Circulating fluidized bed combustion method for pure gas fluidized bed coal gasification fine slag

Abstract

The invention discloses a circulating fluidized bed combustion method for pure gas fluidized bed coal gasification fine slag, which comprises the following steps: adding the gasification fine slag above an air chamber at the bottom of a hearth, simultaneously introducing air or oxygen-enriched air into the air chamber, and carrying out fluidized combustion on the gasification fine slag, the running air speed of the air or oxygen-enriched air is 2-2.5 m / s, the height of the hearth is 34-38m, and the air or oxygen-enriched air is 2-2.5 m / s; the hearth is a heat insulation hearth and is not provided with a water-cooled wall; flue gas obtained after combustion enters the gas-solid separation device to be subjected to gas-solid separation, the separated flue gas enters the tail flue to be subjected to heat exchange, and solid obtained after separation returns to the hearth to be continuously combusted. Rapid fluidization combustion of the gasified fine slag is realized at a relatively low gas speed, and particle aggregation and internal circulation of the gasified fine slag are promoted, so that one-time retention time of the gasified fine slag in the furnace is prolonged; a heat insulation hearth is adopted, a water cooling wall and other heating surfaces are not arranged, it can be guaranteed that the temperature of gasified fine slag is kept at a high level during combustion, and the stability and efficiency of combustion are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of gasification fine slag combustion, and particularly relates to a circulating fluidized bed combustion method for pure gas flow bed coal gasification fine slag. Background Art

[0002] The statements here only provide the background art related to the present invention and do not necessarily constitute the prior art.

[0003] Coal chemical industry is an effective way to transform coal from a single fuel to multiple resources, and it is also the front-end process of processes such as coal-based chemicals, coal-based synthetic natural gas, and coal-based liquid fuels. Solid fuels such as coal, coke, and semi-coke react with gasifying agents under high temperature and high pressure to be converted into syngas, and gasification ash slag is the main solid by-product generated during the coal gasification process. According to different emission methods, gasification ash slag can be divided into coarse slag and fine slag. The coal gasification fine slag is mainly composed of unburned carbon, silicon aluminates, and vitreous bodies.

[0004] Currently, in the building materials field, the gasification fine slag can be used as a concrete admixture, raw material for bricks or ceramsite, which can replace part of cement and sand and gravel, reduce production costs and improve material properties; in the energy industry, the gasification fine slag can be dehydrated and co-fired, with the moisture content of the fine slag reduced to less than 35% and used as a secondary fuel for co-firing, and the annual treatment capacity reaches the ten-thousand-ton level, with significant economic benefits. In addition, the gasification fine slag is also often used to prepare adsorption materials and functional materials for soil and water body remediation or for applications in fields such as supercapacitors and microwave absorption.

[0005] Most of the above-mentioned resource utilization processes of gasification fine slag require decarbonization treatment. Common decarbonization methods for gasification fine slag include combustion decarbonization and washing decarbonization. Among them, compared with washing decarbonization, combustion decarbonization has the advantages of high treatment efficiency, simple equipment, low cost, and environmental friendliness.

[0006] The gasification fine slag has the characteristics of high moisture content (usually above 50%), low volatile matter (<10%), low calorific value (300 - 400 kcal / kg), and high ash content, and its combustion characteristics are significantly inferior to those of conventional fuel coal. The specific manifestations are as follows:

[0007] Difficult ignition: When using a traditional circulating fluidized bed for co-firing gasification fine slag, the gas-solid mixture exchanges radiation heat and convective heat with the water-cooled wall and other heating surfaces arranged in the furnace, which reduces the combustion temperature in the furnace. And the gasification fine slag has low volatile matter and high moisture content, and the required initial ignition temperature is relatively high, and additional heat is needed to evaporate the moisture. Therefore, the relatively low combustion temperature in the traditional circulating fluidized bed furnace is difficult to achieve the effective combustion of gasification fine slag and brings effects such as combustion delay and bed temperature fluctuation.

[0008] Low burnout rate: The particle size of the gasification fine slag is relatively small (the median particle size is about 40 μm), and its residence time in the traditional circulating fluidized bed furnace is short. The unburned carbon is discharged with the fly ash, resulting in a rapid increase in the carbon content of the fly ash and a decrease in the combustion utilization efficiency of the gasification fine slag.

[0009] Poor co-combustion effect: When the mixing ratio with fuel coal is inappropriate, the calorific value of the mixed fuel will decrease significantly, resulting in fluctuations in the boiler load and a reduction in the thermal efficiency. Therefore, in order to improve the combustion characteristics of the gasification fine slag, pretreatment processes such as deep dehydration and grinding are usually adopted, which leads to a significant increase in the utilization cost and energy consumption of the gasification fine slag.

[0010] In addition, based on the principle of gas-solid fluidization, most of the gasification fine slag is Geldart A-type particles, and it is in the pneumatic conveying state under the conventional circulating fluidized bed gas velocity (4.5 - 5 m / s), and effective particle agglomeration and internal circulation cannot be generated. Effective particle agglomeration can increase the effective size of the particles, reduce entrainment, and promote the residence time of the particles in the bed. Internal circulation helps the mixing of particles in the reactor, promotes the uniform distribution of temperature, concentration, and reaction rate in the reactor, improves the reaction efficiency, and maintains a stable bed pressure drop. Summary of the Invention

[0011] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a circulating fluidized bed combustion method for pure-gas entrained flow bed coal gasification fine slag, aiming to improve the reaction activity of the gasification fine slag, increase the primary residence time of the gasification fine slag in the furnace, thereby improving the combustion utilization efficiency of the gasification fine slag, and reducing the rapid increase in the carbon content of the fly ash and the influence of boiler load fluctuations caused by the combustion of the gasification fine slag.

[0012] In order to achieve the above purpose, the present invention is realized through the following technical solutions:

[0013] The present invention provides a circulating fluidized bed combustion method for pure-gas entrained flow bed coal gasification fine slag, including the following steps:

[0014] Add the gasification fine slag above the air chamber at the bottom of the furnace, and at the same time introduce air or oxygen-enriched air into the air chamber to conduct fluidized bed combustion on the gasification fine slag. Among them, the operating wind speed of the air or oxygen-enriched air is 2 - 2.5 m / s, the height of the furnace is 34 - 38 m, the furnace is an adiabatic furnace, and no water-cooled wall is provided;

[0015] The flue gas after combustion enters the gas-solid separation device for gas-solid separation, the separated flue gas enters the tail flue for heat exchange, and the separated solid returns to the furnace for continuous combustion.

[0016] By detecting the physical and chemical properties of the gasification fine slag, the inventor found that the residual carbon in the gasification fine slag can still achieve complete combustion without being crushed and without oxygen diffusion in the vitreous body, that is, the gasification fine slag has the characteristics of carbon-ash separation.

[0017] In the oxygen-enriched air, the oxygen content is generally 21%-35% or even higher.

[0018] The operating gas velocity of a conventional circulating fluidized bed is 4.5-5 m / s. At this gas velocity, the gasification fine slag cannot produce effective particle agglomeration and internal circulation, seriously affecting the combustion characteristics of the gasification fine slag.

[0019] The inventor reduced the operating gas velocity in the furnace to 2-2.5 m / s, which promoted the particle agglomeration of the gasification fine slag, effectively increasing the primary residence time of the gasification fine slag in the furnace; in addition, the agglomerated gasification fine slag is easily captured by the gas-solid separation device, which can then promote the internal circulation of the gasification fine slag to effectively ensure its combustion effect.

[0020] The furnace is set as an adiabatic furnace without water walls, which can reduce heat transfer in the furnace, increase the reaction temperature, and thus effectively improve the carbon burnout efficiency in the gasification fine slag.

[0021] The height of the furnace is designed to be 34-38 m, which is a high furnace design. It can further increase the primary residence time of the gasification fine slag in the furnace, and at the same time effectively increase the heat transfer area of the tail flue to improve the recovery rate of flue gas waste heat.

[0022] Based on the above design, the present invention can achieve 100% pure combustion of the gasification fine slag.

[0023] In some embodiments, the side wall material of the furnace is SiC wear-resistant material.

[0024] In some embodiments, the height of the furnace is 34-38 m.

[0025] In some embodiments, the furnace includes a lower part and an upper part of the furnace, and the height ratio of the lower part to the upper part of the furnace is 1:2-20, preferably 1:3-10.

[0026] Preferably, a lower secondary air inlet and an upper secondary air inlet are provided on the side wall of the lower part of the furnace, and the upper secondary air inlet is located above the lower secondary air inlet. By setting the upper and lower secondary air inlets, the secondary air distribution can be adjusted according to the characteristics of different fuels to enhance the burnout of the secondary air.

[0027] Preferably, the gas-solid separation device is an adiabatic cyclone separator. The cyclone separator is adiabatically arranged to prevent the solid from cooling during the gas-solid separation process, affecting the subsequent circulating combustion effect.

[0028] Further preferably, the adiabatic cyclone separator is communicated with the lower part of the furnace through a return device, which is used to recycle the separated solids back to the furnace for internal circulating combustion.

[0029] In some embodiments, a wind distribution device is arranged above the air chamber, and the wind distribution device is a single wind distribution plate.

[0030] In some embodiments, in the tail flue, a high-temperature superheater, an intermediate-temperature superheater, a low-temperature superheater, a economizer and an air preheater are arranged in sequence along the flue gas flow direction.

[0031] Preferably, the tail flue adopts an adiabatic furnace wall.

[0032] In some embodiments, the operating temperature in the furnace is 900 - 950 °C.

[0033] The beneficial effects obtained by one or more of the above embodiments of the present invention are as follows:

[0034] The gasification fine slag low gas velocity fine particle fast fluidized bed combustion technology proposed by the present invention realizes the fast fluidized bed combustion of gasification fine slag at a lower gas velocity by reducing the operating wind speed (2 - 2.5 m / s), promotes the particle agglomeration and internal circulation of gasification fine slag, and further increases the primary residence time of gasification fine slag in the furnace.

[0035] Adopting an adiabatic furnace without water-cooled walls and other heating surfaces can ensure that the temperature of gasification fine slag is maintained at a relatively high level during combustion, improving the stability and efficiency of combustion.

[0036] Adopting a high furnace design, setting the furnace height to 1.36 - 1.7 times the height of a traditional circulating fluidized bed furnace (20 - 28 m), this furnace height can further increase the primary residence time of gasification fine slag in the furnace.

[0037] Increasing the heat transfer area of the tail flue (increasing proportionally with the furnace height and the tail flue height) can improve the thermal utilization efficiency of gasification fine slag, and further reduce the impact of the increased cost caused by increasing the furnace height. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0039] Figure 1 It is a schematic structural diagram of a circulating fluidized bed combustion system for pure gasification fine slag of the present invention.

[0040] In the figure, 1 - air chamber, 2 - air distribution device, 3 - lower secondary air inlet, 4 - upper secondary air inlet, 5 - gasification fine slag feeding device, 6 - lower part of the furnace, 7 - upper part of the furnace, 8 - horizontal flue, 9 - gas-solid separation device, 10 - return device, 11 - separator outlet flue, 12 - tail flue, 13 - economizer, 14 - low-temperature superheater, 15 - medium-temperature superheater, 16 - high-temperature superheater, 17 - air preheater, 18 - adiabatic furnace wall. Detailed implementation mode

[0041] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0042] The present invention will be further described below in conjunction with embodiments.

[0043] As Figure 1 shown in the combustion system, its main structure is a circulating fluidized bed combustion furnace. The upper part of the furnace 7 adopts an adiabatic furnace chamber without arranging water-cooled walls and other heat absorbers, ensuring that the temperature of the gasification fine slag is maintained at a relatively high level during combustion, improving the stability and efficiency of combustion; increasing the furnace height (the total height of the lower part 6 and the upper part 7 of the furnace), calculating according to the characteristics of low gas velocity and fast fluidization of the gasification fine slag, and setting the furnace height to 1.36 - 1.7 times the height of the traditional circulating fluidized bed furnace (20 - 28 m). This furnace height can increase the primary residence time of the gasification fine slag in the furnace, increase the heat transfer area of the tail flue (the height of the furnace and the tail flue will increase proportionally), improve the heat utilization efficiency of the gasification fine slag, and thus reduce the impact of the increased cost caused by increasing the furnace height.

[0044] The combustion system includes a circulating fluidized bed combustion furnace, a gas-solid separation device and a tail flue connected in sequence. Among them, the circulating fluidized bed combustion furnace is provided with an air chamber 1, an air distribution device and a furnace chamber from bottom to top. The furnace chamber is divided into a lower part and an upper part of the furnace. The side wall of the lower part of the furnace is provided with a lower secondary air inlet and an upper secondary air inlet. The upper secondary air inlet is located above the lower secondary air inlet. The gasification fine slag feeding device is connected to the lower part of the furnace, and the connection part is located above the air distribution device and below the lower secondary air inlet.

[0045] The top of the furnace chamber is connected to the gas-solid separation device through a horizontal flue. The lower part of the gas-solid separation device is connected to the lower part of the furnace through a return device 10. The flue gas outlet of the gas-solid separation device is connected to the tail flue through a separator outlet flue. In the tail flue, along the flue gas flow direction, a high-temperature superheater, a medium-temperature superheater, a low-temperature superheater, an economizer and an air preheater are arranged from top to bottom in sequence. The furnace wall of the tail flue is an adiabatic furnace wall.

[0046] The main process of gasified fine slag combustion includes: feeding the gasified fine slag into Figure 1 the gasified fine slag feeding device 5 in Figure 1 into the lower part 6 of the furnace. The air / oxygen-enriched air in the air chamber 1 enters the lower part 6 of the furnace through the air distribution device 2. The gasified fine slag realizes rapid fluidization under the uniform air distribution of the air distribution device 2 and undergoes fluidized combustion in the furnace.

[0047] The flue gas after combustion reaches the gas-solid separation device 9 through the horizontal flue 8 for gas-solid separation. The separated flue gas enters the separator outlet flue 11 and exchanges heat with the high-temperature superheater 16, medium-temperature superheater 15, low-temperature superheater 14, economizer 13, and air preheater 17 in the tail flue 12 respectively, and then leaves the tail flue 12 and enters the subsequent flue gas purification device.

[0048] The remaining return material separated by the gas-solid separation device 9 is re-fed into the furnace through the return device 10 for full combustion. The external feed water exchanges heat with the high-temperature flue gas through the economizer 13, low-temperature superheater 14, medium-temperature superheater 15, and high-temperature superheater 16 and then is sent to the steam turbine for subsequent power generation.

[0049] In order to achieve the full combustion and utilization of the gasified fine slag, the operation parameters of the circulating fluidized bed boiler are optimized in the present invention: Since the reaction activation energy of the gasified fine slag is similar to that of anthracite, it is necessary to appropriately increase the combustion temperature and the excess air coefficient to ensure the complete combustion of the gasified fine slag. Therefore, the operating temperature of the circulating fluidized bed furnace is controlled at 900 - 950 °C; In order to increase the residence time of the gasified fine slag in the furnace and strengthen the burnout degree, a far lower selection range of fluidization wind speed than the currently commonly used one is considered, and the operating wind speed selection range is 2 - 2.5 m / s; Within this wind speed range, the predicted distribution of the material concentration along the furnace height is very close to the material concentration in the upper part of the conventional fuel circulating fluidized bed furnace. The particle concentration in the upper part 7 of the furnace is 3 - 3.5 kg / m 3 , which can not only meet the heat transfer requirements of convection and radiation, but also form particle clusters, thereby strengthening the internal circulation.

[0050] Specifically, the gasified fine slag feeding device 1 adopts a screw feeding method to feed into the lower part 6 of the combustion chamber of the circulating fluidized bed combustion furnace.

[0051] In order to achieve the full combustion and utilization of the gasified fine slag, the inventor optimizes the operation parameters of the circulating fluidized bed boiler: When the temperature of the furnace is 950 °C and the excess air coefficient of the gas at the inlet of the air distribution device 2 is 1.23, the requirement for the complete combustion of the gasified fine slag can be met; The operating wind speed is selected as 2.3 m / s.

[0052] The air distribution device 2 adopts a single air distribution plate for primary air distribution, and the primary air ratio is 50%; In order to increase the flow velocity at the bottom of the air distribution plate and the uniformity of the front and rear air distribution, differential air distribution is carried out, that is, the peripheral air volume of the air distribution device 2 close to the lower part 6 of the furnace is increased by 20%.

[0053] The air distribution position of the secondary air is set. The lower secondary air inlet 3 is set 3 m above the air distribution device 2, and the upper secondary air inlet 4 is set 5.5 m above the air distribution device 2. By reducing the lower secondary air inlet and increasing the elevation of the upper secondary air inlet, the burnout of the gasified fine slag is promoted.

[0054] The gas-solid separation device 9 adopts a high-efficiency adiabatic cyclone separator, a single separator with a large-diameter cylinder body, and the material is S30815 (253MA).

[0055] Specifically, the return device 10 adopts a low-resistance self-balancing two-way return valve. By increasing the flow area and shortening the horizontal section, the flow resistance of the gasified fine slag is reduced, making the return more uniform.

[0056] Example 1

[0057] The selected gasified fine slag raw material is the gasified fine slag of Guoneng Xinjiang Chemical Industry. The industrial, elemental analysis and thermogravimetric analysis of the gasified fine slag are shown in Table 1. The median particle size of the gasified fine slag is 40 μm Geldart A-type particles, the water content is 62.71 wt%, the lower calorific value is 3870 kJ / kg, and the activation energy is 150.85 kJ / mol, which is close to anthracite and belongs to difficult-to-burn fuel.

[0058] Using Figure 1 The circulating fluidized bed combustion boiler in, the parameters of the LFFF-CFB boiler developed for the disposal demand of 240,000 tons per year of Guoneng Xinjiang Chemical Industry are as follows in Table 2.

[0059] Table 1 Analysis data of gasified fine slag

[0060]

[0061] Table 2 Specific parameters of the LFFF-CFB boiler

[0062] Name Unit Parameter Boiler Load ％ BMCR Main Steam Flow t / h 75 Superheated Steam Outlet Pressure MPa.g 9.8 Superheated Steam Outlet Temperature ℃ 540 Feed Water Temperature ℃ 158 Excess Air Ratio / 1.25 Bed Moisture ℃ 950 Fly Ash: Bottom Ash / 90：10 Furnace Fluidization Velocity m / s 2.3

[0063] The furnace height is increased to 37 m, the furnace cross-section (depth × width) is 7.51 m × 7.51 m, the furnace is an adiabatic furnace without water walls, the bed pressure is 5000 Pa, and the fluidizing gas is air.

[0064] During the stable operation of the system, the operating parameters of each main part are as follows:

[0065] The average furnace temperature of the circulating fluidized bed combustion furnace is 950 °C, and the operating wind speed is 2.3 m / s; the primary air temperature is 203 °C, the inlet flue gas flow rate of the high-temperature superheater 16 is 12.8 m / s, and the inlet flue gas flow rate of the economizer 13 is 8.8 m / s; the outlet water temperature of the high-temperature superheater 16 is 540 °C, and the outlet water temperature of the economizer 13 is 291 °C.

[0066] The gas-solid separation device 9 adopts a high-efficiency adiabatic cyclone separator, with an operating temperature of 950 °C and an inlet air velocity of 25 m / s.

[0067] The return device 10 adopts a low-resistance self-balancing two-way return valve, with an operating temperature of 950 °C, an air velocity in the feed chamber of 0.75 m / s, and an air velocity in the return chamber of 2.7 m / s.

[0068] The relevant operating conditions for a traditional circulating fluidized bed boiler co-firing 20% gasified fine slag: the average temperature of the circulating fluidized combustion furnace hearth (the hearth height is 28 m) is 880 °C, the operating air velocity is 5.0 m / s; the primary air temperature is 220 °C, and water-cooled walls are adopted.

[0069] Through calculation, the primary residence time of the gasified fine slag in the furnace is about 19.5 s. Compared with the primary residence time of the gasified fine slag in the furnace of a traditional circulating fluidized bed boiler (8.0 s), the effective reaction time is increased by about two times. The combustible content of the fly ash sampled during the stable operation of the system was tested, and the test results showed that the carbon content of the fly ash was 3.65%, which was reduced by 75.67% compared with 15% of the traditional fluidized bed gasified fine slag co-firing. This indicates that the low gas velocity fine particle fast fluidized bed combustion technology for pure gasified fine slag proposed by the present invention can significantly improve the utilization efficiency of gasified fine slag.

[0070] Example 2

[0071] The difference from Example 1 is only that: the fluidizing gas adopts oxygen-rich gas (the average oxygen content is 30%), that is, oxygen-rich combustion of the gasified fine slag is carried out.

[0072] The results show that: under the same conditions, the average temperature of the circulating fluidized bed furnace hearth is increased to about 1000 °C, the reaction temperature rises, and the activity of the gasified fine slag is improved; the combustible content of the fly ash was tested, and the test results showed that the carbon content of the fly ash decreased from 3.65% to 2.71%. Oxygen-rich combustion has a promoting effect on the pure combustion efficiency of gasified fine slag.

[0073] Comparative Example 1

[0074] The difference from Example 1 is that: the furnace is provided with water-cooled walls. During operation, the average temperature of the furnace hearth is 880 °C, the outlet water temperature of the high-temperature superheater 16 is 571 °C, and the outlet water temperature of the economizer 13 is 304 °C. Others are the same as in Example 1.

[0075] The combustible content of the fly ash sampled during the stable operation of the system was tested, and the test results showed that the carbon content of the fly ash was 8%.

[0076] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A circulating fluidized bed combustion method for fine slag from pure-gas entrained flow bed coal gasification, characterized in that: It includes the following steps: Add the gasified fine slag above the air chamber at the bottom of the furnace, and at the same time introduce air or oxygen-enriched air into the air chamber to perform fluidized combustion on the gasified fine slag. Among them, the operating wind speed of the air or oxygen-enriched air is 2-2.5 m / s, the height of the furnace is 34-38 m, the furnace is an adiabatic furnace without water-cooled walls; The flue gas after combustion enters the gas-solid separation device for gas-solid separation, the separated flue gas enters the tail flue for heat exchange, and the separated solid returns to the furnace for continuous combustion.

2. The circulating fluidized bed combustion method for the fine slag of pure-gas entrained flow coal gasification according to claim 1, characterized in that: The side wall material of the furnace is SiC wear-resistant material.

3. The circulating fluidized bed combustion method for fine slag of pure gasifier entrained flow gasification according to claim 1, characterized in that: The height of the furnace is 34-38 m.

4. The circulating fluidized bed combustion method for the fine slag of pure-gas entrained flow coal gasification according to claim 1, characterized in that: The furnace includes a lower part and an upper part of the furnace, and the height ratio of the lower part and the upper part of the furnace is 1:2-20, preferably 1:3-10.

5. The circulating fluidized bed combustion method for the fine slag of pure-gas entrained flow coal gasification according to claim 4, characterized in that: The lower secondary air inlet and the upper secondary air inlet are arranged on the side wall of the lower part of the furnace, and the upper secondary air inlet is located above the lower secondary air inlet.

6. The circulating fluidized bed combustion method for the fine slag of pure-gas entrained flow coal gasification according to claim 1, characterized in that: The gas-solid separation device is an adiabatic cyclone separator, and the adiabatic cyclone separator is connected to the lower part of the furnace through a return device.

7. The circulating fluidized bed combustion method for the fine slag of pure-gas entrained flow gasification according to claim 6, characterized in that: The operating temperature in the furnace is 900-950 °C.

8. The circulating fluidized bed combustion method for the fine slag of pure-gas entrained flow coal gasification according to claim 1, characterized in that: A air distribution device is arranged above the air chamber, and the air distribution device is a single air distribution plate.

9. The circulating fluidized bed combustion method for fine slag of pure gas stream bed coal gasification according to claim 1, characterized in that: In the tail flue, a high-temperature superheater, an intermediate-temperature superheater, a low-temperature superheater, an economizer and an air preheater are arranged in sequence along the flue gas flow direction.

10. The circulating fluidized bed combustion method for the fine slag of pure-gas entrained flow coal gasification according to claim 9, characterized in that: The tail flue adopts an adiabatic furnace wall.

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