A zero-water discharge fixed-bed gasification device and method thereof

Abstract

The present invention relates to the technical field of fixed-bed gasification, and particularly relates to a fixed-bed gasification device with zero water discharge and its method. The fixed-bed gasification device of the present invention includes a gasification furnace body, and also includes a heat exchange component, a filtration component and a humidification component. In the present invention, the dust in the coal gas is removed through the filtration component, and the organic condensate and condensate water during the heat exchange of the coal gas are passed through the humidification component, and the water body directly generates the water vapor required by the gasification furnace body and returns to the gasification furnace body. The remaining gas cooled during the humidification process is sent to the heat exchange component to continue heat exchange, thereby realizing zero water discharge during the coal gasification process; the gasification method of the present invention has a simple and reasonable technological process, and directly generates the water vapor required for gasification from the coal gas water generated during the coal gasification process and returns it to the gasification furnace, and finally there is no water discharge during the coal gasification process. The present invention is particularly suitable for the production process of coal gasification for preparing coal gas with less tar content but containing phenolic water.

Description

Technical Field

[0001] The present invention relates to the technical field of fixed bed gasification, and particularly to a fixed bed gasification device with zero water discharge and its method. Background Art

[0002] The fixed bed (also known as the moving bed) gasifier is the oldest coal gasification equipment, which has the characteristics of mature technology, reliable equipment, flexible production operation, and high thermal efficiency in the coal conversion process. Although modern coal gasification technologies are advanced in many aspects such as raw materials and environmental protection, fixed bed gasification still has its appropriate application prospects. Especially after adopting slagging ash discharge, the processing capacity of fixed bed gasification under pressurized conditions is significantly improved, and its environmental protection characteristics are also improved. The raw material preparation of the fixed bed gasifier is simple, with high methane production rate and high-value tar by-products, and high thermal efficiency, which are important characteristics compared with other technologies. Especially the obvious low oxygen consumption makes its application in the field of integrated gasification combined cycle power generation particularly attractive.

[0003] However, due to its own characteristics, during the fixed bed gasification process, the gas contains macromolecular organic substances. Although anthracite is used as the raw material, the generated coal gas water still contains organic matter, and complex processes are required for subsequent treatment to meet the emission standards. Therefore, it is necessary to improve the current fixed bed gasification process. Summary of the Invention

[0004] To solve the above problems, the present invention provides a fixed bed gasification device with zero water discharge and its method, which has a simple structure, a reasonable process, and realizes zero water discharge during the coal gasification process.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A fixed bed gasification device with zero water discharge includes a gasification furnace body. A hot gas outlet is provided at the top of the gasification furnace body, and a slag discharge outlet is provided at the bottom of the gasification furnace body. It further includes a heat exchange component, a filtration component, and a humidification component. The heat exchange component and the humidification component are respectively connected to the gasification furnace body, and the filtration component is connected to the heat exchange component.

[0007] A further improvement to the above technical solution is that it further includes a high-temperature stripping component and an organic matter recovery component. The high-temperature stripping component is respectively connected to the humidification component and the gasification furnace body, and the organic matter recovery component is connected to the humidification component.

[0008] A further improvement to the above technical solution is that it further includes a primary gas cooler, which is respectively connected to the gasification furnace body and the heat exchange component.

[0009] A further improvement to the above technical solution is that the heat exchange component includes a heat exchanger, which is provided with a cooling water inlet, a cooling water outlet, a gas inlet, a gas outlet and a condensate outlet. The gas inlet is connected to the gasifier body and the filtration component, the condensate outlet is connected to the filtration component, the cooling water inlet is respectively connected to the filtration component and the humidification component, and the cooling water outlet is connected to the humidification component.

[0010] A further improvement to the above technical solution is that the filtration component includes a filter, which is provided with a liquid inlet, a liquid outlet and a solid discharge port. The liquid inlet is connected to the condensate outlet, the liquid outlet is respectively connected to the cooling water inlet and the gas inlet through a condensate pump, and the solid discharge port is used for discharging the filtered solids.

[0011] A further improvement to the above technical solution is that the humidification component includes an air humidification tower, which is provided with an air inlet, a hot water inlet, a hot gas outlet and a circulating water outlet. The air inlet is connected to a blower. At a position inside the air humidification tower close to the air inlet, there is a air distribution structure. The hot water inlet is connected to the cooling water outlet, the hot gas outlet is connected to the gasifier body, and a supplementary steam pipeline is connected at the position of the hot water inlet or the hot gas outlet. The circulating water outlet is respectively connected to the cooling water inlet, the high-temperature stripping component and the organic matter recovery component through a circulating water pump.

[0012] A further improvement to the above technical solution is that the high-temperature stripping component includes a high-temperature stripper, which is provided with a circulating water inlet, a high-temperature steam inlet and a stripping gas outlet. The circulating water inlet is connected to the circulating water outlet, and the stripping gas outlet is connected to the gasifier body.

[0013] A further improvement to the above technical solution is that a temperature measuring and controlling device is provided at the hot gas outlet, and a gas preheater is provided between the hot gas outlet and the gasifier body.

[0014] A further improvement to the above technical solution is that the heat exchanger and the air humidification tower are respectively provided with liquid level measuring instruments and are respectively connected with water supply pipelines.

[0015] The gasification method using the above zero-water discharge fixed-bed gasification device includes the following steps:

[0016] When the temperature and organic matter content of the gas leaving the gasifier body are relatively low, it directly enters the heat exchange component. When the temperature and organic matter content of the gas leaving the gasifier body are relatively high, it first enters the gas primary cooler, and after recovering the excess heat and separating out the heavy organic matter, it then enters the heat exchange component;

[0017] The coal gas is cooled by water in the heat exchange component, the organic matter and water vapor are cooled out simultaneously, and condensate is generated. After the solid matter is removed from the condensate by the filtration component, part of the water body is sent to the heat exchange component as cooling water, and the other part of the water body is mixed with the coal gas and then re-enters the heat exchange component;

[0018] The cooling water heated during the heat exchange process of the heat exchange component is sent into the humidification component. Part of the water body contacts the air entering the humidification component, forms saturated water vapor, then leaves the humidification component and enters the gasification furnace body to participate in the reaction. The remaining water body cools down and accumulates. Here, when the amount of water body sent into the heat augmentation component is small, a water replenishing pipeline is used to replenish water into the heat augmentation component. Part of the water body that has cooled down and accumulated is sent to the heat exchange component for use as cooling water, and the remaining part of the water body that has cooled down and accumulated is sent to the high-temperature stripping component and the organic recovery unit for treatment respectively;

[0019] For the water body sent into the high-temperature stripping component, the organic matter in the water body is stripped by high-temperature gas, and the stripping gas is sent into the gasification furnace body to participate in the reaction. For the water body sent into the organic recovery unit, the organic matter in the water is recovered and purified;

[0020] By circulating in this way, zero water discharge during the coal gasification process is achieved.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The fixed-bed gasification device of the present invention includes a gasification furnace body. A hot coal gas outlet is provided at the top of the gasification furnace body, and a slag discharge outlet is provided at the bottom of the gasification furnace body. It further includes a heat exchange component, a filtration component, and a humidification component. The heat exchange component and the humidification component are respectively connected to the gasification furnace body, and the filtration component is connected to the heat exchange component. The structure of the present invention is simple and reasonably designed. Through the reasonable settings of the heat exchange component, the filtration component, and the humidification component, the dust in the coal gas generated by the gasification furnace body is removed by the filtration component. For the organic condensate and condensed water during the heat exchange process of the coal gas, through the humidification component, the water body directly generates the water vapor required by the gasification furnace body and returns to the gasification furnace body again. The remaining gas cooled during the humidification process is sent to the heat exchange component to continue heat exchange, thereby achieving zero water discharge during the coal gasification process. The gasification method of the present invention directly uses the sensible heat of the coal gas for heating the coal gas water, which is the integrated and optimized utilization of energy. The main feature is that it overcomes the problem of a large amount of coal gas water generated during the coal gas generation process that needs to be treated or discharged, effectively solves the problem of coal gas water treatment during the coal gasification process from the source, and has good popularization and application prospects.

[0023] 2. The gasification method of the present invention has a simple and reasonable process flow, stable operation, and simple control. The coal gas water generated during the coal gasification process is directly converted into the steam required for gasification and returned to the gasification furnace. Eventually, there is no water discharge during the coal gasification process. The present invention is particularly suitable for the production process of preparing coal gas by gasifying coal with less tar content but containing phenol. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of Embodiment 1 of the present invention;

[0025] Figure 2 It is a schematic structural diagram of Embodiment 2 of the present invention;

[0026] Figure 3 It is a schematic structural diagram of Embodiment 3 of the present invention;

[0027] Figure 4 It is a schematic structural diagram of Embodiment 4 of the present invention;

[0028] DESCRIPTION OF THE REFERENCE NUMERALS: 1. Gasification furnace body, 11. Hot coal gas outlet, 12. Ash discharge outlet, 2. Heat exchange assembly, 21. Heat exchanger, 211. Cooling water inlet, 212. Cooling water outlet, 213. Coal gas outlet, 214. Coal gas outlet, 215. Condensate outlet, 216. Liquid level measuring instrument, 217. Make-up water pipeline, 3. Filtration assembly, 31. Filter, 311. Liquid inlet, 312. Liquid outlet, 313. Solid discharge port, 314. Condensate pump, 4. Humidification assembly, 41. Air humidification tower, 411. Air inlet, 412. Hot water inlet, 413. Hot gas inlet, 4131. Temperature control instrument, 4132. Gas preheater, 414. Circulating water outlet, 415. Blower, 416. Air distribution structure, 417. Supplementary steam pipeline, 418. Circulating water pump, 5. High-temperature stripping assembly, 51. High-temperature stripper, 511. Circulating water inlet, 512. High-temperature steam inlet, 513. Stripping gas outlet, 6. Organic matter recovery assembly, 7. Primary coal gas cooler. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be further described below with reference to the accompanying drawings.

[0030] Embodiment 1:

[0031] As Figure 1 shown, the zero-water-discharge fixed-bed gasification device described in this embodiment includes a gasification furnace body 1. A hot coal gas outlet 11 is provided at the top of the gasification furnace body 1, and an ash discharge outlet 12 is provided at the bottom of the gasification furnace body 1. It further includes a heat exchange assembly 2, a filtration assembly 3, and a humidification assembly 4. The heat exchange assembly 2 and the humidification assembly 4 are respectively connected to the gasification furnace body 1, and the filtration assembly 3 is connected to the heat exchange assembly 2.

[0032] Specifically, the heat exchange assembly 2 includes a heat exchanger 21. The heat exchanger 21 is provided with a cooling water inlet 211, a cooling water outlet 212, a gas inlet 213, a gas outlet 214, and a condensate outlet 215. The gas inlet 213 is connected to the gasifier body 1. The condensate outlet 215 is connected to the filtration assembly 3. The cooling water inlet 211 is respectively connected to the filtration assembly 3 and the humidification assembly 4. The cooling water outlet 212 is connected to the humidification assembly 4.

[0033] In other embodiments, after the heat exchanger 21, a subsequent cooler may also be provided to cool the gas to a lower temperature using a cooling medium at a lower temperature. The obtained condensate is combined with the condensate obtained from the heat exchanger 21, and the cooled gas enters the washing unit.

[0034] The filtration assembly 3 includes a filter 31. The filter 31 is provided with a liquid inlet 311, a liquid outlet 312, and a solid discharge port 313. The liquid inlet 311 is connected to the condensate outlet 215. The liquid outlet 312 is respectively connected to the cooling water inlet 211 and the gas inlet 213 through a condensate pump 314. The solid discharge port 313 is used to discharge the filtered solids.

[0035] The humidification assembly 4 includes an air humidification tower 41. The air humidification tower 41 is provided with an air inlet 411, a hot water inlet 412, a hot gas outlet 413, and a circulating water outlet 414. The air inlet 411 is connected to a blower 415. At a position inside the air humidification tower 41 near the air inlet 411, a air distribution structure 416 is provided. The hot water inlet 412 is connected to the cooling water outlet 212. The hot gas outlet 413 is connected to the gasifier body 1. A supplementary steam pipeline 417 is connected at the position of the hot water inlet 412 or the position of the hot gas outlet 413. The circulating water outlet 414 is connected to the cooling water inlet 211 through a circulating water pump 418.

[0036] In this embodiment, the gasifier body 1 adopts air gasification, oxygen-enriched gasification or pure oxygen gasification. The temperature of the coal gas leaving the top of the gasifier body 1 is between 250 and 650 °C. The coal gas contains organic matter such as coal tar and water-soluble organic matter (such as phenol), as well as unreacted water vapor. The coal gas is cooled by water in the heat exchanger 21, and the organic matter and water vapor are cooled out simultaneously to generate condensate. The condensate contains dust entrained in the coal gas. The condensate is sent to the filter 31, and the solid matter is removed by the filter 31. Most of the water is sent back to the heat exchanger 21 as part of the cooling water, and a small part of the water is sent to the coal gas inlet of the heat exchanger 21 to be mixed with the coal gas to form a coal gas stream, thereby increasing the water content in the coal gas, which helps to wash away the possible deposits on the inner side of the heat exchanger 21 and can also improve the heat exchange effect. The cooling water used in the heat exchanger 21 is heated during the process of cooling the coal gas. The heated water is sent into the air humidifying tower 41. The air entering the air humidifying tower 41 contacts the heated water, and part of the water evaporates into water vapor. After humidifying the air, it leaves the air humidifying tower 41 and is sent into the gasifier body 1. During the process of contact and evaporation between the air and the heated water, heat is absorbed, causing part of the water to cool down and accumulate at the bottom of the air humidifying tower 41. The temperature of the water accumulated at the bottom of the tower is lower than the temperature of the water entering the tower from the heat exchanger 21. This part of the water is used as circulating water and sent to the heat exchanger 21 to continue cooling the coal gas. In this way, the sensible heat of the coal gas is transferred to the water vapor required by the gasifier body 1 through water, making full use of the thermal energy of the coal gas. In the actual operation process, the air flow rate of the gasifier body 1 is required for production, and the moisture content of the air is also a parameter that needs to be guaranteed. When the temperature at the top of the air humidifying tower 41 cannot reach the required temperature, it means that the heat from the coal gas heat exchanger 21 cannot meet the heat absorption requirement for the generation of water vapor for air humidification. Part of the low-pressure water vapor can be added at the position of the hot water inlet 412, or directly added to the outlet air at the position of the hot gas outlet 413.

[0037] The make-up water may include coal gas washing water containing organic matter and other water bodies containing certain salts, etc.

[0038] In this embodiment, the dust in the coal gas generated by the gasifier body 1 is removed by the filtering assembly 3. The cooling water and condensate water during the heat exchange process of the coal gas are directly used to generate the water vapor required by the gasifier body 1 through the humidifying assembly 4 and then return to the gasifier body 1. The remaining gas cooled during the humidifying process is sent to the heat exchange assembly 2 to continue heat exchange, thus realizing zero discharge of water in the coal gasification process. The gasification method of the present invention directly uses the sensible heat of the coal gas for heating the coal gas water, which is the integrated and optimized utilization of energy. The main feature is to overcome the problem that a large amount of coal gas water needs to be treated or discharged during the coal gas generation process, effectively solving the problem of coal gas water treatment in the coal gasification process from the source and having good promotion and application prospects.

[0039] Embodiment Two:

[0040] As shown Figure 2 in the figure, on the basis of the above embodiments, a high-temperature stripping assembly 5 and an organic matter recovery assembly 6 are additionally provided. The high-temperature stripping assembly 5 is respectively connected to the humidifying assembly 4 and the gasifier body 1, and the organic matter recovery assembly 6 is connected to the humidifying assembly 4. Specifically, the high-temperature stripping assembly 5 includes a high-temperature stripper 51, and the high-temperature stripper 51 is provided with a circulating water inlet 511, a high-temperature steam inlet 512 and a stripping gas outlet 513. The circulating water inlet 511 is connected to the circulating water outlet 414, and the stripping gas outlet 513 is connected to the gasifier body 1. During the air humidifying process in the air humidifying tower 41, part of the water-soluble organic matter is stripped out by the air and enters the gasifier body 1 for reaction together. The un-stripped part of the water-soluble organic matter and other impurities enter the circulating water and are sent to the heat exchanger 21 for cooling the coal gas. During the circulation process, the concentration becomes higher. At this time, part of the circulating water is removed from the circulation loop. One part of it is sent to the high-temperature stripper 51. After the organic matter is extracted by high-temperature steam or other high-temperature gases, the stripping gas is sent to the gasifier body 1 together as reaction gas. The other part can be sent to the organic matter recovery unit 6 for the recovery and purification of the organic matter in the water. Through such circulation, zero water discharge during the coal gasification process is achieved.

[0041] Embodiment Three:

[0042] As shown Figure 3 in the figure, on the basis of the above embodiments, in this embodiment, a primary coal gas cooler 7 is further included, and the primary coal gas cooler 7 is arranged between the gasifier body 1 and the heat exchange assembly 2.

[0043] This embodiment is mainly aimed at the situation where the temperature of the coal gas at the outlet of the gasifier is relatively high when the coal gas at the outlet of the gasifier is led out from the side of the body 1, the sensible heat of the coal gas is more than the heat required for humidifying and evaporating water, or when there is more tar in the coal gas. By setting the primary coal gas cooler 7, on the one hand, the excess heat is recovered, and the remaining sensible heat energy in the coal gas is used for air humidification; on the other hand, the relatively heavy coal tar is first condensed and separated. Specifically, the primary coal gas cooler 7 uses water evaporation cooling and is set to operate under a certain steam pressure. In this case, the wet air enters from both the bottom and the top of the gasifier.

[0044] Embodiment Four:

[0045] As shown Figure 4As shown in the figure, on the basis of the above embodiments, in this embodiment, in order to ensure the stable operation of the condensate pump 314 and the circulating water pump 418, the heat exchanger 21 and the air humidification tower 41 are respectively provided with liquid level gauges 216 and are respectively connected with water supply pipelines 217. A certain liquid level needs to be maintained at the bottoms of the heat exchanger 21 and the air humidification tower 41. According to the liquid level monitored by the liquid level gauge, usually when the liquid level continuously decreases, at this time, through the water supply pipeline 217, for the water level in the heat exchanger 21, the normal operation of the liquid level and the condensate pump can be ensured by adjusting the amount of the filtered liquid entering from the gas inlet 213 of the filter assembly 3, or a certain amount of water can be supplemented from the outside. For the air humidification tower, a certain amount of water can be directly supplemented from the outside to maintain the balance of the overall consumption of condensate and humidifying water. A temperature control device 4131 is provided at the hot gas outlet 413, and a gas preheater 4132 is provided between the hot gas outlet 413 and the gasifier body 1. When leaving the air humidification tower 41, the water vapor content in the air basically reaches saturation. At this time, according to the temperature control device 4131 provided at the hot gas outlet 413, the water vapor content in the air can be known. Since the gasifier body 1 has certain requirements for the water vapor content in the air, by setting the gas preheater 4132 to heat the hot gas temperature, the requirements of the operation of the gasifier body 1 can be met. By increasing the temperature of the inlet air, it is beneficial to increase the calorific value of the gas leaving the furnace. The heating heat source here can be low-pressure steam or hot flue gas, etc.

[0046] The gasification method using the above zero-water-discharge fixed-bed gasification device includes the following steps:

[0047] When the temperature and organic matter content of the gas leaving the gasifier body 1 are relatively low, it directly enters the heat exchange assembly 2. When the temperature and organic matter content of the gas leaving the gasifier body 1 are relatively high, it first enters the gas primary cooler 7. After recovering the excess heat and separating out the heavy organic matter first, it then enters the heat exchange assembly 2;

[0048] The gas is cooled by water in the heat exchange assembly 2, and the organic matter and water vapor are simultaneously cooled out and condensed liquid is generated. After the condensed liquid is removed of solids by the filter assembly 3, part of the water body is sent into the heat exchange assembly 2 as cooling water, and the other part of the water body is mixed with the gas and then re-enters the heat exchange assembly 2;

[0049] The cooling water heated during the heat exchange process of the heat exchange assembly 2 is sent into the humidification assembly 4. Part of the water body contacts the air entering the humidification assembly 4, forms saturated water vapor, then leaves the humidification assembly 4 and enters the gasifier body 1 to participate in the reaction. The remaining water body cools down and accumulates. Here, when the amount of water body sent into the heat augmentation assembly 4 is small, the water supply pipeline 216 is used to supplement the water body into the humidification assembly 4. Part of the water body that cools down and accumulates is sent into the heat exchange assembly 2 as cooling water, and the remaining part of the water body that cools down and accumulates is respectively sent into the high-temperature stripping assembly 5 and the organic recovery assembly 6 for treatment;

[0050] The water body fed into the high-temperature stripping component 5 is stripped of organic matter in the water body by high-temperature gas, and then the stripping gas is fed into the gasifier body 1 to participate in the reaction. The water body fed into the organic recovery component 6 is used for the recovery and purification of organic matter in the water.

[0051] By circulating in this way, zero water discharge during the coal gasification process is achieved.

[0052] In the gasification method of the present invention, a typical operating condition of a low-pressure gasifier is that the temperature of the air in the gasifier body reaches 53 °C after humidification, and the water vapor content at this time is about 15%. The water temperature at the bottom of the air humidification tower drops to about 45 °C, and is sent to the heat exchanger by a circulating water pump. The water is heated to about 65 °C, and the heated water is sent to the top of the air humidification tower to contact the air for humidification.

[0053] In the case of low-pressure pure oxygen gasification, when the gasifier is gasified with pure oxygen under a pressure of 0.2 MPa, the temperature of the circulating water is adjusted to ensure that the outlet temperature of the humidification tower reaches 115 °C, the partial pressure of water vapor is 0.143 MPa, and when the partial pressure of oxygen is 0.057, its moisture content expressed as water vapor: oxygen can reach 3:1 (m 3 / m 3 ) or so.

[0054] Another case is that the gasifier operates under pressure. When the pressure of the gasifier is 4.0 MPa, the temperature of the circulating water is controlled at about 235 °C. Oxygen contacts and humidifies with the circulating water in the air humidification tower. When the oxygen leaves the air humidification tower, its moisture content expressed as water vapor: oxygen can reach 3:1 (m 3 / m 3 ).

[0055] The coal gas is cooled by water at 50-60 °C in the heat exchanger and cooled to about 60 °C. The condensate collected at the bottom of the heat exchanger is removed of solid substances by a filter, and the water body after filtration by the filter is sent to the water side of the heat exchanger for makeup water. Since there is no water evaporation process on the water side of the coal gas cooling heat exchanger, there is basically no scaling problem on the water side, so it is beneficial to the long-term operation of the heat exchanger.

[0056] The ash residue generated by the coal in the gasifier is discharged from the bottom of the gasifier.

[0057] The above are only for example purposes and can be changed according to changes in working conditions such as coal type, oxygen concentration, and operating pressure.

[0058] When applying the gasification method of this embodiment to an existing gasification furnace device system, an existing gas cooling device is adopted. The gas condensate pump sends the filtered condensate to the air humidifier. The air humidifier is an indirect heat exchanger, and water vapor is used as the heating heat source (it can also be other hot gases). The coal gas water is heated by the water vapor on the other side of the air humidifier, and the steam condenses to obtain condensate water. Air is introduced from the bottom of the side of the heat exchanger where the coal gas water is located. After passing through the nozzle or other air distribution structures, the air bubbles and contacts with the water, and then passes through the heat exchange tubes of the heat exchanger. After the water vapor in the air reaches saturation, it leaves the top of the humidifier. After the temperature is increased through the gas preheater, it enters the gasification furnace. Here, it is equivalent to first cooling the coal gas with cooling water and then heating it with water vapor, which requires two operations and consumptions of cooling water and water vapor and is used for the transformation of the existing equipment system.

[0059] The gasification method of the present invention has a simple and reasonable process flow, stable operation, and convenient control. The coal gas water generated during the coal gasification process is directly converted into the water vapor required for gasification and returned to the gasification furnace. Finally, there is no water discharge during the coal gasification process. The present invention is particularly suitable for the production process of gasifying coal with less tar content but containing phenol to produce coal gas.

[0060] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A zero-water-discharge fixed-bed gasification device, comprising a gasification furnace body, wherein a hot gas outlet is arranged at the top end of the gasification furnace body, and a slag discharge outlet is arranged at the bottom end of the gasification furnace body, characterized in that, It further includes a heat exchange component, a filtration component and a humidification component. The heat exchange component and the humidification component are respectively connected to the gasifier body, and the filtration component is connected to the heat exchange component; It further includes a high-temperature stripping component and an organic matter recovery component. The high-temperature stripping component is respectively connected to the humidification component and the gasifier body, and the organic matter recovery component is connected to the humidification component; It further includes a primary gas cooler for gas, and the primary gas cooler for gas is respectively connected to the gasifier body and the heat exchange component; Wherein, the heat exchange component includes a heat exchanger which is provided with a cooling water inlet, a cooling water outlet, a gas inlet, a gas outlet and a condensate outlet. The gas inlet is connected to the gasifier body and the filtration component, the condensate outlet is connected to the filtration component, the cooling water inlet is respectively connected to the filtration component and the humidification component, and the cooling water outlet is connected to the humidification component.

2. The zero-water-discharge fixed-bed gasification device according to claim 1, characterized in that, The filtration component includes a filter which is provided with a liquid inlet, a liquid outlet and a solid discharge port. The liquid inlet is connected to the condensate outlet, the liquid outlet is respectively connected to the cooling water inlet and the gas inlet through a condensate pump, and the solid discharge port is used for discharging the filtered solid matter.

3. A zero-water-discharge fixed-bed gasification device according to claim 2, characterized in that, The humidification component includes an air humidification tower which is provided with an air inlet, a hot water inlet, a hot gas outlet and a circulating water outlet. A blower is connected to the air inlet. A air distribution structure is provided at a position inside the air humidification tower close to the air inlet. The hot water inlet is connected to the cooling water outlet, the hot gas outlet is connected to the gasifier body, a supplementary steam pipeline is connected at the position of the hot water inlet or the hot gas outlet, and the circulating water outlet is respectively connected to the cooling water inlet, the high-temperature stripping component and the organic matter recovery component through a circulating water pump.

4. A zero-water-discharge fixed-bed gasification device according to claim 3, characterized in that The high-temperature stripping component includes a high-temperature stripper which is provided with a circulating water inlet, a high-temperature steam inlet and a stripping gas outlet. The circulating water inlet is connected to the circulating water outlet, and the stripping gas outlet is connected to the gasifier body.

5. A zero-water discharge fixed-bed gasification device according to claim 3, characterized in that, A temperature measuring and controlling device is provided at the hot gas outlet, and a gas preheater is provided between the hot gas outlet and the gasifier body.

6. The zero-water-discharge fixed-bed gasification device according to claim 3, characterized in that, The heat exchanger and the air humidification tower are respectively provided with a liquid level measuring instrument and are respectively connected with a water supply pipeline.

7. A gasification method using the zero-water-discharge fixed-bed gasification device according to any one of claims 1-6, characterized in that, It includes the following steps: When the temperature and organic matter content of the gas leaving the gasifier body are relatively low, it directly enters the heat exchange component. When the temperature and organic matter content of the gas leaving the gasifier body are relatively high, it first enters the primary gas cooler for gas. After recovering the excess heat and separating out the heavy organic matter first, it then enters the heat exchange component; The gas is cooled by water in the heat exchange component, the organic matter and water vapor are cooled out simultaneously, and a condensate is generated. After the condensate is removed of solid matter by the filtration component, part of the water body is sent into the heat exchange component as cooling water, and the other part of the water body is mixed with the gas and then re-enters the heat exchange component; The heated cooling water in the heat exchange process of the heat exchange component is sent into the humidification component. The water body contacts the air or oxygen entering the humidification component. After part of the water body evaporates to form saturated water vapor in the air or oxygen, it leaves the humidification component and enters the gasifier body to participate in the reaction. The remaining water body cools down and accumulates. Here, when the amount of water body sent into the heat augmentation component is small, a make-up water pipeline is used to supplement the water body into the heat augmentation component. Part of the water body with reduced temperature and accumulated is sent into the heat exchange component for use as cooling water, and the remaining part of the water body with reduced temperature and accumulated is sent into the high-temperature stripping component and the organic recovery unit for treatment; For the water body sent into the high-temperature stripping component, the organic matter in the water body is stripped by high-temperature gas, and the stripping gas is sent into the gasifier body to participate in the reaction. For the water body sent into the organic recovery unit, the organic matter in the water is recovered and purified; By circulating in this way, zero water discharge in the coal gasification process is achieved.

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