Method for low-temperature green hydrogen plasma enhanced pyrolysis of oil-rich coal
Patent Information
- Application Number
- CN202611091657.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-22
- Publication Date
- 2026-10-27
AI Technical Summary
目前，富油煤热解多采用中低温隔绝空气热解工艺，但该工艺存在明显缺陷：一是热解过程中煤大分子裂解不充分，焦油收率偏低，通常仅能达到煤质总重的15~20%；二是热解过程中易发生结焦现象，堵塞设备管道，影响装置连续稳定运行，增加设备维护成本；三是传统热解多采用惰性气体作为载气，无法对热解产物进行原位提质，热解气氢碳比偏低，后续合成利用难度大
本发明通过离子液体溶胀解聚与近临界CO2回收的协同预处理，利用低共熔溶剂选择性打断富油煤中的氢键交联，使煤大分子结构发生溶胀松散，进而提升煤颗粒的比表面积与孔隙可及性，为后续绿氢等离子体的深层渗透与均匀反应创造有利通道，避免热解中煤芯裂解不充分的问题，从而大大提升焦油收率，而后通过脉冲调制放电与轴向静磁场约束的协同等离子体调控，将连续的强放电转化为导通-关断的脉冲模式，在导通期利用高浓度H·自由基轰击煤表面断键，在关断期为焦油蒸汽提供呼吸窗口使其快速脱离高温反应区，进而有效避免因连续高能放电导致的焦油二次裂解与焦前体过热，配合轴向磁场对等离子体射流的洛伦兹力约束，进一步提升了H·自由基的生成效率与分布均匀性，从而有效抑制结焦，实现较高的热解效果。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of coal chemical technology, specifically to a low-temperature green hydrogen plasma-enhanced pyrolysis method for oil-rich coal. Background Technology
[0002] Oil-rich coal, a type of coal resource with high volatile matter and high tar yield, is crucial for graded and quality-based utilization through pyrolysis. Pyrolysis produces tar, pyrolysis gas, and upgraded semi-coke, making it a core component of coal-based energy and chemical engineering. Currently, oil-rich coal pyrolysis primarily employs low-temperature, air-isolated pyrolysis processes. However, this process has significant drawbacks: First, the macromolecular cracking of coal is insufficient during pyrolysis, resulting in low tar yields, typically only reaching 15-20% of the total coal weight. Second, coking easily occurs during pyrolysis, clogging equipment and pipelines, affecting continuous and stable operation, and increasing equipment maintenance costs. Third, traditional pyrolysis methods often use inert gases as carrier gases, making in-situ upgrading of pyrolysis products impossible, resulting in a low hydrogen-to-carbon ratio in the pyrolysis gas and hindering subsequent synthesis and utilization.
[0003] Green hydrogen (prepared from renewable energy through water electrolysis) is widely used in the coal chemical industry as a zero-carbon reducing agent and energy carrier. While there have been attempts to introduce green hydrogen into the pyrolysis of oil-rich coal, these are mostly simple hydrogen atmosphere pyrolysis processes. The utilization efficiency of green hydrogen is low, failing to fully leverage its enhancing effect on the pyrolysis reaction, and the core problems of pyrolysis coking and low tar yield remain unresolved.
[0004] Plasma technology is characterized by high activity and high energy density, and can generate a large number of active free radicals (such as H· and OH·), which can enhance the rate of chemical reactions and improve reaction pathways. However, there is currently no technical solution that combines green hydrogen plasma with low-temperature pyrolysis of oil-rich coal, which makes it impossible to achieve synergistic optimization of green hydrogen utilization, pyrolysis enhancement, and coking inhibition, thus hindering the industrialization process of zero-carbon and efficient conversion of oil-rich coal. Summary of the Invention
[0005] The purpose of this invention is to provide a low-temperature green hydrogen plasma-enhanced pyrolysis method for oil-rich coal to solve the problems existing in the prior art.
[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a low-temperature green hydrogen plasma-enhanced pyrolysis method for oil-rich coal, comprising the following steps: (1) The oil-rich coal is crushed and sieved, pretreated with ionic liquid for swelling, and finally the ionic liquid is recovered with near-critical CO2 to obtain pretreated oil-rich coal. (2) The green hydrogen generated by wind and solar green electricity is introduced into the plasma generator, and green hydrogen plasma is generated under the conditions of discharge power of 50~200kW and discharge frequency of 10~50kHz with the assistance of pulse process. (3) The pretreated oil-rich coal is fed into the pyrolysis reactor, and the green hydrogen plasma prepared in step (2) is introduced into the pyrolysis reactor for enhanced pyrolysis. After the reaction is completed, the pyrolysis products are cooled, and the cooling temperature is controlled at 20~50℃ to ensure that the tar is fully condensed and recovered. Then, bag dust is removed, and then alkaline solution is sprayed to remove acidic components such as H2S and CO2 in the pyrolysis gas, so that the acidic component content in the pyrolysis gas after deacidification is 95ppm. Finally, the tar, pyrolysis gas and upgraded semi-coke are separated.
[0007] Furthermore, the oil-rich coal mentioned in step (1) is high-volatile oil-rich coal with a moisture content of 4wt%, a volatile content of 38wt%, and a tar yield of 20wt%.
[0008] Furthermore, the mass ratio of the oil-rich coal to the ionic liquid in step (1) is 1:0.8 to 2.
[0009] Furthermore, the ionic liquid in step (1) is at least one of [Ch][OAc] and [BMIm][OAc].
[0010] Furthermore, the near-critical CO2 recovery conditions described in step (1) are: temperature of 35–50°C and pressure of 8–12 MPa.
[0011] Furthermore, the parameters of the pulse in step (2) are: on-time of 0.5 to 3 ms, off-time of 1 to 10 ms, and duty cycle of 20 to 40%.
[0012] Furthermore, in step (3), an axial static magnetic field with a magnetic field strength of 0.01 to 0.08 T is provided on the outer wall of the pyrolysis reactor to confine the green hydrogen plasma jet.
[0013] Furthermore, the pyrolysis temperature in step (3) is 500~700℃, the pressure is 0.1~0.3MPa, and the time is 10~60min.
[0014] Furthermore, in step (3), CO2 is simultaneously introduced as an auxiliary carrier gas during the pyrolysis process. The volume ratio of CO2 to green hydrogen plasma is 1:2 to 5. CO2 can react with the semi-coke produced by pyrolysis to generate CO, thereby increasing the concentration of effective components in the pyrolysis gas and realizing the in-situ reuse of CO2.
[0015] Furthermore, the flow rate of the green hydrogen plasma in step (3) is 100~500m. 3 / h.
[0016] Furthermore, in step (3), the pyrolysis gas is purified and then supplemented with green hydrogen to adjust the hydrogen-carbon ratio for subsequent oil-gas alcohol-ether synthesis; the upgraded semi-coke is used for the preparation of clean fuels or carbon materials.
[0017] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention employs a synergistic pretreatment process combining ionic liquid swelling and depolymerization with near-critical CO2 recovery. It utilizes a low-eutectic solvent to selectively break hydrogen bond crosslinks in oil-rich coal, causing the coal macromolecules to swell and loosen, thereby increasing the specific surface area and porosity of coal particles. This creates favorable channels for the deep penetration and uniform reaction of subsequent green hydrogen plasma, avoiding insufficient coal core pyrolysis during pyrolysis and significantly improving tar yield. Subsequently, through synergistic plasma control using pulsed modulation discharge and axial static magnetic field confinement, continuous high-energy discharge is converted into a conduction-off pulse mode. During the conduction phase, high-concentration H· radicals bombard the coal surface to break bonds, while during the off phase, a breathing window is provided for tar vapor to quickly escape the high-temperature reaction zone. This effectively avoids secondary tar pyrolysis and overheating of the coke precursor caused by continuous high-energy discharge. Combined with the Lorentz force confinement of the plasma jet by the axial magnetic field, the generation efficiency and distribution uniformity of H· radicals are further improved, effectively suppressing coking and achieving a high pyrolysis effect. Detailed Implementation
[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0019] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The test methods for various indicators of the low-temperature green hydrogen plasma-enhanced pyrolysis method in oil-rich coal in the following embodiments are as follows: Tar yield: Referring to GB / T212 and GB / T1341, the tar vapor generated by pyrolysis is collected after cooling and condensation, and the tar mass is calculated by weighing method. The yield is calculated in combination with the dry basis mass of coal fed into the furnace.
[0020] Coking reduction rate detection: The coking quality in the reactor inner wall, gas distributor and pipeline is measured and compared with the coking amount of conventional pyrolysis to calculate the reduction rate; The conditions of conventional pyrolysis are: the same pyrolysis temperature, pressure, reaction time and coal type as in Example 2, but without the introduction of green hydrogen plasma, no ion liquid pretreatment and no pulse / magnetic field treatment.
[0021] Example 1 (1) The oil-rich coal is crushed and sieved, pretreated with ionic liquid [Ch][OAc] for swelling, and finally recovered with near-critical CO2. The recovery conditions are: temperature 35℃ and pressure 8MPa, to obtain pretreated oil-rich coal; the mass ratio of the oil-rich coal to the ionic liquid [Ch][OAc] is 1:0.8; the oil-rich coal is high volatile oil-rich coal with a moisture content of 4wt%, a volatile matter content of 38wt%, and a tar yield of 20wt%; (2) The green hydrogen generated by wind and solar power is introduced into the plasma generator, and green hydrogen plasma is generated under the conditions of discharge power of 50kW and discharge frequency of 10kHz with the assistance of pulse technology. The pulse parameters are: on time of 0.5ms, off time of 1ms, and duty cycle of 20%. (3) The pretreated oil-rich coal is fed into the pyrolysis reactor, and the green hydrogen plasma prepared in step (2) is simultaneously introduced at a speed of 100 m. 3 A flow rate of / h is introduced into the pyrolysis reactor, and an axial static magnetic field with a strength of 0.01T is set on the outer wall of the pyrolysis reactor to confine the green hydrogen plasma jet for enhanced pyrolysis. The pyrolysis temperature is 500℃, the pressure is 0.1MPa, and the time is 10min. During the pyrolysis process, CO2 is simultaneously introduced as an auxiliary carrier gas, with a volume ratio of CO2 to green hydrogen plasma of 1:2. CO2 can react with the semi-coke produced by pyrolysis to generate CO, increasing the concentration of effective components in the pyrolysis gas and realizing the in-situ reuse of CO2. After the reaction, the pyrolysis products are cooled at a temperature controlled at 20℃ to ensure that the tar is fully condensed and recovered. Then, bag dust is collected, followed by alkaline solution spraying to remove acidic components such as H2S and CO2 from the pyrolysis gas, so that the acidic component content in the deacidified pyrolysis gas is 95ppm. Finally, the tar, pyrolysis gas, and upgraded semi-coke are separated.
[0022] Example 2 (1) The oil-rich coal is crushed and sieved, pretreated with ionic liquid [Ch][OAc] for swelling, and finally recovered with near-critical CO2. The recovery conditions are: temperature 42℃ and pressure 10MPa, to obtain pretreated oil-rich coal; the mass ratio of the oil-rich coal to the ionic liquid [Ch][OAc] is 1:1.4; the oil-rich coal is high volatile oil-rich coal with a moisture content of 4wt%, a volatile matter content of 38wt%, and a tar yield of 20wt%; (2) The green hydrogen generated by wind and solar power is introduced into the plasma generator, and green hydrogen plasma is generated under the conditions of discharge power of 130kW and discharge frequency of 30kHz with the assistance of pulse technology. The pulse parameters are: on time of 1.8ms, off time of 6ms, and duty cycle of 30%. (3) The pretreated oil-rich coal is fed into the pyrolysis reactor, and the green hydrogen plasma prepared in step (2) is simultaneously introduced at a speed of 300 m.3 A flow rate of 0.05T is introduced into the pyrolysis reactor at a rate of 60℃ / h. An axial static magnetic field with a strength of 0.05T is set on the outer wall of the pyrolysis reactor to confine the green hydrogen plasma jet for enhanced pyrolysis. The pyrolysis temperature is 60℃, the pressure is 0.2MPa, and the time is 35min. CO2 is simultaneously introduced as an auxiliary carrier gas during the pyrolysis process. The volume ratio of CO2 to green hydrogen plasma is 1:3.5. CO2 can react with the semi-coke produced by pyrolysis to generate CO, increasing the concentration of effective components in the pyrolysis gas and realizing the in-situ reuse of CO2. After the reaction, the pyrolysis products are cooled at a temperature controlled at 35℃ to ensure that the tar is fully condensed and recovered. Then, bag dust is collected, followed by alkaline solution spraying to remove acidic components such as H2S and CO2 from the pyrolysis gas, so that the acidic component content in the deacidified pyrolysis gas is 95ppm. Finally, the tar, pyrolysis gas, and upgraded semi-coke are separated.
[0023] Example 3 (1) The oil-rich coal is crushed and sieved, pretreated with ionic liquid [Ch][OAc] for swelling, and finally recovered with near-critical CO2. The recovery conditions are: temperature 50℃ and pressure 12MPa, to obtain pretreated oil-rich coal; the mass ratio of the oil-rich coal to the ionic liquid [Ch][OAc] is 1:2; the oil-rich coal is high volatile oil-rich coal with a moisture content of 4wt%, a volatile content of 38wt%, and a tar yield of 20wt%; (2) The green hydrogen generated by wind and solar power is introduced into the plasma generator, and green hydrogen plasma is generated under the conditions of discharge power of 200kW and discharge frequency of 50kHz with the assistance of pulse technology. The pulse parameters are: on time of 3ms, off time of 10ms, and duty cycle of 40%. (3) The pretreated oil-rich coal is fed into the pyrolysis reactor, and the green hydrogen plasma prepared in step (2) is simultaneously introduced at a speed of 500 m. 3 A green hydrogen plasma jet is fed into the pyrolysis reactor at a flow rate of / h, and an axial static magnetic field with a strength of 0.08T is set on the outer wall of the reactor to confine the green hydrogen plasma jet for enhanced pyrolysis. The pyrolysis temperature is 700℃, the pressure is 0.3MPa, and the time is 60min. During the pyrolysis process, CO2 is simultaneously introduced as an auxiliary carrier gas, with a volume ratio of CO2 to green hydrogen plasma of 1:5. CO2 can react with the semi-coke produced by pyrolysis to generate CO, increasing the concentration of effective components in the pyrolysis gas and realizing the in-situ reuse of CO2. After the reaction, the pyrolysis products are cooled at a temperature controlled at 50℃ to ensure that the tar is fully condensed and recovered. Then, bag dust is collected, followed by alkaline solution spraying to remove acidic components such as H2S and CO2 from the pyrolysis gas, so that the acidic component content in the deacidified pyrolysis gas is 95ppm. Finally, the tar, pyrolysis gas, and upgraded semi-coke are separated.
[0024] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that step (1) is omitted, and step (3) is changed to: feeding oil-rich coal into the pyrolysis reactor, while simultaneously introducing the green hydrogen plasma prepared in step (2) at 300m 3 A flow rate of 0.05 T / h is introduced into the pyrolysis reactor, and an axial static magnetic field with a strength of 0.05 T is set on the outer wall of the reactor to confine the green hydrogen plasma jet for enhanced pyrolysis. The pyrolysis temperature is 60℃, the pressure is 0.2 MPa, and the time is 35 min. CO2 is simultaneously introduced as an auxiliary carrier gas during the pyrolysis process, with a CO2 to green hydrogen plasma volume ratio of 1:3.5. CO2 can react with the semi-coke produced by pyrolysis to generate CO, increasing the concentration of effective components in the pyrolysis gas and simultaneously achieving in-situ CO2 release. After the reaction is completed, the pyrolysis products are cooled at a temperature controlled at 35°C to ensure that the tar is fully condensed and recovered. Then, bag filters are used for dust removal, followed by alkaline solution spraying to remove acidic components such as H2S and CO2 from the pyrolysis gas, so that the acidic component content in the deacidified pyrolysis gas is 95ppm. Finally, the tar, pyrolysis gas, and upgraded semi-coke are separated. The oil-rich coal is a high-volatile oil-rich coal with a moisture content of 4wt%, a volatile matter content of 38wt%, and a tar yield of 20wt%. The remaining steps are the same as in Example 2.
[0025] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that step (2) is different. Step (2) is changed to: green hydrogen prepared by wind and solar green electricity is introduced into a plasma generator to generate green hydrogen plasma under the conditions of discharge power of 130kW and discharge frequency of 30kHz; the remaining steps are the same as in Example 2.
[0026] Comparative Example 3 The difference between Comparative Example 3 and Example 2 lies in step (3). Step (3) is changed to: feeding pretreated oil-rich coal into a pyrolysis reactor, while simultaneously introducing the green hydrogen plasma prepared in step (2) at 300m 3 A flow rate of / h is introduced into the pyrolysis reactor for enhanced pyrolysis at a temperature of 60℃, a pressure of 0.2MPa, and a time of 35min. During the pyrolysis process, CO2 is simultaneously introduced as an auxiliary carrier gas, with a volume ratio of CO2 to green hydrogen plasma of 1:3.5. CO2 can react with the semi-coke produced by pyrolysis to generate CO, increasing the concentration of effective components in the pyrolysis gas and simultaneously achieving in-situ CO2 reuse. After the reaction, the pyrolysis products are cooled at a temperature controlled at 35℃ to ensure that the tar is fully condensed and recovered. Then, bag filters are used for dust removal, followed by alkaline solution spraying to remove acidic components such as H2S and CO2 from the pyrolysis gas, resulting in an acidic component content of 95ppm in the deacidified pyrolysis gas. Finally, the tar, pyrolysis gas, and upgraded semi-coke are separated; the remaining steps are the same as in Example 2.
[0027] Comparative Example 4 The difference between Comparative Example 4 and Example 2 is that steps (2) and (3) are different. Step (3) is changed to: green hydrogen prepared by wind and solar green electricity is introduced into a plasma generator to generate green hydrogen plasma under the conditions of discharge power of 130kW and discharge frequency of 30kHz. Change step (3) to: feeding the pretreated oil-rich coal into the pyrolysis reactor, and simultaneously introducing the green hydrogen plasma prepared in step (2) at a speed of 300 m 3 A flow rate of / h is introduced into the pyrolysis reactor for enhanced pyrolysis at a temperature of 60℃, a pressure of 0.2MPa, and a time of 35min. During the pyrolysis process, CO2 is simultaneously introduced as an auxiliary carrier gas, with a volume ratio of CO2 to green hydrogen plasma of 1:3.5. CO2 can react with the semi-coke produced by pyrolysis to generate CO, increasing the concentration of effective components in the pyrolysis gas and simultaneously achieving in-situ CO2 reuse. After the reaction, the pyrolysis products are cooled at a temperature controlled at 35℃ to ensure that the tar is fully condensed and recovered. Then, bag filters are used for dust removal, followed by alkaline solution spraying to remove acidic components such as H2S and CO2 from the pyrolysis gas, resulting in an acidic component content of 95ppm in the deacidified pyrolysis gas. Finally, the tar, pyrolysis gas, and upgraded semi-coke are separated; the remaining steps are the same as in Example 2.
[0028] Example of effect Table 1 below presents the performance analysis results of the low-temperature green hydrogen plasma enhanced pyrolysis method for oil-rich coal using Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention.
[0029] Table 1
[0030] A comparison of the experimental data from the examples and comparative examples in Table 1 reveals that this invention utilizes a synergistic pretreatment process of ionic liquid swelling and depolymerization with near-critical CO2 recovery. This process selectively breaks hydrogen bond crosslinks in oil-rich coal using a low-eutectic solvent, increasing the specific surface area and porosity of coal particles. This creates a favorable channel for the deep penetration and uniform reaction of subsequent green hydrogen plasma, thereby significantly improving tar yield. Subsequently, through synergistic plasma control using pulsed modulation discharge and axial static magnetic field confinement, continuous strong discharge is transformed into a conduction-off pulse mode. During the conduction period, high-concentration H· radicals bombard the coal surface to break bonds, while during the off period, a breathing window is provided for tar vapor to quickly escape the high-temperature reaction zone. Combined with the Lorentz force confinement of the plasma jet by the axial magnetic field, the generation efficiency and distribution uniformity of H· radicals are further improved, effectively suppressing coking and achieving a high pyrolysis effect.
[0031] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.
Claims
1. A method for low-temperature green hydrogen plasma-enhanced pyrolysis of oil-rich coal, characterized in that, Includes the following steps: (1) The oil-rich coal is crushed and sieved, pretreated with ionic liquid for swelling, and finally the ionic liquid is recovered with near-critical CO2 to obtain pretreated oil-rich coal. (2) The green hydrogen generated by wind and solar power is introduced into the plasma generator, and green hydrogen plasma is generated with the assistance of pulse discharge process; (3) The pretreated oil-rich coal is fed into the pyrolysis reactor. The bottom of the reactor is equipped with a separate inert catalytic bed. At the same time, the green hydrogen plasma prepared in step (2) is introduced into the pyrolysis reactor for enhanced pyrolysis. After the reaction is completed, the pyrolysis products are cooled, dusted, and deacidified, and then separated to obtain tar, pyrolysis gas and upgraded semi-coke.
2. The method for low-temperature green hydrogen plasma-enhanced pyrolysis of oil-rich coal according to claim 1, characterized in that, The oil-rich coal mentioned in step (1) is high volatile oil-rich coal with a moisture content of 4wt%, a volatile content of 38wt%, and a tar yield of 20wt%.
3. The method for low-temperature green hydrogen plasma-enhanced pyrolysis of oil-rich coal according to claim 1, characterized in that, The mass ratio of oil-rich coal to ionic liquid in step (1) is 1:0.8 to 2.
4. The method for low-temperature green hydrogen plasma-enhanced pyrolysis of oil-rich coal according to claim 1, characterized in that, The ionic liquid in step (1) is at least one of [Ch][OAc] and [BMIm][OAc].
5. The method for low-temperature green hydrogen plasma-enhanced pyrolysis of oil-rich coal according to claim 1, characterized in that, The near-critical CO2 recovery conditions described in step (1) are: temperature of 35-50℃ and pressure of 8-12MPa.
6. The method for low-temperature green hydrogen plasma-enhanced pyrolysis of oil-rich coal according to claim 1, characterized in that, The parameters of the pulse in step (2) are: on time of 0.5 to 3 ms, off time of 1 to 10 ms, and duty cycle of 20 to 40%.
7. The method for low-temperature green hydrogen plasma-enhanced pyrolysis of oil-rich coal according to claim 1, characterized in that, In step (3), an axial static magnetic field is set on the outer wall of the pyrolysis reactor with a magnetic field strength of 0.01 to 0.08 T.
8. The method for low-temperature green hydrogen plasma-enhanced pyrolysis of oil-rich coal according to claim 1, characterized in that, The pyrolysis temperature in step (3) is 500~700℃, the pressure is 0.1~0.3MPa, and the time is 10~60min.
9. The method for low-temperature green hydrogen plasma-enhanced pyrolysis of oil-rich coal according to claim 1, characterized in that, In step (3), CO2 is simultaneously introduced as an auxiliary carrier gas during the pyrolysis process, and the volume ratio of CO2 to green hydrogen plasma is 1:2 to 5.
10. The method for low-temperature green hydrogen plasma-enhanced pyrolysis of oil-rich coal according to claim 1, characterized in that, The flow rate of the green hydrogen plasma in step (3) is 100~500m. 3 / h.