technical Field

[0001] The present application relates to the technical field of methanol synthesis, and in particular to a methanol synthesis system. Background Art

[0002] Methanol production processes primarily include coal-to-methanol, natural gas-to-methanol, coke oven gas-to-methanol, and biomass pyrolysis gasification gas-to-methanol. In each case, the primary route is the synthesis of methanol from carbon monoxide and hydrogen, or from carbon dioxide and hydrogen. Synthesis pressure levels are categorized as high-pressure, medium-pressure, and low-pressure. Regardless of the method, a compressor is an essential component.

[0003] In the prior art, raw gas (hydrogen and carbon dioxide or hydrogen and carbon monoxide) is compressed by a compressor before entering a methanol synthesis tower. After methanol vapor is synthesized in the tower, it undergoes gas-liquid separation. After the liquid methanol is separated, the reflux gas is recirculated to another compressor to be mixed with the compressed gas from the main gas line. However, using two compressors to compress the raw gas and reflux gas separately results in high manufacturing costs and energy consumption. Utility Model Content

[0004] This application aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the main technical solutions adopted in this application include:

[0005] An embodiment of the present application provides a methanol synthesis system, which includes an induced draft fan, a compressor, a methanol synthesis tower and a gas-liquid separator. The air inlet of the compressor is connected to the air outlet of the induced draft fan through a first pipeline; the air inlet of the methanol synthesis tower is connected to the air outlet of the compressor through a second pipeline; the air inlet of the gas-liquid separator is connected to the air outlet of the methanol synthesis tower through a third pipeline; wherein, the exhaust port of the gas-liquid separator is connected to the air inlet of the induced draft fan through a fourth pipeline, and the methanol synthesis system also includes a pressure reducing device, which is arranged on the fourth pipeline.

[0006] In the methanol synthesis system proposed in the embodiment of the present application, the exhaust port of the gas-liquid separator is connected to the air inlet of the induced draft fan through a fourth pipeline, and a pressure reducing device is provided on the fourth pipeline. In this way, the reflux gas can be compressed by the pressure reducing device and the raw gas can be sent to the methanol synthesis tower after being compressed by the same compressor. There is no need to additionally configure a compressor for pressurizing the reflux gas, which is beneficial to reducing the cost of the methanol synthesis system.

[0007] Optionally, the decompression device includes a decompression tank, the air inlet of the decompression tank is connected to the air outlet of the gas-liquid separator, and the air outlet of the decompression tank is connected to the air inlet of the induced draft fan.

[0008] By reducing the pressure of the reflux gas and then circulating it through a pressure reducing device including a pressure reducing tank, instead of setting up an additional compressor to pressurize the reflux gas and circulate it, the cost of the entire methanol synthesis system can be reduced, and to a certain extent, the operating energy consumption of the methanol synthesis system can be reduced, thereby reducing the operating cost of the methanol synthesis system.

[0009] Optionally, the pressure reducing device further includes a pressure reducing valve, the air inlet of the pressure reducing valve is communicated with the air outlet of the gas-liquid separator, and the air outlet of the pressure reducing valve is communicated with the air inlet of the pressure reducing tank.

[0010] The pressure reducing valve can adjust the pressure of the reflux gas to a preset appropriate size, and then the gas enters the pressure reducing tank. The pressure reducing tank can play a role in buffering and stabilizing the pressure. The pressure of the reflux gas remains relatively stable in the pressure reducing tank, which enables the reflux gas to flow stably into the air inlet of the induced draft fan, thereby improving the stability and reliability of the operation of the methanol synthesis system.

[0011] Optionally, the methanol synthesis system also includes an exhaust pipeline, a first pneumatic valve and a flow meter, the exhaust pipeline has a first opening and a second opening, the first opening is connected to the fourth pipeline and is located between the pressure reducing tank and the pressure reducing valve, the second opening is used for exhaust, the first pneumatic valve and the flow meter are both arranged in the exhaust pipeline, and the first pneumatic valve can selectively control the exhaust pipeline to be on and off.

[0012] The first opening is connected to the fourth pipeline and is located between the pressure reducing tank and the pressure reducing valve, so that the reflux gas containing impurity gas after separation by the gas-liquid separator can be discharged through the exhaust pipeline, thereby improving the purity of the reflux gas entering the air inlet of the induced draft fan and improving the conversion rate of the methanol synthesis system.

[0013] Optionally, the methanol synthesis system further includes a second pneumatic valve and a third pneumatic valve, both of which are arranged in the fourth pipeline, the second pneumatic valve is located between the first opening and the pressure reducing valve, and the third pneumatic valve is located between the first opening and the pressure reducing tank.

[0014] By controlling the opening and closing of the second pneumatic valve and the third pneumatic valve, the components in need of maintenance in the methanol synthesis system can be isolated from the entire methanol synthesis system, thereby improving the maintenance efficiency of the components of the methanol synthesis system.

[0015] Optionally, the methanol synthesis system includes a pre-gas tank and a high-pressure tank, the pre-gas tank is arranged in the first pipeline, and the high-pressure tank is arranged in the second pipeline.

[0016] The front gas tank is arranged on the first pipeline, and the high-pressure tank is arranged on the second pipeline. The front gas tank can make the pressure of the gas entering the compressor more uniform, enable the compressor to work more stably, reduce the damage to the compressor caused by gas pressure fluctuations, and extend the service life of the compressor. The high-pressure tank can store high-pressure raw gas, so that the raw gas can be buffered before entering the methanol synthesis tower, ensuring that the raw gas entering the methanol synthesis tower is evenly distributed.

[0017] Optionally, the methanol synthesis system includes a first heat exchanger, the second pipeline has a first heat exchange channel, and the third pipeline has a second heat exchange channel. The first heat exchange channel and the second heat exchange channel are both arranged in the first heat exchanger to enable heat exchange between the medium in the first heat exchange channel and the medium in the second heat exchange channel.

[0018] The medium in the first heat exchange channel and the medium in the second heat exchange channel perform heat exchange, which can transfer the heat of the synthesis gas after the high-temperature reaction to the low-temperature raw gas, realize heat recovery and utilization, and reduce the energy consumption of the methanol synthesis system.

[0019] Optionally, the methanol synthesis system includes a first branch pipeline and a first heater, one end of the first branch pipeline is connected to the first heat exchange channel, the other end of the first branch pipeline is connected to the air inlet of the methanol synthesis tower, and the first heater is arranged on the first branch pipeline; the methanol synthesis system also includes a fourth pneumatic valve, the fourth pneumatic valve is arranged on the first branch pipeline, and the fourth pneumatic valve can selectively control the opening and closing of the first branch pipeline.

[0020] The first heater is arranged in the first branch pipeline, which can provide double protection for the heating of the raw gas, ensuring that the raw gas can be fully heated to the preset temperature, thereby improving the synthesis efficiency of the methanol synthesis system.

[0021] Optionally, the methanol synthesis system further includes a second heat exchanger, which is disposed in the third pipeline and located between the second heat exchange channel and the air inlet of the gas-liquid separator.

[0022] The second heat exchanger is arranged in the third pipeline and is located between the second heat exchange channel and the air inlet of the gas-liquid separator, which can further cool and dissipate the heat of the synthesis gas so that the methanol vapor in the synthesis gas can be fully condensed in the gas-liquid separator, thereby improving the methanol extraction rate of the methanol synthesis system.

[0023] Optionally, the methanol synthesis system also includes a fifth pneumatic valve, a sixth pneumatic valve, a seventh pneumatic valve, an eighth pneumatic valve and a ninth pneumatic valve, the fifth pneumatic valve being arranged in the first pipeline and located between the front gas tank and the compressor, the sixth pneumatic valve and the seventh pneumatic valve being both arranged in the second pipeline, the sixth pneumatic valve being located between the first heat exchange channel and the air outlet of the high-pressure tank, the seventh pneumatic valve being located between the first heat exchange channel and the air inlet of the methanol synthesis tower, the eighth pneumatic valve and the ninth pneumatic valve being both arranged in the third pipeline, the eighth pneumatic valve being located between the second heat exchange channel and the air outlet of the methanol synthesis tower, and the ninth pneumatic valve being located between the second heat exchange channel and the air inlet of the gas-liquid separator.

[0024] By controlling the opening and closing of the fifth pneumatic valve, the sixth pneumatic valve, the seventh pneumatic valve, the eighth pneumatic valve and the ninth pneumatic valve, the components in need of maintenance in the methanol synthesis system can be isolated from the entire methanol synthesis system, thereby improving the maintenance efficiency of the components of the methanol synthesis system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0026] Figure 1 A schematic structural diagram of a methanol synthesis system provided in one embodiment of the present application;

[0027] Figure 2 A schematic structural diagram of a methanol synthesis system provided in one embodiment of the present application;

[0028] Figure 3 A schematic structural diagram of a first heat exchanger provided in one embodiment of the present application.

[0029] [Description of Reference Numerals]

[0030] Methanol synthesis system 100; induced draft fan 110; compressor 120; methanol synthesis tower 130; gas-liquid separator 140; pressure reducing device 150; pressure reducing tank 151; pressure reducing valve 152; first pipeline 160; second pipeline 170; third pipeline 180; fourth pipeline 190; pre-gas tank 200; high-pressure tank 210; first heat exchanger 220; first heat exchange channel 221; second heat exchange channel 222; heat conducting wall 223; first branch pipeline 230; first heater 240; fourth pneumatic valve 250; first pneumatic valve 260; fifth pneumatic valve 270; sixth pneumatic valve 280; seventh pneumatic valve 290; eighth pneumatic valve 300; ninth pneumatic valve 310; second pneumatic valve 320; third pneumatic valve 330; second heat exchanger 340; exhaust pipeline 350; first opening 351; second opening 352; flow meter 360. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0032] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0033] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0034] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0035] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0036] The term "multiple" used in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two (including two) groups, and "multiple sheets" refers to more than two (including two) sheets.

[0037] Methanol production processes primarily include coal-to-methanol, natural gas-to-methanol, coke oven gas-to-methanol, and biomass pyrolysis gasification gas-to-methanol. In each case, the primary route is the synthesis of methanol from carbon monoxide and hydrogen, or from carbon dioxide and hydrogen. Synthesis pressure levels are categorized as high-pressure, medium-pressure, and low-pressure. Regardless of the method, a compressor is an essential component.

[0038] In the related art, the feed gas (a mixture of hydrogen and carbon dioxide and / or carbon monoxide) is first compressed to a specific pressure by a compressor and then fed into a methanol synthesis tower. Within the tower, the gases undergo complex chemical reactions under the influence of suitable temperature, pressure, and catalysts. However, existing methanol synthesis towers do not achieve 100% conversion per pass. Therefore, the feed gas reacts within the tower to produce synthesis gas rich in methanol vapor. The synthesis gas then enters a gas-liquid separation unit, where liquid methanol is extracted and collected through condensation and separation. The unreacted reflux gas is reintroduced into another compressor. This compressor pressurizes the reflux gas, mixes it with fresh compressed feed gas from the main gas line, and then re-introduces it into the tower to participate in the reaction. However, the purchase, installation, and commissioning of the two compressors are costly, and daily operation, such as motor drive and equipment maintenance, consumes significant energy. Furthermore, the equipment footprint increases, leading to increased failure points and soaring overall manufacturing costs and high operating costs.

[0039] In view of this, an embodiment of the present application provides a methanol synthesis system, which includes an induced draft fan, a compressor, a methanol synthesis tower and a gas-liquid separator. The air inlet of the compressor is connected to the air outlet of the induced draft fan through a first pipeline; the air inlet of the methanol synthesis tower is connected to the air outlet of the compressor through a second pipeline; the air inlet of the gas-liquid separator is connected to the air outlet of the methanol synthesis tower through a third pipeline; wherein, the exhaust port of the gas-liquid separator is connected to the air inlet of the induced draft fan through a fourth pipeline, and the methanol synthesis system also includes a pressure reducing device, which is arranged on the fourth pipeline.

[0040] In the above scheme, the exhaust port of the gas-liquid separator is connected to the air inlet of the induced draft fan through the fourth pipeline. In this way, there is no need to set up two compressors. The reflux gas can be recycled and utilized by one compressor, reducing the manufacturing cost and use cost of the methanol synthesis system.

[0041] In the embodiment of the present application, the main components of the raw gas include carbon monoxide and / or carbon dioxide, and hydrogen. The raw gas reacts in a methanol synthesis tower to generate synthesis gas, which mainly includes carbon monoxide and / or carbon dioxide, hydrogen, and methanol vapor. The synthesis gas liquefies the methanol vapor in a gas-liquid separator to form liquid methanol. After gas-liquid separation, the synthesis gas becomes reflux gas, and the main components of the reflux gas include carbon monoxide and / or carbon dioxide, and hydrogen.

[0042] For the convenience of description, the following embodiments are described by taking a methanol synthesis system according to an embodiment of the present application as an example.

[0043] Figure 1 A schematic structural diagram of a methanol synthesis system provided in one embodiment of the present application; Figure 2 A schematic structural diagram of a methanol synthesis system provided in one embodiment of the present application; Figure 3 A schematic structural diagram of a first heat exchanger provided in one embodiment of the present application.

[0044] Please refer to Figure 1 and Figure 2 In this embodiment, the methanol synthesis system 100 includes an induced draft fan 110, a compressor 120, a methanol synthesis tower 130 and a gas-liquid separator 140. The air inlet of the compressor 120 is connected to the air outlet of the induced draft fan 110 through a first pipeline 160; the air inlet of the methanol synthesis tower 130 is connected to the air outlet of the compressor 120 through a second pipeline 170; the air inlet of the gas-liquid separator 140 is connected to the air outlet of the methanol synthesis tower 130 through a third pipeline 180; wherein, the exhaust port of the gas-liquid separator 140 is connected to the air inlet of the induced draft fan 110 through a fourth pipeline 190. The methanol synthesis system 100 also includes a pressure reducing device 150, which is arranged on the fourth pipeline 190.

[0045] The induced draft fan 110 can introduce raw gas (primarily including carbon monoxide and / or carbon dioxide, and hydrogen) into the methanol synthesis system 100. The raw gas enters the induced draft fan 110 through its air inlet and exits the induced draft fan 110 through its air outlet. After exiting the induced draft fan 110, the raw gas flows into the first pipeline 160 and then flows from the first pipeline 160 to the air inlet of the compressor 120. The raw gas is compressed in the compressor 120. For example, the raw gas can be compressed to 5 MPa-10 MPa. After being compressed in the compressor 120, the raw gas can leave the compressor 120 from the air outlet of the compressor 120, and then flow from the air outlet of the compressor 120 through the second pipeline 170 to the air inlet of the methanol synthesis tower 130. The methanol synthesis tower 130 can perform a synthesis reaction on the raw gas to generate methanol vapor. At this time, the synthesis gas includes carbon monoxide and / or carbon dioxide, hydrogen and methanol vapor. The synthesis gas flows from the air outlet of the methanol synthesis tower 130 through the third pipeline 180. Since the liquefaction temperature of methanol vapor is higher than the liquefaction temperature of hydrogen, carbon monoxide and carbon dioxide under the same temperature and pressure, the methanol vapor is liquefied into methanol liquid by controlling the temperature in the third pipeline 180 to obtain a gas-liquid mixture containing methanol liquid, which enters the air inlet of the gas-liquid separator 140. The gas-liquid separator 140 is used to separate the gas and liquid components. Therefore, the methanol liquid is separated from the gas in the mixture through the gas-liquid separator 140 and output from the liquid outlet of the gas-liquid separator 140 to obtain crude methanol.

[0046] The single-pass conversion rate of the methanol synthesis tower 130 is usually in the range of about 15% to 30%. The specific value depends on the process conditions and catalyst performance. Therefore, the single-pass conversion rate of the raw gas in the methanol synthesis tower 130 is not high. The gas (carbon monoxide and / or carbon dioxide, hydrogen) separated in the gas-liquid separator 140 needs to be further refluxed for re-reaction and recycling to improve the raw material utilization rate and the overall conversion rate.

[0047] The raw gas must be compressed under a certain pressure to react and synthesize methanol within the methanol synthesis column 130. Therefore, it is compressed by compressor 120 to increase its pressure before being fed into the methanol synthesis column 130. The synthesis gas after the synthesis reaction in the methanol synthesis column 130 and after passing through the methanol synthesis column 130 and the gas-liquid separator 140 still maintains a certain pressure. Taking the medium-pressure methanol production process as an example, the pressure decay is approximately 50% or more, depending on the conversion rate. Therefore, in related art, a separate compressor is used to compress the separated gas to a certain pressure before mixing it with the compressed raw gas from the main gas line and feeding it into the methanol synthesis column for the synthesis reaction. This requires the use of two compressors for the methanol synthesis reaction. Furthermore, industrial compressors are very expensive, large in size, weight, and power, resulting in high costs and energy consumption.

[0048] As the key technical content of this embodiment, after the reflux gas is separated in the gas-liquid separator 140, the reflux gas can enter the fourth pipeline 190 from the gas outlet of the gas-liquid separator 140. The fourth pipeline 190 is provided with a pressure reducing device 150. The pressure reducing device 150 can reduce the pressure of the reflux gas. The reflux gas flows through the pressure reducing device 150 to reduce the pressure of the reflux gas, and then flows from the pressure reducing device 150 to the air inlet of the induced draft fan 110 to mix with the raw gas, and then enters the compressor 120 again from the air outlet of the induced draft fan 110. In this way, there is no need to set up another compressor. The reflux gas, that is, the unreacted gas, can be recycled and utilized by one compressor 120, thereby reducing the number of compressors used in the methanol synthesis system 100.

[0049] Moreover, the coordinated operation of the induced draft fan 110 and the compressor 120 enables the raw gas synthesis reaction to generate methanol, and the reflux gas is reused to operate continuously and stably without the need for other additional operations, thereby reducing the operating cost of the methanol synthesis system 100.

[0050] Please refer to Figure 1 and Figure 2 In this embodiment, the pressure reducing device 150 includes a pressure reducing tank 151. The air inlet of the pressure reducing tank 151 is connected to the air outlet of the gas-liquid separator 140, and the air outlet of the pressure reducing tank 151 is connected to the air inlet of the induced draft fan 110. In this embodiment, the pressure reducing tank 151 is provided in the fourth pipeline 190. The pressure reducing tank 151 adjusts the high-pressure gas at the inlet to a stable low-pressure gas at the outlet, so that it can be mixed with the low-pressure feed gas and introduced into the reaction system through the induced draft fan 110. In this embodiment, the pressure reducing device 150 including the pressure reducing tank 151 reduces the pressure of the reflux gas and then circulates it, instead of providing an additional compressor to pressurize the reflux gas for circulation. This can reduce the cost of the entire methanol synthesis system 100 and, to a certain extent, reduce the operating energy consumption of the methanol synthesis system 100, thereby reducing the operating cost of the methanol synthesis system 100.

[0051] In this embodiment, the pressure reducing tank 151 is not specifically limited and can be a mechanical pressure reducing tank, an electronic pressure reducing tank, or a pilot pressure reducing tank. In a specific embodiment, the pressure reducing tank 151 can be an expansion tank. According to the ideal gas state equation PV=nRT, where P is pressure, V is volume, n is the amount of substance, R is the ideal gas constant, and T is temperature, the pressure of the return gas is reduced to an appropriate value by utilizing the principle that the pressure decreases when the volume of the gas expands, and then the return gas is directed to the front end of the induced draft fan 110. This not only meets the process requirements, but also eliminates the need for a separate compressor for the return gas, thereby enabling the entire process to be implemented with a single compressor. For future large-scale industrial applications, this can maximize the economic value of the project by reducing investment.

[0052] Please refer to Figure 1 and Figure 2 In this embodiment, the pressure reducing device 150 also includes a pressure reducing valve 152, the air inlet of the pressure reducing valve 152 is connected to the air outlet of the gas-liquid separator 140, the air inlet of the pressure reducing tank 151 is connected to the air outlet of the pressure reducing valve 152, and the air outlet of the pressure reducing tank 151 is connected to the air inlet of the induced draft fan 110.

[0053] In this embodiment, the pressure reducing tank 151 and the pressure reducing valve 152 both have a pressure reducing function. After the raw gas is compressed by the compressor 120, the pressure is relatively high. Even if the methanol vapor is separated by the gas-liquid separator 140, when the reflux gas flows from the outlet of the gas-liquid separator 140 to the fourth pipeline 190, the pressure of the reflux gas is still relatively high. For example, the pressure of the reflux gas in the fourth pipeline 190 is about 2MPa-3MPa. The reflux gas flows from the outlet of the gas-liquid separator 140 to the air inlet of the pressure reducing valve 152, from the air outlet of the pressure reducing valve 152 to the air inlet of the pressure reducing tank 151, and from the air outlet of the pressure reducing tank 151 to the air inlet of the induced draft fan 110. The reflux gas is mixed with the raw gas at the air inlet of the induced draft fan 110.

[0054] When the reflux gas flows through the pressure reducing valve 152, the pressure of the reflux gas decreases. The pressure reducing valve 152 can adjust the pressure of the reflux gas to a preset appropriate size, and then enter the pressure reducing tank 151. The pressure reducing tank 151 can play a role of buffering and pressure stabilization. The pressure of the reflux gas remains relatively stable in the pressure reducing tank 151, so that the reflux gas can flow stably into the air inlet of the induced draft fan 110, thereby improving the stability and reliability of the operation of the methanol synthesis system 100.

[0055] Please refer to Figure 1 and Figure 2 In this embodiment, the methanol synthesis system 100 further includes an exhaust pipeline 350, which has a first opening 351 and a second opening 352. The first opening 351 is connected to the fourth pipeline 190 and is located between the pressure reducing tank 151 and the pressure reducing valve 152. The second opening 352 is used for exhaust. In some embodiments, the gas flowing out through the second opening 352 can be used in the gasification processing system of biomass materials for combustion.

[0056] Exemplarily, an impurity gas detection device can be provided on the fourth pipeline 190, and the impurity gas detection device can be located between the first opening 351 and the pressure reducing tank 151. The impurity gas detection device is used to detect the concentration of impurity gas (such as nitrogen, etc.) in the reflux gas and feed it back to the system controller. When the concentration of the impurity gas is higher than the set value, the system controller can use the exhaust pipeline 350 to discharge the impurity gas from the exhaust pipeline 350.

[0057] The first opening 351 is connected to the fourth pipeline 190 and is located between the pressure reducing tank 151 and the pressure reducing valve 152. In this way, the reflux gas containing impurity gas after separation by the gas-liquid separator 140 can be discharged through the exhaust pipeline 350, thereby improving the purity of the reflux gas entering the air inlet of the induced draft fan 110 and improving the conversion rate of the methanol synthesis system 100.

[0058] Please refer to Figure 1 and Figure 2 In this embodiment, the methanol synthesis system 100 includes a first pneumatic valve 260 and a flow meter 360 . The first pneumatic valve 260 and the flow meter 360 are both arranged in the exhaust pipe 350 . The first pneumatic valve 260 can selectively control the exhaust pipe 350 to be on or off.

[0059] For example, when the presence and content of impurity gas in the reflux gas are detected, the first pneumatic valve 260 can be opened to allow the reflux gas containing the impurity gas to be discharged through the exhaust pipe 350. The flow meter 360 can monitor the flow rate data of the exhaust gas in the exhaust pipe 350 in real time, providing intuitive and accurate parameters to the staff, thereby precisely controlling the flow rate of the exhaust gas and reducing unnecessary waste.

[0060] Please refer to Figure 1 and Figure 2 In this embodiment, the methanol synthesis system 100 also includes a second pneumatic valve 320 and a third pneumatic valve 330. The second pneumatic valve 320 and the third pneumatic valve 330 are both arranged in the fourth pipeline 190. The second pneumatic valve 320 is located between the first opening 351 and the pressure reducing valve 152, and the third pneumatic valve 330 is located between the first opening 351 and the pressure reducing tank 151.

[0061] For example, the second pneumatic valve 320 can selectively control the opening and closing of the fourth pipeline 190, and the third pneumatic valve 330 can selectively control the opening and closing of the fourth pipeline 190. When the exhaust pipeline 350 fails and needs maintenance, the second pneumatic valve 320 and the third pneumatic valve 330 can be closed to separate the exhaust pipeline 350 from the entire methanol synthesis system 100, without shutting down the entire methanol synthesis system 100, thereby improving maintenance efficiency.

[0062] Please refer to Figure 1 and Figure 2 In this embodiment, the methanol synthesis system 100 includes a pre-gas tank 200 and a high-pressure tank 210 . The pre-gas tank 200 is disposed in the first pipeline 160 , and the high-pressure tank 210 is disposed in the second pipeline 170 .

[0063] The front gas tank 200 is arranged in the first pipeline 160. The front gas tank 200 is located between the induced draft fan 110 and the compressor 120. The front gas tank 200 can buffer the gas delivered by the induced draft fan 110. During the process of the induced draft fan 110 delivering gas, the pressure of the gas may fluctuate. The front gas tank 200 can make the pressure of the gas entering the compressor 120 more uniform, so that the compressor 120 can work more stably, reduce damage to the compressor 120 caused by gas pressure fluctuations, and extend the service life of the compressor 120.

[0064] The high-pressure tank 210 is arranged in the second pipeline 170. The high-pressure tank 210 is arranged between the compressor 120 and the methanol synthesis tower 130. After the raw gas is compressed by the compressor 120, the raw gas can flow from the outlet of the compressor 120 to the high-pressure tank 210. The high-pressure tank 210 can store the high-pressure raw gas, so that the raw gas can be buffered before entering the methanol synthesis tower 130, ensuring that the raw gas entering the methanol synthesis tower 130 is evenly distributed. Moreover, the high-pressure tank 210 can also prevent the raw gas from flowing back to a certain extent, thereby improving the stability and reliability of the operation of the compressor 120.

[0065] Methanol synthesis requires a certain temperature, please refer to Figures 1 to 3 In this embodiment, the methanol synthesis system 100 includes a first heat exchanger 220, the second pipeline 170 has a first heat exchange channel 221, and the third pipeline 180 has a second heat exchange channel 222. The first heat exchange channel 221 and the second heat exchange channel 222 are both arranged in the first heat exchanger 220 to enable heat exchange between the medium in the first heat exchange channel 221 and the medium in the second heat exchange channel 222.

[0066] Both the first heat exchange channel 221 and the second heat exchange channel 222 are located within the first heat exchanger 220. The raw gas flows from the high-pressure tank 210 to the first heat exchange channel 221, and the synthesis gas flows from the outlet of the methanol synthesis tower 130 to the second heat exchange channel 222. The raw gas in the first heat exchange channel 221 can exchange heat with the synthesis gas in the second heat exchange channel 222. The raw gas in the first heat exchange channel 221 absorbs heat from the synthesis gas in the second heat exchange channel 222, increasing its temperature. The synthesis gas in the second heat exchange channel 222 releases heat, decreasing its temperature. This allows the heat from the high-temperature reaction-generated synthesis gas to be transferred to the low-temperature raw gas, preheating the low-temperature raw gas. This also reduces the temperature of the reaction-generated synthesis gas, facilitating the liquefaction of methanol vapor, achieving heat recovery, and reducing the energy consumption of the methanol synthesis system 100. Furthermore, since both the first heat exchange channel 221 and the second heat exchange channel 222 are located within the first heat exchanger 220, there is no need for separate heating and cooling components, reducing the manufacturing cost of the methanol synthesis system 100.

[0067] Please refer to Figures 1 to 3 In this embodiment, a heat-conducting wall 223 is provided between the first heat exchange channel 221 and the second heat exchange channel 222 , and the heat-conducting wall 223 is constructed as a metal material.

[0068] For example, the metal material can be copper, which allows the medium in the first heat exchange channel 221 to quickly complete heat exchange with the medium in the second heat exchange channel 222. The metal heat-conducting wall 223 can serve as a direct contact surface between the medium in the first heat exchange channel 221 and the medium in the second heat exchange channel 222, allowing the heat in the high-temperature synthesis gas to be quickly transferred to the low-temperature feed gas, thereby improving heat exchange efficiency.

[0069] Please refer to Figure 1 and Figure 2 In this embodiment, the methanol synthesis system 100 includes a first branch pipeline 230 and a first heater 240. One end of the first branch pipeline 230 is connected to the first heat exchange channel 221, and the other end of the first branch pipeline 230 is connected to the air inlet of the methanol synthesis tower 130. The first heater 240 is arranged on the first branch pipeline 230; the methanol synthesis system 100 also includes a fourth pneumatic valve 250. The fourth pneumatic valve 250 is arranged on the first branch pipeline 230, and the fourth pneumatic valve 250 can selectively control the opening and closing of the first branch pipeline 230.

[0070] One end of the first branch pipe 230 is connected to the first heat exchange channel 221, and the other end of the first branch pipe 230 is connected to the air inlet of the methanol synthesis tower 130. The raw gas can flow from the first heat exchange channel 221 to the first branch pipe 230, and then from the first branch pipe 230 to the air inlet of the methanol synthesis tower 130. The first heater 240 and the fourth pneumatic valve 250 are both disposed on the first branch pipe 230. For example, when the raw gas absorbs less heat in the first heat exchange channel 221, the fourth pneumatic valve 250 opens, allowing the raw gas to enter the first branch pipe 230. The first heater 240 heats the raw gas, allowing it to enter the methanol synthesis tower 130 at an appropriate temperature. When the raw gas absorbs enough heat in the first heat exchange channel 221 to enter the methanol synthesis tower 130, the fourth pneumatic valve 250 closes, and the raw gas does not enter the methanol synthesis tower 130 through the first branch pipe 230.

[0071] The first heater 240 is disposed in the first branch pipeline 230 , which can provide double protection for the heating of the raw gas, ensuring that the raw gas can be fully heated to a preset temperature, thereby improving the synthesis efficiency of the methanol synthesis system 100 .

[0072] Please refer to Figure 1 and Figure 2In this embodiment, the methanol synthesis system 100 further includes a second heat exchanger 340 . The second heat exchanger 340 is disposed in the third pipeline 180 and is located between the second heat exchange channel 222 and the air inlet of the gas-liquid separator 140 .

[0073] The synthesis gas flows from the gas outlet of the methanol synthesis tower 130 to the second heat exchange channel 222, then from the second heat exchange channel 222 to the second heat exchanger 340, and from the second heat exchanger 340 to the gas-liquid separator 140. The second heat exchanger 340 is disposed in the third pipeline 180 and is located between the second heat exchange channel 222 and the gas inlet of the gas-liquid separator 140. This further cools and dissipates the heat of the synthesis gas, allowing the methanol vapor in the synthesis gas to condense and liquefy, allowing for subsequent sufficient separation in the gas-liquid separator 140, thereby improving the methanol extraction rate of the methanol synthesis system 100.

[0074] Please refer to Figure 1 and Figure 2 In this embodiment, the methanol synthesis system 100 further includes a fifth pneumatic valve 270, a sixth pneumatic valve 280, a seventh pneumatic valve 290, an eighth pneumatic valve 300, and a ninth pneumatic valve 310. The fifth pneumatic valve 270 is arranged in the first pipeline 160 and is located between the pre-gas tank 200 and the compressor 120. The sixth pneumatic valve 280 and the seventh pneumatic valve 290 are both arranged in the second pipeline 170. The sixth pneumatic valve 280 is located between the first heat exchange channel 221 and the gas outlet of the high-pressure tank 210. The seventh pneumatic valve 290 is located between the first heat exchange channel 221 and the gas inlet of the methanol synthesis tower 130. The eighth pneumatic valve 300 and the ninth pneumatic valve 310 are both arranged in the third pipeline 180. The eighth pneumatic valve 300 is located between the second heat exchange channel 222 and the gas outlet of the methanol synthesis tower 130. The ninth pneumatic valve 310 is located between the second heat exchange channel 222 and the gas inlet of the gas-liquid separator 140.

[0075] The fifth pneumatic valve 270 is arranged in the first pipeline 160. The fifth pneumatic valve 270 can selectively control the on-off of the first pipeline 160. The fifth pneumatic valve 270 is located between the front gas tank 200 and the compressor 120. The sixth pneumatic valve 280 can selectively control the on-off of the second pipeline 170. The sixth pneumatic valve 280 is located between the high-pressure tank 210 and the first heat exchange channel 221. For example, when the compressor 120 and the high-pressure tank 210 are partially damaged and need to be repaired, the fifth pneumatic valve 270 and the sixth pneumatic valve 280 can be controlled to close, and then the compressor 120 and the high-pressure tank 210 can be repaired without shutting down the entire methanol synthesis system 100, thereby improving maintenance efficiency.

[0076] The seventh pneumatic valve 290 selectively opens and closes the second pipeline 170. When the temperature of the raw gas reaches a preset value after heat exchange in the first heat exchange channel 221, the seventh pneumatic valve 290 is opened, allowing the raw gas to flow from the seventh pneumatic valve 290 to the air inlet of the methanol synthesis column 130. This eliminates the need for the first heater 240 and reduces the operating cost of the methanol synthesis system 100. The eighth pneumatic valve 300 selectively opens and closes the third pipeline 180. The eighth pneumatic valve 300 is located between the second heat exchange channel 222 and the methanol synthesis column 130. For example, when the methanol synthesis column 130 malfunctions and requires maintenance, the seventh and eighth pneumatic valves 290 and 300 can be controlled to close, isolating the methanol synthesis column 130 from the methanol synthesis system 100 without shutting down the entire methanol synthesis system 100, thereby improving maintenance efficiency. The ninth pneumatic valve 310 is located between the second heat exchange channel 222 and the air inlet of the gas-liquid separator 140. When the second heat exchanger 340 fails and needs maintenance, the eighth pneumatic valve 300 and the ninth pneumatic valve 310 are controlled to close, and the second heat exchanger 340 is isolated from the methanol synthesis system 100 without shutting down the entire methanol synthesis system 100, thereby improving maintenance efficiency.

[0077] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0078] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0079] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

[0080] Although the embodiments of the present application have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A methanol synthesis system, characterized in that: include: induced draft fan; A compressor, wherein the air inlet of the compressor is connected to the air outlet of the induced draft fan through a first pipeline; a methanol synthesis tower, wherein the air inlet of the methanol synthesis tower is connected to the air outlet of the compressor through a second pipeline; a gas-liquid separator, wherein the gas inlet of the gas-liquid separator is connected to the gas outlet of the methanol synthesis tower through a third pipeline; The exhaust port of the gas-liquid separator is connected to the air inlet of the induced draft fan through a fourth pipeline. The methanol synthesis system further includes a pressure reducing device, which is arranged on the fourth pipeline.

2. The methanol synthesis system according to claim 1, characterized in that: The decompression device includes a decompression tank, the air inlet of the decompression tank is communicated with the air outlet of the gas-liquid separator, and the air outlet of the decompression tank is communicated with the air inlet of the induced draft fan.

3. The methanol synthesis system according to claim 2, characterized in that: The pressure reducing device further comprises a pressure reducing valve, the air inlet of the pressure reducing valve is communicated with the air outlet of the gas-liquid separator, and the air outlet of the pressure reducing valve is communicated with the air inlet of the pressure reducing tank.

4. The methanol synthesis system according to claim 3, characterized in that: The methanol synthesis system also includes an exhaust pipeline, a first pneumatic valve and a flow meter. The exhaust pipeline has a first opening and a second opening. The first opening is connected to the fourth pipeline and is located between the pressure reducing tank and the pressure reducing valve. The second opening is used for exhaust. The first pneumatic valve and the flow meter are both arranged in the exhaust pipeline. The first pneumatic valve can selectively control the opening and closing of the exhaust pipeline.

5. The methanol synthesis system according to claim 4, characterized in that: The methanol synthesis system also includes a second pneumatic valve and a third pneumatic valve. The second pneumatic valve and the third pneumatic valve are both arranged in the fourth pipeline. The second pneumatic valve is located between the first opening and the pressure reducing valve, and the third pneumatic valve is located between the first opening and the pressure reducing tank.

6. The methanol synthesis system according to claim 1, characterized in that: The methanol synthesis system includes a front gas tank and a high-pressure tank. The front gas tank is arranged on the first pipeline, and the high-pressure tank is arranged on the second pipeline.

7. The methanol synthesis system according to claim 6, characterized in that: The methanol synthesis system includes a first heat exchanger, the second pipeline has a first heat exchange channel, and the third pipeline has a second heat exchange channel. The first heat exchange channel and the second heat exchange channel are both arranged in the first heat exchanger to enable heat exchange between the medium in the first heat exchange channel and the medium in the second heat exchange channel.

8. The methanol synthesis system according to claim 7, characterized in that: The methanol synthesis system includes a first branch pipeline and a first heater, one end of the first branch pipeline is connected to the first heat exchange channel, the other end of the first branch pipeline is connected to the air inlet of the methanol synthesis tower, and the first heater is arranged in the first branch pipeline; The methanol synthesis system further includes a fourth pneumatic valve, which is disposed on the first branch pipeline and can selectively control the opening and closing of the first branch pipeline.

9. The methanol synthesis system according to claim 7, characterized in that: The methanol synthesis system further includes a second heat exchanger, which is disposed in the third pipeline and located between the second heat exchange channel and the air inlet of the gas-liquid separator.

10. The methanol synthesis system according to claim 7, characterized in that: The methanol synthesis system also includes a fifth pneumatic valve, a sixth pneumatic valve, a seventh pneumatic valve, an eighth pneumatic valve and a ninth pneumatic valve. The fifth pneumatic valve is arranged in the first pipeline and is located between the front gas tank and the compressor. The sixth pneumatic valve and the seventh pneumatic valve are both arranged in the second pipeline. The sixth pneumatic valve is located between the first heat exchange channel and the air outlet of the high-pressure tank. The seventh pneumatic valve is located between the first heat exchange channel and the air inlet of the methanol synthesis tower. The eighth pneumatic valve and the ninth pneumatic valve are both arranged in the third pipeline. The eighth pneumatic valve is located between the second heat exchange channel and the air outlet of the methanol synthesis tower. The ninth pneumatic valve is located between the second heat exchange channel and the air inlet of the gas-liquid separator.

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