Hydropyrolysis quality-divided utilization system and process for low-rank coal

Abstract

The invention discloses a low-rank coal hydropyrolysis quality-divided utilization system and process, and belongs to the field of low-rank coal utilization, the low-rank coal hydropyrolysis quality-divided utilization system comprises a pyrolysis furnace, a coal gas purification and oil recovery module, a pressure swing adsorption hydrogen production module, a fixed bed hydrogenation catalytic cracking module and an indirect combustion type hot blast stove; the pyrolyzing furnace comprises a pyrolyzing furnace dry distillation section and a pyrolyzing furnace cooling section, and the lower part of the dry distillation section is connected with the cooling section; an inlet of the coal gas purification and oil recovery module is connected with an outlet of the dry distillation section, and an outlet is connected with the pressure swing adsorption hydrogen production module; the pressure swing adsorption hydrogen production module is respectively connected to the fixed bed hydrogenation catalytic cracking module, the mixing tank and the indirect combustion type hot blast stove; an inlet of the fixed bed hydrogenation catalytic cracking module is connected with the tar temporary storage tank, and an outlet is connected with the oil storage tank and the mixing tank. According to the novel pyrolysis technology, self-produced hydrogen serves as a heat carrier, generation of hydrogen free radicals is facilitated, the hydrogen heat carrier is heated through the indirect combustion type hot blast stove, and the product gas quality is improved.

Description

Technical Field

[0001] The present invention relates to low-rank coal utilization technology, and in particular to a low-rank coal hydropyrolysis fractionation utilization system and process. Background Art

[0002] Low-rank coal is coal with a low degree of coalification, mainly including lignite, long flame coal, weakly sticky coal, etc. The 2022 "China Mineral Resources Report" shows that my country's coal reserves are as high as 207.885 billion tons, of which low-rank coal reserves account for 57.38%, with reserves as high as 119.3 billion tons. Low-rank coal has the characteristics of high reactivity, rich chemical energy, and high oxygen content, and its potential utilization value is very high. At present, there are two main ways to utilize low-rank coal, namely direct combustion and pyrolysis. At present, about 80% of low-rank coal is used for combustion. Although combustion provides a lot of heat energy, it also causes energy loss, wastes precious hydrogen-carbon components and oil and gas energy in coal, and produces a large amount of carbon dioxide during combustion, and the greenhouse effect is obvious. Pyrolysis is to place low-rank coal in a specific atmosphere and heat it to 400-650℃, where it will undergo pyrolysis to generate three-phase products: gas, liquid, and solid. The gas phase product is dry distillation gas, the liquid phase product is tar, and the solid phase product is semi-coke, thereby achieving the quality improvement of low-rank coal. Therefore, vigorously developing low-rank coal fractionation utilization technology and achieving clean and high-value utilization of low-rank coal will not only help promote the early realization of green and environmentally friendly development in the coal chemical industry, but will also be of great significance to optimizing the energy structure and ensuring energy supply security.

[0003] The current mainstream low-rank coal pyrolysis process is the pyrolysis technology that uses a multi-stage vertical furnace as a pyrolysis reactor and gas as a carrier. The gas carrier usually uses flue gas or coal gas. The gas cold carrier enters the dry distillation section from the bottom of the dry distillation section after being heated by the heating furnace. The low-rank coal undergoes a series of physical and chemical reactions such as dehydration, cracking, polycondensation, and hydrogenation under the heating of the heat carrier, producing coal gas, semi-coke, and gaseous tar. The coal gas and gaseous tar are drawn out from the upper part of the dry distillation section together with the gas carrier and enter the downstream purification section. The high-temperature semi-coke enters the cooling section and is shipped out as a product after quenching.

[0004] After years of development, the above technology has become mature, but there are still some shortcomings. First, the quality of tar is poor. Due to the excessive content of heavy components such as colloids and asphaltene, the tar density is high. In addition, the content of unsaturated hydrocarbons is high, and the stability of tar is poor. Second, the effective components such as H2 and CH4 in the coal gas are low, and the calorific value is low. This is because a large amount of nitrogen will be mixed into the gas carrier when it is heated by the heating furnace, resulting in a large amount of nitrogen in the product coal gas, which is limited in its utilization. Third, the investment is high. Due to the high cost of the heating furnace, the overall investment of this technology is high, the payback period is long, and the market competitiveness is not strong.

[0005] Therefore, there is an urgent need for a low-grade coal hydrogen pyrolysis fractionation utilization system and process and system to significantly improve the quality of tar and coal gas, increase the value of resource utilization, and significantly reduce investment costs, thereby achieving a significant increase in economic benefits. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the present invention provides a low-rank coal hydrogen pyrolysis and fractional utilization system and process, which adopts hydrogen heat carrier pyrolysis technology, intermittent combustion hot blast furnace heating technology, and fixed bed hydrocatalytic cracking technology to greatly improve the quality of tar and coal gas, improve the resource utilization value, and greatly reduce investment costs, thereby achieving a significant increase in economic benefits.

[0007] The first aspect of the present invention discloses a low-rank coal hydropyrolysis fractionation utilization system, comprising: a pyrolysis furnace, a coal gas purification and oil recovery module, a pressure swing adsorption hydrogen production module, a fixed bed hydrocatalytic cracking module and an intermittently fired hot blast furnace;

[0008] The pyrolysis furnace comprises a pyrolysis furnace retorting section and a pyrolysis furnace cooling section, and is used for pyrolyzing low-rank coal, wherein a coal bunker is arranged above the pyrolysis furnace retorting section and is connected to the pyrolysis furnace cooling section below;

[0009] The gas inlet of the gas purification and oil recovery module is connected to the gas outlet of the pyrolysis furnace distillation section, and the gas outlet of the gas purification and oil recovery module is connected to the gas inlet of the pressure swing adsorption hydrogen production module; a tar temporary storage tank is arranged below the gas purification and oil recovery module for the preparation and collection of primary tar;

[0010] The gas outlet of the pressure swing adsorption hydrogen production module is divided into three routes, which are respectively connected to the fixed bed hydrocatalytic cracking module, the mixing tank and the intermittently fired hot blast furnace for the preparation and transportation of hydrogen;

[0011] The inlet of the fixed-bed hydrocatalytic cracking module is connected to the tar temporary storage tank, and the outlet thereof is respectively connected to the oil storage tank and the mixing tank for the preparation and collection of tar.

[0012] Preferably, a scraper is provided below the cooling section of the pyrolysis furnace for collecting and transporting the semi-coke.

[0013] Preferably, a belt conveyor is also provided above the dry distillation section of the pyrolysis furnace for transporting the low-rank coal to the coal bunker.

[0014] The second aspect of the present invention discloses a low-rank coal hydropyrolysis fractionation and utilization process, based on the low-rank coal hydropyrolysis fractionation and utilization system, comprising the following steps:

[0015] Step 1, placing low-rank coal raw materials into a pyrolysis furnace for dry distillation to obtain gas and semi-coke;

[0016] Step 2, the gas obtained in step 1 is transported to the gas purification and oil recovery module for treatment to obtain primary tar and hydrogen-rich gas;

[0017] Step 3, sending the hydrogen-rich coal gas obtained in step 2 to a pressure swing adsorption hydrogen production module to extract hydrogen to obtain hydrogen and desorbed gas;

[0018] Step 4, a portion of the hydrogen obtained in step 3 and the primary tar obtained in step 2 are sent to a fixed bed hydrocatalytic cracking module to react under set catalytic conditions to obtain tar and tail gas;

[0019] Step 5, another part of the hydrogen obtained in step 3 is sent to the cooling section of the pyrolysis furnace to exchange heat with the high-temperature semi-coke produced in the dry distillation section to recover heat;

[0020] Step 6, the hot hydrogen after heat exchange in step 5 is sent to the intermittently fired hot blast furnace, and after being heated, is sent to the dry distillation section of the pyrolysis furnace to serve as a heat carrier for coal pyrolysis;

[0021] In step 7, the desorbed gas in step 3 and the tail gas in step 4 are sent to a mixing tank. After mixing, a portion is sent to an intermittently fired hot blast furnace for combustion as a heat source for the intermittently fired hot blast furnace, and the remaining portion is sent out as product gas.

[0022] Preferably, step 1 specifically includes: transporting the low-rank coal raw material to the coal bunker through a belt conveyor, and performing dry distillation in a high-temperature hydrogen atmosphere in the dry distillation section of the pyrolysis furnace to cause cracking, hydrogenation, isomerization, and polycondensation reactions, and the internal volatile matter and a small amount of fixed carbon are converted into gas and precipitated.

[0023] Preferably, the particle size of the low-rank coal raw material is in the range of 8 to 80 mm, the volatile matter content on an air-dried basis is not less than 25%, and the total water content is not higher than 16%.

[0024] Preferably, the high temperature ranges from 300°C to 650°C, the bottom temperature of the pyrolysis furnace retorting section is 650°C, the upper temperature is 300°C, and the pressure of the pyrolysis furnace is normal pressure.

[0025] Preferably, in step 4, the volume ratio of hydrogen to tar is 1000:1.

[0026] Preferably, in step 4, the temperature of the fixed bed reactor is in the range of 380° C. to 420° C., and the reaction pressure is in the range of 16 to 20 MPa.

[0027] Preferably, in step 5, after the heat exchange, the semi-coke temperature drops to about 100° C., and the moisture content of the semi-coke is maintained below 12% after water spray cooling.

[0028] The present invention adopts the following technical solution.

[0029] Compared with the prior art, the beneficial effects of the present invention include at least:

[0030] 1. The present invention uses a new pyrolysis process and uses self-produced hydrogen as a heat carrier, which is helpful for the generation of hydrogen free radicals in the coal pyrolysis process. Hydrogen free radicals can promote cracking, hydrogenation, isomerization and other reactions in the coal pyrolysis process. Therefore, the pyrolysis tar has good quality, the content of components below 360°C in the distillate oil is greater than 50%, and the total content of colloid + asphaltene is not higher than 45%, which is a good raw material for hydrogenation catalytic cracking.

[0031] 2. Compared with the prior art, the present invention adopts an intermittent hot air furnace to heat the hydrogen heat carrier, and the smoke generated by combustion cannot directly contact the hydrogen heat carrier, so the product gas has good quality, the effective component content (CH4+H2+CO+CmHn) can reach more than 90%, and the calorific value is not less than 4200kcal / Nm 3 .

[0032] 3. Compared with the existing technology, the present invention has lower investment cost and better economic benefits. Compared with the heating furnace process, the indirect combustion hot blast furnace is used as the heating equipment for the hydrogen carrier, and the investment cost is greatly reduced. At the same time, the gas and tar produced by this technology are of better quality and higher market value. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the process flow of low-rank coal hydropyrolysis;

[0034] In the figure: 1-belt conveyor; 2-coal bunker; 3-pyrolysis furnace distillation section; 4-pyrolysis furnace cooling section; 5-scraper; 6-gas purification and oil recovery module; 7-tar temporary storage tank; 8-pressure swing adsorption hydrogen production module; 9-fixed bed hydrocatalytic cracking module; 10-oil storage tank; 11-mixing tank; 12-intermittently fired hot air furnace; 13-air blower; 14-flue gas induced draft fan; A-coal gas; B-flue gas; C-air; D-semi-coke. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0036] Low-rank coal is coal with a low degree of coalification, mainly including lignite, long flame coal, weakly sticky coal, etc. Low-rank coal can be converted into semi-coke, tar and coal gas through low-temperature pyrolysis. Semi-coke can be used to produce calcium carbide or prepare adsorbent materials, tar can be used to prepare special base oils, and pyrolysis coal gas can be used to prepare hydrogen or burn for power generation.

[0037] At present, the coal pyrolysis technology using gas as heat carrier has been developed relatively maturely and has been widely used. The gas heat carrier is usually flue gas or coal gas. Since flue gas is an inert gas, it has no promoting effect on hydrogenation, isomerization and other reactions in the coal pyrolysis process, so the quality of the produced tar is poor, such as high content of heavy components and unsaturated components. In addition, when flue gas is used as a heat carrier, the pyrolysis coal gas and flue gas are mixed together, which is raw coal gas. Since the effective components in raw coal gas are low, the calorific value is extremely low. When coal gas is used as a heat carrier, the coal gas contains a certain amount of hydrogen, which is conducive to the hydrogenation, isomerization and other reactions in the coal pyrolysis process. However, due to the low hydrogen content in the coal gas, the promotion effect is not significant, and the improvement of tar quality is not obvious. At the same time, when gas is used as a heating carrier, a heating furnace is usually required. Due to the high cost of the heating furnace, the overall investment cost is high.

[0038] The low-rank coal hydropyrolysis fractionation utilization system and process proposed in the present invention found that when hydrogen is used as a heat carrier, it can significantly promote hydrogenation, isomerization and other reactions in the coal pyrolysis process, greatly increase the content of light components and saturated hydrocarbons in tar, and use an intermittent hot blast furnace instead of a heating furnace, which can not only reduce investment costs, but also avoid mixing flue gas into the coal gas. The effective components of the product coal gas are greater than 90% and the calorific value is not less than 4200kcal / Nm 3 .

[0039] like Figure 1 As shown, the present invention discloses a low-rank coal hydropyrolysis fractionation utilization system, comprising: a pyrolysis furnace, a coal gas purification and oil recovery module 6, a pressure swing adsorption hydrogen production module 8, a fixed bed hydrocatalytic cracking module 9 and an intermittently fired hot blast furnace 12;

[0040] The pyrolysis furnace comprises a pyrolysis furnace retorting section 3 and a pyrolysis furnace cooling section 4, wherein a coal bunker 2 is arranged above the pyrolysis furnace retorting section 3, and a scraper 5 is arranged below the pyrolysis furnace cooling section 4 for pyrolysis of low-rank coal;

[0041] The gas inlet of the gas purification and oil recovery module 6 is connected to the gas outlet of the pyrolysis furnace distillation section 3, and the gas outlet of the gas purification and oil recovery module 6 is connected to the gas inlet of the pressure swing adsorption hydrogen production module 8. A tar temporary storage tank 7 is provided below the gas purification and oil recovery module 6 for collecting primary tar;

[0042] The gas outlet of the pressure swing adsorption hydrogen production module 8 is divided into three routes, which are respectively connected to the fixed bed hydrocatalytic cracking module 9, the mixing tank 11 and the intermittently fired hot blast furnace 12 for the preparation and transportation of hydrogen;

[0043] The inlet of the fixed bed hydrocatalytic cracking module 9 is also connected to the tar temporary storage tank 7, and the outlet thereof is respectively connected to the oil storage tank 10 and the mixing tank 11, so as to obtain high-quality tar.

[0044] In a preferred but non-limiting embodiment of the present invention, the low-rank coal hydropyrolysis fractionation and utilization system also includes an air blower 13 and a flue gas induced draft fan 14, wherein the air blower 13 is connected to the inlet of the intermittently fired hot blast furnace 12, for providing the air C required for the combustion of the coal gas; the flue gas induced draft fan 14 is connected to the outlet of the intermittently fired hot blast furnace 12, for delivering the flue gas B generated by the combustion of the coal gas to the downstream processing section.

[0045] Example 2 of the present invention discloses a low-rank coal hydropyrolysis fractionation and utilization process, and the process steps are as follows:

[0046] Step 1, placing low-rank coal raw materials in a pyrolysis furnace for dry distillation to obtain gas and semi-coke D;

[0047] Specifically, the low-rank coal raw material is transported to the coal bunker 2 through a belt conveyor 1, and is subjected to dry distillation in a high-temperature hydrogen atmosphere in the dry distillation section 3 of the pyrolysis furnace, where a series of reactions such as cracking, hydrogenation, isomerization, and polycondensation occur, and the volatile matter and a small amount of fixed carbon inside are converted into gas and precipitated;

[0048] In a preferred but non-limiting embodiment of the present invention, the particle size of the low-rank coal raw material ranges from 8 to 80 mm, the volatile matter content on an air-dried basis is not less than 25%, and the total water content is not more than 16%;

[0049] The high temperature range is 300°C to 650°C, the bottom temperature of the pyrolysis furnace retorting section is about 650°C, the upper temperature is about 300°C, and the pyrolysis furnace pressure is normal pressure;

[0050] Step 2: The gas obtained in step 1 is transported to the gas purification and oil recovery module 6, and after being subjected to spray dust removal, ammonia water washing, electric coke capture and oil removal, and sedimentation separation treatment, primary tar and hydrogen-rich gas are obtained;

[0051] The primary tar is stored in a tar temporary storage tank 7 .

[0052] Step 3, sending the hydrogen-rich coal gas obtained in step 2 to the pressure swing adsorption hydrogen production module 8 to obtain hydrogen and desorbed gas after hydrogen extraction;

[0053] Step 4, a portion of the hydrogen obtained in step 3 and the tar obtained in step 2 are sent to a fixed bed hydrocatalytic cracking module 9, and react under set catalytic conditions to obtain tar and tail gas;

[0054] The volume ratio of hydrogen to tar is about 1000:1, which varies with the quality of the tar;

[0055] Specifically, under the action of a catalyst with alumina and molecular sieve as carriers and Ni, Mo, and W as active components, the primary tar obtained in step 2 undergoes hydrogenation, cracking, isomerization and other reactions in the fixed-bed hydrocatalytic cracking module 9, further increasing the content of light components and saturated components in the tar, while removing most of the sulfur and nitrogen compounds to obtain high-quality tar and tail gas. The tar is stored in an oil storage tank 10, wherein the temperature of the fixed-bed reactor is in the range of 380°C to 420°C, and the reaction pressure is in the range of 16 to 20 MPa.

[0056] It is worth noting that high-quality tar can be used as a raw material for producing lubricant base oil. The present invention uses self-produced hydrogen as a heat carrier, which helps to produce hydrogen free radicals during coal pyrolysis. Hydrogen free radicals can promote cracking, hydrogenation, isomerization and other reactions, thereby achieving the goal of improving tar quality.

[0057] Step 5, another part of the hydrogen obtained in step 3 is sent to the cooling section 4 of the pyrolysis furnace to exchange heat with the high-temperature semi-coke produced in the dry distillation section 3 to recover heat;

[0058] In a preferred but non-limiting embodiment of the present invention, after the heat exchange, the semi-coke temperature drops to about 100° C., and water can be sprayed directly for cooling, and the moisture content of the semi-coke is kept below 12%. The obtained product semi-coke is collected and transported by a scraper 5;

[0059] The semi-coke product can be used to produce calcium carbide, prepare adsorption materials, etc. Hydrogen cold carrier is used for quenching, and the sensible heat of the semi-coke is fully utilized to achieve efficient use of heat.

[0060] Step 6, the hot hydrogen after heat exchange in step 5 is sent to the intermittently fired hot blast furnace 12, and after being heated, is sent to the dry distillation section 3 of the pyrolysis furnace to serve as a heat carrier for coal pyrolysis;

[0061] An intermittently fired hot air furnace is used to heat the hydrogen heat carrier to avoid the mixing of flue gas. The product gas has a high content of effective components and greatly reduces investment costs.

[0062] In step 7, the desorbed gas in step 3 and the tail gas in step 4 are sent to a mixing tank 11. After mixing, a part of them is sent to an intermittently fired hot blast furnace 12 for combustion as a heat source for the intermittently fired hot blast furnace, and the remaining part is sent out as product gas A, which can be used for power generation, production of carbon black, etc., thereby achieving the goal of high-value utilization of pyrolysis gas.

[0063] Through the above process, low-rank coal raw materials are pyrolyzed and separated to obtain high-quality tar, high-purity coal gas and semi-coke, realizing the high-value utilization of low-rank coal.

[0064] This scheme uses low-rank coal as raw material, extracts hydrogen from pyrolysis coal gas, uses it as a carrier for coal gas pyrolysis and hydrogen required for hydrocatalytic cracking, and uses an intermittently fired hot air furnace as a device for heating the hydrogen carrier, which can significantly reduce investment costs and produce high-quality tar, high-purity coal gas and semi-coke. Therefore, it is a low-rank coal processing technology with high economic benefits.

[0065] The hydrogen pyrolysis process described in this technology has wide applicability, especially for the processing and comprehensive utilization of low-rank coal and oil shale. Compared with other processes, this technology has good tar quality, high coal gas purity, high thermal utilization efficiency, mature and reliable process, low investment cost, and very good economic benefits.

[0066] Compared with the prior art, the beneficial effects of the present invention include at least:

[0067] 1. The present invention uses a new pyrolysis process and uses self-produced hydrogen as a heat carrier, which is helpful for the generation of hydrogen free radicals in the coal pyrolysis process. Hydrogen free radicals can promote cracking, hydrogenation, isomerization and other reactions in the coal pyrolysis process. Therefore, the pyrolysis tar has good quality, the content of components below 360°C in the distillate oil is greater than 50%, and the total content of colloid + asphaltene is not higher than 45%, which is a good raw material for hydrogenation catalytic cracking.

[0068] 2. Compared with the prior art, the present invention adopts an intermittent hot air furnace to heat the hydrogen heat carrier, and the smoke generated by combustion cannot directly contact the hydrogen heat carrier, so the product gas has good quality, the effective component content (CH4+H2+CO+CmHn) can reach more than 90%, and the calorific value is not less than 4200kcal / Nm 3 .

[0069] 3. Compared with the existing technology, the present invention has lower investment cost and better economic benefits. Compared with the heating furnace process, the indirect combustion hot blast furnace is used as the heating equipment for the hydrogen carrier, and the investment cost is greatly reduced. At the same time, the gas and tar produced by this technology are of better quality and higher market value.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A low-rank coal hydropyrolysis and fractionation utilization system, characterized by: include: A pyrolysis furnace, a coal gas purification and oil recovery module (6), a pressure swing adsorption hydrogen production module (8), a fixed bed hydrocatalytic cracking module (9) and an intermittently fired hot blast furnace (12); The pyrolysis furnace comprises a pyrolysis furnace retorting section (3) and a pyrolysis furnace cooling section (4), and is used for pyrolyzing low-rank coal, wherein a coal bunker (2) is arranged above the pyrolysis furnace retorting section (3) and is connected to the pyrolysis furnace cooling section (4) below; The gas inlet of the gas purification and oil recovery module (6) is connected to the gas outlet of the pyrolysis furnace dry distillation section (3), and the gas outlet of the gas purification and oil recovery module (6) is connected to the gas inlet of the pressure swing adsorption hydrogen production module (8); a tar temporary storage tank (7) is arranged below the gas purification and oil recovery module (6) for the preparation and collection of primary tar; The gas outlet of the pressure swing adsorption hydrogen production module (8) is divided into three routes, which are respectively connected to the fixed bed hydrocatalytic cracking module (9), the mixing tank (11) and the intermittently fired hot blast furnace (12) for the preparation and transportation of hydrogen; The inlet of the fixed bed hydrocatalytic cracking module (9) is connected to the tar temporary storage tank (7), and the outlet thereof is respectively connected to the oil storage tank (10) and the mixing tank (11) for the preparation and collection of tar.

2. A low-rank coal hydropyrolysis fractionation and utilization system according to claim 1, characterized in that: A scraper (5) is provided below the cooling section (4) of the pyrolysis furnace for collecting and transporting the semi-coke.

3. A low-rank coal hydropyrolysis fractionation and utilization system according to claim 1, characterized in that: A belt conveyor (1) is also provided above the pyrolysis furnace dry distillation section (3) for conveying low-rank coal to the coal bunker (2).

4. A low-rank coal hydropyrolysis fractionation and utilization process, based on a low-rank coal hydropyrolysis fractionation and utilization system according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1, placing low-rank coal raw materials into a pyrolysis furnace for dry distillation to obtain gas and semi-coke; Step 2, the gas obtained in step 1 is transported to the gas purification and oil recovery module (6) and processed to obtain primary tar and hydrogen-rich gas; Step 3, sending the hydrogen-rich coal gas obtained in step 2 to a pressure swing adsorption hydrogen production module (8) to extract hydrogen to obtain hydrogen and desorbed gas; Step 4, a portion of the hydrogen obtained in step 3 and the primary tar obtained in step 2 are sent to a fixed bed hydrocatalytic cracking module (9), and reacted under set catalytic conditions to obtain tar and tail gas; Step 5, another part of the hydrogen obtained in step 3 is sent to the cooling section (4) of the pyrolysis furnace to exchange heat with the high-temperature semi-coke produced in the dry distillation section (3) to recover heat; Step 6, the hot hydrogen after heat exchange in step 5 is sent to the intermittently fired hot blast furnace (12), and after being heated, is sent to the dry distillation section (3) of the pyrolysis furnace to serve as a heat carrier for coal pyrolysis; In step 7, the desorbed gas in step 3 and the tail gas in step 4 are sent to a mixing tank (11), and after mixing, a portion is sent to an intermittently fired hot blast furnace (12) for combustion as a heat source for the intermittently fired hot blast furnace, and the remaining portion is sent out as product gas.

5. A low-rank coal hydropyrolysis fractionation and utilization process according to claim 4, characterized in that: Step 1 specifically includes: transporting the low-rank coal raw material to the coal bunker (2) via a belt conveyor (1), and performing dry distillation in a high-temperature hydrogen atmosphere of a pyrolysis furnace dry distillation section (3), where cracking, hydrogenation, isomerization, and polycondensation reactions occur, and the volatile matter and a small amount of fixed carbon inside are converted into gas and precipitated.

6. A low-rank coal hydropyrolysis fractionation and utilization process according to claim 5, characterized in that: The particle size of the low-rank coal raw material ranges from 8 to 80 mm, the volatile matter content on an air-dried basis is not less than 25%, and the total water content is not higher than 16%.

7. The low-rank coal hydropyrolysis fractionation and utilization process according to claim 5, characterized in that: The high temperature ranges from 300°C to 650°C, the bottom temperature of the pyrolysis furnace retorting section is 650°C, the upper temperature is 300°C, and the pressure of the pyrolysis furnace is normal pressure.

8. The low-rank coal hydropyrolysis fractionation and utilization process according to claim 4, characterized in that: In step 4, the volume ratio of hydrogen to tar is 1000:

1.

9. A low-rank coal hydropyrolysis fractionation and utilization process according to claim 4, characterized in that: In step 4, the temperature of the fixed bed reactor is in the range of 380° C. to 420° C., and the reaction pressure is in the range of 16 to 20 MPa.

10. The low-rank coal hydropyrolysis fractionation and utilization process according to claim 4, characterized in that: In step 5, after the heat exchange, the semi-coke temperature drops to about 100° C., and the moisture content of the semi-coke is maintained below 12% after water spray cooling.

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