Method for strengthening co-pyrolysis synergistic effect based on hydrothermal-forming pretreatment

Abstract

The invention discloses a method for strengthening a co-pyrolysis synergistic effect based on hydrothermal-forming pretreatment. The method comprises the following steps: 1, grinding and screening raw materials, namely oil-rich coal and lignin, and then drying; 2, uniformly mixing with a CaO catalyst, and carrying out hydrothermal pretreatment to obtain a mixture to be formed; 3, mixing the to-be-formed mixture with deionized water, and carrying out double-roller forming treatment to obtain a formed substance; 4, carrying out a co-pyrolysis reaction on the molded product to generate solid semi-coke and a pyrolysis oil gas product; and 5, condensing and separating the pyrolysis oil-gas product to obtain pyrolysis tar and pyrolysis gas, and collecting solid semi-coke. According to the invention, the CaO catalyst, the hydrothermal pretreatment and the double-roller forming are utilized to synergistically improve the yield and the quality of the co-pyrolysis product of the oil-rich coal and the lignin, so that the co-pyrolysis synergistic effect of the oil-rich coal and the lignin can be enhanced to improve the yield of high-value components, and the emission of greenhouse gases and pollutants in the pyrolysis process can be reduced; and high-value utilization of oil-rich coal and waste lignin resources is realized.

Description

Technical Field

[0001] This invention belongs to the field of clean coal utilization and biomass energy conversion technology, specifically involving a method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment. Background Technology

[0002] As an important raw material for energy conversion, the limitations of traditional pyrolysis technology for oil-rich coal are becoming increasingly apparent. On the one hand, the pyrolysis of oil-rich coal alone suffers from poor quality of pyrolysis products, low yield of high-value components, insufficient proportion of high-quality components in tar, and limited production of high-calorific-value gases in pyrolysis gas. On the other hand, the pyrolysis process is accompanied by a large amount of greenhouse gas emissions and poor quality of semi-coke products, making it difficult to meet the needs of low-carbon and efficient energy transition.

[0003] Co-pyrolysis of oil-rich coal and biomass offers a new direction for solving the aforementioned problems. As a renewable carbon-neutral resource, co-pyrolysis of oil-rich coal and biomass can produce synergistic effects, potentially improving the distribution and quality of pyrolysis products. Lignin, due to its unique aromatic structure, is highly compatible with oil-rich coal, and the active sites and free radicals generated during its pyrolysis can promote the decomposition of coal macromolecules. However, existing co-pyrolysis technologies still face many challenges, such as the lack of effective control methods for the pyrolysis process, making it difficult to directionally increase the yield of high-value-added components in tar and pyrolysis gas. Furthermore, the low contact efficiency of reactive sites after raw material mixing makes it difficult to fully realize the synergistic effect between lignin and oil-rich coal. Summary of the Invention

[0004] The technical problem this invention aims to solve is to address the shortcomings of the existing technology by providing a method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment. This method utilizes CaO catalyst, hydrothermal pretreatment, and roller forming to synergistically improve the yield and quality of co-pyrolysis products of oil-rich coal and lignin. It can both enhance the synergistic effect of co-pyrolysis to increase the yield of high-value components and reduce greenhouse gas and pollutant emissions during pyrolysis, providing technical support for the clean and efficient conversion of coal and biomass. This solves the major problem of existing co-pyrolysis processes being unable to achieve the synergistic effect of oil-rich coal and lignin, and being unable to improve product quality and yield.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment, characterized in that the method includes the following steps: Step 1: Raw material pretreatment: The oil-rich coal is ground and sieved to obtain raw coal powder of a set particle size, and then dried to remove moisture; the lignin is ground and sieved to obtain raw lignin powder of a set particle size, and then dried to remove moisture. Step 2, hydrothermal pretreatment: The raw coal powder and raw lignin powder dried and pretreated in Step 1 are mixed evenly with CaO catalyst to obtain a blend. Then, the blend is subjected to hydrothermal pretreatment, dried and dehydrated, and then ground and sieved to obtain a mixture to be formed with a set particle size. Step 3, Molding process: Mix the mixture to be molded in Step 2 with deionized water, then perform roller molding in the molding machine, and then dry and dehydrate to obtain the molded product with the set particle size; Step 4, Co-pyrolysis: The molded material from Step 3 is placed in a fixed-bed pyrolysis furnace for co-pyrolysis reaction to generate solid semi-coke and pyrolysis oil and gas products; Step 5, Product Separation: The pyrolysis oil and gas products from Step 4 are sent to a cooling pump collection tank for condensation and separation to obtain pyrolysis tar and pyrolysis gas. After the co-pyrolysis reaction is completed, the residual solids in the fixed-bed pyrolysis furnace are collected to obtain solid semi-coke.

[0006] The above-mentioned method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment is characterized in that, in step one, the raw material oil-rich coal is sourced from Huangling Coal Mine in Shaanxi Province, and the raw material lignin is selected from enzymatically hydrolyzed lignin from Shandong Longli Biotechnology Co., Ltd.; the raw material lignin in step one is first washed with a large amount of deionized water until the pH is neutral; the drying pretreatment temperature of the raw material coal powder and raw material lignin powder in step one does not exceed 105℃.

[0007] The above-mentioned method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment is characterized in that, in step one, the raw material oil-rich coal is ground and passed through a 200-mesh sieve to obtain raw coal powder with a particle size of less than 0.074 mm accounting for more than 50%; the raw material lignin is ground and passed through a 200-mesh sieve to obtain raw lignin powder with a particle size of less than 0.074 mm accounting for more than 50%.

[0008] The above-mentioned method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment is characterized in that the mass ratio of the pretreated raw coal powder, the pretreated raw lignin powder and the CaO catalyst in step two is 8:2:0.1.

[0009] The above-mentioned method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment is characterized in that the reaction temperature of the hydrothermal pretreatment in step two is 180°C and the reaction duration is 24h; the drying and dehydration temperature does not exceed 105°C; and the proportion of particles with a particle size of less than 0.074mm in the mixture to be formed is greater than 50%.

[0010] The above-mentioned method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment is characterized in that, in step three, the mixture to be formed is mixed with deionized water at a ratio of 8g to 10g of deionized water per 10g of the forming mixture; the pressure of the roller forming process is 4MPa and is carried out 2 to 3 times; the drying and dehydration temperature does not exceed 105℃; and the particle size of the formed product is 6mm.

[0011] The above-mentioned method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment is characterized in that, before the co-pyrolysis reaction in step four, the air in the fixed bed pyrolysis furnace is replaced with carrier gas N2 for 5 minutes and the air tightness is checked. The co-pyrolysis reaction is started after the carrier gas flow rate stabilizes at 100 mL / min.

[0012] The above-mentioned method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment is characterized in that the co-pyrolysis reaction in step four adopts a programmed temperature control process: first, the temperature is gradually increased to 650℃ at a rate of 10℃ / min, and then the reaction is continued at a constant temperature of 650℃ for 1 hour.

[0013] The above-mentioned method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment is characterized in that, during the heating process of the co-pyrolysis reaction in step four, when the temperature reaches 200°C, a gas bag is immediately activated to collect the gas generated by pyrolysis.

[0014] The above-mentioned method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment is characterized in that, in step five, the pyrolysis oil and gas products are carried by a carrier gas into a cooling pump collection tank, and after condensation, an oil-water mixture system containing pyrolysis tar is obtained. The oil-water mixture system is subjected to tar dehydration treatment according to GB / T480-2010 "Test Method for Low-Temperature Dry Distillation of Coal in Aluminum Distillation Pots" to obtain pyrolysis tar and water.

[0015] Compared with the prior art, the present invention has the following advantages: 1. This invention involves pretreating oil-rich coal and lignin, then blending them with a CaO catalyst for hydrothermal pretreatment (HTP). The hydrothermal pretreatment breaks chemical bonds and restructures the raw materials, improving their activity. Following roller forming (RPB), the mixture undergoes co-pyrolysis. The CaO-HTP synergistic treatment promotes the hydrolysis and interfacial interaction of the oil-rich coal and lignin macromolecules. The roller forming process alters the morphology of the formed product, enhancing the interaction between reactants and improving heat transfer efficiency. Simultaneously, it increases the secondary reaction in the diffusion of pyrolysis oil and gas from the inside out, improving the yield of high-value components. This significantly enhances the synergistic yield-increasing effect of co-pyrolysis of oil-rich coal and lignin.

[0016] 2. This invention uses CaO catalyst. On the one hand, a mixture containing a high concentration of calcium ions is obtained through hydrothermal pretreatment, which plays a catalytic role in the subsequent co-pyrolysis reaction. On the other hand, it synergistically improves the yield of pyrolysis oil and gas and the content of light products, and increases the yield of high value-added gas phase components, such as increasing the yield of H2 and CH4 and decreasing the yield of CO2. This solves the defect that hydrothermal pretreatment significantly increases the yield of co-pyrolysis tar but decreases the yield of pyrolysis gas.

[0017] 3. This invention employs a roller forming process to transform the powdered hydrothermal pretreatment product into spherical granules before co-pyrolysis. On the one hand, the granules have better flowability and can pass through the co-pyrolysis equipment uniformly, reducing blockage and uneven heat transfer, ensuring the stability of the co-pyrolysis process, and facilitating continuous pyrolysis. On the other hand, the granules have a moderate specific surface area, effectively avoiding over-reaction or coking, resulting in more uniform heat exchange and material distribution, improving co-pyrolysis efficiency and ensuring product consistency.

[0018] 4. The co-pyrolysis products of this invention increase the yield of co-pyrolysis tar by 51.48%, with the yields of monocyclic aromatic hydrocarbons and aliphatic compounds increasing by 110.40% and 71.10%, respectively, while the yield of pyrolysis water decreases by 81.13%. The co-pyrolysis gas yield increases by 16.01%, with the yields of H2 and CH4 increasing by 55.20% and 40.91%, respectively, while the yields of CO and CO2 decrease by 67.24% and 33.19%, respectively. At the same time, the yield of co-pyrolysis semi-coke decreases by 3.84%, and the semi-coke particles agglomerate into relatively regular lumps with a denser surface, fewer debris, and a relatively concentrated pore distribution, reducing the emission of greenhouse gases and pollutants during pyrolysis. Therefore, the co-pyrolysis method of this invention significantly improves the product quality.

[0019] 5. The co-pyrolysis method of the present invention not only breaks through the bottleneck of low efficiency and poor product quality of traditional co-pyrolysis, but also realizes the high-value utilization of oil-rich coal and waste lignin resources, showing significant technical advantages and application potential in the fields of clean coal conversion and biomass resource utilization.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of the present invention.

[0022] Figure 2 The images show the surface morphology of the solid semi-coke obtained in Embodiment 1 and Comparative Example 4 of the present invention. Detailed Implementation

[0023] In Example 1 and Comparative Examples 1-4 of this invention, the oil-rich coal was sourced from Huangling Coal Mine in Shaanxi Province (abbreviated as H), and the lignin was selected from enzymatically hydrolyzed lignin (abbreviated as E) from Shandong Longli Biotechnology Co., Ltd. The lignin was first washed with a large amount of water until the pH was neutral.

[0024] Example 1 like Figure 1 As shown, this embodiment includes the following steps: Step 1: Raw material pretreatment: The raw material Huangling coal is ground and then sieved through a 200-mesh sieve to obtain raw material Huangling coal powder with a particle size of less than 0.074mm accounting for more than 50%. Then, it is dried in an oven at 105℃ to remove moisture. The raw material enzymatically hydrolyzed lignin, which has been washed and is now neutral, is ground and then sieved through a 200-mesh sieve to obtain raw material enzymatically hydrolyzed lignin powder with a particle size of less than 0.074mm accounting for more than 50%. Then, it is dried in an oven at 105℃ to remove moisture. Step 2, hydrothermal pretreatment: The raw material Huangling coal powder, which has been dried and pretreated in Step 1, the raw material enzymatic hydrolysis lignin powder, and CaO catalyst are mixed evenly at a mass ratio of 8:2:0.1 to obtain a blend. Then, the blend is subjected to hydrothermal pretreatment at 180℃ for 24 hours. After the pretreatment, it is dried and dehydrated in an oven at 105℃. Then, it is ground and sieved to obtain a mixture to be formed with a particle size of less than 0.074mm and a particle size of more than 50%. Step 3, Molding process: Mix the mixture to be molded in Step 2 with deionized water at a ratio of 10g molding mixture to 8g deionized water, then perform two roller molding processes in the molding machine at a pressure of 4MPa, and then dry and dehydrate in a 105℃ oven to obtain a molded product with a particle size of 6mm. Step 4, Co-pyrolysis: Place 10g of the molded material from Step 3 into a fixed-bed pyrolysis furnace for co-pyrolysis reaction. First, replace the air in the fixed-bed pyrolysis furnace with carrier gas N2 for 5 minutes and check the airtightness. After the carrier gas flow rate stabilizes at 100mL / min, start the co-pyrolysis reaction. Use programmed temperature control to control the reaction process: first, gradually increase the temperature to 650℃ at a rate of 10℃ / min. When the temperature reaches 200℃, immediately use the gas bag to collect the gas generated by pyrolysis. Then, continue the reaction at a constant temperature of 650℃ for 1 hour to ensure that the components of the pyrolysis process are fully carried out and solid semi-coke and pyrolysis oil and gas products are generated. Step 5, Product Separation: The pyrolysis oil and gas products from Step 4 are carried by a carrier gas and sent to a cooling pump collection tank for condensation and separation to obtain an oil-water mixture containing pyrolysis tar and pyrolysis gas. The oil-water mixture is subjected to tar dehydration treatment according to GB / T480-2010 "Test Method for Low-Temperature Dry Distillation of Coal in Aluminum Distillation Tank" to obtain pyrolysis tar and water. After the co-pyrolysis reaction is completed, the residual solids in the fixed-bed pyrolysis furnace are collected to obtain solid semi-coke; the product is denoted as H8E2-CaO-HTP-RPB.

[0025] Comparative Example 1 The difference between this comparative example and Example 1 is that steps two and three are omitted. Instead, the raw coal powder and the raw enzymatically hydrolyzed lignin powder after drying and pretreatment in step one are directly mixed evenly at a mass ratio of 8:2 to obtain a blend. Then, the co-pyrolysis process in step four and the product separation process in step five are carried out. The product is denoted as H8E2.

[0026] Comparative Example 2 The difference between this comparative example and Example 1 is that no CaO catalyst was added in step two. The pre-treated raw coal powder and the pre-treated raw enzymatically hydrolyzed lignin powder were mixed evenly at a mass ratio of 8:2 to obtain a blend, which was then subjected to hydrothermal pretreatment. Then, the co-pyrolysis reaction in step four and the product separation process in step five were carried out. The product was denoted as H8E2-HTP.

[0027] Comparative Example 3 The difference between this comparative example and Example 1 is that no CaO catalyst was added in step two. The pre-treated raw coal powder and the pre-treated raw enzymatically hydrolyzed lignin powder were mixed evenly at a mass ratio of 8:2 to obtain a blend, which was then subjected to hydrothermal pretreatment. Then, the molding process in step three, the co-pyrolysis reaction in step four, and the product separation process in step five were carried out. The product was denoted as H8E2-HTP-RPB.

[0028] Comparative Example 4 The difference between this comparative example and Example 1 is that the molding process in step three is omitted, and the mixture to be molded obtained in step two is directly subjected to the co-pyrolysis reaction in step four and the product separation process in step five; the product is denoted as H8E2-CaO-HTP.

[0029] Figure 2Figures 1 and 4 show the surface morphology of the solid semi-coke obtained in Example 1 and Comparative Example 4 of the present invention. Figures (a) and (b) are low-magnification and high-magnification surface morphology of the solid semi-coke obtained in Comparative Example 4, respectively. The surface of the solid semi-coke exhibits a clear porous structure, indicating that the hydrothermal pretreatment process loosens the internal structure of the raw material, providing a channel for the release of volatiles during pyrolysis. Figures (c) and (d) are low-magnification and high-magnification surface morphology of the solid semi-coke obtained in Example 1, respectively. Compared with Comparative Example 4, the semi-coke structure is significantly reshaped by the physical compaction effect of the roller forming process. The solid semi-coke particles are tightly aggregated, the number of large pores is sharply reduced, and a dense aggregate with nanoscale micropores is formed on the surface. This indicates that the roller forming process enhances the contact between particles by physically constraining the raw material particles, controls the release path of volatiles during pyrolysis, and transforms the semi-coke structure from a loose porous type to a dense aggregate type. Therefore, the densified semi-coke structure obtained by the method of the present invention can not only improve its mechanical strength and selective adsorption capacity as an adsorbent material, but its rich micropores and agglomeration interfaces also provide a stable structural basis for its subsequent use as a catalyst support, creating favorable conditions for the high-value utilization of semi-coke.

[0030] The Huangling coal (abbreviated as H), enzymatically hydrolyzed lignin (abbreviated as E), and the blend (abbreviated as H8E2) obtained by uniformly mixing the two at a mass ratio of 8:2, used in Example 1 of this invention were subjected to hydrothermal pretreatment in step two and molding process in step three, respectively. The concentration of inorganic metal ions (HTP) in the blend solution system after hydrothermal pretreatment and the drop strength (HTP-RPB) of the molded product were detected, and the results are shown in Table 1 below.

[0031] Table 1

[0032] As shown in Table 1, after hydrothermal pretreatment, inorganic metal ions in the inert mineral components of raw material Huangling coal and enzymatically hydrolyzed lignin dissolve, especially Ca and Mg ions, which have excellent catalytic effects. During the subsequent drying process, these ions undergo ion exchange with the functional groups on the surface of the raw material and are deposited on the surface, thus playing a catalytic role in the subsequent pyrolysis process. At the same time, after roller forming, the enzymatically hydrolyzed lignin acts as a binder, improving the strength of the formed product and facilitating the smooth progress of subsequent co-pyrolysis.

[0033] The distribution of co-pyrolysis products, the composition of co-pyrolysis gaseous products, and the composition of pyrolysis tar in Examples 1 and Comparative Examples 1-4 of the present invention were detected, and the results are shown in Tables 2-4 below.

[0034] Table 2 Distribution of pyrolysis products in Example 1 and Comparative Examples 1-4 of the present invention

[0035] Table 3. Composition of the co-pyrolysis gas phase products of Example 1 and Comparative Examples 1-4 of the present invention

[0036] Table 4. Composition of pyrolysis tar in Example 1 and Comparative Examples 1-4 of the present invention.

[0037] As shown in Tables 2-4, compared with Comparative Example 1, the pyrolysis tar yield in Comparative Example 3 increased by 85.84%, with the yields of monocyclic aromatic hydrocarbons and aliphatic compounds increasing by 4.95% and 74.47%, respectively, while the pyrolysis water yield decreased by 89.68%. The pyrolysis gas yield decreased by 37.65%, but the yields of H2 and CH4 increased by 7.07% and 33.83%, respectively, while the yields of CO and CO2 decreased by 0.45% and 33.69%, respectively. The co-pyrolysis semi-coke yield increased by 2.90%. Furthermore, combined with Comparative Example 2, it is shown that the hydrothermal pretreatment process of the present invention improves the activity of raw materials, increases the yield of high-value components, and significantly enhances the synergistic effect of co-pyrolysis of oil-rich coal and lignin.

[0038] Compared with Comparative Example 1, the pyrolysis tar yield in Comparative Example 4 increased by 66.99%, with the yields of monocyclic aromatic hydrocarbons and aliphatic compounds increasing by 33.66% and 60.44%, respectively, while the pyrolysis water yield decreased by 54.68%. The pyrolysis gas yield increased by 18.58%, with the yields of H2 and CH4 increasing by 26.30% and 27.96%, respectively, while the yields of CO and CO2 decreased by 23.93% and 26.80%, respectively. The co-pyrolysis semi-coke yield decreased by 9.10%. This indicates that the present invention, by selecting CaO catalyst, synergistically improves the pyrolysis oil and gas yield and the content of light products, and enhances the yield of high-value-added gas phase composition.

[0039] Compared with Comparative Example 1, in Example 1 of this invention, the CaO-HTP synergistic treatment promoted the hydrolysis and interfacial interaction of oil-rich coal and lignin macromolecules, and the RPB enhanced the interaction between reactants, improving heat transfer efficiency. At the same time, it increased the secondary reaction in the diffusion and transfer process of pyrolysis oil and gas from the inside to the outside, resulting in a 51.48% increase in co-pyrolysis tar yield, with monocyclic aromatic hydrocarbon and aliphatic compound yields increasing by 110.40% and 71.10%, respectively, while the pyrolysis water yield decreased by 81.13%. The co-pyrolysis gas yield increased by 16.01%, with H2 and CH4 yields increasing by 55.20% and 40.91%, respectively, while the CO and CO2 yields decreased by 67.24% and 33.19%, respectively. The co-pyrolysis semi-coke yield decreased by 3.84%, and the semi-coke particles agglomerated tightly, with a sharp reduction in the number of large pores, forming a dense aggregate mainly composed of nanoscale micropores on the surface. The densified semi-coke structure not only enhances its mechanical strength and selective adsorption capacity as an adsorbent material, but its abundant micropores and agglomeration interfaces also provide a stable structural basis for its subsequent use as a catalyst support, creating favorable conditions for the high-value utilization of semi-coke.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment, characterized in that, The method includes the following steps: Step 1: Raw material pretreatment: The oil-rich coal is ground and sieved to obtain raw coal powder of a set particle size, and then dried to remove moisture; the lignin is ground and sieved to obtain raw lignin powder of a set particle size, and then dried to remove moisture. Step 2, hydrothermal pretreatment: The raw coal powder and raw lignin powder dried and pretreated in Step 1 are mixed evenly with CaO catalyst to obtain a blend. Then, the blend is subjected to hydrothermal pretreatment, dried and dehydrated, and then ground and sieved to obtain a mixture to be formed with a set particle size. Step 3, Molding process: Mix the mixture to be molded in Step 2 with deionized water, then perform roller molding in the molding machine, and then dry and dehydrate to obtain the molded product with the set particle size; Step 4, Co-pyrolysis: The molded material from Step 3 is placed in a fixed-bed pyrolysis furnace for co-pyrolysis reaction to generate solid semi-coke and pyrolysis oil and gas products; Step 5, Product Separation: The pyrolysis oil and gas products from Step 4 are sent to a cooling pump collection tank for condensation and separation to obtain pyrolysis tar and pyrolysis gas. After the co-pyrolysis reaction is completed, the residual solids in the fixed-bed pyrolysis furnace are collected to obtain solid semi-coke.

2. The method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment according to claim 1, characterized in that, The oil-rich coal used in step one is sourced from Huangling Coal Mine in Shaanxi Province, and the lignin used is enzymatically hydrolyzed lignin from Shandong Longli Biotechnology Co., Ltd. The lignin used in step one is first washed with a large amount of deionized water until the pH is neutral. The drying pretreatment temperature of the coal powder and lignin powder used in step one does not exceed 105℃.

3. The method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment according to claim 1, characterized in that, In step one, the oil-rich coal is ground and passed through a 200-mesh sieve to obtain coal powder with a particle size of less than 0.074 mm accounting for more than 50%; the lignin is ground and passed through a 200-mesh sieve to obtain lignin powder with a particle size of less than 0.074 mm accounting for more than 50%.

4. The method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment according to claim 1, characterized in that, In step two, the mass ratio of the pre-treated raw coal powder, the pre-treated raw lignin powder, and the CaO catalyst is 8:2:0.

1.

5. The method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment according to claim 1, characterized in that, The hydrothermal pretreatment in step two is carried out at a reaction temperature of 180°C for a duration of 24 hours; the drying and dehydration temperature does not exceed 105°C; and the proportion of particles with a diameter less than 0.074 mm in the mixture to be formed is greater than 50%.

6. The method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment according to claim 1, characterized in that, In step three, the mixture to be formed is mixed with deionized water at a ratio of 8g to 10g of deionized water per 10g of the forming mixture; the pressure of the roller forming process is 4MPa, and it is carried out 2 to 3 times; the drying and dehydration temperature does not exceed 105℃; the particle size of the formed product is 6mm.

7. The method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment according to claim 1, characterized in that, Before the co-pyrolysis reaction described in step four, the air in the fixed-bed pyrolysis furnace is replaced with carrier gas N2 for 5 minutes, and the airtightness is checked. The co-pyrolysis reaction is started after the carrier gas flow rate stabilizes at 100 mL / min.

8. The method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment according to claim 1, characterized in that, The co-pyrolysis reaction described in step four is controlled by a programmed temperature increase: the temperature is gradually increased to 650℃ at a rate of 10℃ / min, and then the reaction is continued at a constant temperature of 650℃ for 1 hour.

9. The method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment according to claim 1, characterized in that, During the heating process of the co-pyrolysis reaction described in step four, when the temperature reaches 200°C, the gas bag is immediately activated to collect the gas generated by pyrolysis.

10. The method for enhancing the synergistic effect of co-pyrolysis based on hydrothermal-forming pretreatment according to claim 1, characterized in that, The pyrolysis oil and gas products described in step five are carried by a carrier gas into a cooling pump collection tank. After condensation, an oil-water mixture containing pyrolysis tar is obtained. The oil-water mixture is then subjected to tar dehydration treatment according to GB / T480-2010 "Test Method for Low-Temperature Dry Distillation of Coal in Aluminum Distillation Pots" to obtain pyrolysis tar and water.

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