Method for preparing syngas by multi-stage self-heating catalytic deoxidation conversion of oxygen-containing coal-bed gas
By performing multi-stage autothermal catalytic deoxygenation conversion on oxygen-containing coalbed methane, and by segmenting the treatment and optimizing steam utilization, the problems of reaction temperature control and heat utilization have been solved, achieving energy conservation and emission reduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTHWEST RES & DESIGN INST OF CHEM IND
- Filing Date
- 2023-12-29
- Publication Date
- 2026-06-09
AI Technical Summary
In existing methods for producing syngas from oxygen-containing coalbed methane, the reaction temperature is difficult to control, easily leading to overheating and severe carbon precipitation, which reduces catalyst activity. At the same time, the circulating gas compressor increases investment and power consumption, and the excessively high water-to-carbon ratio is uneconomical.
The purified and desulfurized oxygenated coalbed methane is divided into multiple streams and processed in stages through a multi-stage self-heating catalytic deoxygenation reactor. Steam is added only in the first stage to control the reaction temperature, and heat utilization is optimized by using steam to reform methane, thus avoiding the need for a recirculating gas compressor.
This achieves controllable reaction temperature, reduces the amount of heating steam, improves heat utilization efficiency, saves energy and investment, and avoids the use of a recirculating gas compressor.
Smart Images
Figure CN117776105B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of coal chemical technology, specifically to a method for the multi-stage autothermal catalytic deoxygenation and conversion of oxygen-containing coalbed methane into syngas. Background Technology
[0002] The statements in this section provide only background information relevant to the disclosure of this application and may not constitute prior art.
[0003] Oxygen removal from oxygen-containing coalbed methane generally employs a single-stage autothermal catalytic combustion deoxygenation process. However, oxygen-containing coalbed methane not only contains a large amount of methane, but also a small amount of olefins and trace amounts of heavy hydrocarbons. Under high oxygen conditions, its combustion reaction is a strongly exothermic reaction, which makes it difficult to control the reaction temperature during the catalytic combustion process of oxygen-containing coalbed methane, which is prone to overheating and carbon precipitation reaction. The precipitated carbon black covers the catalyst surface, reducing the catalyst activity.
[0004] To control the reaction temperature, traditional single-stage autothermal catalytic combustion deoxygenation processes typically use a recirculating gas compressor to pressurize the reaction outlet gas and mix it with the inlet fresh gas to control the oxygen content of the inlet reaction gas, thereby controlling the reaction temperature. Although this method controls the reaction temperature, the return of the recirculating gas reduces the single-pass conversion rate of methane in the coalbed methane, increases the reactor size, and requires the installation of a recirculating gas compressor, increasing investment and compressor power consumption.
[0005] To reduce carbon deposition, a higher water-to-carbon ratio is generally used in current production plants to suppress carbon black formation. The water-to-carbon ratio is crucial for the smooth progress of the methane conversion reaction; a higher ratio not only benefits the reaction itself but also prevents carbon deposition and eliminates carbon black. A higher steam volume can suppress harmful carbon deposition and prevent adverse effects, but excessive steam volume is economically unreasonable and increases the system load.
[0006] This technology divides the purified, desulfurized, and preheated oxygen-containing coalbed methane into multiple streams. The first stream of oxygen-containing coalbed methane is mixed with steam and then enters the first-stage autothermal catalytic deoxygenation reformer for autothermal catalytic deoxygenation and methane steam reforming. The gas exiting the first-stage autothermal catalytic deoxygenation reformer is mixed with the second stream of oxygen-containing coalbed methane and then enters the second-stage autothermal catalytic deoxygenation reformer for autothermal catalytic deoxygenation and methane steam reforming, and so on. The gas exiting the final stage autothermal catalytic deoxygenation reformer then enters a pure oxygen (or air) reformer for a conversion reaction, converting most of the remaining methane into hydrogen, carbon monoxide, and carbon dioxide. This technology determines the number of reactor stages based on the oxygen content of the coalbed methane, and performs staged autothermal catalytic deoxygenation conversion of oxygen-containing coalbed methane. Steam is added only in the first stage. In the reactor, the oxygen-containing coalbed methane undergoes exothermic oxygen combustion and endothermic steam reforming with methane simultaneously. The reaction temperature is controllable. Under the condition of meeting the catalyst's requirements for the ratio of added steam to methane, the amount of heating steam required is less than that required for single-stage autothermal catalytic deoxygenation conversion. Compared with single-stage autothermal catalytic deoxygenation reaction, heat utilization is more efficient and there is no need to set up a recirculating gas compressor, saving the power consumption and investment of recirculating gas compression. Summary of the Invention
[0007] The purpose of this invention is to address the shortcomings of current methods for producing syngas from oxygen-containing coalbed methane by providing a multi-stage autothermal catalytic deoxygenation conversion method for producing syngas from oxygen-containing coalbed methane. This method allows for controllable reaction temperature, requires less heating steam, and achieves more efficient heat utilization, thus saving energy and investment.
[0008] The technical solution of the present invention is as follows:
[0009] A method for producing syngas from oxygen-containing coalbed methane through multi-stage autothermal catalytic deoxygenation includes the following steps:
[0010] Step (1) divides the purified, desulfurized, and preheated oxygen-containing coalbed methane into multiple streams;
[0011] In step (2), the first stream of oxygen-containing coalbed methane is first mixed with steam, and then enters the first stage of the autothermal catalytic deoxygenation conversion reactor for autothermal catalytic deoxygenation and methane steam reforming reaction.
[0012] Step (3): The gas from the outlet of the first stage autothermal catalytic deoxygenation conversion reactor is mixed with the second stream of oxygen-containing coalbed gas and then enters the second stage autothermal catalytic deoxygenation conversion reactor for autothermal catalytic deoxygenation and methane steam reforming reaction, and so on.
[0013] Step (4): The outlet gas of the last self-heating catalytic deoxygenation reactor is then introduced into a pure oxygen conversion reactor or an air conversion reactor for conversion reaction.
[0014] According to a preferred embodiment, the number of streams in step (1) is determined by the oxygen content in the oxygen-containing coalbed methane. The method for determining the oxygen content is as follows: combustible gases explode under oxygen-rich conditions; therefore, it is first necessary to determine that the oxygen content of each mixed gas segment is outside its explosion range. The oxygen content affects the outlet temperature; by controlling the outlet temperature of each segment below 630°C, and ensuring the auto-ignition temperature when mixed with the remaining gas, the number of streams is adjusted, and the oxygen content of each segment is adjusted accordingly.
[0015] According to a preferred embodiment, the temperature of each stage of the autothermal catalytic deoxygenation conversion reaction in steps (2) and (3) is determined by the catalyst activity temperature and tolerance temperature.
[0016] According to a preferred embodiment, the water-to-carbon ratio (H2O / ΣC) in the inlet gas of the first-stage self-heating catalytic deoxygenation reactor is 2.5–3.2.
[0017] According to a preferred embodiment, in step (4), the amount of pure oxygen or air added to the pure oxygen conversion reactor or air conversion reactor is controlled by the methane content at the outlet of the pure oxygen conversion reactor or air conversion reactor, and the volume fraction of methane content at the outlet of the pure oxygen conversion reactor or air conversion reactor is ≤1%.
[0018] According to a preferred embodiment, the synthesis gas output after step (4) can be converted and decarbonized to produce ammonia or hydrogen, or converted to methanol after a conversion reaction.
[0019] Compared with existing technologies, the advantages of this invention are:
[0020] 1. A method for multi-stage autothermal catalytic deoxygenation conversion of oxygen-containing coalbed methane to syngas, wherein the number of reactor stages is determined according to the oxygen content of the coalbed methane, and the oxygen-containing coalbed methane is subjected to staged autothermal catalytic deoxygenation conversion, with steam added only in the first stage. In the reactor, the oxygen-containing coalbed methane undergoes exothermic oxygen combustion and endothermic steam reforming reaction with methane simultaneously. The reaction temperature is controllable. Under the condition that the catalyst meets the requirements for the ratio of added steam to methane, the amount of heating steam is less than that of single-stage autothermal catalytic deoxygenation conversion.
[0021] 2. A method for multi-stage autothermal catalytic deoxygenation and conversion of oxygen-containing coalbed methane into syngas, which, compared with single-stage autothermal catalytic deoxygenation reaction, makes fuller use of heat and eliminates the need for a circulating gas compressor, thus saving on the power consumption and investment of circulating gas compression.
[0022] 3. A method for converting oxygen-containing coalbed methane into syngas through multi-stage autothermal catalytic deoxygenation, wherein the outlet gas temperature of the final autothermal catalytic deoxygenation reaction is guaranteed to be above the auto-ignition point to save heating energy consumption. Attached Figure Description
[0023] Figure 1A schematic diagram of the two-stage autothermal catalytic deoxygenation conversion process of oxygen-containing coalbed methane to syngas. Figure 1 In this diagram, E1 is an oxygen-containing coalbed methane preheater, R1 is a first-stage self-heating catalytic deoxygenation reactor, R2 is a second-stage self-heating catalytic deoxygenation reactor, Ro is a single-stage pure oxygen (or air) conversion reactor, and X1 is a subsequent conversion syngas application process system, which may be used for conversion decarbonization to produce synthetic ammonia, pressure swing adsorption to produce hydrogen, or conversion reaction to produce methanol.
[0024] Logistics numbers 1 and 2 represent oxygen-containing coalbed methane before and after preheating, respectively; c1 and c2 represent oxygen-containing coalbed methane going to the first and second stage autothermal catalytic deoxygenation reactors (R1 and R2), respectively; i1 and i2 represent the inlet gas of the first and second stage autothermal catalytic deoxygenation reactions, respectively; O1 and O2 represent the outlet gas of the first and second stage autothermal catalytic deoxygenation reactions, respectively; 3 represents steam going to the first stage autothermal catalytic deoxygenation reactor (R1); 4 represents pure oxygen (or air) going to the pure oxygen (or air) conversion reactor (Ro); 5 represents the inlet gas of the pure oxygen (or air) conversion reactor (Ro); and 6 represents the outlet gas of the pure oxygen (or air) conversion reactor (Ro), i.e., the product synthesis gas.
[0025] Figure 2 A schematic diagram of a three-stage autothermal catalytic deoxygenation conversion process for producing syngas from oxygen-containing coalbed methane. Figure 2 In this diagram, E1 is an oxygen-containing coalbed methane preheater, R1, R2, and R3 are the first, second, and third stage self-heating catalytic deoxygenation reactors, respectively, Ro is a single-stage pure oxygen (or air) conversion reactor, and X1 is the subsequent conversion syngas application process system, which may be used for decarbonization to produce synthetic ammonia, pressure swing adsorption to produce hydrogen, or conversion reaction to produce methanol.
[0026] Logistics numbers 1 and 2 represent oxygen-containing coalbed methane before and after preheating, respectively; c1, c2, and c3 represent oxygen-containing coalbed methane going to the first, second, and third stage autothermal catalytic deoxygenation reactors (R1 and R2), respectively; i1, i2, and i3 represent the inlet gas of the first, second, and third stage autothermal catalytic deoxygenation reactions, respectively; O1, O2, and O3 represent the outlet gas of the first, second, and third stage autothermal catalytic deoxygenation reactions, respectively; 3 represents steam going to the first stage autothermal catalytic deoxygenation reactor (R1); 4 represents pure oxygen (or air) going to the pure oxygen (or air) conversion reactor (Ro); 5 represents the inlet gas of the pure oxygen (or air) conversion reactor (Ro); and 6 represents the outlet gas of the pure oxygen (or air) conversion reactor (Ro), i.e., the product synthesis gas.
[0027] Figure 3 A schematic diagram of the n-stage autothermal catalytic deoxygenation conversion process of oxygen-containing coalbed methane to syngas. Figure 3In this diagram, E1 is an oxygen-containing coalbed methane preheater, R1 is a first-stage autothermal catalytic deoxygenation reactor, R2 is a second-stage autothermal catalytic deoxygenation reactor, Rn is an n-stage (n=3, 4...) autothermal catalytic deoxygenation reactor, Ro is a single-stage pure oxygen (or air) conversion reactor, and X1 is the subsequent conversion syngas application process system, which may be used for conversion decarbonization to produce synthetic ammonia, pressure swing adsorption to produce hydrogen, or conversion reaction to produce methanol.
[0028] Logistics numbers 1 and 2 represent oxygen-containing coalbed methane before and after preheating, respectively; c1 to cn represent oxygen-containing coalbed methane going to each stage of the autothermal catalytic deoxygenation reactor (R1 to Rn); i1 to in represent the inlet gas of each stage of the autothermal catalytic deoxygenation reaction; O1 to On represent the outlet gas of each stage of the autothermal catalytic deoxygenation reaction; 3 represents steam going to the first stage of the autothermal catalytic deoxygenation reactor (R1); 4 represents pure oxygen (or air) going to the pure oxygen (or air) conversion reactor (Ro); 5 represents the inlet gas of the pure oxygen (or air) conversion reactor (Ro); and 6 represents the outlet gas of the pure oxygen (or air) conversion reactor (Ro), i.e., the product synthesis gas. Detailed Implementation
[0029] The features and performance of the present invention will be further described in detail below with reference to embodiments. The given embodiments do not limit the scope of the present invention; the present invention extends to any new feature or any new combination disclosed in this specification, as well as any new method or process step or any new combination disclosed. It should be noted that, unless otherwise specified, the methods used in the present invention are conventional methods; and unless otherwise specified, the experimental materials used in the present invention are commercially available.
[0030] Example 1
[0031] The composition (v%) of the oxygen-containing coalbed methane to be treated in this embodiment is: 50% CH4, 10% O2, and 40% N2. The gas volume is 50,000 Nm³. 3 / h, pressure 0.4MPa(G), temperature 350℃.
[0032] Steam: Temperature 350℃, Pressure 0.5MPa(G), Flow rate 24650Nm³ 3 / h.
[0033] Based on the oxygen content of 10% in the oxygen-containing coalbed methane, the oxygen-containing coalbed methane is divided into multiple gas streams, requiring that the oxygen content in each gas stream is lower than the oxygen content required for the explosion of the oxygen-containing coalbed methane. Then, the outlet temperature is calculated based on the oxygen content, and the outlet temperature of each segment is controlled below 630℃, which is the auto-ignition temperature when mixed with the remaining gas. The number of gas streams in the oxygen-containing coalbed methane is then adjusted again.
[0034] The schematic diagram of the multi-stage autothermal catalytic deoxygenation conversion process for producing syngas from oxygen-containing coalbed methane in this embodiment is shown below. Figure 1As shown, a two-stage self-heating catalytic deoxygenation conversion process is adopted:
[0035] The raw material, oxygen-containing coalbed methane, was divided into two gas streams (each with a flow rate of 20,000 Nm³ / h). 3 / h, 30000Nm 3 / h) respectively enters the first stage and the second stage self-heating catalytic deoxygenation reactor:
[0036] The first part involves mixing oxygen-containing coalbed methane with steam, at a steam flow rate of 24650 Nm³. 3 The mixture contains 4.5% O2, 17.9% CH4, and has a water-to-carbon ratio of 3.08. It enters the first-stage autothermal catalytic deoxygenation reactor (R1) for autothermal catalytic deoxygenation. The outlet gas temperature of the first-stage autothermal catalytic deoxygenation reactor is 549℃, O2 is completely removed, and the CH4 content is 9.5%.
[0037] The outlet gas from the first stage of the autothermal catalytic deoxygenation reaction is directly reacted with the second stage of fresh oxygen-containing coalbed methane (30,000 Nm³). 3 The mixture ( / h) is fed into the second-stage autothermal catalytic deoxygenation reactor (R2). The inlet gas for the second-stage autothermal catalytic deoxygenation reaction has an O2 content of 3.8%, a CH4 content of 21.1%, and a temperature of 470℃. After the second-stage autothermal catalytic deoxygenation reaction, the outlet gas temperature is 614℃, O2 is completely removed, and the CH4 content is 13.6%.
[0038] The outlet gas from the second-stage autothermal catalytic deoxygenation reaction is mixed with pure oxygen (pure oxygen flow rate 7734 Nm). 3 The gas, at a temperature of 580℃, enters the pure oxygen conversion reactor (Ro). After the conversion reaction, the outlet gas temperature is 900℃, and the methane content is 0.1%. The composition of each material in the gas output from the Ro reactor is shown in the table below:
[0039] materials <![CDATA[H2]]> CO <![CDATA[CO2]]> <![CDATA[N2]]> <![CDATA[CH4]]> <![CDATA[H2O]]> Composition (v%) 36.9 12.6 5.6 22.8 0.1 22
[0040] The syngas has a high nitrogen content, so after a subsequent conversion and decarbonization reaction, it can be used as a feedstock for ammonia synthesis.
[0041] In this example, the amount of steam added is 24650 Nm. 3 / h, the subsequent self-heating catalytic deoxygenation reaction and pure oxygen (or air) conversion reaction can meet the reaction requirements, reducing steam consumption by 263,100 tons per year compared with the single-stage deoxygenation process under the same conditions.
[0042] Example 2
[0043] The composition (vol%) of the oxygen-containing coalbed methane to be treated in this embodiment is: 50% CH4, 10% O2, 40% N2. The gas volume is 50,000 Nm³. 3 / h, pressure 0.4MPa(G), temperature 350℃.
[0044] Steam: Temperature 350℃, Pressure 0.5MPa(G), Flow rate 18000Nm³ 3 / h.
[0045] Based on the oxygen content of 10% in the oxygen-containing coalbed methane, the oxygen-containing coalbed methane is divided into multiple gas streams, requiring that the oxygen content in each gas stream is lower than the oxygen content required for the explosion of the oxygen-containing coalbed methane. Then, the outlet temperature is calculated based on the oxygen content, and the outlet temperature of each segment is controlled below 630℃, which is the auto-ignition temperature when mixed with the remaining gas. The number of gas streams in the oxygen-containing coalbed methane is then adjusted again.
[0046] A schematic diagram of a multi-stage autothermal catalytic deoxygenation conversion process for oxygen-containing coalbed methane to syngas is shown below. Figure 2 As shown, a three-stage self-heating catalytic deoxygenation conversion process is adopted:
[0047] The raw material, oxygen-containing coalbed methane, was divided into three gas streams (each with a flow rate of 15000 Nm³ / h). 3 / h, 22750Nm 3 / h, 12250Nm 3 / h) respectively enters the first, second, and third stage self-heating catalytic deoxygenation reactors:
[0048] The first part is a mixture of oxygen-containing coalbed methane and steam. The mixed gas contains 4.5% O2, 18.2% CH4, and has a water-to-carbon ratio of 3.0. It enters the first-stage autothermal catalytic deoxygenation reactor (R1) for autothermal catalytic deoxygenation reaction. The outlet gas temperature of the first-stage autothermal catalytic deoxygenation reaction is 551℃, the O2 is completely reacted, and the CH4 content is 9.7%.
[0049] The outlet gas from the first stage of the autothermal catalytic deoxygenation reaction is directly reacted with the second part of fresh oxygen-containing coalbed methane (22750 Nm³). 3 The mixture ( / h) is fed into the second-stage autothermal catalytic deoxygenation reactor (R2). The inlet gas for the second-stage autothermal catalytic deoxygenation reaction has an O2 content of 3.8%, a CH4 content of 21.3%, and a temperature of 470℃. After the second-stage autothermal catalytic deoxygenation reaction, the outlet gas temperature is 616℃, O2 is completely removed, and the CH4 content is 13.7%.
[0050] The outlet gas from the second-stage autothermal catalytic deoxygenation reaction is directly reacted with the fresh oxygen-containing coalbed methane from the third stage (12250 Nm³). 3 The mixture ( / h) is fed into the third-stage autothermal catalytic deoxygenation reactor (R3). The inlet gas of the third-stage autothermal catalytic deoxygenation reaction has an O2 content of 1.6%, a CH4 content of 17.9%, and a temperature of 570℃. After the third-stage autothermal catalytic deoxygenation reaction, the outlet gas temperature is 631℃, O2 is completely removed, and the CH4 content is 14.8%.
[0051] The outlet gas from the third-stage autothermal catalytic deoxygenation reaction is mixed with pure oxygen (pure oxygen flow rate 7473 Nm). 3 The gas, at a temperature of 593℃, enters the pure oxygen conversion reactor (Ro). After the conversion reaction, the outlet gas temperature is 900℃, and the methane content is 0.1%. The composition of each material in the gas output from the Ro reactor is shown in the table below:
[0052] materials <![CDATA[H2]]> CO <![CDATA[CO2]]> <![CDATA[N2]]> <![CDATA[CH4]]> <![CDATA[H2O]]> Composition (v%) 38.6 14.4 4.9 24.3 0.1 17.6
[0053] The syngas has a high nitrogen content, so after a subsequent conversion and decarbonization reaction, it can be used as a feedstock for ammonia synthesis.
[0054] In this embodiment, the first stage of steam replenishment is 18000 Nm. 3 With a capacity of / h, subsequent autothermal catalytic deoxygenation and pure oxygen (or air) conversion reactions can meet the reaction requirements. Compared with the single-stage autothermal catalytic deoxygenation conversion process under the same conditions, it reduces steam consumption by 305,800 tons per year and by 42,800 tons compared with the two-stage autothermal catalytic deoxygenation conversion process.
[0055] Example 3
[0056] The composition (vol%) of the oxygen-containing coalbed methane to be treated in this embodiment is: 40% CH4, 12% O2, 48% N2. The gas volume is 50,000 Nm³. 3 / h, pressure 0.4MPa(G), temperature 350℃.
[0057] Steam: Temperature 350℃, Pressure 0.5MPa(G), Flow rate 15500Nm³ 3 / h.
[0058] Based on the oxygen content of 12% in the oxygen-containing coalbed methane, the oxygen-containing coalbed methane is divided into multiple gas streams, requiring that the oxygen content in each gas stream is lower than the oxygen content required for the explosion of the oxygen-containing coalbed methane. Then, the outlet temperature is calculated based on the oxygen content, and the outlet temperature of each segment is controlled below 630℃. The temperature is then mixed with the remaining gas to reach the auto-ignition temperature. The number of gas streams in the oxygen-containing coalbed methane is then adjusted again.
[0059] A schematic diagram of a multi-stage autothermal catalytic deoxygenation conversion process for oxygen-containing coalbed methane to syngas is shown below. Figure 2 As shown, a two-stage self-heating catalytic deoxygenation conversion process is adopted:
[0060] The raw material, oxygen-containing coalbed methane, was divided into two gas streams (15000 Nm³ and 15000 Nm³ respectively). 3 / h, 35000Nm 3 / h) respectively enters the first stage and the second stage self-heating catalytic deoxygenation reactor:
[0061] The first part is an oxygen-containing coalbed methane mixed with steam. The mixed gas has an O2 content of 5.9%, a CH4 content of 19.7%, and a water-to-carbon ratio of 2.58. It enters the first-stage autothermal catalytic deoxygenation reactor (R1) for autothermal catalytic deoxygenation reaction. The outlet gas temperature of the first-stage autothermal catalytic deoxygenation reaction is 593℃, the O2 is completely reacted, and the CH4 content is 8.6%.
[0062] The outlet gas from the first stage of the autothermal catalytic deoxygenation reaction is directly reacted with the second stage of fresh oxygen-containing coalbed methane (35000 Nm³). 3 The mixture is fed into the second-stage autothermal catalytic deoxygenation reactor (R2) at a temperature of 465°C. The inlet gas for the second-stage autothermal catalytic deoxygenation reaction has an O2 content of 6%, a CH4 content of 24.4%, and a temperature of 465°C. After the second-stage autothermal catalytic deoxygenation reaction, the outlet gas temperature is 668°C, O2 is completely removed, and the CH4 content is 12.6%.
[0063] The outlet gas from the second-stage autothermal catalytic deoxygenation reaction is mixed with pure oxygen (pure oxygen flow rate 6764 Nm). 3 The gas, at a rate of 630℃ / h, enters the pure oxygen conversion reactor (Ro). After the conversion reaction, the outlet gas temperature is 950℃, and the methane content is 0.1%. The composition of the gas output from the Ro reactor is shown in the table below:
[0064] materials <![CDATA[H2]]> CO <![CDATA[CO2]]> <![CDATA[N2]]> <![CDATA[CH4]]> <![CDATA[H2O]]> Composition (v%) 38.9 15.6 4.4 24.2 0.1 16.8
[0065] The syngas contains high levels of H2, CO, and N2, so after subsequent conversion reactions, it can be used as a methanol feedstock, or after conversion decarbonization reactions, it can be used to produce hydrogen or synthetic ammonia.
[0066] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.
Claims
1. A method for multi-stage autothermal catalytic deoxygenation and conversion of oxygen-containing coalbed methane into syngas, characterized in that, Includes the following steps: Step (1) divides the purified, desulfurized, and preheated oxygen-containing coalbed methane into multiple streams; Step (2): The first oxygen-containing coalbed methane is first mixed with steam, and then enters the first stage of the autothermal catalytic deoxygenation conversion reactor for autothermal catalytic deoxygenation and methane steam reforming reaction; Step (3): The outlet gas from the first stage autothermal catalytic deoxygenation conversion reactor is mixed with the second stream of oxygen-containing coalbed gas and then enters the second stage autothermal catalytic deoxygenation conversion reactor for autothermal catalytic deoxygenation and methane steam reforming reaction, and so on. Step (4): The outlet gas of the last self-heating catalytic deoxygenation conversion reactor is then introduced into a pure oxygen conversion reactor or an air conversion reactor for conversion reaction. The number of streams in the multi-stream process in step (1) is determined by the oxygen content in the oxygen-containing coalbed methane. Specifically, the oxygen content in the single stream is lower than the explosion range of the oxygen-containing coalbed methane, and the output temperature at the outlet of the self-heating catalytic deoxygenation conversion reactor is lower than 630°C. The water-to-carbon ratio (H2O / ΣC) in the inlet gas of the first-stage self-heating catalytic deoxygenation reactor is 2.5–3.
2.
2. The method for multi-stage autothermal catalytic deoxygenation and conversion of oxygen-containing coalbed methane to syngas according to claim 1, characterized in that, The temperature of each stage of the autothermal catalytic deoxygenation conversion reaction in steps (2) and (3) is determined by the catalyst activity temperature and tolerance temperature.
3. The method for multi-stage autothermal catalytic deoxygenation and conversion of oxygen-containing coalbed methane to syngas according to claim 1, characterized in that, In step (4), the amount of pure oxygen or air added to the pure oxygen conversion reactor or air conversion reactor is controlled by the methane content at the outlet of the pure oxygen conversion reactor or air conversion reactor, and the volume fraction of methane content at the outlet of the pure oxygen conversion reactor or air conversion reactor is ≤1%.
4. The method for multi-stage autothermal catalytic deoxygenation and conversion of oxygen-containing coalbed methane to syngas according to claim 1, characterized in that, The synthesis gas output after step (4) is completed can be converted into ammonia or hydrogen after decarbonization, or into methanol after conversion reaction.