Process and system for the production of syngas from a methane-containing feed gas

Abstract

The present application relates to the technical field of methane conversion process, in particular to a method and system for preparing synthesis gas from a methane-containing raw gas, the method comprising: (1) sequentially compressing and purifying the methane-containing raw gas to obtain purified raw gas and water mixture, and obtaining the mixed raw material; (2) sequentially performing first heat exchange, first preheating, second preheating and reforming reaction on the mixed raw material in a heat exchange reforming reactor to obtain high-temperature reforming gas; performing second heat exchange on the high-temperature reforming gas and the vaporized raw material after the first heat exchange, and then performing the first heat exchange again to obtain low-temperature reforming gas; (3) sequentially cooling and gas-liquid separating the low-temperature reforming gas to obtain reforming dry gas as synthesis gas; wherein the heat required for the first preheating, the second preheating and the reforming reaction is provided by combustion of the methane-containing raw gas. The method has high methane conversion rate and total carbon atom utilization rate, and also has the characteristics of simple process, easy to be prised and installed, high energy efficiency and the like.

Description

Technical Field

[0001] This invention relates to the field of methane conversion process technology, specifically to a method and a system for preparing syngas from methane feedstock gas. Background Technology

[0002] Syngas is an important raw material for the production of bulk chemicals such as methanol and jet fuel, as well as a series of basic organic chemicals. Traditionally, syngas is obtained mainly through gasification or reforming of fossil fuels such as coal or natural gas. However, driven by global climate change, the market demand for clean and low-carbon energy sources such as green methanol and green jet fuel is rapidly increasing, and the production of green syngas is a primary research direction for achieving green and low-carbon chemical production.

[0003] Currently, there are several main routes for producing green syngas: First, the inversion reaction of renewable CO2 with green hydrogen to obtain syngas; second, the biomass gasification route, which is similar to coal gasification, using agricultural and forestry solid waste as gasification feedstock, and obtaining crude syngas through gasification and pyrolysis in an oxygen and steam atmosphere, which is then purified to obtain syngas; third, the biomethane route, which is similar to the natural gas to syngas production route, using livestock and poultry manure and municipal waste as raw materials, which are anaerobic fermented to obtain biogas (of which methane accounts for about 50%, and the remainder is mainly CO2), and the biogas is purified and CO2 removed to obtain biomethane with a composition similar to natural gas, and the biomethane is then reformed to produce syngas.

[0004] Biogas is a clean, low-carbon, and renewable energy source. Taking the synthesis of green methanol as an example, using biogas as a raw material to produce methanol via green syngas is one of the important ways to produce green methanol. Moreover, it has a significant cost advantage compared to electronic methanol via water electrolysis and biomethanol via biomass gasification.

[0005] Both the purification of biogas to obtain biomethane and the reforming of biomethane to produce syngas have mature commercial technologies. However, from an atom economy perspective, CO2 in biogas can also participate in the reforming reaction to generate syngas, making it more economical to use biogas directly as a reforming feedstock without pre-removing CO2, and also saving the cost of the first step of biomethane production.

[0006] my country's biogas plants are relatively scattered, not located in chemical industrial parks, and are relatively small in scale. Therefore, it is difficult to directly replicate chemical plants for converting biogas into syngas. Existing natural gas (or methane) conversion processes have problems such as long processes, many pieces of equipment, large land area, and dependence on well-developed public utilities.

[0007] To address the needs of small and medium-sized methane-containing feedstock gas conversion, this invention provides a method and system for preparing syngas from methane-containing feedstock gas. Summary of the Invention

[0008] The purpose of this invention is to overcome the above-mentioned technical problems and provide a method and system for preparing syngas from methane feedstock gas. This method has a high methane conversion rate and total carbon atom utilization rate. At the same time, this method also has the characteristics of simple process, easy skid-mounting, and high energy efficiency.

[0009] To achieve the above objectives, a first aspect of the present invention provides a method for preparing syngas from methane feedstock gas, the method comprising:

[0010] (1) The methane-containing raw gas is compressed and purified sequentially to obtain purified raw gas and water, which are then mixed to obtain a mixed raw material.

[0011] (2) The mixed raw materials are subjected to a first heat exchange, a first preheat, a second preheat, and a reforming reaction in a heat exchange reforming reactor in sequence to obtain high-temperature reformed gas. After the gasified raw materials after the first heat exchange are subjected to a second heat exchange, the first heat exchange is performed again to obtain low-temperature reformed gas.

[0012] (3) The low-temperature reformed gas is cooled and separated into gas and liquid in sequence to obtain reformed dry gas as syngas;

[0013] The heat required for the first preheating, the second preheating, and the reforming reaction is provided by the combustion of the methane-containing feed gas.

[0014] Preferably, the heat exchange reforming reactor is a combustion furnace with at least one reaction tube connected in parallel, and the furnace temperature of the combustion furnace is provided by the combustion of the methane-containing feed gas.

[0015] Preferably, the top of the reaction tube is provided with a feed pipe and a discharge pipe. The shell of the reaction tube is divided into a heat recovery zone, a heat exchange reaction zone and a preheating zone from top to bottom, and the height of the heat recovery zone is within the insulation material of the combustion furnace. The heat recovery zone is provided with a heat exchange component. The heat exchange reaction zone is provided with a catalyst bed arranged in a ring around the central tube, and the heat exchange reaction zone is divided into a heat exchange section and a reaction section. The two ends of the heat exchange component are respectively connected to the feed pipe and the central tube.

[0016] A second aspect of the present invention provides a system for preparing syngas from methane feedstock gas, the system comprising a compression unit, a purification unit, a reforming unit, a cooling unit and a separation unit connected in sequence;

[0017] The reforming unit is selected from a heat exchange reforming reactor, which is a combustion furnace with at least one parallel reaction tube inside, and the furnace temperature of the combustion furnace is provided by the combustion of the methane-containing feed gas; the top of the reaction tube is provided with a feed pipe and a discharge pipe, and the shell of the reaction tube is divided into a heat recovery zone, a heat exchange reaction zone and a preheating zone from top to bottom, and the height of the heat recovery zone is within the insulation material of the combustion furnace; the heat recovery zone is provided with a heat exchange component; the heat exchange reaction zone is provided with a catalyst bed arranged in a ring around the central tube, and the heat exchange reaction zone is divided into a heat exchange section and a reaction section; the two ends of the heat exchange component are respectively connected to the feed pipe and the central tube.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] (1) The method provided by this invention uses methane-containing feed gas as both a feedstock and a heat source for the reforming reaction, eliminating the need for additional energy and reducing the types of feedstocks. Simultaneously, a heat exchange reformer integrates the heat from the first heat exchange, first preheating, second preheating, reforming reaction, and high-temperature reformed gas, enhancing mass and heat transfer, improving reaction efficiency, and eliminating the need for a complex steam generation system. Furthermore, the miniaturization of the reformer saves significant equipment space, reduces the number of units, and facilitates skid-mounting. Therefore, the method provided by this invention has a high methane conversion rate and energy utilization rate.

[0020] (2) The method provided by the present invention compresses and purifies methane gas in sequence and then uses it directly as a raw material for reforming reaction. That is, CO2 also participates in the reaction to generate syngas components, which significantly improves the carbon atom utilization rate of the raw material and reduces the unit consumption of product gas.

[0021] (3) The method provided by the present invention, in particular, decarbonizes the reformed dry gas and partially removes CO2. The CO2 removal rate can be flexibly adjusted according to the fluctuation of raw materials, load fluctuation and the change of downstream syngas ratio requirements, thereby improving the adaptability and robustness of the system. Attached Figure Description

[0022] Figure 1 This invention provides a schematic diagram of a system for preparing syngas from methane feedstock gas.

[0023] Figure 2 This is a schematic diagram of the structure of a heat exchange reforming reactor provided by the present invention.

[0024] Explanation of reference numerals in the attached figures

[0025] a. Methane-containing feed gas; b. Water; c. CO2 supplement; d. Compressed feed gas; e. Purified feed gas; f. Low-temperature reformed gas; g. Cooled reformed gas; h. Reformed dry gas; i. Recovered acid water; j. Deacidified water; k. Acidic gas; l. Exhaust gas; m. Syngas.

[0026] 1. Compression unit; 2. Purification unit; 3. Reforming unit; 4. Cooling unit; 5. Separation unit; 6. Deacidification unit; 7. Decarbonization unit.

[0027] 3-1. Heat recovery zone; 3-2. Heat exchange reaction zone; 3-3. Preheating zone;

[0028] 01. Feed pipe; 02. Discharge pipe; 03. Heat exchange component; 04. Connecting pipe; 05. Central pipe; 06. Feed distributor; 07. Support component; 08. Catalyst bed; 09. Connecting component; 010. Flange cover; 011. Top welded flange; 012. Shell; 013. Bottom welded head; 014. Thermocouple sheath. Detailed Implementation

[0029] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0030] In this invention, unless otherwise specified, "first" and "second" do not indicate a sequence or limit the various materials or steps, but are used only to distinguish or indicate that they are not the same material or step. For example, "first heat exchange" and "second heat exchange" are used only to indicate that they are not the same heat exchange.

[0031] In this invention, unless otherwise specified, the “top” of the container refers to 0-10% of the container’s height from top to bottom; the “upper part” of the container refers to 10-40% of the container’s height from top to bottom; the “middle part” of the container refers to 40-70% of the container’s height from top to bottom; the “lower part” of the container refers to 70-90% of the container’s height from top to bottom; and the “bottom” of the container refers to 90-100% of the container’s height from top to bottom.

[0032] The first aspect of this invention provides a method for preparing syngas from methane feedstock gas, the method comprising:

[0033] (1) The methane-containing raw gas is compressed and purified sequentially to obtain purified raw gas and water, which are then mixed to obtain a mixed raw material.

[0034] (2) The mixed raw materials are subjected to a first heat exchange, a first preheat, a second preheat, and a reforming reaction in a heat exchange reforming reactor in sequence to obtain high-temperature reformed gas. After the gasified raw materials after the first heat exchange are subjected to a second heat exchange, the first heat exchange is performed again to obtain low-temperature reformed gas.

[0035] (3) The low-temperature reformed gas is cooled and separated into gas and liquid in sequence to obtain reformed dry gas as syngas;

[0036] The heat required for the first preheating, the second preheating, and the reforming reaction is provided by the combustion of the methane-containing feed gas.

[0037] The method provided by this invention only includes methane feedstock gas, electricity, tap water and air, all of which are raw materials with complete urban pipeline infrastructure, greatly reducing the difficulty of application.

[0038] The method for preparing syngas from methane-containing feedstock gas provided by this invention not only has the characteristics of high methane conversion rate, high energy utilization efficiency and high total carbon atom utilization rate, but also has the characteristics of simple process, easy skid-mounting and high energy efficiency, and has a wide range of application prospects.

[0039] In this invention, preferably, in step (1), the CH4 content in the methane-containing feed gas is 40-95 mol%, for example, 40 mol%, 45 mol%, 50 mol%, 55 mol%, 60 mol%, 65 mol%, 70 mol%, 80 mol%, 90 mol%, 93 mol%, 95 mol%, and any value within any range of any two values, preferably 50-70 mol%.

[0040] In this invention, preferably, in step (1), the CO2 content in the methane-containing raw gas is 10-60 mol%, for example, 10 mol%, 20 mol%, 30 mol%, 35 mol%, 40 mol%, 45 mol%, 50 mol%, 60 mol%, and any value within any range of any two values, preferably 30-50 mol%.

[0041] In this invention, the content parameters of each component in the methane-containing feed gas were measured using the methods of GB / T 13610-2020, GB / T11060.5-2010 and DB43 / T 2306-2022.

[0042] In this invention, more preferably, in step (1), the molar ratio of CH4 to CO2 in the methane-containing feed gas is 1:0.1-2, for example, 1:0.1, 1:0.2, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, and any value within the range of any two values, preferably 1:0.4-1.5. This setting is beneficial for increasing the proportion of effective gas in the syngas product, thereby improving the total carbon atom utilization rate of the feed gas.

[0043] In this invention, preferably, when the CO2 content in the methane-containing feed gas is <10 mol%, supplementary CO2 is added to meet the requirement of a CO2 content of 10-60 mol%.

[0044] In this invention, a wide range of types of methane-containing feed gas can be selected, as long as the above-mentioned limitations are met. Preferably, the methane-containing feed gas is selected from at least one of natural gas, biogas, and coke oven gas.

[0045] In some embodiments of the present invention, preferably, the temperature of the methane-containing feed gas is 0-40°C, for example, 0°C, 10°C, 20°C, 30°C, 40°C, or any value within the range of any two values; the pressure is 0-0.5 MPa, for example, 0 MPa, 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, or any value within the range of any two values.

[0046] In this invention, all pressure parameters are gauge pressures.

[0047] In this invention, preferably, the pressure of the compressed raw material gas obtained by compression is 0.5-3 MPa, for example, 0.5 MPa, 0.8 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 2.8 MPa, 3 MPa, and any value within the range of any two values.

[0048] In this invention, the purification aims to remove sulfur, chlorine, and oxygen impurities from the compressed feed gas. Preferably, the purified feed gas has a sulfur content ≤ 3.5 × 10⁻⁶. -5 mol%, chlorine content ≤0.1mg / Nm 3 Oxygen content ≤ 5 mg / Nm 3 .

[0049] In this invention, the sulfur content is the sum of the contents of organic sulfur and inorganic sulfur.

[0050] In this invention, preferably, the purification method is selected from hydrodesulfurization and adsorption desulfurization, wherein the hydrodesulfurization aims to convert organic sulfur into inorganic sulfur and reduce the organic sulfur content; the adsorption desulfurization aims to remove inorganic sulfur to obtain a sulfur content that meets the above-mentioned range.

[0051] In some embodiments of the present invention, preferably, compressed raw gas is contacted with a hydrodesulfurization catalyst and hydrodesulfurized to obtain a hydrodesulfurization product; the hydrodesulfurization product is contacted with an adsorption desulfurization catalyst and reacted to obtain an adsorption desulfurization product as the purified raw gas.

[0052] In this invention, preferably, the active component of the hydrodesulfurization catalyst is Co and / or Mo, the support is alumina, and the mass ratio of the active component to the support is 0.1-0.3:1, for example, 0.1:1, 0.2:1, 0.3:1, or any value within the range of any two values.

[0053] In this invention, preferably, the conditions for hydrodesulfurization include: a temperature of 250-350°C, a pressure of 0.5-2.5 MPa, and a gas space velocity of 2000-6000 h⁻¹. -1 Preferably, the organic sulfur content in the hydrodesulfurization product is ≤3×10⁻⁶. - 6 mol%.

[0054] In this invention, preferably, the adsorption desulfurization catalyst includes, but is not limited to, ZnO, Fe2O3, etc.

[0055] In this invention, preferably, the conditions for adsorption desulfurization include: a temperature of 250-350℃, a pressure of 0.5-2.5 MPa, and a gas space velocity of 2000-6000 h⁻¹. -1 Preferably, the sulfur content in the adsorption desulfurization product is ≤3.5×10⁻⁶. -5 mol%.

[0056] In this invention, in step (1), the water includes, but is not limited to, desalinated water, deionized water, etc.

[0057] In this invention, the amount of water used is not limited, as long as the mixed raw materials satisfy the following: the molar ratio of H2O to CH4 is 1.5-3.5, for example, 1.5, 1.8, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.8, 3, 3.2, 3.5, and any value within the range of any two values, preferably 2-3, more preferably 2.1-2.5.

[0058] In this invention, compared with the existing L-shaped furnace or cylindrical furnace with built-in straight-through reaction tubes, the present invention adopts a heat exchange reforming reactor, especially a combustion furnace with at least one parallel reaction tube. On the one hand, the unique reaction tube structure design integrates the reforming reaction and heat exchange inside the reaction tube, enhances mass and heat transfer, improves reaction efficiency, and eliminates the need for a complex steam generation system. On the other hand, the miniaturization of the reforming furnace saves a lot of equipment space.

[0059] In this invention, preferably, the heat exchange reforming reactor is a combustion furnace with at least one reaction tube connected in parallel, and the furnace temperature of the combustion furnace is provided by the combustion of the methane-containing feed gas.

[0060] In this invention, unless otherwise specified, the heat exchange reforming reactor includes a combustion furnace and at least one reaction tube arranged in parallel, with the reaction tube disposed inside the combustion furnace.

[0061] In this invention, more preferably, the furnace temperature of the combustion furnace is 800-1200℃, for example, 800℃, 900℃, 1000℃, 1050℃, 1100℃, 1150℃, 1200℃, and any value within the range of any two values.

[0062] In this invention, the combustion furnace includes a furnace body, a burner, a blower, temperature measuring conditions, and control elements, etc. This invention will not elaborate on these, as long as the combustion of the methane-containing raw gas is carried out in the combustion furnace and the furnace temperature is maintained at 800-1200℃.

[0063] In this invention, such as Figure 2 As shown, the top of the reaction tube is provided with a feed pipe 01 and a discharge pipe 02. The shell 012 of the reaction tube is divided into a heat recovery zone 3-1, a heat exchange reaction zone 3-2 and a preheating zone 3-3 from top to bottom. The height of the heat recovery zone 3-1 is within the insulation material of the combustion furnace. The heat recovery zone 3-1 is provided with a heat exchange component 03. The heat exchange reaction zone 3-2 is provided with a catalyst bed 08 arranged in a ring around the central tube 05, which divides the heat exchange reaction zone 3-2 into a heat exchange section and a reaction section. The two ends of the heat exchange component 03 are respectively connected to the feed pipe 01 and the central tube 05.

[0064] In this invention, the mixed raw material undergoes the first heat exchange in the heat recovery zone 3-1 via the feed pipe 01, and the vaporized raw material undergoes the first preheating and the second preheating in the heat exchange reaction zone 3-2 and the preheating zone 3-3 respectively. The preheated raw material passes through the reaction section from bottom to top, contacts the loaded reforming catalyst and undergoes the reforming reaction, and the high-temperature reformed gas undergoes the second heat exchange with the vaporized raw material, and then undergoes the first heat exchange, and the low-temperature reformed gas is discharged through the discharge pipe 02.

[0065] In this invention, the heat recovery zone 3-1 is used to perform a first heat exchange on the mixed raw material passing through the feed pipe 01 in the heat exchange component 03 to obtain vaporized raw material; the heat exchange section of the heat exchange reaction zone 3-2 and the preheating zone 3-3 are used to perform the first preheating and the second preheating on the vaporized raw material respectively to obtain preheated raw material; the reaction section is used to bring the preheated raw material from bottom to top into contact with the reforming catalyst packed in the catalyst bed 08 and perform a reforming reaction to obtain reformed gas. After performing a second heat exchange with the vaporized raw material in the central pipe 05, the reformed gas is sent to the heat recovery zone 3-1 to perform the first heat exchange with the mixed raw material in the heat exchange component 03 to obtain low-temperature reformed gas f, which is discharged through the discharge pipe 02.

[0066] In this invention, the entire outer shell of the reaction tube is made of high-temperature resistant metal thermally conductive material. That is, the outer shell of the heat recovery zone, the outer shell of the heat exchange reaction zone, and the outer shell of the preheating zone are all made of high-temperature resistant metal thermally conductive material, including but not limited to high-nickel alloy material. After the reaction tube is inserted into the combustion furnace, the height of the heat recovery zone is within the insulation material of the combustion furnace, while the heat exchange reaction zone and the preheating zone are located inside the furnace chamber.

[0067] In this invention, unless otherwise specified, the preheated raw material passes through the reaction section from bottom to top, contacts the packed reforming catalyst and undergoes a reforming reaction to obtain high-temperature reformed gas. The gas then undergoes a second heat exchange with the vaporized raw material from bottom to top, and then a first heat exchange with the mixed raw material to obtain low-temperature reformed gas that is discharged.

[0068] In this invention, preferably, the height-to-diameter ratio of the reaction tube is 15-30, for example, 15, 18, 20, 22, 25, 28, 30, or any value within the range of any two values, wherein the height-to-diameter ratio is the ratio of the height to the inner diameter of the reaction tube.

[0069] In this invention, the inner diameter of the reaction tube is 80-150 mm, for example, 80 mm, 100 mm, 120 mm, 150 mm, or any value within the range of any two values.

[0070] In this invention, preferably, as follows: Figure 2As shown, the height ratio of the heat recovery zone 3-1, the heat exchange reaction zone 3-2, and the preheating zone 3-3 is 13-25:68-75:4-17.

[0071] In this invention, such as Figure 2 As shown, the connection of the two ends of the heat exchange component 03 to the feed pipe 01 and the center pipe 05 respectively means that, according to the material flow direction, the inlet end of the heat exchange component 03 is connected to the feed pipe 01, and the outlet end is connected to the center pipe 05.

[0072] In this invention, the heat exchange component 03 is selected from wound tube heat exchange tube, spiral tube heat exchange tube, coil heat exchange tube, finned heat exchange tube, and microchannel heat exchange tube; more preferably, the heat exchange component 03 is a coil heat exchange tube with a coil number of not less than 15 turns, so that the mixed raw material passes through the heat exchange component 03 for the first heat exchange to obtain vaporized raw material.

[0073] In this invention, such as Figure 2 As shown, preferably, the heat recovery zone 3-1 is further provided with a receiving pipe 04, the two ends of which are connected to the heat exchange component 03 and the central pipe 05, respectively. That is, the inlet end of the receiving pipe 04 is connected to the heat exchange component 03, and the outlet end is connected to the central pipe 05.

[0074] In this invention, such as Figure 2 As shown, preferably, the receiving pipe 04 is positioned after or before the heat exchange component 03, according to the material flow direction, and more preferably after. This arrangement is more conducive to gas phase preheating and liquid phase vaporization in the mixed raw materials.

[0075] In this invention, such as Figure 2 As shown, preferably, the receiving pipe 04 and the heat exchange component 03 are connected by a connector 09.

[0076] In this invention, such as Figure 2 As shown, preferably, the inner diameter of the heat exchange component 03 is less than or equal to the inner diameter of the receiving pipe 04 and the inner diameter of the central pipe 05;

[0077] In this invention, such as Figure 2 As shown, more preferably, the inner diameter ratio of the heat exchange component 03, the receiving pipe 04, and the central pipe 05 is 1:1.2-3:3-7.5. This arrangement helps to control the gas velocity of the vaporized raw material and avoids excessively high gas velocity from affecting the heat exchange effect.

[0078] In this invention, such as Figure 2As shown, preferably, the heat exchange section is the area formed by the inner diameter of the central tube 05; the reaction section is the annular area formed by the outer diameter of the central tube 05 and the inner wall of the heat exchange reaction zone 3-2. This configuration ensures that the reforming reaction occurs within the annular gap between the shell of the heat exchange reaction zone and the central tube, resulting in low reaction thermal resistance, small radial temperature difference, low risk of carbon buildup, and high reaction efficiency. It also avoids the need for a high-temperature waste heat recovery device, resulting in a small reaction system size, small footprint, and ease of skid-mounting.

[0079] In this invention, such as Figure 2 As shown, the reaction section is provided with a catalyst bed 08 filled with reforming catalyst. Preferably, the height of the catalyst bed is equal to the height of the heat exchange reaction zone II.

[0080] In this invention, such as Figure 2 As shown, preferably, the inner diameter ratio of the central tube 05 and the housing 012 is 0.4-0.6:1, for example, 0.4:1, 0.5:1, 0.6:1, and any value within the range of any two values.

[0081] In this invention, such as Figure 2 As shown, preferably, the central tube 05 is further provided with a first preconversion layer filled with a first preconversion catalyst; more preferably, the height ratio of the first preconversion layer to the central tube 05 is 0.1-0.5:1, for example, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, and any value in any range of any two values.

[0082] In this invention, such as Figure 2 As shown, preferably, the preheating zone 3-3 is provided with a second preconversion layer filled with a second preconversion catalyst; more preferably, the height ratio of the second preconversion layer to the preheating zone 3-3 is 0.1-1:1, for example, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 1:1, and any value within the range of any two values.

[0083] In this invention, such as Figure 2 As shown, if a first pre-conversion layer is provided inside the central tube 05, then a second pre-conversion layer must be provided in the preheating zone 3-3, and the height ratio of the second pre-conversion layer to the preheating zone 3-3 is 1:1. That is to say, only if the height of the second pre-conversion layer is equal to the height of the preheating zone 3-3 is it considered that a first pre-conversion layer is provided in the central tube 05; otherwise, only a second pre-conversion layer with a lower height is considered in the preheating zone 3-3.

[0084] In this invention, such as Figure 2As shown, preferably, the preheating zone 3-3 is provided with a feed distributor 06 connected to the central tube 05. In this invention, the feed distributor 06 serves two purposes: firstly, to support the catalyst bed 08, and secondly, to uniformly distribute the preheated raw materials.

[0085] In this invention, such as Figure 2 As shown, preferably, the preheating zone 3-3 is also provided with a support member 07 that connects to the feed distributor 06.

[0086] In this invention, such as Figure 2 As shown, preferably, the feed pipe 01 and the discharge pipe 02 are disposed on the top of the housing 012.

[0087] In this invention, it is sufficient that the feed pipe 01 is connected to the heat exchange component 03. For example... Figure 2 As shown, the feed pipe 01 can also extend to the heat recovery zone 3-1 and connect with the heat exchange component 03, so that the mixed raw materials enter the heat exchange component 03 through the feed pipe 01 in sequence to carry out the first heat exchange in the heat recovery zone 3-1.

[0088] In this invention, such as Figure 2 As shown, preferably, the top of the housing 012 is provided with a flange cover 010 connected by a top welding flange 011, and the bottom is provided with a bottom welding head 013; more preferably, the flange cover 010 is provided with the feed pipe 01 and the discharge pipe 02.

[0089] In this invention, such as Figure 2 As shown, preferably, at least one thermocouple sheath 014 is also provided on the top of the housing 012. That is, at least one thermocouple sheath 014 is also provided on the flange cover 10.

[0090] In this invention, such as Figure 2 As shown, more preferably, the bottom of at least one of the thermocouple sleeves 014 extends above the reaction section for detecting the outlet temperature of the catalyst bed, i.e., the temperature of the reformed gas outlet heat recovery zone 3-2.

[0091] In this invention, such as Figure 2 As shown, more preferably, the bottom of at least one of the thermocouple sheaths 014 extends above the heat recovery zone 3-1 for detecting the temperature of the low-temperature reforming gas f.

[0092] In this invention, preferably, the reforming catalyst comprises a first active component and a first auxiliary agent, wherein the first active component is selected from nickel, and the first auxiliary agent is selected from at least one of lithium, sodium, potassium, magnesium, calcium, copper, cerium, and zinc. In this invention, the reforming catalyst further comprises a support, which includes, but is not limited to, alumina.

[0093] In this invention, preferably, based on the total weight of the reforming catalyst, the content of the first active component is 10-20 wt%, for example, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, or any value within the range of any two values; the content of the first auxiliary agent is 1-5 wt%, for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, or any value within the range of any two values.

[0094] In this invention, the reforming catalyst has an external dimension of 5-15 mm, preferably 6-10 mm. The shape of the reforming catalyst in this invention includes, but is not limited to, ring-shaped, porous columnar, Q-shaped, honeycomb-shaped, butterfly-shaped, etc.

[0095] In this invention, the first preconversion catalyst and the second preconversion catalyst may be the same or different, but preferably the same.

[0096] In this invention, the first pre-conversion catalyst and the second pre-conversion catalyst each independently include: a second active component and a second auxiliary agent; wherein the second active component is selected from nickel, and the second auxiliary agent is selected from at least one of lithium, sodium, potassium, magnesium, calcium, copper, cerium, and zinc. In this invention, the first pre-conversion catalyst and the second pre-conversion catalyst also each independently include a support, which includes, but is not limited to, alumina.

[0097] In this invention, the content of the second active component is 25-40 wt%, for example, 25 wt%, 28 wt%, 30 wt%, 32 wt%, 35 wt%, 38 wt%, 40 wt%, or any value within the range of any two values, based independently on the total weight of the first preconversion catalyst and the second preconversion catalyst; the content of the second auxiliary agent is 1-5 wt%, for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, or any value within the range of any two values.

[0098] In this invention, the external dimensions of the first preconversion catalyst and the second preconversion catalyst are each independently 5-15 mm, preferably 4-8 mm. In this invention, the shapes of the first and second preconversion catalysts include, but are not limited to, ring-shaped, porous columnar, Q-shaped, honeycomb-shaped, butterfly-shaped, etc.

[0099] In this invention, the first heat exchange aims to heat the methane-containing feed gas in the mixed raw materials and vaporize the water to obtain vaporized feed. Preferably, in step (2), the temperature of the vaporized feed is 180-450℃, for example, 180℃, 200℃, 300℃, 330℃, 350℃, 380℃, 400℃, 430℃, 450℃, and any value within any range of any two values, preferably 330-430℃.

[0100] In this invention, preferably, the vaporization rate of water in the vaporization raw material is ≥50%, for example, 50%, 60%, 80%, 85%, 90%, 95%, 100%, and any value within the range of any two values, preferably 80-100%.

[0101] In this invention, the vaporization rate parameter is obtained by heat transfer and gas-liquid balance simulation calculation.

[0102] In this invention, the first preheating and the second preheating are intended to bring the temperature of the vaporized feedstock to the inlet temperature of the reforming reaction. Preferably, the temperature of the preheated feedstock obtained by sequentially undergoing the first and second preheating is 400-650°C, for example, 400°C, 420°C, 450°C, 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 580°C, 600°C, 620°C, 650°C, and any value within any range of any two values, preferably 450-600°C, more preferably 500-550°C.

[0103] In this invention, the temperature of the preheated raw material is equivalent to Figure 2 The inlet temperature of catalyst bed 08.

[0104] In this invention, such as Figure 2 As shown, the temperature of the reforming reaction is generally expressed by the range of the inlet temperature and the outlet temperature of the catalyst bed 08; wherein, the inlet temperature of the catalyst bed 08 is equivalent to the temperature of the preheated feedstock; and the outlet temperature of the catalyst bed 08 is equivalent to the temperature of the reformed gas after the second heat exchange.

[0105] In this invention, preferably, in step (2), the conditions for the reforming reaction include: a temperature of 400-980℃, for example, 400℃, 420℃, 450℃, 500℃, 510℃, 520℃, 530℃, 540℃, 550℃, 580℃, 600℃, 620℃, 650℃, 680℃, 700℃, 750℃, 800℃, 850℃, 900℃, 920℃, 940℃, 950℃, 980℃, and any value within the range of any two values, preferably 450-980℃, more preferably 500-950℃, and even more preferably 550-940℃.

[0106] In this invention, preferably, in step (2), the conditions for the reforming reaction further include: a pressure of 0.5-2.5 MPa, for example, 0.5 MPa, 0.8 MPa, 1 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, 1.6 MPa, 1.8 MPa, 2 MPa, 2.2 MPa, 2.5 MPa, and any value within the range of any two values, preferably 0.8-2 MPa, more preferably 0.8-1.5 MPa, and even more preferably 1-1.5 MPa.

[0107] In this invention, preferably, in step (2), the conditions for the reforming reaction further include: the volume hourly space velocity (VHSV) of the preheated feedstock, calculated as CH4, is 500-2000 h⁻¹. -1 For example, 500h -1 600h -1 800h -1 900h -1 1000h -1 1100h -1 1200h -1 1300h -1 1500h -1 1800h -1 2000h -1 And any value within the range of any two values, preferably 800-1500h. -1 More preferably 1000-1300h -1 .

[0108] In this invention, the volumetric space velocity parameter is a value under standard conditions.

[0109] In this invention, the second heat exchange aims to provide the heat of the high-temperature reformed gas to the vaporized feedstock. Preferably, the temperature of the reformed gas after the second heat exchange is 900-980°C, for example, 900°C, 920°C, 930°C, 940°C, 950°C, 960°C, 980°C, or any value within a range of any two of these values, preferably 900-950°C, and more preferably 920-940°C.

[0110] In this invention, the first heat exchange aims to further recover and utilize the heat of the high-temperature reformed gas, that is, to transform the mixed feedstock into a vaporized feedstock, and to transform the reformed gas after the second heat exchange into low-temperature reformed gas. Preferably, the temperature of the low-temperature reformed gas is 300-400℃, for example, 300℃, 320℃, 330℃, 340℃, 350℃, 380℃, 400℃, and any value within any range of any two of these values, preferably 320-350℃.

[0111] In this invention, preferably, the CH4 content in the low-temperature reforming gas is ≤1 mol%, for example, 1 mol%, 0.8 mol%, 0.6 mol%, 0.5 mol%, 0.4 mol%, 0.3 mol%, 0.2 mol%, 0.1 mol%, 0.05 mol%, 0.01 mol%, and any value within a range of any two values, preferably ≤0.6 mol%.

[0112] In this invention, more preferably, the H2O content in the low-temperature reforming gas is 20-30 mol%, for example, 20 mol%, 21 mol%, 22 mol%, 23 mol%, 24 mol%, 25 mol%, 26 mol%, 27 mol%, 28 mol%, 29 mol%, 30 mol%, and any value within the range of any two values.

[0113] In this invention, more preferably, the low-temperature reforming gas has an H2 content of 35-55 mol%, preferably 38-50 mol%; a CO content of 10-25 mol%, preferably 12-22 mol%; and a CO2 content of 0-15 mol%, preferably 6-12 mol%.

[0114] In this invention, the low-temperature reformed gas is sequentially cooled and separated to remove H2O. Preferably, in step (3), the reformed dry gas has an H2 content of 60-70 mol%, preferably 61-66 mol%; a CO content of 15-30 mol%, preferably 25-28 mol%; and a CO2 content of 8-20 mol%, preferably 10-15 mol%.

[0115] In this invention, unless otherwise specified, the H2O content in the reformed dry gas is 0 mol%.

[0116] In this invention, preferably, the temperature of the reformed dry gas is ≤50℃, more preferably 0-50℃, for example, 50℃, 40℃, 30℃, 20℃, 10℃, 0℃, and any value within the range of any two values.

[0117] In this invention, preferably, the carbon-to-hydrogen ratio of the reformed dry gas is 1-2, for example, 1, 1.2, 1.5, 1.6, 1.8, 2, or any value within a range of any two values, wherein...

[0118] In this invention, unless otherwise specified, the methane conversion rate of the low-temperature reformed gas and the dry reformed gas is the same, the only difference being that the low-temperature reformed gas contains water.

[0119] In this invention, preferably, the method further includes: decarbonizing the reformed dry gas to obtain a synthesis gas with a carbon-to-hydrogen ratio of 2-2.1, for example, 2.01, 2.02, 2.03, 2.04, 2.05, 2.06, 2.08, 2.1, and any value within a range of any two values.

[0120] In this invention, the decarbonization treatment methods include, but are not limited to, pressure swing adsorption, chemical absorption, etc., such as VPSA, membrane separation, physical absorption or organic amine chemical absorption, to obtain syngas with a specific hydrogen-to-carbon ratio.

[0121] In this invention, preferably, the method further includes: performing deacidification treatment on the gas-liquid separation to obtain deacidified water and acidic gas; more preferably, the deacidified water is returned as circulating water and mixed into the water.

[0122] A second aspect of the present invention provides a schematic diagram of a system for preparing syngas from methane feedstock gas, as shown in Figure 1. The system includes a compression unit 1, a purification unit 2, a reforming unit 3, a cooling unit 4, and a separation unit 5 connected in sequence.

[0123] The reforming unit is selected from a heat exchange reforming reactor, which is a combustion furnace with at least one parallel reaction tube inside. The furnace temperature of the combustion furnace is provided by the combustion of the methane-containing feed gas. The top of the reaction tube is provided with a feed pipe 01 and a discharge pipe 02. The shell of the reaction tube is divided into a heat recovery zone 3-1, a heat exchange reaction zone 3-2, and a preheating zone 3-3 from top to bottom. The height of the heat recovery zone 3-1 is within the insulation material of the combustion furnace. The heat recovery zone 3-1 is provided with a heat exchange component 03. The heat exchange reaction zone 3-2 is provided with a catalyst bed 08 arranged in a ring around the central tube 05, dividing the heat exchange reaction zone 3-2 into a heat exchange section and a reaction section. The two ends of the heat exchange component 03 are respectively connected to the feed pipe 01 and the central tube 05.

[0124] In this invention, such as Figure 1 As shown, the compression unit 1 is used to compress the methane-containing feed gas a to obtain compressed feed gas d; the purification unit 2 is used to purify the compressed feed gas d to obtain purified feed gas e; the reforming unit 3 is used to sequentially perform a first heat exchange, a first preheating, a second preheating, and a reforming reaction on the mixture of purified feed gas e and water b to obtain high-temperature reformed gas. After performing a second heat exchange with the vaporized feed gas after the first heat exchange, the first heat exchange is performed again to obtain low-temperature reformed gas f; the cooling unit 4 is used to cool the low-temperature reformed gas f to obtain cooled reformed gas g; the separation unit 5 is used to separate the cooled reformed gas g to obtain reformed dry gas h and recovered acid water i.

[0125] In this invention, such as Figure 1 As shown, the compression unit 1 is also connected to a CO2 supplementation pipeline, and the CO2 content in the methane-containing feed gas a is adjusted by adding supplementary CO2 c.

[0126] In this invention, such as Figure 1 As shown, the compression unit 1 is used to mix and compress methane-containing feed gas a and optional supplementary CO2c to obtain compressed feed gas d.

[0127] In this invention, such as Figure 1 As shown, the purification unit 2 includes a hydrodesulfurization reactor and an adsorption desulfurization reactor connected in sequence, which are used to purify the compressed raw material gas d to obtain purified raw material gas e.

[0128] In this invention, the reforming unit is selected from a heat exchange reforming reactor, and all are subject to the above-mentioned limitations, which will not be elaborated here.

[0129] In this invention, such as Figure 1As shown, preferably, the system further includes a decarbonization unit 7 connected to the separation unit 5, used to decarbonize the reformed dry gas h to obtain syngas m with a carbon-to-hydrogen ratio of 2-2.1, and to obtain exhaust gas l for direct discharge.

[0130] In this invention, such as Figure 1 As shown, preferably, the system further includes a deacidification unit 6 connected to the separation unit 5, used to deacidify the recovered acid water i obtained from the separation, to obtain deacidified water j which is returned and mixed into the water b, and to obtain acidic gas k which is directly discharged.

[0131] In this invention, the deacidification unit j is a stripping tower.

[0132] In one specific embodiment of the present invention, the system includes a compression unit 1, a purification unit 2, a reforming unit 3, a cooling unit 4, a separation unit 5, a decarbonization unit 7, and a deacidification unit 6 connected in sequence.

[0133] The compression unit 1 is used to mix and compress methane-containing feed gas a and optional supplementary CO2 c to obtain compressed feed gas d; the purification unit 2 includes a hydrodesulfurization reactor and an adsorption desulfurization reactor connected in sequence, which are used to purify the compressed feed gas d to obtain purified feed gas e.

[0134] The reforming unit 3 is selected from a heat exchange reforming reactor, which is a combustion furnace with at least one parallel reaction tube inside. The furnace temperature is provided by the combustion of the methane-containing feed gas. The top of the reaction tube is provided with a feed pipe 01 and a discharge pipe 02. The shell of the reaction tube is divided into a heat recovery zone 3-1, a heat exchange reaction zone 3-2, and a preheating zone 3-3 from top to bottom. The height of the heat recovery zone 3-1 is within the insulation material of the combustion furnace. The heat recovery zone 3-2 is provided with a heat exchange component 03. The heat exchange reaction zone 3-2 is provided with a surrounding central tube 03. A catalyst bed 08 is arranged in a ring, and the heat exchange reaction zone 3-2 is divided into a heat exchange section and a reaction section. The two ends of the heat exchange component 03 are respectively connected to the feed pipe 01 and the central pipe 05. It is used to sequentially perform a first heat exchange, a first preheating, a second preheating, and a reforming reaction on the mixed raw material containing purified raw material gas e and water b to obtain high-temperature reformed gas. After the gasified raw material after the first heat exchange is subjected to a second heat exchange, the first heat exchange is performed again to obtain low-temperature reformed gas f. The cooling unit 4 is used to cool the low-temperature reformed gas f to obtain cooled reformed gas g. The liquid separation unit 5 is used to separate the cooled reformed gas g to obtain reformed dry gas h.

[0135] The decarbonization unit 7 is used to decarbonize the reformed dry gas h to obtain syngas m and exhaust gas l; the deacidification unit 6 is connected to the separation unit 5 and the reforming unit 3, and is used to deacidify the recovered acid water i from the separation unit 5 to obtain acid gas k, and to obtain deacidified water j which is returned and mixed into water b and sent to the reforming unit 3.

[0136] According to a particularly preferred embodiment of the present invention, a method for preparing syngas from methane feedstock gas, the method comprising:

[0137] (1) The methane-containing raw gas is compressed and purified sequentially to obtain purified raw gas and water, and a mixed raw material is obtained; wherein, the methane-containing raw gas has a CH4 content of 40-95 mol% and a CO2 content of 10-60 mol%; and the molar ratio of H2O to CH4 in the mixed raw material is 2.1-2.5.

[0138] (2) The mixed raw materials are subjected to a first heat exchange, a first preheat, a second preheat, and a reforming reaction in a heat exchange reforming reactor in sequence to obtain high-temperature reformed gas. After the gasified raw materials after the first heat exchange are subjected to a second heat exchange, the first heat exchange is performed again to obtain low-temperature reformed gas.

[0139] (3) The low-temperature reformed gas is cooled and separated into gas and liquid in sequence to obtain reformed dry gas as syngas;

[0140] The heat required for the first preheating, the second preheating, and the reforming reaction is provided by the combustion of the methane-containing feed gas.

[0141] The heat exchange reforming reactor is a combustion furnace with at least one reaction tube connected in parallel, and the furnace temperature of the combustion furnace is provided by the combustion of the methane-containing feed gas; the furnace temperature of the combustion furnace is 800-1200℃.

[0142] The reaction tube is equipped with a feed pipe and a discharge pipe at its top. The shell of the reaction tube is divided into a heat recovery zone, a heat exchange reaction zone, and a preheating zone from top to bottom. The height of the heat recovery zone is within the insulation material of the combustion furnace. The heat recovery zone is equipped with a heat exchange component. The heat exchange reaction zone is equipped with a catalyst bed arranged in a ring around the central tube, and the heat exchange reaction zone is divided into a heat exchange section and a reaction section. The two ends of the heat exchange component are respectively connected to the feed pipe and the central tube.

[0143] The present invention will be described in detail below through embodiments.

[0144] Reforming catalyst A1 comprises an alumina support, 15 wt% nickel, and 1.5 wt% zinc; reforming catalyst A1 is a 4-pore cylindrical shape with external dimensions of [missing information]. The hole diameter is 1.5mm.

[0145] Pre-conversion catalyst A2 comprises an alumina support, 35 wt% nickel, and 2.5 wt% zinc; the pre-conversion catalyst A2 is a 4-pore cylindrical shape with external dimensions of [missing information]. The hole diameter is 1.5mm.

[0146]

[0147] According to the composition of syngas products, the following conditions must be met: The percentage of available carbon (CO2 + CO) in the syngas product is calculated to obtain the total carbon atom utilization rate, i.e.

[0148]

[0149] Example 1

[0150] System such as Figures 1-2 As shown, it includes a compression unit 1, a purification unit 2, a reforming unit 3, a cooling unit 4, a separation unit 5, and a decarbonization unit 7 connected in sequence, as well as a deacidification unit 6 connected to the separation unit 5; wherein, the reforming unit 3 is selected from a heat exchange reforming reactor, including a combustion furnace and four reaction tubes arranged in parallel;

[0151] Each reaction tube's shell 012 is divided into three interconnected zones from top to bottom: a heat recovery zone 3-1, a heat exchange reaction zone 3-2, and a preheating zone 3-3. The heat recovery zone 3-1 is equipped with a heat exchange component 03, a connector 09, and a receiving pipe 04 connected in sequence. The heat exchange reaction zone 3-2 is equipped with a catalyst bed 08 arranged in a ring around the central tube 05, dividing the heat exchange reaction zone 3-2 into a heat exchange section and a reaction section. The two ends of the heat exchange component 03 are connected to the feed pipe 01 and the central tube 05. The preheating zone 3-3 is equipped with a feed distributor 06 and a support component 07. The top of the shell 012 is equipped with a flange cover 010, which is equipped with two thermocouple sleeves 014, one feed pipe 01, and one discharge pipe 02. The bottom of one thermocouple sleeve 014 extends to the top of the reaction section, and the bottom of the other thermocouple sleeve 014 extends to the top of the heat recovery zone 3-1.

[0152] The reaction tube has a height-to-diameter ratio of 25 and an inner diameter of 100 mm. The height ratio of the heat recovery zone 3-1, the heat exchange reaction zone II, and the preheating zone III is 22:74:4. The inner diameter ratio of the heat exchange component 03, the receiving pipe 04, and the central pipe 05 is 1:1.3:3.1. The inner diameter ratio of the central pipe 05 and the shell 012 is 0.5:1.

[0153] The central tube 05 is filled with pre-conversion catalyst A2, and the height ratio of the first pre-conversion layer to the central tube 05 is 0.25:1; the preheating zone 3-3 is filled with pre-conversion catalyst A2, and the height ratio of the second pre-conversion layer to the preheating zone 3-3 is 1:1.

[0154] The method is performed in the above system and includes:

[0155] (1) Mix natural gas (composition shown in Table 1, temperature 25℃, pressure 0.22MPa) and supplemented CO2 to make the molar ratio of CH4 to CO2 in the mixture 1:0.7. After the mixture is compressed to 1.5MPa by a compressor, it is heated to 320℃, 10% volume fraction of hydrogen is added, and then it is passed into a hydrodesulfurization reactor and an adsorption desulfurization reactor connected in sequence for purification.

[0156] The hydrodesulfurization reactor is loaded with a hydrodesulfurization catalyst, the active components of which are Co and Mo in a mass ratio of 2:1; the support is alumina, and the ratio of active component to support is 0.2:1; the reaction temperature in the hydrodesulfurization reactor is 320℃, the reaction pressure is 1.5MPa, and the gas space velocity is 4000h⁻¹. 1 After the mixed gas passes through the hydrodesulfurization reactor, the organic sulfur content is 3×10⁻⁶. -6 mol%, the mixed gas after hydrodesulfurization is continued to be fed into the adsorption desulfurization reactor;

[0157] The adsorption desulfurization reactor is filled with an adsorption desulfurization catalyst, which is ZnO. The reaction temperature in the adsorption desulfurization reactor is 320℃, the reaction pressure is 1.5MPa, and the gas space velocity is 4000h. 1 The total sulfur content in the mixed gas after adsorption desulfurization is 3×10⁻⁶. -5 mol%;

[0158] Using municipal tap water as raw material, deionized water is obtained after treatment by a pure water machine. The deionized water is mixed with purified raw material gas to obtain a mixed raw material with a molar ratio of H2O to CH4 of 2.5:1.

[0159] (2) The above mixed raw materials are subjected to a first heat exchange to obtain vaporized raw materials at a temperature of 350℃ (the vaporization rate of water is 100%).

[0160] Using the above-mentioned natural gas combustion for heating, the furnace temperature is 1100℃, and the above-mentioned vaporized raw materials are subjected to first preheating and second preheating in sequence to obtain preheated raw materials with a temperature of 600℃;

[0161] The preheated raw material and reforming catalyst A1 are brought into contact and reformed to obtain reformed gas. The reformed gas is then subjected to a second heat exchange with the vaporized raw material to obtain reformed gas with a temperature of 950°C. The first heat exchange is then performed to obtain low-temperature reformed gas P1 with a temperature of 350°C (composition shown in Table 1).

[0162] The reforming reaction was carried out at a temperature of 600-950℃ and a pressure of 1.5 MPa. The volume hourly space velocity (VHSV) of the preheated feedstock, calculated as CH4, was 1000 h⁻¹. -1 ;

[0163] (3) Cool the above-mentioned low-temperature reformed gas P1 to 35°C and perform gas-liquid separation to obtain reformed dry gas Q1 (composition shown in Table 1). Perform decarbonization treatment to obtain syngas product W1 with a carbon-hydrogen ratio of 2.05.

[0164] Among them, the carbon-hydrogen ratio of the above-mentioned reformed dry gas Q1 is 1.38, the methane conversion rate is 97.1%, and the CO2 removal rate is 78.6%.

[0165] Of the aforementioned syngas product W1, the total carbon atom utilization rate is 76.9%.

[0166] Table 1

[0167]

[0168]

[0169] Example 2

[0170] According to the system provided in Example 1,

[0171] The method provided in Example 1 is different,

[0172] In step (1), biogas (composition shown in Table 2, temperature 30℃, pressure 0.11MPa) is used as raw material gas, and the biogas is compressed to 1.5MPa. The reaction pressure of both the hydrodesulfurization reactor and the adsorption desulfurization reactor is 1.5MPa.

[0173] The molar ratio of H2O to CH4 in the mixed raw materials is 2.2:1;

[0174] (2) The above raw materials are subjected to a first heat exchange to obtain vaporized raw materials at a temperature of 320℃ (the vaporization rate of water is 100%).

[0175] Using the above-mentioned biogas combustion for heating, the furnace temperature is 1000℃, and the above-mentioned gasified raw materials are subjected to first preheating and second preheating in sequence to obtain preheated raw materials with a temperature of 550℃.

[0176] The preheated raw material and reforming catalyst A1 are brought into contact and reformed to obtain reformed gas. The reformed gas is then subjected to a second heat exchange with the vaporized raw material to obtain reformed gas with a temperature of 925°C. The first heat exchange is then performed to obtain low-temperature reformed gas P2 with a temperature of 350°C (composition shown in Table 2).

[0177] The reforming reaction was carried out at a temperature of 550-925℃ and a pressure of 1.5 MPa. The volume hourly space velocity (VHSV) of the preheated feedstock, calculated as CH4, was 1000 h⁻¹. -1 ;

[0178] (3) Cool the above-mentioned low-temperature reformed gas P2 to 35°C and perform gas-liquid separation to obtain reformed dry gas Q2 (composition shown in Table 2). Perform decarbonization treatment to obtain syngas product W2 with a carbon-hydrogen ratio of 2.05.

[0179] Among them, the reformed dry gas Q2 has a carbon-to-hydrogen ratio of 1.45, a methane conversion rate of 95.5%, and a CO2 removal rate of 70.4%.

[0180] Of the aforementioned syngas product W2, the total carbon atom utilization rate is 78.4%.

[0181] Table 2

[0182]

[0183] Example 3

[0184] The system provided according to Example 1;

[0185] The method provided in Example 1 is different,

[0186] In step (1), biogas (composition shown in Table 3, temperature 30℃, pressure 0.11MPa) is used as raw material gas, and the biogas is compressed to 0.85MPa. The reaction pressure of the hydrodesulfurization reactor and the adsorption desulfurization reactor is 0.85MPa.

[0187] The molar ratio of H2O to CH4 in the mixed raw materials is 2.2:1;

[0188] (2) The above raw materials are subjected to a first heat exchange to obtain vaporized raw materials at a temperature of 310℃ (the vaporization rate of water is 100%).

[0189] Using the above-mentioned biogas combustion for heating, the furnace temperature is 1000℃, and the above-mentioned gasified raw materials are subjected to first preheating and second preheating in sequence to obtain preheated raw materials with a temperature of 550℃.

[0190] The above-mentioned preheated raw materials and reforming catalyst A1 are brought into contact and reformed to obtain reformed gas. The reformed gas undergoes a second heat exchange with the vaporized raw materials to obtain a second heat exchange at a temperature of 925℃. After the second heat exchange, the reformed gas undergoes the above-mentioned first heat exchange to obtain low-temperature reformed gas P3 at a temperature of 350℃ (composition shown in Table 3).

[0191] The reforming reaction was carried out at a temperature of 550-925℃ and a pressure of 0.8 MPa. The volume hourly space velocity (VHSV) of the preheated feedstock, calculated as CH4, was 1000 h⁻¹. -1 ;

[0192] (3) Cool the above-mentioned low-temperature reformed gas P3 to 38°C and perform gas-liquid separation to obtain reformed dry gas Q3 (composition shown in Table 3). Perform decarbonization treatment to obtain syngas product W3 with a carbon-hydrogen ratio of 2.05.

[0193] Among them, the reformed dry gas Q3 has a carbon-to-hydrogen ratio of 1.45, a methane conversion rate of 95.9%, and a CO2 removal rate of 64.8%.

[0194] Of the aforementioned syngas product W3, the total carbon atom utilization rate is 78.8%.

[0195] Table 3

[0196]

[0197]

[0198] Example 4

[0199] The system provided according to Example 1;

[0200] The method provided in Example 1 is different,

[0201] In step (1), biogas (composition shown in Table 4, temperature 30℃, pressure 0.11MPa) is used as raw material gas, and the biogas is compressed to 2.5MPa. The reaction pressure of both the hydrodesulfurization reactor and the adsorption desulfurization reactor is 2.5MPa.

[0202] The molar ratio of H2O to CH4 in the mixed raw materials is 2.2:1;

[0203] (2) The above raw materials are subjected to a first heat exchange to obtain vaporized raw materials at a temperature of 310℃ (the vaporization rate of water is 100%).

[0204] Using the above-mentioned biogas combustion for heating, the furnace temperature is 1000℃, and the above-mentioned gasified raw materials are subjected to first preheating and second preheating in sequence to obtain preheated raw materials with a temperature of 550℃.

[0205] The above-mentioned preheated raw materials and reforming catalyst A1 are brought into contact and reformed to obtain reformed gas. The reformed gas undergoes a second heat exchange with the vaporized raw materials to obtain a second heat exchange at a temperature of 925℃. After the second heat exchange, the reformed gas undergoes the above-mentioned first heat exchange to obtain low-temperature reformed gas P4 at a temperature of 350℃ (composition shown in Table 4).

[0206] The reforming reaction was carried out at a temperature of 550-925℃ and a pressure of 2.5 MPa. The volume hourly space velocity (VHSV) of the preheated feedstock, calculated as CH4, was 1000 h⁻¹. -1 ;

[0207] (3) Cool the above-mentioned low-temperature reformed gas P4 to 38°C and perform gas-liquid separation to obtain reformed dry gas Q4 (composition shown in Table 4). Perform decarbonization treatment to obtain syngas product W4 with a carbon-hydrogen ratio of 2.05.

[0208] Among them, the reformed dry gas Q4 has a carbon-to-hydrogen ratio of 1.39, a methane conversion rate of 89.9%, and a CO2 removal rate of 72.4%.

[0209] Of the aforementioned syngas product W4, the total carbon atom utilization rate is 73.9%.

[0210] Table 4

[0211]

[0212] Example 5

[0213] The system provided according to Example 1;

[0214] The method provided in Example 1 is different,

[0215] In step (1), biogas (composition shown in Table 5, temperature 30℃, pressure 0.11MPa) is used as raw material gas, and the biogas is compressed to 2.5MPa. The reaction pressure of both the hydrodesulfurization reactor and the adsorption desulfurization reactor is 2.5MPa.

[0216] The molar ratio of H2O to CH4 in the mixed raw materials is 2.2:1;

[0217] (2) The above raw materials are subjected to a first heat exchange to obtain vaporized raw materials at a temperature of 310℃ (the vaporization rate of water is 100%).

[0218] Using the above-mentioned biogas combustion for heating, the furnace temperature is 1000℃, and the above-mentioned gasified raw materials are subjected to first preheating and second preheating in sequence to obtain preheated raw materials with a temperature of 550℃.

[0219] The above-mentioned preheated raw materials and reforming catalyst A1 are brought into contact and reformed to obtain reformed gas. The reformed gas undergoes a second heat exchange with the vaporized raw materials to obtain a second heat exchange at a temperature of 925℃. After the second heat exchange, the reformed gas undergoes the above-mentioned first heat exchange to obtain low-temperature reformed gas P5 at a temperature of 350℃ (composition shown in Table 5).

[0220] The reforming reaction was carried out at a temperature of 550-925℃ and a pressure of 2.5 MPa. The volume hourly space velocity (VHSV) of the preheated feedstock, calculated as CH4, was 5000 h⁻¹. -1 ;

[0221] (3) Cool the above-mentioned low-temperature reformed gas P5 to 38°C and perform gas-liquid separation to obtain reformed dry gas Q5 (composition shown in Table 5). Perform decarbonization treatment to obtain syngas product W5 with a carbon-hydrogen ratio of 2.05.

[0222] Among them, the carbon-hydrogen ratio of the above-mentioned reformed dry gas Q5 is 1.31, the methane conversion rate is 82.2%, and the CO2 removal rate is 70.3%.

[0223] Of the aforementioned syngas product W5, the total carbon atom utilization rate is 67.6%.

[0224] Table 5

[0225]

[0226]

[0227] Example 6

[0228] The system provided according to Example 1;

[0229] The method provided in Example 1 is different,

[0230] In step (1), no additional CO2 is added to the raw materials, and the molar ratio of H2O to CH4 in the mixed raw materials is 2.5:1;

[0231] In step (2), the above-mentioned natural gas is used for heating, the furnace temperature is 1000℃, and the preheated raw material is obtained at a temperature of 450℃; the temperature of the reformed gas after the second heat exchange is 880℃; the temperature of the above-mentioned reforming reaction is 450-880℃.

[0232] Under the same conditions, a low-temperature reformed gas P6 with a temperature of 950℃ was obtained (composition shown in Table 6);

[0233] (3) Cool the above-mentioned low-temperature reformed gas P6 to 38°C and perform gas-liquid separation to obtain reformed dry gas Q6 (composition shown in Table 6). Since CO2 was not added to the raw material, the hydrogen-to-carbon ratio in the reformed dry gas Q6 is higher than that of the qualified product gas. Some hydrogen needs to be removed to obtain syngas product W6 with a carbon-to-hydrogen ratio of 2.05.

[0234] Among them, the carbon-to-hydrogen ratio of the above-mentioned reformed dry gas Q6 is 2.89, the methane conversion rate is 95.4%, and the H2 removal rate is 27.3%.

[0235] Among them, the total carbon atom utilization rate of the above-mentioned syngas product W6 is 100%.

[0236] Table 6

[0237]

[0238]

[0239] Example 7

[0240] The system provided in Example 1 differs in that,

[0241] The height ratio of the heat recovery zone 3-1, the heat exchange reaction zone 3-2, and the preheating zone 3-3 is 10:85:5.

[0242] The method provided in Example 1 differs from the method described above in that it is performed within the aforementioned system.

[0243] In step (2), the temperature of the vaporized raw material is 162°C and the vaporization rate of water is 74%; the temperature of the preheated raw material is 400°C; and the temperature of the reformed gas after the second heat exchange is 800°C.

[0244] The reforming reaction was carried out at a temperature of 400-800℃ and a pressure of 1.5 MPa. The volume hourly space velocity (VHSV) of the preheated feedstock, calculated as CH4, was 1000 h⁻¹. -1 ;

[0245] Under the same conditions, a low-temperature reformed gas P7 with a temperature of 400℃ was obtained (composition shown in Table 7);

[0246] In step (3), the other conditions remain the same, and reformed dry gas Q7 (composition shown in Table 7) and syngas product W7 with a carbon-hydrogen ratio of 2.05 are obtained.

[0247] Among them, the reformed dry gas Q7 has a carbon-to-hydrogen ratio of 1.13, a methane conversion rate of 72.9%, and a CO2 removal rate of 68.8%.

[0248] Among them, the total carbon atom utilization rate of the aforementioned syngas product W7 is 59.5%.

[0249] Table 7

[0250]

[0251]

[0252] Example 8

[0253] The system provided in Example 1 differs in that,

[0254] The ratio of the inner diameter of the central tube 05 to that of the shell 012 is 0.3:1.

[0255] The method provided in Example 1 differs from the method described above in that it is performed within the aforementioned system.

[0256] In step (2), the temperature of the vaporized raw material is 172°C and the vaporization rate of water is 95%; the temperature of the preheated raw material is 410°C; and the temperature of the reformed gas after the second heat exchange is 860°C.

[0257] The reforming reaction was carried out at a temperature of 410-860℃ and a pressure of 1.5 MPa. The volume hourly space velocity (VHSV) of the preheated feedstock, calculated as CH4, was 1000 h⁻¹. -1 ;

[0258] Under the same conditions, a low-temperature reformed gas P8 with a temperature of 300℃ was obtained (composition shown in Table 8);

[0259] In step (3), the other conditions remain the same, and reformed dry gas Q8 (composition shown in Table 8) and syngas product W8 with a carbon-hydrogen ratio of 2.05 are obtained.

[0260] Among them, the reformed dry gas Q8 has a carbon-to-hydrogen ratio of 1.16, a methane conversion rate of 75.8%, and a CO2 removal rate of 69.0%.

[0261] Among them, the total carbon atom utilization rate of the above-mentioned syngas product W8 is 61.6%.

[0262] Table 8

[0263]

[0264]

[0265] Example 9

[0266] The system provided in Example 1 differs in that,

[0267] The central tube 05 is not filled with pre-conversion catalyst A2; pre-conversion catalyst A2 is only filled in the preheating zone 3-3, and the height ratio of the second pre-conversion layer to the preheating zone 3-3 is 1:1.

[0268] The method provided in Example 1 differs from the method described above in that it is performed within the aforementioned system.

[0269] In step (2), the temperature of the vaporized raw material is 174°C and the vaporization rate of water is 96%; the temperature of the preheated raw material is 360°C; and the temperature of the reformed gas after the second heat exchange is 870°C.

[0270] The reforming reaction was carried out at a temperature of 360-870℃ and a pressure of 1.5 MPa. The volume hourly space velocity (VHSV) of the preheated feedstock, calculated as CH4, was 1000 h⁻¹. -1 ;

[0271] Under the same conditions, a low-temperature reformed gas P9 with a temperature of 300℃ was obtained (composition shown in Table 9);

[0272] In step (3), the other conditions remain the same, and reformed dry gas Q9 (composition shown in Table 9) and syngas product W9 with a carbon-hydrogen ratio of 2.05 are obtained.

[0273] Among them, the reformed dry gas Q9 has a carbon-to-hydrogen ratio of 1.25, a methane conversion rate of 83.3%, and a CO2 removal rate of 70.2%.

[0274] Of the aforementioned syngas product W9, the total carbon atom utilization rate is 67%.

[0275] Table 9

[0276]

[0277] Comparative Example 1

[0278] The system provided in Example 1 differs in that,

[0279] The reforming unit employs a tubular fixed-bed reforming reactor without internal heat exchange components.

[0280] The height-to-diameter ratio of the reaction tube is 13.8, and the inner diameter is 96 mm.

[0281] The method is performed in the above system, except that...

[0282] In step (2), the above raw materials are introduced from the top of the reactor and pass through the catalyst bed from top to bottom. They come into contact with the packed reforming catalyst A1 and undergo a reforming reaction before being discharged to obtain low-temperature reforming gas DP1 (composition shown in Table 10) at a temperature of 850°C.

[0283] The furnace temperature is 1100℃, the reforming reaction temperature is 550-850℃, the pressure is 2.5MPa, and the volume hourly space velocity (VHSV) of the preheated feedstock (calculated as CH4) is 1000 h⁻¹. -1 The molar ratio of H2O to CH4 in the mixed raw materials is 3:1.

[0284] In step (3), the above-mentioned low-temperature reformed gas DP1 is cooled to 35°C and gas-liquid separation is performed to obtain reformed dry gas DQ1 (composition shown in Table 10). The gas is then decarbonized to obtain syngas product DW1 with a carbon-to-hydrogen ratio of 2.05.

[0285] Among them, the reformed dry gas DQ1 has a carbon-to-hydrogen ratio of 1.27, a methane conversion rate of 85.4%, and a CO2 removal rate of 65.1%.

[0286] Among them, the total carbon atom utilization rate of the above-mentioned syngas product DW1 is 68.6%.

[0287] Table 10

[0288]

[0289]

[0290] As can be seen from the above examples and comparative examples, the method provided by the present invention has a high methane conversion rate and total carbon atom utilization rate. At the same time, the method does not pre-remove CO2, that is, it directly uses CO2-containing methane-rich feed gas for reforming reaction, combined with decarbonization treatment, to partially remove CO2, thereby controlling the carbon-hydrogen ratio of the syngas product.

[0291] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing syngas from methane feedstock gas, characterized in that, The method includes: (1) The methane-containing raw gas is compressed and purified sequentially to obtain purified raw gas and water, which are then mixed to obtain a mixed raw material. (2) The mixed raw materials are subjected to a first heat exchange, a first preheat, a second preheat, and a reforming reaction in a heat exchange reforming reactor in sequence to obtain high-temperature reformed gas. After the gasified raw materials after the first heat exchange are subjected to a second heat exchange, the first heat exchange is performed again to obtain low-temperature reformed gas. (3) The low-temperature reformed gas is cooled and separated into gas and liquid in sequence to obtain reformed dry gas as syngas; The heat required for the first preheating, the second preheating, and the reforming reaction is provided by the combustion of the methane-containing feed gas.

2. The method according to claim 1, wherein, In step (1), The methane-containing feed gas contains 40-95 mol% CH4, preferably 50-70 mol%. And / or, the CO2 content in the methane-containing feed gas is 10-60 mol%, preferably 30-50 mol%; And / or, in the methane-containing feed gas, the molar ratio of CH4 to CO2 is 1:0.1-2, preferably 1:0.4-1.5; And / or, when the CO2 content in the methane-containing feed gas is <10 mol%, supplementary CO2 is added; And / or, the methane-containing feed gas is selected from at least one of natural gas, biogas, and coke oven gas; And / or, the temperature of the methane-containing feed gas is 0-40°C and the pressure is 0-0.5 MPa; And / or, the pressure of the compressed raw material gas obtained by the compression is 0.5-3 MPa; And / or, the sulfur content in the purified raw gas is ≤3.5×10⁻⁶. -5 mol%, chlorine content ≤0.1mg / Nm 3 Oxygen content ≤ 5 mg / Nm 3 ; And / or, the purification method is selected from hydrodesulfurization and adsorption desulfurization; And / or, in the mixed raw materials, the molar ratio of H2O to CH4 is 1.5-3.5, preferably 2-3, and more preferably 2.1-2.

5.

3. The method according to claim 1 or 2, wherein, In step (2), The heat exchange reforming reactor is a combustion furnace with at least one reaction tube connected in parallel, and the furnace temperature of the combustion furnace is provided by the combustion of the methane-containing feed gas.

4. The method according to claim 3, wherein, The furnace temperature of the combustion furnace is 800-1200℃; And / or, the top of the reaction tube is provided with a feed pipe and a discharge pipe, and the shell of the reaction tube is divided into a heat recovery zone, a heat exchange reaction zone and a preheating zone from top to bottom, and the height of the heat recovery zone is within the insulation material of the combustion furnace; the heat recovery zone is provided with a heat exchange component; the heat exchange reaction zone is provided with a catalyst bed arranged in a ring around the central tube, and the heat exchange reaction zone is divided into a heat exchange section and a reaction section; the two ends of the heat exchange component are respectively connected to the feed pipe and the central tube.

5. The method according to claim 4, wherein, The height-to-diameter ratio of the reaction tube is 15-30, where the height-to-diameter ratio is the ratio of the height to the inner diameter of the reaction tube. And / or, the height ratio of the heat recovery zone, the heat exchange reaction zone, and the preheating zone is 13-25:68-75:4-17; And / or, the heat recovery zone is further provided with a receiving pipe, the two ends of which are respectively connected to the heat exchange component and the central pipe; And / or, according to the material flow direction, the receiving pipe is disposed after or before the heat exchange component, preferably after; And / or, the receiving pipe and heat exchange components are connected by connectors; And / or, the inner diameter ratio of the heat exchange component, the receiving pipe and the central pipe is 1:1.2-3:3-7.5; And / or, the inner diameter ratio of the central tube to the shell is 0.4-0.6:1; And / or, the central tube is provided with a first preconversion layer filled with a first preconversion catalyst; Preferably, the height ratio of the first pre-conversion layer to the central tube is 0.1-0.5:1; Preferably, the preheating zone is provided with a second preconversion layer filled with a second preconversion catalyst; Preferably, the height ratio of the second preconversion layer to the preheating zone is 0.1-1:1; And / or, the preheating zone is provided with a feed distributor connected to the central tube; And / or, the feed pipe and discharge pipe are disposed at the top of the housing; And / or, at least one thermocouple sheath is also provided on the top of the housing; More preferably, the bottom of at least one of the thermocouple sheaths extends above the reaction section; More preferably, the bottom of at least one of the thermocouple sheaths extends above the heat recovery zone.

6. The method according to claim 5, wherein, The reforming catalyst includes a first active component and a first auxiliary agent, wherein the first active component is selected from nickel, and the first auxiliary agent is selected from at least one of lithium, sodium, potassium, magnesium, calcium, copper, cerium and zinc; Preferably, based on the total weight of the reforming catalyst, the content of the first active component is 10-20 wt%, and the content of the first auxiliary agent is 1-5 wt%. Preferably, the first preconversion catalyst and the second preconversion catalyst each independently comprise: a second active component and a second auxiliary agent, wherein the second active component is selected from nickel, and the second auxiliary agent is selected from at least one of lithium, sodium, potassium, magnesium, calcium, copper, cerium and zinc; Preferably, the content of the second active component is 25-40 wt%, and the content of the second auxiliary agent is 1-5 wt%, each independently based on the total weight of the first preconversion catalyst and the second preconversion catalyst.

7. The method according to any one of claims 1-6, wherein, In step (2), The temperature of the vaporized feedstock is 180-450℃, preferably 330-430℃; Preferably, in the vaporization feedstock, the vaporization rate of water is ≥50%, and more preferably 80-100%; And / or, the temperature of the preheated raw material obtained by sequentially undergoing the first preheating and the second preheating is 400-650℃, preferably 450-600℃, and more preferably 500-550℃; And / or, the conditions for the reforming reaction include: a temperature of 400-980°C, preferably 450-980°C, more preferably 500-950°C, and even more preferably 550-940°C; And / or, the conditions for the reforming reaction further include: a pressure of 0.5-2.5 MPa, preferably 0.8-2 MPa, more preferably 1-1.5 MPa; And / or, the conditions for the reforming reaction further include: a volume hourly space velocity (VHSV) of the preheated feedstock, calculated as CH4, of 500-2000 h⁻¹. -1 Preferably 800-1500h -1 More preferably 1000-1300h -1 ; And / or, the temperature of the second heat-exchanged reformed gas is 900-980℃, preferably 900-950℃, and more preferably 920-940℃; And / or, the temperature of the low-temperature reforming gas is 300-400°C, preferably 320-350°C; And / or, in the low-temperature reformed gas, the CH4 content is ≤1 mol%, preferably ≤0.6 mol%; And / or, the H2O content in the low-temperature reformed gas is 20-30 mol%.

8. The method according to any one of claims 1-7, wherein, In step (3), The reformed dry gas has an H2 content of 60-70 mol%, preferably 61-66 mol%; a CO content of 15-30 mol%, preferably 25-28 mol%; and a CO2 content of 8-20 mol%, preferably 10-15 mol%. And / or, the temperature of the reformed dry gas is ≤50℃, preferably 0-50℃; And / or, the carbon-to-hydrogen ratio of the reformed dry gas is 1-2. And / or, the method further includes: decarbonizing the reformed dry gas to obtain syngas with a carbon-to-hydrogen ratio of 2-2.1; And / or, the method further includes: performing deacidification treatment on the gas-liquid separation to obtain recycled acid water, thereby obtaining deacidified water and acidic gas; Preferably, the deacidified water is returned as circulating water and mixed into the water.

9. A system for preparing syngas from methane feedstock gas, characterized in that, The system includes a compression unit, a purification unit, a reforming unit, a cooling unit, and a separation unit connected in sequence. The reforming unit is selected from a heat exchange reforming reactor, which is a combustion furnace with at least one parallel reaction tube inside, and the furnace temperature of the combustion furnace is provided by the combustion of the methane-containing feed gas; the top of the reaction tube is provided with a feed pipe and a discharge pipe, and the shell of the reaction tube is divided into a heat recovery zone, a heat exchange reaction zone and a preheating zone from top to bottom, and the height of the heat recovery zone is within the insulation material of the combustion furnace; the heat recovery zone is provided with a heat exchange component; the heat exchange reaction zone is provided with a catalyst bed arranged in a ring around the central tube, and the heat exchange reaction zone is divided into a heat exchange section and a reaction section; the two ends of the heat exchange component are respectively connected to the feed pipe and the central tube.

10. The system according to claim 9, wherein, The compression unit is also connected to a CO2 supplementation pipeline, and the CO2 content in the methane-containing feed gas is adjusted by adding supplementary CO2. And / or, the purification unit includes a hydrodesulfurization reactor and an adsorption desulfurization reactor connected in sequence; And / or, the system further includes a decarbonization unit connected to the separation unit for decarbonizing the reformed dry gas to obtain syngas with a carbon-to-hydrogen ratio of 2-2.1; And / or, the system further includes a deacidification unit connected to the separation unit, for deacidifying the recovered acid water obtained from the separation unit, and returning the deacidified water to be mixed into the water.

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