阅读说明：本技术 利用固体颗粒热载体热解气化的梯级余热回收装置及方法 (Step waste heat recovery device and method utilizing pyrolysis gasification of solid particle heat carrier ) 是由 左宗良 张敬奎 罗思义 于庆波 周恩泽 郭建翔 于 2019-12-12 设计创作，主要内容包括：本发明的利用固体颗粒热载体热解气化的梯级余热回收装置及方法。装置包括气化炉,热解炉,固体分离器及烟气处理系统,气化炉,热解炉和固体分离器依次连接,气化炉与热解炉的烟道出口汇合并与烟气处理系统连接。方法为：高温颗粒进入气化炉,含碳固废材料A在气化剂携带下进入气化炉,经气化反应生成可燃煤气与一次降温后颗粒,降温后颗粒与含碳固废材料B进入热解炉进行热解反应,生成热解气和固体半焦,经筛分后,固体半焦产率为20-23％,固定碳含量高达77-79.1％,作为气化炉燃料。该发明将固体颗粒余热回收效率提高至80-84％,<Image he="61" wi="52" file="DDA0002319584880000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>效率提高至70-77％,同时可获得热值为5000-7000kJ/<Sup>3</Sup>的可燃性洁净煤气,并减少CO<Sub>2</Sub>排放量。(The invention relates to a step waste heat recovery device and method by utilizing pyrolysis gasification of a solid particle heat carrier. The device comprises a gasification furnace, a pyrolysis furnace, a solid separator and a flue gas treatment system, wherein the gasification furnace, the pyrolysis furnace and the solid separator are sequentially connected, and the gasification furnace is converged with a flue outlet of the pyrolysis furnace and is connected with the flue gas treatment system. The method comprises the following steps: the high-temperature particles enter a gasification furnace, the carbon-containing solid waste material A enters the gasification furnace under the carrying of a gasification agent, combustible gas and particles after primary cooling are generated through gasification reaction, the particles after cooling and the carbon-containing solid waste material B enter a pyrolysis furnace for pyrolysis reaction to generate pyrolysis gas and solid semicoke, and after screening, the yield of the solid semicoke is 20-23%, the content of fixed carbon reaches 77-79.1%, and the solid semicoke is used as a gasification furnace fuel. The invention improves the waste heat recovery efficiency of the solid particles to 80-84%, the efficiency is improved to 70-77%, and the heat value is 5000- 3 Combustible clean gas and CO reduction 2 And (4) discharging the amount.)

1. Utilize solid particle heat carrier pyrolysis gasification's step waste heat recovery device, its characterized in that, including gasifier, pyrolysis oven, solid separator and flue gas processing system, wherein:

the gasification furnace, the pyrolysis furnace and the solid separator are sequentially connected, and the gasification furnace is converged with a flue outlet of the pyrolysis furnace and is connected with a flue gas treatment system.

2. The step waste heat recovery device for pyrolysis and gasification of the solid particle heat carrier according to claim 1, wherein the step waste heat recovery device comprises: the flue gas treatment system comprises a cyclone separator, a gas-liquid separator and a purifier, and all the components are connected in sequence;

the gasification furnace is a fixed bed or a fluidized bed, and is provided with a particle feeding device, a gasification furnace fuel nozzle and a particle outlet;

the pyrolysis furnace is a fixed bed, and a stirring device is arranged in the pyrolysis furnace;

the particle outlet of the gasification furnace is connected with the particle feeding device of the pyrolysis furnace, and the particle outlet of the pyrolysis furnace is connected with the solid separator.

3. The cascade waste heat recovery device for pyrolysis gasification of a solid particle heat carrier according to claim 1, wherein the solid separator is connected with a gasifier fuel nozzle through a lifting device.

4. The method for recycling waste heat in the step of the pyrolysis gasification of the solid particle heat carrier by adopting the device for recycling waste heat in the step of the pyrolysis gasification of the solid particle heat carrier, which is disclosed by claim 1, is characterized by comprising the following steps of:

step 1, recovering waste heat of high-temperature particles:

high-temperature particles enter a gasification furnace, and carbon-containing solid waste material A enters under the carrying of a gasification agentThe gasification furnace is characterized in that high-temperature particles move from top to bottom in the gasification furnace, a gasification agent and a carbon-containing solid waste material A are subjected to gasification reaction in the gasification furnace to generate combustible gas, and particles after primary cooling are obtained, wherein the temperature of the high-temperature particles is 900-1200 ℃, and the gasification reaction components in the gasification agent are as follows according to the mol ratio: c element (0.2-1) in the carbon-containing solid waste material A is 1, and the mass ratio of the C element to the C element is as follows: c element in the carbon-containing solid waste material A is 1 (0.02-0.05), and the gasifying agent is steam and CO₂Rich in CO₂Flue gas or air, said CO being rich₂The gas is CO-containing gas generated by industrial furnaces or boilers₂The gasification reaction component in the waste gas and the gasification agent is H₂O、CO₂Or O₂The carbon element content of the carbon-containing solid waste material A is 20-70%;

step 2, recovering waste heat of medium-low temperature particles:

after primary cooling, the particles and the carbon-containing solid waste material B enter a pyrolysis furnace, and the carbon-containing solid waste material B is prepared by the following steps: 1, moving the particles in a pyrolysis furnace from top to bottom, carrying out pyrolysis reaction on a carbon-containing solid waste material B in the furnace to generate pyrolysis gas and solid semicoke, and obtaining the cooled particles, wherein the carbon element content of the carbon-containing solid waste material A is 20-70%;

step 3, solid separation:

and feeding the cooled mixture of the particles and the solid semicoke into a solid separator, and screening and separating in the solid separator to obtain the cooled particles and the solid semicoke, wherein the solid semicoke is fed into a gasification furnace and used as fuel to provide heat for the gasification furnace, the yield of the solid semicoke is 20-23%, and the content of fixed carbon in the solid semicoke is 77-79.1%.

5. The method for recovering waste heat in a step of pyrolysis gasification by using a solid particle heat carrier according to claim 4, wherein in the step 1, the high-temperature particles are blast furnace slag particles or steel slag particles discharged from steel smelting, and the particle size is 1-10 mm, wherein:

the blast furnace slag particles comprise 41.21 percent of CaO and 8.22 percent of MgO in percentage by mass，SiO₂34.38％，Al₂O₃11.05％，Fe₂O₃2.78％，TiO₂0.35%, the rest is other;

the steel slag particles comprise, by mass, CaO 41.18%, MgO 9.26%, and SiO₂20.49％，Al₂O₃3.08％，Fe₂O₃20.35%, the rest others.

6. The method for recovering waste heat in the step of pyrolysis gasification by using solid particle heat carrier according to claim 4, wherein in the step 1, the gasifying agent is rich in CO₂Flue gas, CO in flue gas₂The content is 10-40%, and the content of N is 60-90%.

7. The method for recovering waste heat in a step by utilizing pyrolysis gasification of a solid particle heat carrier according to claim 4, wherein the carbon-containing solid waste material A or B is pulverized coal, biomass, sludge, plastics, rubber industry, agriculture and biology carbon-containing waste material, and the carbon-containing solid waste material A or B needs to be dried before entering a pyrolysis furnace or a gasification furnace.

8. The method as claimed in claim 4, wherein in step 2, the pyrolysis gas comprises coal gas, the pyrolysis gas is merged with the combustible coal gas obtained in step 1, the condensable tar in the pyrolysis gas and the semicoke and ash in the combustible coal gas are separated through a gas-liquid separator, the smoke and dust are separated through a purifier to obtain clean coal gas, and the heat value of the clean coal gas is 5000-³。

9. The method for the step waste heat recovery of the pyrolysis gasification by using the solid particle heat carrier is characterized in that the thermal efficiency of the method for the step waste heat recovery of the pyrolysis gasification by using the solid particle heat carrier reaches 80-84% after the step waste heat recovery,

The technical field is as follows:

the invention belongs to the technical field of waste heat recovery and energy conservation, and particularly relates to a step waste heat recovery device and method for pyrolysis gasification by utilizing a solid particle heat carrier.

Background art:

the production process in the industries of metallurgy, building materials, chemical engineering and the like has a large amount of high-temperature solid bulk materials and solid particles, such as sintered ores, pellets, direct reduced iron and the like. In addition, metallurgical slag (such as blast furnace slag, steel slag, copper slag, nickel slag and the like) and the like are byproducts discharged in a metal smelting process, the discharge temperature is high (>1200 ℃), and a large amount of sensible heat is contained. At present, the traditional treatment mode of metallurgical slag is a water quenching method, a large amount of water resources are consumed by the treatment mode, and the environmental pollution caused by slag flushing water is serious. Only taking blast furnace slag as an example, the tapping temperature of the blast furnace slag is about 1500 ℃, and the sensible heat of each ton of slag approximately equals 60kg of standard coal. The annual output of the blast furnace slag 2018 in China can reach 2.5 hundred million tons, and about 1500 million tons of standard coal are met. Therefore, the realization of the high-efficiency clean waste heat recovery of the metallurgical industry solid waste is the key of energy conservation and emission reduction of the industry in China.

In order to realize the high-efficiency recovery of the waste heat of the metallurgical slag, change the current situation of water consumption and serious pollution caused by the traditional method and realize the energy-saving and emission-reduction transformation at the tail end of the process flow, the dry granulation and waste heat recovery process of the metallurgical slag converts liquid high-temperature slag into solid high-temperature (about 1100 ℃) particles through a granulation device (such as a rotating cup, a rotating drum, a rotating disc and the like) on the premise of not consuming new water, and then the high-temperature sensible heat of the particles is recovered through direct or indirect contact with a heat transfer medium. With the development and maturity of the granulation technology and process, the slag particles obtained by dry granulation have good sphericity and high vitreous body content, and are convenient for subsequent waste heat recovery and resource utilization.

The existing waste heat recovery process of high-temperature solid particles is mainly a physical method. The method takes water, air and the like as heat exchange media, has the characteristics of more energy conversion times and low waste heat recovery efficiency, can generate hot water, steam, hot air and the like after recovery, and is difficult to improve the quality essentially. The physical method is adopted to recover the waste heat to generate hot water or hot steam, and the thermal efficiency is 76％，

The efficiency was 14.4%, 34.2%. The chemical method mainly absorbs the high-temperature sensible heat of the particles through a typical endothermic chemical reaction to generate a chemical product with higher added value of the product. The method converts heat energy of the particles into chemical energy, and improves the recovery processEfficiency. In the prior patents, CN 201910236543.6, CN 201910305887.8, CN200910012471.3, CN 201510283249.2, etc. all use slag as a heat carrier to drive coal gasification reaction to prepare synthesis gas.

Therefore, how to efficiently recover the sensible heat of the high-temperature particles in industrial production and reduce the energy consumption in the production process is an urgent problem to be solved in China. This also draws high attention from universities, research institutes and enterprises at home and abroad, but no report on the popularization and application of related technologies in this field exists at present.

The invention content is as follows:

the invention aims to overcome the defects in the prior art, and provides a step waste heat recovery device and method for pyrolysis gasification by using a solid particle heat carrier, which can realize the aim of efficiently recovering waste heat of high-temperature solid particles and solve the technical problems of difficult recovery and low recovery efficiency of the waste heat of the high-temperature solid particles.

In order to achieve the purpose, the invention adopts the following technical scheme:

utilize solid particle heat carrier pyrolysis gasification's step waste heat recovery device, including gasifier, pyrolysis oven, solid separator and flue gas processing system, wherein:

the gasification furnace, the pyrolysis furnace and the solid separator are sequentially connected, and the gasification furnace is converged with a flue outlet of the pyrolysis furnace and is connected with a flue gas treatment system.

The flue gas treatment system comprises a cyclone separator, a gas-liquid separator and a purifier, and all the components are connected in sequence.

The gasification furnace is a fixed bed or a fluidized bed, and is provided with a particle feeding device, a gasification furnace fuel nozzle and a particle outlet.

The pyrolysis furnace is a fixed bed, and a stirring device is arranged in the pyrolysis furnace.

The particle outlet of the gasification furnace is connected with the particle feeding device of the pyrolysis furnace, and the particle outlet of the pyrolysis furnace is connected with the solid separator.

The solid separator is connected with the fuel nozzle of the gasification furnace through a lifting device. The semicoke mixture separated by the solid separator provides fuel for the gasification furnace.

The method for recovering the waste heat by adopting the step waste heat recovery device utilizing the pyrolysis gasification of the solid particle heat carrier comprises the following steps:

step 1, recovering waste heat of high-temperature particles:

the method comprises the following steps that high-temperature particles enter a gasification furnace, carbon-containing solid waste materials A enter the gasification furnace under the carrying of a gasification agent, the high-temperature particles move from top to bottom in the gasification furnace under the action of self gravity, the gasification agent and the carbon-containing solid waste materials A are subjected to gasification reaction in the gasification furnace to generate combustible gas, and particles after primary cooling are obtained, wherein the temperature of the high-temperature particles is 900-1200 ℃, the gasification reaction components in the gasification agent are in a molar ratio: c element (0.2-1) in the carbon-containing solid waste material A is 1, and the mass ratio of the C element to the C element is as follows: c element in the carbon-containing solid waste material A is 1 (0.02-0.05);

step 2, recovering waste heat of medium-low temperature particles:

after primary cooling, the particles and the carbon-containing solid waste material B enter a pyrolysis furnace, and the carbon-containing solid waste material B is prepared by the following steps: and (3) after primary cooling, enabling the particles to move from top to bottom in the pyrolysis furnace, enabling the carbon-containing solid waste material B to perform pyrolysis reaction in the furnace to generate pyrolysis gas and solid semicoke, and obtaining the cooled particles.

Step 3, solid separation:

and feeding the cooled mixture of the particles and the solid semicoke into a solid separator, and screening and separating in the solid separator to obtain the cooled particles and the solid semicoke, wherein the solid semicoke is fed into a gasification furnace and used as fuel to provide heat for the gasification furnace, the yield of the solid semicoke is 20-23%, and the content of fixed carbon in the solid semicoke is 77-79.1%.

In the step 1, the high-temperature particles are blast furnace slag particles or steel slag particles discharged by steel smelting, and the particle size is 1-10 mm, wherein:

the blast furnace slag particles comprise 41.21 percent of CaO, 8.22 percent of MgO and SiO by mass percentage₂34.38％，Al₂O₃11.05％，Fe₂O₃2.78％，TiO₂0.35%, the rest is other;

the steel slag particles comprise, by mass, CaO 41.18%, MgO 9.26%, and SiO₂20.49％，Al₂O₃3.08％，Fe₂O₃20.35%, the rest others.

In the step 1, the gasifying agent is water vapor and CO₂Rich in CO₂Gas or air, said CO being enriched₂The gas is CO-containing gas generated by industrial furnaces or boilers₂The gasification reaction component in the waste gas and the gasification agent is H₂O、CO₂Or O₂。

In the step 1, the gasifying agent is rich in CO₂Flue gas, CO in flue gas₂The content is 10-40%, and the content of N is 60-90%.

In the step 1, the gasification reaction quickly absorbs the heat of the particles and generates combustible gas; meanwhile, the temperature of the high-temperature particles is rapidly cooled, the temperature of the particles after primary cooling is 500-800 ℃, and the particles after primary cooling enter a particle feeding device of the pyrolysis furnace through a particle outlet.

In the step 1, the combustible gas carries semicoke and ash.

In the step 1, the chemical reaction equation of the gasification reaction of the gasification furnace is as follows:

C+CO₂(g)＝2CO(g) 173.4kJ/mol (1)

C+H₂O(g)＝CO(g)+H₂(g) 135.6kJ/mol (2)

in the steps 1 and 2, the carbon-containing solid waste material A or B is coal powder, biomass, sludge, plastics, rubber and other industrial, agricultural and biological carbon-containing waste materials, and the carbon element content of the carbon-containing solid waste material A or B is 20-70%.

In the steps 1 and 2, the carbon-containing solid waste material A or B needs to be dried before entering the pyrolysis furnace or the gasification furnace.

In the steps 1 and 2, the carbon-containing solid waste material is coal powder.

In the step 2, the pyrolysis reaction quickly absorbs the heat of the particles after the primary cooling, the temperature of the particles after the primary cooling is further cooled, and the temperature of the particles after the cooling is less than or equal to 200 ℃. And the cooled particles and solid semicoke generated after pyrolysis enter a solid separator through a particle outlet.

In the step 2, the pyrolysis gas comprises coal gas, the pyrolysis gas is converged with the combustible coal gas obtained in the step 1, the condensable tar in the pyrolysis gas and the semicoke and ash in the combustible coal gas are separated through a gas-liquid separator, and the smoke dust is separated through a purifier to obtain clean coal gas. The heat value of the clean gas is 7000kJ/m³。

The cascade waste heat recovery method for pyrolysis gasification by using solid particle heat carrier has the advantages that after cascade waste heat recovery, the heat efficiency reaches 80-84%,

the efficiency is 70-77%.

The invention has the beneficial effects that:

(1) the process system and the method can efficiently recover the solid particle waste heat, improve the solid particle waste heat recovery efficiency to 80-84%,the efficiency is improved to 70-77%;

(2) the method can convert the solid particle waste heat into the heat value of 5000-7000 kJ/based on the standard deviation of the heat value³The combustible clean coal gas, the solid semicoke with the fixed carbon content of 77-79.1 percent and other products with high added value;

(3) the system and the method adopt rich CO while protecting the environment and saving resources₂When the flue gas is a gasifying agent, the waste heat of each kg of slag particles is recovered, and the greenhouse gas CO can be reduced₂More than 30L.

Description of the drawings:

FIG. 1 is a process flow diagram of a step waste heat recovery method by pyrolysis gasification of a solid particle heat carrier in embodiment 1 of the invention;

fig. 2 is a schematic structural view of a step waste heat recovery device utilizing pyrolysis gasification of a solid particle heat carrier according to embodiment 1 of the present invention;

FIG. 3 is a process flow diagram of a step waste heat recovery method by pyrolysis gasification of a solid particle heat carrier in embodiment 2 of the invention;

fig. 4 is a schematic structural diagram of a step waste heat recovery device utilizing pyrolysis gasification of a solid particle heat carrier according to embodiment 2 of the present invention; wherein:

the method comprises the following steps of 1-a gasification furnace, 2-a pyrolysis furnace, 3-a solid separator, 4-a cyclone separator, 5-a gas-liquid separator, 6-a purifier, 7-a high-temperature particle feeding device, 8-a storage bin, 9-a gasification furnace fuel nozzle, 10-a gasification furnace particle outlet, 11-a medium-low temperature particle feeding device, 12-a pyrolysis furnace fuel nozzle, 13-a stirring device and 14-a pyrolysis furnace particle outlet.

The specific implementation mode is as follows:

the present invention will be described in further detail with reference to examples.

The following is a calculation of the materials required and the products produced during the gasification and pyrolysis process according to the law of conservation of mass and energy, taking 1kg of slag particles as an example.

The calculation conditions were as follows:

the inlet temperature of high-temperature slag particles in the gasification furnace is 1100 ℃, and the outlet temperature is 700 ℃; the inlet temperature of the medium-low temperature slag particles in the pyrolysis furnace is 700 ℃, the outlet temperature is 100 ℃, and the specific heat capacity of the slag is C_m11.2 kJ/(kg. DEG C.), the mass of slag particles is m₁。

The fuels in the gasification furnace and the pyrolysis furnace are coal powder, wherein the coal powder comprises 64.4 percent of C, 4.2 percent of H, 8.8 percent of O, 20 percent of ash content, 44.8 percent of fixed carbon, 32.8 percent of volatile matter, and C, the specific heat capacity of the coal powder_m21.1 kJ/(kg. DEG C.), and the coal powder mass m₂And (4) showing.

The gasifying agent is rich in CO₂Flue gas, the flue gas component being (CO)₂＝40％，N₂60%) specific heat capacity C_m3Is represented by N₂Specific heat capacity of 1.03 kJ/(kg. DEG C), CO₂Specific heat capacity of 0.84 kJ/(kg. DEG C), and gasification agent mass m₃And (4) showing.

The outlet temperature of the coal gas generated by the gasification furnace is 800 ℃; the outlet temperature of the pyrolysis gas generated by the pyrolysis furnace is 300 ℃.

The carbon conversion rate and the pyrolysis conversion rate in the gasification process are calculated according to 100 percent.

(1) Gasification furnace

According to the law of conservation of energy: the heat released by the slag is the heat absorbed by the gasification reaction, and the amount of the coal powder required by the gasification reaction is as follows:

the heat revenue terms are as follows:

1) physical heat of slag substitution

Q_in-1＝C_m1×1×t₁＝1.2×1×(1100)kJ＝1320.0kJ (3)

2) Physical heat brought in by coal dust

Q_in-2＝C_m2×m₂×t₂＝1.1×m₂×(20) (4)

3) Physical heat carried in by gasifying agent

Q_in-3＝C_m3×m₃×t₃＝0.954×m₃×(20) (5)

The heat removal term is as follows:

4) heat absorbed by gasification reaction

5) The particles take away physical heat

Q_out-2＝C_m1×1×t_1'＝1.2×1×(700)kJ＝840.0kJ (7)

6) Physical heat brought out by coal slag

Q_out-3＝C_m2×m₂×0.2×t_2'＝1.1×m₂×0.2×900＝198×m₂kJ (8)

7) Physical heat brought out by flue gas

According to the coal dust and CO₂The gasification reaction mass relationship can be given as:

according to the law of conservation of energy, Q_in＝Q_outThe simultaneous equation can calculate that 0.0296kg of coal powder needs to be consumed and 0.089kg of CO (about 71L) is generated when 1kg of slag particles are processed in the gasifier according to the set conditions, and the thermal efficiency of the gasifier is 57.4%. If the waste heat recovery of the flue gas in the cooler is considered, when the waste heat recovery rate of the flue gas is 60%, the thermal efficiency of the gasification furnace can reach 82%. CO-Rich gasification process₂The gasifying agent is CO-containing gas produced by industrial furnace or boiler₂Exhaust gases, i.e. with the process according to the invention, can absorb 0.07kg of CO per 1kg of slag treated₂The waste gas can absorb CO annually according to the calculation of 2.5 million tons of slag generated annually in China₂Up to 1750 ten thousand tons. The results of calculation of the input amount of the materials of the gasification furnace and the output amount of the products are shown in table 1.

TABLE 1 calculation results of input of materials and output of products in gasification furnace

TABLE 2 balance of heat budget of gasifier

(2) Pyrolysis process

The heat of decomposition of coal is 448kJ/(kg), and the thermal decomposition products of coal are CO and H₂Calculating that C element in the coal powder is converted into fixed carbon and CO, and H element is completely converted into H₂。

Similarly, the calculation results of the input amount of the material and the output amount of the product in the pyrolysis furnace are shown in table 3.

TABLE 3 calculation results of input of materials and output of products in pyrolysis furnace

TABLE 4 pyrolysis furnace heat budget balance table

According to the set conditions, 1.263kg of coal powder is consumed to process 1kg of slag particles in the pyrolysis furnace, 0.195kg (about 155L) of CO and H are generated₂0.053kg (about 590L) to produce 0.818kg of semicoke, and the theoretical thermal efficiency of the pyrolysis furnace is 82.3%.

The efficiency is calculated as follows.

Through integral calculation, the integral heat efficiency of the process system consisting of the gasification furnace and the pyrolysis furnace can reach 84.7 percent,

the efficiency can reach 77.4%.

Theoretical analysis and calculation of the gasification and pyrolysis parts in the step waste heat recovery device and method utilizing pyrolysis and gasification of the solid particle heat carrier can show that the invention provides a brand-new idea for step waste heat recovery of high-temperature particles.

Utilize solid particle heat carrier pyrolysis gasification's step waste heat recovery device, including gasifier, pyrolysis oven, solid separator and flue gas processing system, wherein:

the gasification furnace, the pyrolysis furnace and the solid separator are sequentially connected, and the gasification furnace is converged with a flue outlet of the pyrolysis furnace and is connected with a flue gas treatment system.

The flue gas treatment system comprises a cyclone separator, a gas-liquid separator and a purifier, and all the components are connected in sequence.

The gasification furnace is a fixed bed or a fluidized bed, and is provided with a particle feeding device, a gasification furnace fuel nozzle and a particle outlet.

The pyrolysis furnace is a fixed bed, and a stirring device is arranged in the pyrolysis furnace.

The particle outlet of the gasification furnace is connected with the particle feeding device of the pyrolysis furnace, and the particle outlet of the pyrolysis furnace is connected with the solid separator.

The solid separator is connected with the fuel nozzle of the gasification furnace through a lifting device. The semicoke mixture separated by the solid separator provides fuel for the gasification furnace.

The method for recovering the waste heat by adopting the step waste heat recovery device utilizing the pyrolysis gasification of the solid particle heat carrier comprises the following steps:

step 1, recovering waste heat of high-temperature particles:

the method comprises the following steps that high-temperature particles enter a gasification furnace, carbon-containing solid waste materials A enter the gasification furnace under the carrying of a gasification agent, the high-temperature particles move from top to bottom in the gasification furnace under the action of self gravity, the gasification agent and the carbon-containing solid waste materials A are subjected to gasification reaction in the gasification furnace to generate combustible gas, and particles after primary cooling are obtained, wherein the temperature of the high-temperature particles is 900-1200 ℃, the gasification reaction components in the gasification agent are in a molar ratio: c element (0.2-1) in the carbon-containing solid waste material A is 1, and the mass ratio of the C element to the C element is as follows: c element in the carbon-containing solid waste material A is 1 (0.02-0.05);

step 2, recovering waste heat of medium-low temperature particles:

after primary cooling, the particles and the carbon-containing solid waste material B enter a pyrolysis furnace, and the carbon-containing solid waste material B is prepared by the following steps: and (3) after primary cooling, enabling the particles to move from top to bottom in the pyrolysis furnace, enabling the carbon-containing solid waste material B to perform pyrolysis reaction in the furnace to generate pyrolysis gas and solid semicoke, and obtaining the cooled particles.

Step 3, solid separation:

and feeding the cooled mixture of the particles and the solid semicoke into a solid separator, and screening and separating in the solid separator to obtain the cooled particles and the solid semicoke, wherein the solid semicoke is fed into a gasification furnace and used as fuel to provide heat for the gasification furnace, the yield of the solid semicoke is 20-23%, and the content of fixed carbon in the solid semicoke is 77-79.1%.

In the step 1, the high-temperature particles are blast furnace slag particles or steel slag particles discharged by steel smelting, and the particle size is 1-10 mm, wherein:

the blast furnace slag particles comprise 41.21 percent of CaO, 8.22 percent of MgO and SiO by mass percentage₂34.38％，Al₂O₃11.05％，Fe₂O₃2.78％，TiO₂0.35%, the rest is other;

the steel slag particles comprise, by mass, CaO 41.18%, MgO 9.26%, and SiO₂20.49％，Al₂O₃3.08％，Fe₂O₃20.35%, the rest others.

In the step 1, the gasifying agent is water vapor and CO₂Rich in CO₂Gas or air, said CO being enriched₂The gas is CO-containing gas generated by industrial furnaces or boilers₂The gasification reaction component in the waste gas and the gasification agent is H₂O、CO₂Or O₂。

In the step 1, the gasifying agent is rich in CO₂Flue gas, CO in flue gas₂The content is 10-40%, and the content of N is 60-90%.

In the step 1, the gasification reaction quickly absorbs the heat of the particles and generates combustible gas; meanwhile, the temperature of the high-temperature particles is rapidly cooled, the temperature of the particles after primary cooling is 500-800 ℃, and the particles after primary cooling enter a particle feeding device of the pyrolysis furnace through a particle outlet.

In the step 1, the combustible gas carries semicoke and ash.

In the step 1, the chemical reaction equation of the gasification reaction of the gasification furnace is as follows:

C+CO₂(g)＝2CO(g) 173.4kJ/mol (1)

C+H₂O(g)＝CO(g)+H₂(g) 135.6kJ/mol (2)

in the steps 1 and 2, the carbon-containing solid waste material A or B is coal powder, biomass, sludge, plastics, rubber and other industrial, agricultural and biological carbon-containing waste materials, and the carbon element content of the carbon-containing solid waste material A or B is 20-70%.

In the steps 1 and 2, the carbon-containing solid waste material A or B needs to be dried before entering the pyrolysis furnace or the gasification furnace.

In the steps 1 and 2, the carbon-containing solid waste material is coal powder.

In the step 2, the pyrolysis reaction quickly absorbs the heat of the particles after the primary cooling, the temperature of the particles after the primary cooling is further cooled, and the temperature of the particles after the cooling is less than or equal to 200 ℃. And the cooled particles and solid semicoke generated after pyrolysis enter a solid separator through a particle outlet.

In the step 2, the pyrolysis gas comprises coal gas, the pyrolysis gas is converged with the combustible coal gas obtained in the step 1, the condensable tar in the pyrolysis gas and the semicoke and ash in the combustible coal gas are separated through a gas-liquid separator, and the smoke dust is separated through a purifier to obtain clean coal gas. The heat value of the clean gas is 7000kJ/m³。

The cascade waste heat recovery method for pyrolysis gasification by using solid particle heat carrier has the advantages that after cascade waste heat recovery, the heat efficiency reaches 80-84%,

the efficiency is 70-77%.

In the following examples, coal dust having a C of 64.4%, H of 4.2%, O of 8.8%, ash content of 20%, fixed carbon content of 44.8%, volatile matter content of 32.8%, specific heat capacity C of coal dust was used_m21.1 kJ/(kg. multidot. C.).