Coal fixed bed pyrolysis device

Abstract

The invention relates to the technical field of efficient and clean conversion and utilization of coal, and discloses a coal fixed bed pyrolysis device, which comprises: a gas distribution assembly, which comprises a main body pipeline and at least three groups of gas inlet branch pipelines communicated with the main body pipeline, and is used for introducing at least one of nitrogen, hydrogen and carbon dioxide gas; a first ball valve, a first pressure gauge, a first gas filter, a mass flow meter and second ball valves located on the two sides of the mass flow meter are sequentially arranged on each gas inlet branch pipeline in the gas inlet direction, the high-precision mass flow meter and an auxiliary structure are adopted for the coal fixed bed pyrolysis device, multiple paths of gas are precisely matched, and the problem that data of a traditional device is not reliable is solved; and three-section temperature control is linked with a thermocouple, so that the temperature is uniform and stable. A two-stage condensation separation system is innovated, a pipeline heating belt is matched, products are efficiently separated, blockage is prevented, programmed control and safety protection are achieved through a control system, operation is convenient and fast, and stability is high.

Description

Technical Field

[0001] This invention relates to the field of efficient and clean coal conversion and utilization technology, specifically to a coal fixed-bed pyrolysis device. Background Technology

[0002] Coal is an important component of my country's energy structure, and its efficient and clean utilization is of great significance for ensuring national energy security and environmental protection. Pyrolysis technology, as one of the key pathways for coal conversion and utilization, can convert coal into high-value-added products such as tar, coal gas, and semi-coke, and is an important means to achieve graded conversion and clean utilization of coal. Fixed-bed pyrolysis devices are widely used in coal pyrolysis research due to their simple structure, stable operation, and suitability for small-scale experimental research and process development. However, existing small-scale fixed-bed pyrolysis devices for laboratory use still have some technical limitations in their design and application: Traditional devices often employ rotor flowmeters or simple mass flow controllers, which struggle to achieve high-precision and stable proportioning and control of multiple gases (such as nitrogen, hydrogen, and carbon dioxide), affecting experimental repeatability and data reliability. Pyrolysis reactions are highly temperature-sensitive, and existing devices frequently use single-stage heating, making it difficult to achieve uniform axial temperature control of the reactor. This is especially problematic for small particulate materials like pulverized coal, leading to uneven distribution of pyrolysis products. Tar and gaseous products generated during pyrolysis are prone to condensation or blockage in the pipelines. Existing devices often use simple cold traps or separators, resulting in unsatisfactory separation effects and impacting product analysis and experimental continuity. Therefore, we propose a coal fixed-bed pyrolysis device to address these issues. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a coal fixed-bed pyrolysis device, which solves the problems of low precision in multi-channel gas ratio control, uneven axial temperature of the reactor leading to unbalanced product distribution, easy condensation and blockage of pipelines by pyrolysis products, and poor separation effect in existing small-scale laboratory fixed-bed pyrolysis devices.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a coal fixed-bed pyrolysis device, comprising: A gas dispensing assembly includes a main pipeline and at least three sets of inlet branch pipelines connected to the main pipeline for introducing at least one of nitrogen, hydrogen, and carbon dioxide gas; each set of inlet branch pipelines is provided with a ball valve, a pressure gauge, a gas filter, a mass flow meter, and ball valves located on both sides of the mass flow meter in sequence along the inlet direction; a one-way valve is provided at the end of each inlet branch pipeline. The reaction assembly includes a reactor connected to a gas supply assembly via the main pipeline, a thermocouple sleeve inserted inside the reactor, and an electric heating furnace movably mounted outside the reactor. The product collection assembly includes a tar collector, a secondary gas-liquid separator, and a gas washing bottle, which are sequentially connected to the outlet of the reactor; the tar collector is provided with a cooling jacket, which is connected to a refrigeration cycle machine located on one side of the tar collector. The system includes a control cabinet and a controller installed in the control cabinet. The controller is electrically connected to the gas dispensing component, the reaction component, and the product collection component, respectively, for centralized monitoring and control of each component.

[0005] Preferably, a pressure gauge 2 is installed on the main pipeline.

[0006] Preferably, the gas dispensing assembly further includes a delivery pipe and a needle valve; on one of the inlet branch pipes, the delivery pipe is connected in parallel at the pipe node between ball valves on both sides of the mass flow meter, and the needle valve is disposed on the delivery pipe.

[0007] Preferably, the air inlet branch pipe of the first conveying pipe is a branch pipe for introducing nitrogen gas.

[0008] Preferably, the product collection assembly further includes a second conveying pipe connecting the reactor outlet to the tar collector, a third conveying pipe connecting the tar collector to the secondary gas-liquid separator, and a fourth conveying pipe connecting the secondary gas-liquid separator to the gas washing bottle.

[0009] Preferably, the outlet pipe of the gas washing bottle is provided with a gas filter, a pressure gauge, and a needle valve in sequence.

[0010] Preferably, the controller is communicatively connected to each of the mass flow meters, the electric heating furnace, and the refrigeration cycle machine, for programmed setting and closed-loop control of the inlet flow rate, reaction temperature, and cooling temperature.

[0011] Preferably, the thermocouple sheath contains a built-in thermocouple, which is connected to the signal input terminal of the controller.

[0012] Preferably, the electric heating furnace is mounted via a movable slide rail, and the movable slide rail is connected to a drive mechanism, which is connected to the controller.

[0013] Preferably, the secondary gas-liquid separator is also equipped with a cooling jacket and connected to the refrigeration cycle machine, so that the tar collector and the secondary gas-liquid separator constitute a two-stage condensation separation system. Beneficial effects

[0014] This invention provides a fixed-bed coal pyrolysis apparatus. Compared with the prior art, it has the following advantages: This fixed-bed coal pyrolysis device represents a breakthrough optimization of key process steps, providing more reliable experimental support for coal pyrolysis research. Regarding the two core influencing factors of gas ratio and temperature control, the device employs a high-precision mass flow meter, coupled with multi-stage filtration, one-way valves, and a nitrogen branch auxiliary adjustment structure. This achieves high-precision and stable ratio and delivery of multiple gases such as nitrogen, hydrogen, and carbon dioxide, completely resolving the problems of poor experimental repeatability and unreliable data caused by insufficient control accuracy of traditional rotor flow meters. Simultaneously, through the linkage of a three-stage temperature-controlled electric heater with a built-in K-type thermocouple sheath, combined with closed-loop controller adjustment, the axial temperature uniformity of the reactor is significantly improved, with a temperature deviation of ≤±1℃ in the constant-temperature section. This effectively avoids the problem of uneven pyrolysis product distribution caused by uneven heating temperatures in a single stage for small particulate materials such as pulverized coal. Meanwhile, in terms of product processing and experimental continuity, the device innovatively designs a two-stage condensation separation system. Both the tar collector and the secondary gas-liquid separator are equipped with cooling jackets and linked to a -20℃ refrigeration cycle machine. Combined with the pipeline heating belt anti-condensation design, the separation efficiency and recovery rate of tar and coal gas are greatly improved. This completely solves the pain points of poor separation effect and easy condensation and pipeline blockage of traditional simple cold traps or separators. The entire device realizes the programmed setting and centralized monitoring of air inlet flow, reaction temperature and cooling temperature through the control system. It also has safety protection functions such as over-temperature and over-pressure alarms. It is easy to operate and highly stable, providing a high-precision and high-reliability experimental platform for the process research of coal classification conversion and clean utilization. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure and connection of the present invention.

[0016] In the diagram: 101. Main pipeline; 102. Branch pipeline; 103. Ball valve 1; 104. Pressure gauge 1; 105. Gas filter 1; 106. Mass flow meter; 107. Ball valve 2; 108. Delivery pipeline 1; 109. Needle valve 1; 110. Check valve; 111. Pressure gauge 2; 112. Reactor; 113. Thermocouple sheath; 114. Electric heating furnace; 115. Delivery pipeline 2; 116. Tar collector; 117. Secondary gas-liquid separator; 118. Gas washing bottle; 119. Gas filter 2; 120. Pressure gauge 3; 121. Needle valve 2; 122. Refrigeration cycle unit; 123. Delivery pipeline 3; 124. Delivery pipeline 4. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1 As shown: A coal fixed-bed pyrolysis unit includes: A gas distribution assembly includes a main pipeline 101 and at least three sets of inlet branch pipelines 102 connected to the main pipeline 101 for introducing at least one of nitrogen, hydrogen, and carbon dioxide gas; each set of inlet branch pipelines 102 is provided with a ball valve 103, a pressure gauge 104, a gas filter 105, a mass flow meter 106, and a ball valve 107 located on both sides of the mass flow meter 106 in sequence along the inlet direction; a one-way valve 110 is provided at the end of the inlet branch pipeline 102, and a pressure gauge 111 is provided on the main pipeline 101; The gas distribution assembly also includes a delivery pipe 108 and a needle valve 109; on one of the inlet branch pipes 102, a delivery pipe 108 is connected in parallel at the pipe node between ball valves 107 located on both sides of the mass flow meter 106, and the needle valve 109 is provided on the delivery pipe 108. The air inlet branch pipe 102 of the conveying pipe 108 is a branch pipe for introducing nitrogen gas; The reaction assembly includes a reactor 112 connected to a gas supply assembly via a main pipe 101, a thermocouple sleeve 113 inserted inside the reactor 112, and an electric heating furnace 114 that is axially movable and sleeved outside the reactor 112. The product collection assembly includes a tar collector 116, a secondary gas-liquid separator 117, and a gas washing bottle 118, which are sequentially connected to the outlet of the reactor 112. The tar collector 116 is equipped with a cooling jacket, which is connected to a refrigeration cycle machine 122 located on one side of the tar collector 116. The product collection assembly also includes a second conveying pipe 115 connecting the outlet of the reactor 112 to the tar collector 116, a third conveying pipe 123 connecting the tar collector 116 to the secondary gas-liquid separator 117, and a fourth conveying pipe 124 connecting the secondary gas-liquid separator 117 to the gas washing bottle 118. A second gas filter 119, a third pressure gauge 120, and a second needle valve 121 are sequentially installed on the outlet pipe of the gas washing bottle 118. The system includes a control cabinet and a controller installed in the control cabinet. The controller is electrically connected to the gas dispensing assembly, the reaction assembly and the product collection assembly, respectively, for centralized monitoring and control of each assembly. The controller is connected to each mass flow meter 106, electric heating furnace 114 and refrigeration cycle machine 122 for programmed setting and closed-loop control of inlet flow, reaction temperature and cooling temperature. Thermocouple is built into thermocouple sheath 113, and thermocouple is connected to signal input terminal of controller; The electric heating furnace 114 is installed via a movable slide rail, and the movable slide rail is connected to a drive mechanism, which is connected to a controller; the secondary gas-liquid separator 117 is also equipped with a cooling jacket and is connected to a refrigeration cycle machine 122, so that the tar collector 116 and the secondary gas-liquid separator 117 constitute a two-stage condensation separation system.

[0019] In this implementation plan: During the use of the coal fixed-bed pyrolysis unit, the tightness and integrity of the connections of the gas distribution components, reaction components, product collection components, and control system are checked one by one. Special attention is paid to checking that the main pipeline 101 and the gas inlet branch pipeline 102 are free from damage and leaks; that ball valves 103, 107, 109, 121, etc., operate flexibly and have good sealing performance; that gas filters 105 and 119 have no filter blockage and meet the 7μm pore size filtration requirements; and that the mass flow meter 106, pressure gauges, and other instruments are properly wired and their displays are zeroed. Weigh 5g of pulverized coal that meets the particle size requirements according to the process requirements, open the feed port of reactor 112, and evenly fill the pulverized coal into the bed inside the reactor to ensure uniform material distribution and avoid local accumulation that would affect the pyrolysis effect. After filling, seal the feed port of the reactor. The experimental process parameters are input into the host computer of the control system, including: the flow rate settings for three inlet gases such as nitrogen, hydrogen, and carbon dioxide, which can be adjusted as needed within the range of 0-200 ml / min, and the flow rate parameters are calibrated according to the mass flow meter 106; the heating program of the electric heating furnace 114, with a target reaction temperature of 500-800℃ and a design temperature of 850℃, setting three temperature control parameters and the holding time of the constant temperature section to ensure that the temperature deviation of the constant temperature section is ≤±1℃; the cooling temperature setting of the refrigeration cycle machine 122 is -20℃ to match the condensation requirements of the tar collector 116 and the secondary gas-liquid separator 117; at the same time, alarm thresholds for over-temperature exceeding the design temperature of 850℃ and over-pressure exceeding the design pressure of 0.3MPa are set, as well as emergency shutdown procedures. Open ball valve 103 on nitrogen inlet branch pipe 102. Nitrogen enters the pipe after being depressurized by the cylinder. The inlet pressure is monitored in real time by pressure gauge 104. After passing through gas filter 105 to remove impurities, it flows through mass flow meter 106 for precise flow measurement. The mass flow meter feeds the flow signal back to the controller to achieve closed-loop regulation. At this time, ball valves 107 on both sides of the mass flow meter are open. Nitrogen enters the main pipe 101 through check valve 110. Pressure gauge 111 on the main pipe monitors the mixed gas pressure. If rapid purging or flow adjustment is required, auxiliary control can be achieved through delivery pipe 108 and needle valve 109 connected in parallel to the nitrogen branch pipe to ensure that air in reactor 112 and the entire gas system is completely discharged to prevent oxygen from affecting the pyrolysis reaction. According to experimental requirements, ball valves 103 on the inlet branch pipes 102 corresponding to hydrogen and carbon dioxide are opened sequentially. After being monitored by their respective pressure gauges, filtered by gas filters, and measured by mass flow meters, the two gases converge into the main pipe 101 through one-way valve 110, forming a mixed gas with nitrogen. The controller synchronously adjusts the output of the three mass flow meters according to preset mixing parameters to ensure that the three gases are stably mixed in the set ratio. The mixed gas is continuously delivered to reactor 112 through the main pipe. One-way valve 110 effectively prevents gas backflow and ensures gas mixing stability. The control system activates the drive mechanism, moving the electric heater 114 axially along the sliding rail to precisely mount it outside the reactor 112, ensuring full coverage of the heating area. The electric heater 114 is then started, beginning heating according to a preset multi-stage heating program. The heater employs a three-stage temperature control mode, with a 304SS outer shell and a maximum design temperature of 850℃. A K-type thermocouple integrated into the thermocouple sheath 113 monitors the internal bed temperature of the reactor in real time within a 0-1000℃ range, transmitting the temperature signal to the controller. The controller compares the measured temperature with the set temperature and dynamically adjusts the heating power of the electric heater, achieving closed-loop temperature control to ensure uniform axial temperature within the reactor and meet the temperature stability requirements of pulverized coal pyrolysis. When the internal temperature of the reactor reaches the preset reaction temperature, the control system automatically switches to constant temperature mode. Temperature data is continuously fed back through thermocouples, and the electric heating furnace finely adjusts the heating power to maintain the temperature deviation in the constant temperature section ≤ ±1℃, providing a stable temperature environment for the pulverized coal pyrolysis reaction. The mixed gas enters through the upper inlet of reactor 112 and flows evenly through the pulverized coal bed from top to bottom. Under preset temperature and pressure conditions, the pulverized coal undergoes a pyrolysis reaction, producing products such as tar, coal gas, and semi-coke. During the reaction, thermocouples continuously monitor the bed temperature, mass flow meters maintain a stable gas flow rate, and controllers collect key parameters such as temperature, flow rate, and pressure in real time, recording experimental data simultaneously for subsequent analysis. The reactor is made of 316L stainless steel, which is resistant to high temperatures and corrosion, and can withstand a design pressure of 0.3 MPa, ensuring the safe conduct of the reaction. The mixed products generated by pyrolysis are discharged through the lower port of reactor 112 and enter the second conveying pipeline 115. To prevent tar from condensing and clogging inside the pipeline, a heating belt is wrapped around the outside of the second conveying pipeline. The heating belt continuously heats the pipeline to ensure that the temperature inside the pipeline is maintained above the tar dew point, thus ensuring that the product is smoothly conveyed to the product collection component. The mixed products enter the tar collector 116 via conveying pipe 115. The tar collector is made of 316L stainless steel and is equipped with a cooling jacket. It is connected to a refrigeration cycle unit 122 via a pipe. The refrigeration cycle unit provides a cooling medium at -20℃ to cool the tar collector. The mixed products exchange heat with the cooling jacket inside the tar collector, and the tar vapor condenses into liquid tar, which is deposited at the bottom of the collector, achieving preliminary separation of tar and coal gas. The operating temperature of the tar collector is controlled between 25-150℃, with a design temperature of 200℃ to meet the condensation and separation requirements. The coal gas and a small amount of uncondensed tar vapor, after initial separation by the tar collector, enter the secondary gas-liquid separator 117 through pipeline 123. The secondary gas-liquid separator is also equipped with a cooling jacket and is connected to the refrigeration cycle unit 122, forming a two-stage condensation separation system. This further reduces the gas temperature, with an operating temperature of 25-50℃ and a design temperature of 80℃. This ensures that the remaining tar vapor is fully condensed, and the liquid products remain in the separator, effectively improving the tar recovery rate and preventing tar from being lost with the gas or clogging subsequent pipelines. After two-stage separation, the coal gas enters the gas washing bottle 118 through the four-stage pipeline 124. The gas washing bottle is made of glass / PP and contains absorbent liquid to purify acidic impurities and trace dust in the coal gas. The purified gas is then filtered again through the second gas filter 119, the pressure is monitored by the third pressure gauge 120, and finally the emission rate is adjusted by the second needle valve 121. Gas sampling and testing can be performed according to experimental needs, or the gas can be vented after alkaline washing. This scheme achieves breakthrough optimization of key process steps, providing more reliable experimental support for coal pyrolysis research. Regarding the two core influencing factors of gas ratio and temperature control, the device employs a high-precision mass flow meter, coupled with multi-stage filtration, one-way valves, and a nitrogen branch auxiliary adjustment structure, to achieve high-precision and stable ratio and delivery of multiple gases such as nitrogen, hydrogen, and carbon dioxide. This completely solves the problems of poor experimental repeatability and unreliable data caused by insufficient control accuracy of traditional rotor flow meters. Simultaneously, through the linkage of a three-stage temperature-controlled electric heating furnace with a built-in K-type thermocouple thermocouple sheath, combined with closed-loop controller adjustment, the axial temperature uniformity of the reactor is significantly improved, with a temperature deviation of ≤±1℃ in the constant temperature section. This effectively avoids the problem of uneven pyrolysis product distribution caused by uneven heating temperature in a single stage for small particulate materials such as pulverized coal. Meanwhile, in terms of product processing and experimental continuity, the device innovatively designs a two-stage condensation separation system. Both the tar collector and the secondary gas-liquid separator are equipped with cooling jackets and linked to a -20℃ refrigeration cycle machine. Combined with the pipeline heating belt anti-condensation design, the separation efficiency and recovery rate of tar and coal gas are greatly improved. This completely solves the pain points of poor separation effect and easy condensation and pipeline blockage of traditional simple cold traps or separators. The entire device realizes the programmed setting and centralized monitoring of air inlet flow, reaction temperature and cooling temperature through the control system. It also has safety protection functions such as over-temperature and over-pressure alarms. It is easy to operate and highly stable, providing a high-precision and high-reliability experimental platform for the process research of coal classification conversion and clean utilization.

[0020] It should be noted that all electrical equipment involved in this product is powered by an external power source, and the power connection methods of each electrical device are existing mature technologies, which are well known to those in the field, and will not be elaborated further here.

[0021] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0022] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A coal fixed-bed pyrolysis device, characterized in that: include: A gas distribution assembly includes a main pipe (101) and at least three sets of inlet branch pipes (102) connected to the main pipe (101) for introducing at least one of nitrogen, hydrogen and carbon dioxide gas; each set of inlet branch pipes (102) is provided with a ball valve (103), a pressure gauge (104), a gas filter (105), a mass flow meter (106), and a ball valve (107) located on both sides of the mass flow meter (106) in sequence along the inlet direction; a one-way valve (110) is provided at the end of each inlet branch pipe (102). The reaction assembly includes a reactor (112) connected to a gas supply assembly via the main pipe (101), a thermocouple sleeve (113) inserted inside the reactor (112), and an electric heater (114) movably mounted on the outside of the reactor (112). The product collection assembly includes a tar collector (116), a secondary gas-liquid separator (117), and a gas washing bottle (118) that are sequentially connected to the outlet of the reactor (112); the tar collector (116) is provided with a cooling jacket, which is connected to a refrigeration cycle machine (122) located on one side of the tar collector (116). The system includes a control cabinet and a controller installed in the control cabinet. The controller is electrically connected to the gas dispensing component, the reaction component, and the product collection component, respectively, for centralized monitoring and control of each component.

2. The coal fixed-bed pyrolysis apparatus according to claim 1, characterized in that: Pressure gauge 2 (111) is installed on the main pipeline (101).

3. The coal fixed-bed pyrolysis apparatus according to claim 1, characterized in that: The gas dispensing assembly also includes a first delivery pipe (108) and a first needle valve (109); on one of the inlet branch pipes (102), the first delivery pipe (108) is connected in parallel at the pipe node between the second ball valve (107) located on both sides of its mass flow meter (106), and the first needle valve (109) is provided on the first delivery pipe (108).

4. The coal fixed-bed pyrolysis apparatus according to claim 1, characterized in that: The gas inlet branch pipe (102) of the first conveying pipe (108) is a branch pipe for introducing nitrogen gas.

5. The coal fixed-bed pyrolysis apparatus according to claim 1, characterized in that: The product collection assembly also includes a second (115) conveying pipe connecting the outlet of the reactor (112) to the tar collector (116), a third (123) conveying pipe connecting the tar collector (116) to the secondary gas-liquid separator (117), and a fourth (124) conveying pipe connecting the secondary gas-liquid separator (117) to the gas washing bottle (118).

6. The coal fixed-bed pyrolysis apparatus according to claim 1, characterized in that: The outlet pipe of the gas washing bottle (118) is equipped with a second gas filter (119), a third pressure gauge (120), and a second needle valve (121) in sequence.

7. The coal fixed-bed pyrolysis apparatus according to claim 1, characterized in that: The controller is communicatively connected to each of the mass flow meters (106), the electric heating furnace (114), and the refrigeration cycle machine (122) for programmed setting and closed-loop control of the inlet flow rate, reaction temperature, and cooling temperature.

8. The coal fixed-bed pyrolysis apparatus according to claim 1, characterized in that: The thermocouple is built into the thermocouple sleeve (113), and the thermocouple is connected to the signal input terminal of the controller.

9. The coal fixed-bed pyrolysis apparatus according to claim 1, characterized in that: The electric heating furnace (114) is mounted via a movable slide rail, and the movable slide rail is connected to a drive mechanism, which is connected to the controller.

10. The coal fixed-bed pyrolysis apparatus according to claim 1, characterized in that: The secondary gas-liquid separator (117) is also equipped with a cooling jacket and is connected to the refrigeration cycle machine (122) so that the tar collector (116) and the secondary gas-liquid separator (117) constitute a two-stage condensation separation system.

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