A coal hydrogenation gasification furnace system with liquid slag discharge moving bed and a hydrogenation gasification method

Abstract

The present invention belongs to the technical field of coal chemical processing, and discloses a coal hydrogasification furnace system and a hydrogasification method of a liquid slag removal moving bed. In the hydrogasification system of the present invention, the gas outlet of the hydrogasifier is sequentially connected to the air inlet of the hydrogen membrane separator through a pressure reducing tank, a chilled water scrubber, and a gas-liquid separator. A hydrogen outlet and a methane-rich outlet are provided on the hydrogen membrane separator, wherein the hydrogen outlet of the hydrogen membrane separator is divided into two paths and connected to the second air inlet and the third air inlet of the hydrogasifier, and the pressure reducing tank, the chilled water scrubber and the liquid outlet of the gas-liquid separator are all connected to a tar collector. The hydrogasification method of the present invention can realize the controllable product components in the process of stabilizing the hydrogasification of coal, enhance the adaptability of raw materials and the diversity of products, and the methane yield and the yield of high light aromatics (BTX, PCXN) are high.

Description

Technical Field

[0001] This invention belongs to the technical field of coal chemical processing, specifically relating to a coal hydrogenation gasification furnace system with a liquid slag discharge moving bed and a hydrogenation gasification method. Background Technology

[0002] Energy is a crucial pillar of social and economic development. As a major global energy producer and consumer, my country's future development will require even more energy, generate more emissions, and face greater resource and environmental pressures. Coal production and consumption have consistently dominated my country's energy structure. Therefore, efficiently converting the carbon and hydrogen abundant in coal into high-value-added chemical products is a core issue in the low-carbon utilization of modern coal chemical technologies, including coal-to-methane, coal-to-oil, and coal-to-chemicals.

[0003] However, existing coal-to-methane and coal-to-oil technologies mainly rely on high-temperature, high-pressure coal gasification to convert coal into syngas, followed by organic synthesis. This results in high energy consumption, high investment, and high water consumption in the overall process. In contrast, coal hydrogenation gasification technology produces a single component of gas and, under high temperature and pressure, can achieve high methane yield, high yield of light aromatics (BTX, PCXN), and high thermal efficiency, attracting increasing attention in the field of clean coal technology both domestically and internationally.

[0004] A search of similar technologies revealed two main issues: First, Chinese patent application CN102559310A discloses a method for producing natural gas and other hydrocarbons through coal hydrogasification using industrial waste gases such as coke oven gas. In this process, heating raw coal to 300℃ causes pyrolysis, producing tar, which easily leads to blockages and hinders transportation. Furthermore, the input heat is insufficient to reach the activation temperature for the hydrogasification reaction, making it impossible to obtain high-quality products and ensure stable system operation. Second, Chinese patent application CN108774549A discloses a method for producing natural gas and other hydrocarbons through hydrogasification of pulverized coal using a fluidized bed. This production process is relatively complex, requiring coal to be ground to 125µm-180µm, resulting in high subsequent investment, short coal sample residence time, and incomplete hydrogasification reaction. Additionally, the furnace structure is complex, the scale is small, and its scalability needs further investigation.

[0005] Therefore, developing a liquid slag discharge moving bed coal hydrogenation gasifier, hydrogenation gasification system, and hydrogenation gasification method with high thermal efficiency, simple gasification system, good stability, adjustable product composition, and superior quality is an urgent problem to be solved. Summary of the Invention

[0006] This invention addresses the technical problems of existing coal hydrogasification methods, such as long process routes, high investment, low thermal efficiency, complex gasification systems, poor stability, and inferior product quality. It provides a liquid-state slag-discharge moving bed coal hydrogasification furnace, hydrogasification system, and hydrogasification method that features high thermal efficiency, a simple gasification system, good stability, adjustable product composition, and superior product quality. This liquid-state slag-discharge moving bed coal hydrogasification furnace, hydrogasification system, and hydrogasification method can stably achieve the coal hydrogasification process, with adjustable product composition, enhanced feedstock adaptability and product diversity, and higher yields of methane and high-quality light aromatics (BTX, PCXN).

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a coal hydrogenation gasification furnace system with a liquid slag-discharging moving bed, wherein the gas outlet of the hydrogenation gasification furnace is connected to the gas inlet of a pressure reducing tank via a pipeline, the gas outlet of the pressure reducing tank is connected to the gas inlet of a quench water washing tower via a pipeline, the gas outlet of the quench water washing tower is connected to the gas inlet of a gas-liquid separator via a pipeline, the liquid outlets of the pressure reducing tank, the quench water washing tower, and the gas-liquid separator are all connected to the liquid inlet of a tar collector, the gas outlet of the gas-liquid separator is connected to the gas inlet of a hydrogen membrane separator via a pipeline, the hydrogen membrane separator is provided with a hydrogen outlet and a methane-rich outlet respectively, and the hydrogen outlet of the hydrogen membrane separator is connected to the second and third gas inlets of the hydrogenation gasification furnace via two pipelines.

[0008] As a further supplement to the above technical solution, a circulating gas compressor is installed on each of the two pipelines between the hydrogen outlet of the hydrogen membrane separator and the second and third inlets of the hydrogenation gasification furnace to provide power for transportation.

[0009] As a further supplement to the above technical solution, the hydrogenation gasification furnace includes a pressure-resistant steel shell and a refractory material integrally cast and molded, and the furnace cavity is cast with refractory material inside. A solid inlet and a solid outlet are respectively provided on the top and bottom of the hydrogenation gasification furnace. A first air inlet, a second air inlet, and a third air inlet are respectively provided on the side wall of the hydrogenation gasification furnace from bottom to top. The air outlet is located on the side wall of the hydrogenation gasification furnace and above the third air inlet. The furnace cavity is divided from bottom to top into an oxidized slag layer, a reduction gasification layer, a hydrogenation gasification methanation layer, a hydrogenation pyrolysis layer, and a drying layer. The first air inlet, the second air inlet, and the third air inlet are respectively located in the oxidized slag layer, the hydrogenation gasification methanation layer, and the hydrogenation pyrolysis layer. The reduction gasification layer is located between the first air inlet and the second air inlet.

[0010] As a further supplement to the above technical solution, an ash collection area is provided in the furnace cavity below the oxidized slag layer, which is connected to the black water treatment system, wherein the black water treatment system provides circulating quench water to the ash collection area for cooling the molten ash.

[0011] As a further supplement to the above technical solution, the height-to-diameter ratio of the hydrogenation gasification furnace is 10-50.

[0012] As a further supplement to the above technical solution, the ratio of the distance between the first air inlet and the second air inlet within the furnace cavity to the height of the hydrogenation gasification furnace is 1 / 5 to 1 / 3; the ratio of the distance between the second air inlet and the third air inlet within the furnace cavity to the height of the hydrogenation gasification furnace is 1 / 6 to 1 / 4; and the ratio of the distance between the third air inlet and the top of the furnace cavity to the height of the hydrogenation gasification furnace is 1 / 5 to 1 / 3.

[0013] As a further supplement to the above technical solution, the first air inlet is at an angle of 60-90° to the axis of the hydrogenation gasification furnace, which facilitates the feeding of the first stream of material into the oxidized slag layer at a specific angle.

[0014] A hydrogasification method employs a coal hydrogasification furnace system with a liquid slag-discharge moving bed as described in the above-mentioned technical solution, and includes the following steps:

[0015] Step 1: Pulverized coal with a particle size of 5-50mm and a moisture content of less than 5wt% is added into the furnace cavity through the solid inlet. The first stream of material containing high-pressure oxygen and water vapor, the second stream of material containing hydrogen and water vapor, and the third stream of material containing hydrogen are sequentially fed into the oxidized slag layer, the hydrogasification methanation layer, and the hydropyrolysis layer of the hydrogasification furnace, respectively. The operating pressure of the hydrogasification furnace is 2MPa-10MPa. The ratio of oxygen to coal feed in the first stream of material is 0.2-1Nm3 / kg, the ratio of hydrogen to coal feed in the second stream of material is 0.2-1Nm3 / kg, and the mass flow ratio of hydrogen to coal feed in the third stream of material is 0-1Nm3 / kg.

[0016] Step 2: The oxygen in the first stream of material in Step 1 undergoes an oxygen-enriched combustion reaction with the gasification residue in the oxidized slag layer and the reducing gasification layer. The water vapor in the first stream of material is used to protect the nozzle of the first air inlet, thus obtaining oxygen-enriched combustion gas products and molten ash. The reaction temperature of the oxidized slag is 1400-1800℃.

[0017] Step 3: The oxygen-enriched combustion gas products obtained in Step 2 undergo a gasification reaction in the semi-coke contact between the reducing gasification layer and the hydrochemical methanation layer, thus obtaining the reducing gasification layer gas products and gasification residue.

[0018] Step 4: The hydrogen in the second stream of material in Step 1 comes into contact with the gaseous products of the reduction gasification layer and the pyrolysis semi-coke of the hydrogenation pyrolysis layer in Step 3 and undergoes a hydrogenation gasification methanation reaction, that is, the gaseous products of the hydrogenation gasification methanation layer and the gasification residue are obtained. The temperature of the hydrogenation gasification methanation reaction is 600-1200℃.

[0019] Step 5: The hydrogen in the third material of Step 1 comes into contact with the coal in the drying layer of Step 4 and undergoes a hydropyrolysis reaction, which yields hydropyrolysis gaseous products and pyrolysis semi-coke. These are then transported to a pressure reducing tank through the gas outlet to obtain liquid products and purified gas. The purified gas is then sequentially passed through a quench water washing tower and a gas-liquid separator to obtain gaseous and liquid products. The gaseous products are separated by a hydrogen membrane separator to obtain methane-rich gas and hydrogen. The hydrogen is divided into two streams and fed into the hydrogasification furnace through the second and third inlets under the action of a circulating gas compressor to participate in the reaction. The methane-rich gas is the obtained product gas. The liquid products are separated into liquid oil and water after stratification and are uniformly recycled to the tar collector.

[0020] In step 5, the temperature-controlled hydropyrolysis reaction produces the following product composition: above 900℃, methane is mainly generated; at 800-900℃, BTX and PCX can be produced in abundance; and at 400-600℃, light oil products can be produced in abundance.

[0021] As a further explanation and limitation of the above technical solution, in step 2, the ratio of oxygen to coal in the first material must be such that an oxygen-enriched combustion reaction occurs, and the heat generated by the oxygen-enriched combustion reaction is sufficient to cause the coal in the reducing gasification layer to undergo a gasification reaction. The reaction temperature of the oxidizing slag layer exceeds the ash flow temperature, and the following chemical reactions mainly occur:

[0022]

[0023]

[0024] CO + O2 = CO2

[0025]

[0026] As a further explanation and limitation of the above technical solution, in step 3, the reaction occurring in the reducing gasification layer is a coal gasification reaction, which is the main water gas producing layer. The temperature of the reducing layer is 1000-1300℃, and the following chemical reactions mainly occur:

[0027]

[0028]

[0029] As a further explanation and limitation of the above technical solution, in step 4, the amount of hydrogen and water vapor in the second material and the amount of coal processed should be such that a hydrogenation gasification methanation reaction can occur under the action of the gas products of the reducing gasification layer. The mixture obtained instantaneously upon contact between the hydrogen and water vapor in the second material and the gas products of the reducing gasification layer and the pyrolysis semi-coke of the hydrogenation pyrolysis layer mainly undergoes the following chemical reactions:

[0030]

[0031] CO + 3H₂ = CH₄ + H₂O

[0032] CO + H₂O = CO₂ + H₂;

[0033] The reaction for the formation of light oil is as follows:

[0034] nCO + (2n + 1)H₂ = C n H 2n+2 +nH2O

[0035] 2nCO + (n+1)H2 = C n H 2n+2 +nCO2.

[0036] As a further explanation and limitation of the above technical solution, in step 5, the mixture formed when the hydrogen in the third material comes into contact with the gas products of the hydrotreated methanation layer and the coal in the drying layer undergoes a hydropyrolysis reaction. The hydropyrolysis layer is the generation layer for pyrolysis tar and pyrolysis gas, and is also the key layer for the production of gaseous-liquid fuels. The large organic molecules in the coal are thermally decomposed to generate active small molecules, which react with hydrogen to generate hydrocarbon compounds. The main chemical reactions are as follows:

[0037] CH x O y +H2→C+CO+CH4+C m H n +BTX+PCX

[0038] CO + 3H₂ = CH₄ + H₂O

[0039] nCO + (2n + 1)H₂ = C n H 2n+2 +nH2O

[0040]

[0041] C m H n +H2=C m H n+2 .

[0042] Compared with existing coal-to-methane and coal-to-oil technologies, this invention has the following advantages:

[0043] 1. The hydrogasification system and method developed in this invention can stably realize the hydrogasification process of coal, and the product composition can be adjusted, which enhances the adaptability of raw materials and the diversity of products. Moreover, the product has a high yield of methane and high yield of light aromatics (BTX, PCXN).

[0044] 2. The liquid slag discharge moving bed gasifier designed in this invention has the advantages of high gasification efficiency and low wastewater discharge. However, the methane content in the gas is only 5-7%, and its economic efficiency for co-producing methane and light hydrocarbons needs to be improved.

[0045] 3. The hydrogasification system developed in this invention adopts a highly efficient coal gasification theory that combines moving bed liquid slag gasification with hydrogasification. This system efficiently converts carbon and hydrogen elements in coal into methane and light oil in situ, improving the overall economic efficiency of coal-to-oil and coal-to-methane systems. Calculations show that for indirect liquefaction coal-to-oil processes, the synthesis scale can be reduced by approximately one-third, and system energy efficiency can be increased by 10-20%.

[0046] 4. The hydrogenation gasification system developed in this invention, applied to the coal-to-methane process, achieves completely non-synthetic methane production through hydrogen recycling, improving overall energy efficiency by 20-25% and reducing investment by over 20%. Simultaneously, in the fields of coal-to-natural gas and coal-to-oil, it pioneers a technological route for the efficient production of methane-rich and light oil from low-rank coal, offering advantages such as simple processes and minimal pollutant emissions, thus promoting the large-scale, efficient conversion and utilization of low-rank coal. Attached Figure Description

[0047] Figure 1 This is a process flow diagram of the hydrogasification system in this invention;

[0048] Figure 2 This is a structural diagram of the hydrogenation gasification furnace in an embodiment of the present invention.

[0049] In the diagram: 10 is the hydrogenation gasifier, 20 is the pressure reducing tank, 30 is the quench water washing tower, 40 is the gas-liquid separator, 50 is the tar collector, 60 is the hydrogen membrane separator, and 70 is the circulating gas compressor.

[0050] The structure of the hydrogasification furnace includes: a solid outlet (104), a solid inlet (105), a gas outlet (106), a furnace cavity (107), an ash collection area (108), an oxidized slag layer (109), a reducing gasification layer (110), a hydrogasification methanation layer (111), a hydropyrolysis layer (112), and a drying layer (113). Detailed Implementation

[0051] To further illustrate the technical solution of the present invention, the following description is in conjunction with the appendix. Figures 1 to 2 Within the scope of protection disclosed in the technical solution, the specific structure and dimensions of the hydrogenation gasification furnace involved in the present invention will be further described through the preferred embodiment.

[0052] As attached Figures 1 to 2 As shown, a liquid slag-discharge moving bed coal hydrogasification furnace and hydrogasification system are disclosed. The hydrogasification system mainly includes a hydrogasification furnace 10, a pressure reducing tank 20, a quench water washing tower 30, a gas-liquid separator 40, a tar collector 50, and a hydrogen membrane separator 60. The hydrogasification furnace 10 is integrally cast from a pressure-resistant steel shell and refractory material, and the interior of the hydrogasification furnace 10 is a furnace cavity 107 cast from refractory material. A solid inlet 105 and a solid outlet 104 are respectively provided on the top and bottom of the hydrogasification furnace 10. A first air inlet 101, a second air inlet 102, a third air inlet 103, and an outlet 106 are respectively provided on the side wall of the hydrogasification furnace 10 from top to bottom. The first air inlet 101 is connected to the hydrogasification furnace 10. The included angle of the axis of the gasifier 10 is 60-90°, which facilitates the feeding of the first stream of material into the oxidized slag layer 109 along a specific angle direction. The first air inlet 101 is used to feed the first stream of material containing oxygen and water vapor into the oxidized slag layer 109. The second air inlet 102 is used to feed the second stream of material containing hydrogen and water vapor into the hydrochemical methanation layer 111. The third air inlet 103 is used to feed the third stream of material containing hydrogen into the hydropyrolysis layer 112.

[0053] In the above embodiments, the internal design structure and dimensional parameters of the hydrogenation gasification furnace are as follows:

[0054] (I) The furnace chamber 107 is divided from bottom to top into an ash collection zone 108, an oxidized slag layer 109, a reduction gasification layer 110, a hydrochemical methanation layer 111, a hydropyrolysis layer 112, and a drying layer 113. The ash collection zone 108 is connected to a black water treatment system, which provides circulating quench water to the ash collection zone 108 to cool the molten ash. The first air inlet 101, the second air inlet 102, and the third air inlet 103 are respectively located in the oxidized slag layer 109, the hydrochemical methanation layer 111, and the hydropyrolysis layer 112. The reduction gasification layer 110 is located between the first air inlet 101 and the second air inlet 102, and the drying layer 113 is located between the second air inlet 102 and the third air inlet 103.

[0055] (ii) The height-to-diameter ratio of the hydrogasification furnace is 10-50; the ratio of the distance between the first air inlet 101 and the second air inlet 102 in the furnace cavity to the height of the hydrogasification furnace 10 is 1 / 5-1 / 3; the ratio of the distance between the second air inlet 102 and the third air inlet 103 in the furnace cavity to the height of the hydrogasification furnace 10 is 1 / 6-1 / 4; the ratio of the distance between the third air inlet 103 and the top of the furnace cavity to the height of the hydrogasification furnace 10 is 1 / 5-1 / 3.

[0056] In this preferred embodiment, the height-to-diameter ratio of the liquid slag-discharge moving bed coal hydrogasification furnace is 20; the distance between the first air inlet 101 and the second air inlet 102 within the furnace cavity is 1 / 4 of the height of the hydrogasification furnace 10; the distance between the second air inlet 102 and the third air inlet 103 within the furnace cavity is 1 / 5 of the height of the hydrogasification furnace 10; the distance from the third air inlet 103 to the top of the furnace cavity is 1 / 4 of the height of the hydrogasification furnace 10; and the angle between the first air inlet 101 and the axis of the hydrogasification furnace 10 is 85°.

[0057] The piping connections for each reaction unit in this hydrogasification system are as follows:

[0058] The outlet 106 of the hydrogasification furnace 10 is connected to the inlet of the pressure reducing tank 20 via a pipeline. The outlet of the pressure reducing tank 20 is connected to the inlet of the quench water washing tower 30 via a pipeline. The outlet of the quench water washing tower 30 is connected to the inlet of the gas-liquid separator 40 via a pipeline. The outlet of the gas-liquid separator 40 is connected to the inlet of the hydrogen membrane separator 60 via a pipeline. The hydrogen membrane separator 60 is provided with a hydrogen outlet and a methane-rich outlet. The hydrogen outlet of the hydrogen membrane separator 60 is connected to the second inlet 102 and the third inlet 103 of the hydrogasification furnace 10 via two pipelines. The liquid outlets of the pressure reducing tank 20, the quench water washing tower 30, and the gas-liquid separator 40 are all connected to the liquid inlet of the tar collector 50. A circulating gas compressor 70 is installed on each of the two pipelines between the hydrogen outlet of the hydrogen membrane separator 60 and the second inlet 102 and the third inlet 103 of the hydrogenation gasification furnace 10 to provide power for conveying.

[0059] A hydrogasification method using a coal hydrogasification furnace system with a liquid slag-discharge moving bed as described in the above embodiments includes the following steps:

[0060] Step 1: Pulverized coal with a particle size of 5-50 mm and a moisture content of less than 5 wt% is added into the furnace cavity 107 through the solid inlet 105. The first stream of material containing high-pressure oxygen and water vapor, the second stream of material containing hydrogen and water vapor, and the third stream of material containing hydrogen are sequentially fed into the oxidized slag layer 109, the hydrochemical methanation layer 111, and the hydropyrolysis layer 112 of the hydrogasification furnace 10, respectively. The operating pressure of the hydrogasification furnace 10 is 2 MPa-10 MPa. The ratio of oxygen to coal feed in the first stream of material is 0.2-1 Nm3 / kg, the ratio of hydrogen to coal feed in the second stream of material is 0.2-1 Nm3 / kg, and the mass flow ratio of hydrogen to coal feed in the third stream of material is 0-1 Nm3 / kg.

[0061] Step 2: The oxygen in the first stream of material in Step 1 undergoes an oxygen-enriched combustion reaction with the gasification residue in the oxidized slag layer 109 and the reducing gasification layer 110. The water vapor in the first stream of material is used to protect the nozzle of the first air inlet 101, thus obtaining oxygen-enriched combustion gas products and molten ash. The temperature of the oxidized slag reaction is 1400-1800℃.

[0062] Step 3: The oxygen-enriched combustion gas products obtained in Step 2 undergo a gasification reaction in the semi-coke contact between the reducing gasification layer 110 and the hydrogasification methanation layer 111, thereby obtaining the reducing gasification layer gas products and gasification residue.

[0063] Step 4: The hydrogen in the second stream of material in Step 1 comes into contact with the gaseous products of the reduction gasification layer 110 and the pyrolysis semi-coke of the hydrogenation pyrolysis layer 112 in Step 3 and undergoes a hydrogenation gasification methanation reaction, that is, the gaseous products of the hydrogenation gasification methanation layer 111 and the gasification residue are obtained. The temperature of the hydrogenation gasification methanation reaction is 600-1200℃.

[0064] Step 5: The hydrogen in the third material of Step 1 comes into contact with the coal in the drying layer 113 of Step 4 and undergoes a hydrogenation pyrolysis reaction to obtain hydrogenation pyrolysis gas products and pyrolysis semi-coke. These are then transported to the pressure reducing tank 20 through the outlet 106 for pressure reduction to obtain liquid products and purified gas. The purified gas is then sequentially passed through the quench water washing tower 30 for quench water washing and the gas-liquid separator 40 for gas-liquid separation to obtain gaseous products and liquid products. The gaseous products are separated by the hydrogen membrane separator 60 to obtain methane-rich gas and hydrogen. The hydrogen is divided into two paths and sent to the hydrogenation gasification furnace 10 through the second inlet 102 and the third inlet 103 under the action of the circulating gas compressor 70 to participate in the reaction. The methane-rich gas is the obtained product gas. The liquid products are separated into liquid oil and water and then uniformly recycled to the tar collector 50.

[0065] In step 5, the temperature-controlled hydropyrolysis reaction produces the following product composition: above 900℃, methane is mainly generated; at 800-900℃, BTX and PCX can be produced in abundance; and at 400-600℃, light oil products can be produced in abundance.

[0066] In step 2, the ratio of oxygen to coal in the first material must be such that an oxygen-enriched combustion reaction occurs, and the heat generated by the oxygen-enriched combustion reaction is sufficient to cause the coal in the reducing gasification layer to undergo a gasification reaction. The reaction temperature of the oxidizing slag layer 109 exceeds the ash flow temperature, and the following chemical reactions mainly occur:

[0067]

[0068]

[0069] CO + O2 = CO2

[0070]

[0071] In step 3, the reaction occurring in the reducing gasification layer 110 is a coal gasification reaction, which is the main water gas generation layer. The temperature of the reducing layer is 1000-1300℃, and the following chemical reactions mainly occur:

[0072]

[0073]

[0074] In step 4, the amount of hydrogen and water vapor in the second stream of material relative to the amount of coal processed should be such that a hydrogenation gasification methanation reaction can occur under the action of the gas products in the reducing gasification layer 110. The mixture obtained instantaneously upon contact between the hydrogen and water vapor in the second stream of material and the gas products in the reducing gasification layer 110 and the pyrolysis semi-coke in the hydrogenation pyrolysis layer 112 mainly undergoes the following chemical reactions:

[0075]

[0076] CO + 3H₂ = CH₄ + H₂O

[0077] CO + H₂O = CO₂ + H₂;

[0078] The reaction for the formation of light oil is as follows:

[0079] nCO + (2n + 1)H₂ = C n H 2n+2 +nH2O

[0080] 2nCO + (n+1)H2 = C n H 2n+2 +nCO2.

[0081] In step 5, the hydrogen in the third material comes into contact with the gaseous products of the hydrotreated methanation layer 111 and the coal in the drying layer 113, resulting in a mixture that undergoes a hydropyrolysis reaction. The hydropyrolysis layer 112 is the generation layer for pyrolysis tar and pyrolysis gas, and is also a key layer for producing gaseous-liquid fuels. The large organic molecules in the coal undergo thermal decomposition to generate small reactive molecules, which then react with hydrogen to produce hydrocarbon compounds. The main chemical reactions are as follows:

[0082] CH x O y +H2→C+CO+CH4+C m H n +BTX+PCX

[0083] CO + 3H₂ = CH₄ + H₂O

[0084] nCO + (2n + 1)H₂ = C n H 2n+2 +nH2O

[0085]

[0086] C m H n +H2=C m H n+2 .

[0087] Fundamental research was conducted on the pressurized pyrolysis and gasification of coal using the liquid slag-discharge moving bed hydrogasification process described in the above embodiments. We obtained the pressurized pyrolysis characteristics of coal and the high-temperature, high-pressure gasification reaction kinetics of Shenmu coal. Simultaneously, a liquid slag-discharge moving bed gasification experimental device with a processing capacity of 1 t / d (6.0 MPa, 1500℃) was established, and experimental research on methane-rich and oil-rich gasification technology was carried out using petroleum coke and Shenmu bituminous coal as experimental raw materials. The gasifier operating conditions were: maximum operating pressure 5.3 MPa, O2 3–6 Nm³ / h, air 2–6 Nm³ / h, steam 0.1–0.3 kg / h, and hydrogen 3–6 Nm³ / h. The gas at the gasifier outlet contained 20–30% CO, 35–50% H2, 6–12% CO2, and 16–27% CH4. The methane content in the crude gas was closely related to the gasification feedstock and operating conditions. The main conclusions are as follows:

[0088] (1) The methane content in the gas is closely related to the location of hydrogen addition in the gasifier. When hydrogen is passed through the gasifier at a temperature of 900-1000℃, the methane content in the gas can reach more than 25%, which is about 2-3 times that of conventional liquid slag gasification; while in the gasifier at a temperature below 700℃, the increase in methane content in the gas is significantly reduced.

[0089] (2) Increasing the system pressure can significantly increase the methane content in the coal gas. Under normal pressure hydrogenation conditions, the increase in methane content in crude coal gas is not significant. Increasing the pressure can significantly increase the yield of methane and small molecule hydrocarbons, but when the system pressure is increased to above 4.0 MPa, the increase in methane content tends to level off. When the operating pressure is increased from 4.0 MPa to 5.0 MPa, the methane content only increases by ~5%.

[0090] (3) The hydrogenation reactivity of the gasification feedstock has a significant impact on the methane content in the coal gas. Petroleum coke has very weak hydrogenation reactivity, and the increase in methane content in the coal gas after hydrogen is introduced into the gasifier is small; while Shenmu bituminous coal has high reactivity, and the methane content increases significantly after hydrogen is introduced into the gasifier, more than 5 times that of petroleum coke under the same conditions.

[0091] (4) Introducing hydrogen into the gasifier can increase the content of small molecule hydrocarbons in the crude coal gas to a certain extent, but the increase is smaller than that of methane, with the increase of small molecules below C6 being about 50-80%.

[0092] Experimental results show that introducing hydrogen gas at a suitable location in the moving bed can significantly increase the content of methane and small molecule hydrocarbons in the coal gas.

[0093] Table 1 Industrial and Elemental Analysis of Coal

[0094]

[0095] Table 2. Ash fusion point, ash composition, and particle size distribution of raw materials fed into the furnace.

[0096]

[0097]

[0098] Table 3 Composition of Coal Gas

[0099]

[0100]

[0101] As can be seen from Table 3, the CH4 content in the product gas can reach more than 23.93%, indicating high economic value.

[0102] The above experimental results verify the feasibility of increasing the yield of methane and light hydrocarbons in coal gas by modifying the hydrogenation process of a moving bed liquid slag gasifier.

[0103] The foregoing has shown and described the main features and advantages of the present invention. It will be apparent to those skilled in the art that the specific embodiments of the present invention are not limited to the details of the exemplary embodiments described above. Furthermore, without departing from the spirit or essential characteristics of the present invention, the inventive concept and design ideas of the present invention can be implemented in other specific forms, and these should be equivalently included within the protection scope disclosed in the technical solutions of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and thus all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included within the present invention.

[0104] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A coal hydrogenation gasification furnace system with a liquid slag-discharging moving bed, characterized in that: The height-to-diameter ratio of the hydrogenation gasification furnace (10) is 20-50. The hydrogenation gasification furnace (10) is integrally cast from a pressure-resistant steel shell and refractory material, and its interior is made of refractory material to form a furnace cavity (107). A solid inlet (105) and a solid outlet (104) are respectively provided on the top and bottom of the hydrogenation gasification furnace (10). A first air inlet (101), a second air inlet (102), and a third air inlet (103) are respectively provided on the side wall of the hydrogenation gasification furnace (10) from bottom to top. The gas inlet (106) is located on the side wall of the hydrogasification furnace (10) and above the third gas inlet (103), dividing the furnace cavity (107) from bottom to top into an oxidized slag layer (109), a reduction gasification layer (110), a hydrogasification methanation layer (111), a hydropyrolysis layer (112), and a drying layer (113). The first gas inlet (101), the second gas inlet (102), and the third gas inlet (103) are respectively located on the oxidized slag layer (109), the hydrogasification methanation layer (111), the first gas inlet (101), the second gas inlet (102), and the third gas inlet (103) on the side wall of the hydrogasification furnace (10) and above the third gas inlet (103). 111) In the hydropyrolysis layer (112), the reduction gasification layer (110) is located between the first inlet (101) and the second inlet (102); the outlet (106) of the hydrogasification furnace (10) is connected to the inlet of the pressure reducing tank (20) through a pipe, the outlet of the pressure reducing tank (20) is connected to the inlet of the quench water scrubbing tower (30) through a pipe, the outlet of the quench water scrubbing tower (30) is connected to the inlet of the gas-liquid separator (40) through a pipe, and the pressure reducing tank (20) The liquid outlets of the quench water washing tower (30) and the gas-liquid separator (40) are all connected to the liquid inlet of the tar collector (50). The gas outlet of the gas-liquid separator (40) is connected to the gas inlet of the hydrogen membrane separator (60) through a pipe. The hydrogen membrane separator (60) is provided with a hydrogen outlet and a methane-rich outlet. The hydrogen outlet of the hydrogen membrane separator (60) is connected to the second gas inlet (102) and the third gas inlet (103) of the hydrogenation gasification furnace (10) through two pipes.

2. The coal hydrogenation gasification furnace system with a liquid slag discharge moving bed according to claim 1, characterized in that: A circulating gas compressor (70) is installed on each of the two pipelines between the hydrogen outlet of the hydrogen membrane separator (60) and the second inlet (102) and the third inlet (103) of the hydrogenation gasification furnace (10) to provide power for conveying.

3. The coal hydrogenation gasification furnace system with a liquid slag discharge moving bed according to claim 2, characterized in that: An ash collection area (108) is provided in the furnace cavity (107) located below the oxidized slag layer (109), which is connected to the black water treatment system, wherein the black water treatment system provides circulating quench water to the ash collection area (108) for cooling the molten ash.

4. The coal hydrogenation gasification furnace system with a liquid slag discharge moving bed according to claim 3, characterized in that: The ratio of the distance between the first air inlet (101) and the second air inlet (102) in the furnace cavity to the height of the hydrogenation gasification furnace (10) is 1 / 5 to 1 / 3; the ratio of the distance between the second air inlet (102) and the third air inlet (103) in the furnace cavity to the height of the hydrogenation gasification furnace (10) is 1 / 6 to 1 / 4; the ratio of the distance between the third air inlet (103) and the top of the furnace cavity to the height of the hydrogenation gasification furnace (10) is 1 / 5 to 1 / 3.

5. The coal hydrogenation gasification furnace system with a liquid slag discharge moving bed according to claim 4, characterized in that: The first air inlet (101) is at an angle of 60-90° to the axis of the hydrogenation gasification furnace (10), which facilitates the feeding of the first stream of material into the oxidized slag layer (109) along a specific angle direction.

6. A method for hydrogasification, using a coal hydrogasification furnace system with a liquid slag-discharge moving bed as described in claim 5, comprising the following steps: Step 1: Pulverized coal with a particle size of 5-50 mm and a moisture content of less than 5 wt% is added into the furnace cavity (107) through the solid inlet (105). The first stream of material containing high-pressure oxygen and water vapor, the second stream of material containing hydrogen and water vapor, and the third stream of material containing hydrogen are sequentially fed into the oxidized slag layer (109), the hydrochemical methanation layer (111), and the hydropyrolysis layer (112) of the hydrochemical gasification furnace (10), respectively. The operating pressure of the hydrogenation gasification furnace (10) is 2MPa-10MPa, and the relationship between oxygen and coal feed rate in the first feed stream is 0.2-1Nm. 3 / kg, the relationship between hydrogen and coal feed rate in the second feed stream is 0.2-1 Nm³. 3 / kg, the mass flow ratio of hydrogen to coal in the third stream is 0-1Nm 3 / kg; Step 2: The oxygen in the first material in Step 1 undergoes an oxygen-enriched combustion reaction with the gasification residue in the oxidized slag layer (109) and the reducing gasification layer (110). The water vapor in the first material is used to protect the nozzle of the first air inlet (101), thus obtaining oxygen-enriched combustion gas products and molten ash. The temperature of the oxidized slag reaction is 1400-1800℃. Step 3: The oxygen-enriched combustion gas products obtained in Step 2 undergo a gasification reaction in the semi-coke contact between the reducing gasification layer (110) and the hydrochemical methanation layer (111), thus obtaining the reducing gasification layer gas products and gasification residue. Step 4: The hydrogen in the second material of Step 1 comes into contact with the gas products of the reduction gasification layer of Step 3 and the pyrolysis semi-coke of the hydrogenation pyrolysis layer (112) and undergoes a hydrogenation gasification methanation reaction, that is, the gas products of the hydrogenation gasification methanation layer and the gasification residue are obtained. The temperature of the hydrogenation gasification methanation reaction is 600-1200℃. Step 5: The hydrogen in the third material of Step 1 comes into contact with the coal in the drying layer (113) of Step 4 and undergoes a hydrogenation pyrolysis reaction to obtain hydrogenation pyrolysis gas products and pyrolysis semi-coke. These are transported to the pressure reducing tank (20) through the gas outlet (106) for pressure reduction to obtain liquid products and purified gas. The purified gas is sequentially passed through the quench water washing tower (30) for quench water washing and the gas-liquid separator (40) for gas-liquid separation to obtain gaseous products and liquid products. The gaseous products are separated by the hydrogen membrane separator (60) to obtain methane-rich gas and hydrogen. The hydrogen is divided into two paths and sent to the hydrogenation gasification furnace (10) through the second inlet (102) and the third inlet (103) under the action of the circulating gas compressor (70) to participate in the reaction. The methane-rich gas is the obtained product gas. The liquid products are separated into liquid oil and water after stratification and are uniformly recycled to the tar collector (50). The product composition of the hydrogenation pyrolysis reaction in step 5 is as follows: above 900℃, methane is mainly produced; at 800-900℃, BTX and PCX can be produced in abundance. By controlling the temperature to 400-600℃, light oil products can be produced in abundance.

7. The hydrogasification method according to claim 6, characterized in that: In step 2, the ratio of oxygen to coal in the first material must be such that an oxygen-enriched combustion reaction occurs and the heat generated by the oxygen-enriched combustion reaction is sufficient to cause the coal in the reducing gasification layer to undergo a gasification reaction. The reaction temperature of the oxidizing slag layer (109) exceeds the ash flow temperature, and the following chemical reactions mainly occur: ； ； ； 。 8. The hydrogasification method according to claim 7, characterized in that: In step 3, the reaction occurring in the reducing gasification layer (110) is a coal gasification reaction, which is the main water gas generation layer. The temperature of the reducing layer is 1000-1300℃, and the following chemical reactions mainly occur: ； 。 9. The hydrogasification method according to claim 8, characterized in that: In step 4, the amount of hydrogen and water vapor in the second stream of material relative to the amount of coal processed should be such that a hydrogenation gasification methanation reaction can occur under the action of the gas products of the reducing gasification layer (110). The mixture obtained instantaneously upon contact between the hydrogen and water vapor in the second stream of material and the gas products of the reducing gasification layer (110) and the pyrolysis semi-coke of the hydrogenation pyrolysis layer (112) mainly undergoes the following chemical reactions: ； ； ； The reaction for the formation of light oil is as follows: ； 。 10. A hydrogasification method according to claim 9, characterized in that: In step (5), the hydrogen in the third material comes into contact with the gaseous products of the hydrotreated methanation layer (111) and the coal in the drying layer (113) to form a mixture, which undergoes a hydropyrolysis reaction. The hydropyrolysis layer (112) is the generation layer for pyrolysis tar and pyrolysis gas, and is also the key layer for the production of gaseous-liquid fuels. The large organic molecules in the coal are thermally decomposed to generate active small molecules, and react with hydrogen to generate hydrocarbon compounds. The following chemical reactions mainly occur: ； ； ； ； 。

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