Method for treating carbon-containing solid waste and device therefor

Abstract

This invention provides a method and apparatus for treating carbon-containing solid waste, belonging to the fields of thermal modification and high-temperature melting combustion technology. The method includes: providing a first oxidant condition to cause thermal modification of the carbon-containing solid waste under the first oxidant condition. The thermal modification includes: a first thermal modification of a first proportion of exposed carbon in the carbon-containing solid waste under the first oxidant condition, and a second thermal modification of carbon with a first particle size encapsulated in the carbon-containing solid waste under the first oxidant condition. The first proportion of exposed carbon undergoes the first thermal modification to generate a thermally modified product, and the first particle size encapsulated carbon undergoes the second thermal modification and is then broken down to form carbon with a second particle size encapsulated. The oxygen equivalent ratio of the first oxidant in the first oxidant condition is 0.15-0.5. The thermally modified product includes activated carbon and combustible gas.

Description

Technical Field

[0001] This invention belongs to the field of thermal modification and melting combustion technology, and particularly relates to a method and apparatus for treating carbon-containing solid waste. Background Technology

[0002] Coal is widely used as a raw material or fuel in industries such as chemical, steel, and non-ferrous metals. However, its production inevitably generates carbon-containing solid waste, such as gasification ash from fluidized bed gasification and melting, carbon-containing steel slag from steelmaking, and aluminum and graphite from aluminum smelting. This carbon-containing solid waste is mainly composed of carbon and inorganic components. Carbon exists primarily on the surface of inorganic components or is encapsulated by them, either as exposed carbon or coated carbon. The carbon content in this solid waste ranges from 10% to 60%. This high carbon content limits the resource utilization of inorganic components; furthermore, the high degree of graphitization of exposed and coated carbon, lacking volatile components, makes it difficult to burn, thus increasing the difficulty of disposing of this carbon-containing solid waste.

[0003] Furthermore, during the implementation of this invention, it was discovered that the treatment of carbon-containing solid waste suffers from problems such as high reagent consumption, lack of landfill options and environmental pollution, low co-firing ratio of combustion decarbonization technology due to the high degree of graphitization in the carbon-containing solid waste, leading to unstable boiler operation and high carbon content in the treated residue. Therefore, there is an urgent need for a method for treating carbon-containing solid waste that can achieve carbon removal and the recovery and reuse of inorganic components. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] Based on the above-mentioned technical problems, the present invention provides a method and apparatus for treating carbon-containing solid waste, aiming to at least partially solve the above problems and realize the treatment of carbon-containing solid waste and the resource utilization of inorganic components.

[0006] (II) Technical Solution

[0007] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0008] As a first aspect of the present invention, a method for treating carbonaceous solid waste is provided, comprising:

[0009] Provide a first oxidant condition to cause the carbon-containing solid waste to undergo thermal modification under the first oxidant condition, wherein the thermal modification includes: a first thermal modification of a first proportion of exposed carbon in the carbon-containing solid waste under the first oxidant condition, and a second thermal modification of carbon with a first particle size in the carbon-containing solid waste under the first oxidant condition, wherein the first proportion of exposed carbon generates a thermally modified product after undergoing the first thermal modification, and the carbon with the first particle size is crushed to form carbon with a second particle size after undergoing the second thermal modification;

[0010] In the first oxidant condition, the oxygen equivalent ratio of the first oxidant is 0.15-0.5;

[0011] Thermally modified products include activated carbon and combustible gases.

[0012] In one embodiment, the carbon-containing solid waste treatment method further includes:

[0013] Provide a second oxidant condition so that the thermally modified product undergoes a first melt combustion reaction under the second oxidant condition; and

[0014] The carbon encapsulated by the second particle size undergoes a second melting and combustion reaction under the second oxidant conditions;

[0015] Among them, the thermally modified product undergoes a first melting and combustion reaction under the second oxidant condition to generate slag and carbon dioxide, and the carbon with the second particle size undergoes a second melting and combustion reaction under the second oxidant condition to generate slag and carbon dioxide.

[0016] In the second oxidant condition, the oxygen equivalent ratio of the second oxidant is 0.6-0.85.

[0017] In one embodiment, the first proportion of exposed carbon accounts for 20%-70% of the total mass of exposed carbon in the carbon-containing solid waste.

[0018] In one embodiment, a first proportion of exposed carbon undergoes a first thermal modification under a first oxidant condition, generating a first heat of reaction. This first heat of reaction is used to maintain a first reaction temperature, which is 800°C-950°C.

[0019] In one embodiment, the thermally modified product generates a second heat of reaction after undergoing a first melting and combustion reaction under a second oxidant condition. The second heat of reaction is used to maintain a second reaction temperature, which is 1300°C-1600°C.

[0020] In one embodiment, the duration of the first thermal modification change of the first proportion of exposed carbon under the first oxidant condition is 1-10 min.

[0021] In one embodiment, the duration of the first melt combustion reaction of the thermally modified product under the second condition is 6-60 s.

[0022] In one embodiment, the first oxidant includes at least one of the following:

[0023] Air, air-rich air, or pure oxygen;

[0024] The second oxidizing agent includes at least one of the following:

[0025] Air, air-rich air, or pure oxygen.

[0026] In one embodiment, the combustible gas includes at least one of hydrogen, carbon monoxide, and methane.

[0027] As a second aspect of the present invention, a carbon-containing solid waste treatment apparatus is provided, comprising:

[0028] A thermal modification unit is used to perform thermal modification changes on carbon-containing solid waste under a first oxidant condition. The thermal modification changes include: a first thermal modification change on a first proportion of exposed carbon in the carbon-containing solid waste under a first oxidant condition, and a second thermal modification change on carbon with a first particle size in the carbon-containing solid waste under a first oxidant condition. The first proportion of exposed carbon generates a thermally modified product after undergoing the first thermal modification change, and the carbon with the first particle size is crushed to form carbon with a second particle size after undergoing the second thermal modification change.

[0029] Among them, the oxygen equivalent ratio of the first oxidant in the first oxidant condition is 0.15-0.5; the mass percentage of exposed carbon in the first proportion of the total exposed carbon in the carbon-containing solid waste is 20%-70%;

[0030] Thermally modified products include activated carbon and combustible gases.

[0031] In one embodiment, the carbonaceous solid waste treatment device further includes:

[0032] A melting combustion unit, connected to a thermal modification unit, is used to receive the thermally modified product and the second-size encapsulated carbon, and to conduct a melting combustion reaction under a second oxidant condition, wherein the melting combustion reaction includes:

[0033] The thermally modified product undergoes a first melting and combustion reaction under the second oxidant condition; and

[0034] The carbon encapsulated by the second particle size undergoes a second melting and combustion reaction under the second oxidant conditions;

[0035] The thermally modified product undergoes a first melting and combustion reaction under the second oxidant condition to generate slag and carbon dioxide, while the carbon encapsulated in the second particle size undergoes a second melting and combustion reaction under the second oxidant condition to generate slag and carbon dioxide.

[0036] In the second oxidant condition, the oxygen equivalent ratio of the second oxidant is 0.6-0.85.

[0037] In one embodiment, the thermal modification unit and the melting combustion unit are arranged as an integrated structure or as separate structures.

[0038] In one embodiment, where the thermal modification unit and the melting combustion unit are arranged in a separate structure, the combustion unit further includes:

[0039] The first oxidant inlet is used to supply the first oxidant to the combustion unit;

[0040] Fuel inlet, used to supply carbonaceous solid waste to the combustion unit;

[0041] The thermally modified outlet is used to discharge the thermally modified products and the second-size encapsulated carbon.

[0042] In one embodiment, where the thermal modification unit and the melting combustion unit are arranged in a separate structure, the melting combustion unit further includes:

[0043] The second oxidant inlet is used to supply a second oxidant to the molten combustion unit;

[0044] The melting and combustion inlet is connected to the thermal modification outlet and is used to receive the thermally modified products and second-size encapsulated carbon discharged from the thermal modification unit.

[0045] The slag outlet is used to discharge the slag from the molten combustion unit; and

[0046] The vent is used to discharge carbon dioxide from the molten combustion unit.

[0047] In one embodiment, the thermal modification unit includes any one of a fluidized bed, a bubbling bed, or a flow tubular reactor.

[0048] In one embodiment, the melting and combustion unit includes any one of a fluidized bed, a rotary kiln, or a cupola furnace.

[0049] (III) Beneficial Effects

[0050] According to embodiments of the present invention, carbon in carbon-containing solid waste mainly exists in the form of exposed carbon and encapsulated carbon. Under the first oxidant condition, the exposed carbon and encapsulated carbon in the carbon-containing solid waste can undergo thermal modification. During the first thermal modification process of the first proportion of exposed carbon under the first oxidant condition, the first proportion of exposed carbon can be combusted and gasified, and the generated combustible gas is released from the exposed carbon, opening the pore structure of the exposed carbon. During the combustion and gasification process, the carbon chains of the exposed carbon can also be broken, thereby destroying the graphitized structure of the exposed carbon. This transforms the exposed carbon, which has a dense pore structure, a high degree of graphitization, and low activity, into loose and porous activated carbon with a low degree of graphitization and high activity. This solves the problem that exposed carbon is difficult to combust due to its poor activity caused by a high degree of graphitization, making it impossible to dispose of exposed carbon. For coated carbon, under the first oxidant conditions, the coated carbon particles of the first size collide and rub against each other, and gradually change from the first size coated carbon to the second size coated carbon after thermal modification, i.e. thermal breakage. This destroys the outer surface structure of the coated carbon, making it easier for subsequent processing. Attached Figure Description

[0051] Figure 1 This is a schematic diagram illustrating the principle of the carbon-containing solid waste treatment method in this embodiment of the invention;

[0052] Figure 2 This is a schematic flowchart of the carbon-containing solid waste treatment method in an embodiment of the present invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0054] To address the challenges posed by the high carbon content in carbon-containing solid waste, which limits the resource utilization of inorganic components; the high degree of graphitization of exposed and encapsulated carbon in carbon-containing solid waste, making it difficult to burn and increasing the difficulty of decarbonization treatment; and the problems of high reagent consumption, environmental pollution, unstable boiler operation, and high carbon content in the residue after treatment, this invention proposes a method and apparatus for treating carbon-containing solid waste. This method utilizes thermal modification technology to break down the graphitized structure of exposed carbon, converting the less active exposed carbon into more active activated carbon; and breaks down the first-size encapsulated carbon particles to form a second-size encapsulated carbon. Then, high-temperature melting and combustion technology (above 1300℃) is used to melt and burn the activated carbon, as well as the outer shell of the second-size encapsulated carbon, allowing the exposed carbon to melt and burn. This achieves the decarbonization treatment of exposed and encapsulated carbon in carbon-containing solid waste, yielding reusable inorganic components.

[0055] In view of this, as a first aspect of the present invention, a method for treating carbonaceous solid waste is provided, comprising:

[0056] Provide a first oxidant condition to cause the carbon-containing solid waste to undergo thermal modification under the first oxidant condition, wherein the thermal modification includes: a first thermal modification of a first proportion of exposed carbon in the carbon-containing solid waste under the first oxidant condition, and a second thermal modification of carbon with a first particle size in the carbon-containing solid waste under the first oxidant condition, wherein the first proportion of exposed carbon generates a thermally modified product after undergoing the first thermal modification, and the carbon with the first particle size is crushed to form carbon with a second particle size after undergoing the second thermal modification;

[0057] In the first oxidant condition, the oxygen equivalent ratio of the first oxidant is 0.15-0.5;

[0058] Thermally modified products include activated carbon and combustible gases.

[0059] Figure 1 This is a schematic diagram illustrating the principle of the carbon-containing solid waste treatment method in this embodiment of the invention; Figure 2 This is a schematic flowchart of the carbon-containing solid waste treatment method in an embodiment of the present invention.

[0060] The following combination Figure 1 and Figure 2 The process of the carbon-containing solid waste treatment method in this invention will be described in detail.

[0061] like Figure 1 and Figure 2 As shown, carbon-containing solid waste includes exposed carbon and coated carbon. Exposed carbon is carbon attached to the surface of inorganic components, while coated carbon is carbon coated by inorganic components. A first oxidant condition is provided so that a first proportion of exposed carbon in the carbon-containing solid waste undergoes a first thermal modification under the first oxidant condition; and coated carbon of a first particle size undergoes a second thermal modification under the first oxidant condition. The oxygen equivalent ratio of the first oxidant in the first oxidant condition is 0.15-0.5, and the first oxidant includes at least one of air, air-enriched air, or pure oxygen.

[0062] Furthermore, the first thermal modification change of exposed carbon under the first oxidant condition is manifested as follows:

[0063] The first proportion of exposed carbon in carbon-containing solid waste undergoes a first thermal modification under the first oxidant condition to generate a thermally modified product and a first heat of reaction. The first heat of reaction is used to maintain a first reaction temperature, which is 800℃-950℃. The mass percentage of the first proportion of exposed carbon in the carbon-containing solid waste is 20%-70%. The duration of the first thermal modification of the first proportion of exposed carbon under the first oxidant condition is 1-10 minutes. The thermally modified product includes combustible gas and activated carbon. The combustible gas includes at least one of hydrogen, carbon monoxide, methane, and carbon dioxide. This can be understood as follows: the primary oxidant, with an oxygen equivalent ratio of 0.15-0.5, enables 20%-70% of the exposed carbon in carbonaceous solid waste to release the first heat of reaction during a 1-10 minute combustion / gasification reaction (first thermal modification). This first heat of reaction maintains the first reaction temperature of 800℃-950℃ required for the thermal modification (first reaction). Simultaneously, 20%-70% of the exposed carbon comes into contact with oxygen (with an oxygen equivalent ratio of 0.15-0.5) and produces thermally modified products and combustible gases during combustion / gasification. The combustible gases released during the combustion / gasification of exposed carbon precipitate from the pores of the exposed carbon, opening its pore structure and disrupting the graphitized structure on its surface. This transforms dense, difficult-to-burn exposed carbon into loose, porous, and highly active activated carbon. The pore structure of this activated carbon is 3-10 times higher than that of bare carbon; compared with the activity of bare carbon with a dense graphitized structure, the activity of this loose and porous activated carbon is increased by 30%-200%, and the higher activity of the activated carbon prepares it for subsequent treatments.

[0064] The second thermal modification change that occurs when carbon encapsulated in the first particle size undergoes under the first oxidant condition is manifested as follows:

[0065] After undergoing a second thermal modification, the carbon particles with the first diameter undergo breakage to form carbon particles with the second diameter. This can be understood as follows: at the first reaction temperature, the carbon particles with the second diameter change from a solid to a fluidized state, causing friction and collisions between them, thermally breaking them down and disrupting the outer surface structure of the carbon particles. Furthermore, the first reaction temperature can also be used to heat the carbon particles with the second diameter to the first reaction temperature, increasing their sensible heat capacity for subsequent processing. The first reaction temperature is achieved by releasing the heat of reaction from the first thermal modification of 20%-70% of the exposed carbon in the carbon-containing solid waste, using this heat to maintain the required temperature of 800-950℃ for the thermal modification.

[0066] In implementing this invention, the oxygen equivalent ratio of the first oxidant in the first oxidant condition is limited to 0.1-0.5. This allows the exposed carbon in the carbon-containing solid waste to be converted into highly active activated carbon, improving the activity of the exposed carbon. This ensures that the exposed carbon can be processed more effectively in subsequent treatments. Simultaneously, the released heat of reaction can maintain the temperature for thermal modification and the second thermal modification of the carbon with a first particle size to obtain carbon with a second particle size. If the oxygen equivalent ratio in the first oxidant is further increased based on the first oxidant condition, it will not cause all the exposed carbon to be converted into activated carbon, thus not further improving the activity of the exposed carbon; nor will it cause all the carbon in the exposed carbon to be converted into carbon dioxide after combustion / gasification, resulting in a high carbon content in the obtained solid product, limiting the resource utilization of inorganic components; simultaneously, it will not cause the carbon in the carbon with a second particle size to be converted into carbon dioxide after combustion, thus achieving carbon removal from the exposed carbon.

[0067] According to embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the carbon-containing solid waste treatment method further includes: providing a second oxidant condition so that the thermally modified product undergoes a first melting combustion reaction under the second oxidant condition; and the second particle size encapsulated carbon undergoes a second melting combustion reaction under the second oxidant condition; wherein the oxygen equivalent ratio of the second oxidant in the second oxidant condition is 0.6-0.85, and the second oxidant includes at least one of air, air-enriched air, or pure oxygen.

[0068] Furthermore, the specific manifestations of the first melt combustion reaction of the thermally modified product under the second oxidant condition are as follows:

[0069] After the thermally modified product undergoes a first melting and combustion reaction under the second oxidant condition, it generates slag and carbon dioxide, while simultaneously releasing a second heat of reaction, which is used to maintain the second reaction temperature. The second reaction temperature is 1300℃-1600℃, and the duration of the first melting and combustion reaction of the thermally modified product under the second condition is 6-60s.

[0070] This can be understood as follows: when the oxygen equivalent ratio of the second oxidant is 0.6-0.85, the thermally modified product produced after the first thermal modification of the exposed carbon comes into contact with the second oxidant and burns rapidly. For example, the first melting and combustion reaction may be completed within a few seconds (6-60s), releasing the second heat of reaction to maintain the melting and combustion reaction (second reaction) at 1300℃-1600℃. This allows the activated carbon in the thermally modified product to burn into carbon dioxide, while the inorganic components in the activated carbon are melted to generate slag, thus achieving higher value utilization of the inorganic components in the slag.

[0071] The second particle size encapsulating carbon undergoes a second melting and combustion reaction under the second oxidant conditions, which manifests as follows:

[0072] The second-sized carbon particles undergo a second melting and combustion reaction under the second oxidant condition to generate slag and carbon dioxide. This can be understood as follows: the second-sized carbon particles utilize the heat released from the first melting and combustion reaction of the thermally modified product under the second oxidant condition, generating a temperature of 1300℃-1600℃ (the second reaction temperature). This heat melts and opens the slag shell (inorganic component slag shell) on the outer surface of the second-sized carbon particles, exposing the carbon encased within the inorganic components. The exposed carbon then contacts the second oxidant and burns to generate carbon dioxide. Simultaneously, the inorganic components within the second-sized carbon particles are melted and burned to form slag, thus achieving the decarburization treatment of the encapsulated carbon.

[0073] In embodiments of the present invention, by utilizing two processing steps—thermal modification and molten combustion—complete combustion of exposed carbon and carbon encapsulated in carbon can be achieved, converting carbon in carbon-containing solid waste into carbon dioxide. The remaining inorganic components in the carbon-containing solid waste can be melted at a high temperature (1300℃-1600℃) to form slag. Because the resulting slag contains no carbon or only a small amount of carbon, it does not limit the higher-value applications of the inorganic components. For example, the slag can be used as a raw material for metal extraction, a raw material for microcrystalline glass, and a cement admixture.

[0074] As a second aspect of the present invention, a carbon-containing solid waste treatment device is provided, comprising: a thermal modification unit.

[0075] The thermal modification unit is used to thermally modify carbon-containing solid waste under the first oxidant condition. The thermal modification includes: a first thermal modification of a first proportion of exposed carbon in the carbon-containing solid waste under the first oxidant condition, and a second thermal modification of carbon with a first particle size encapsulated in the carbon-containing solid waste under the first oxidant condition. The first proportion of exposed carbon undergoes the first thermal modification to generate a thermally modified product, and the first particle size encapsulated carbon undergoes the second thermal modification and is then broken down to form carbon with a second particle size encapsulated. The oxygen equivalent ratio of the first oxidant under the first oxidant condition is 0.15-0.5. The mass percentage of the first proportion of exposed carbon in the carbon-containing solid waste is 20%-70%. The thermally modified products include activated carbon and combustible gas.

[0076] According to an embodiment of the present invention, the device further includes a melting and combustion unit.

[0077] The melting and combustion unit is connected to the thermal modification unit and is used to receive the thermally modified product and the second-size coated carbon and to undergo a melting and combustion reaction under the conditions of a second oxidant. The melting and combustion reaction includes: the thermally modified product undergoing a first melting and combustion reaction under the conditions of a second oxidant; and the second-size coated carbon undergoing a second melting and combustion reaction under the conditions of a second oxidant. The thermally modified product generates slag and carbon dioxide after the first melting and combustion reaction under the conditions of a second oxidant, and the second-size coated carbon generates slag and carbon dioxide after the second melting and combustion reaction under the conditions of a second oxidant. The oxygen equivalent ratio of the second oxidant under the second oxidant conditions is 0.6-0.85.

[0078] According to embodiments of the present invention, the thermal modification unit and the melting combustion unit are arranged as an integral structure or as separate structures.

[0079] According to an embodiment of the present invention, when the thermal modification unit and the melting combustion unit are arranged in a separate structure, the thermal modification unit further includes: a first oxidant inlet, a fuel inlet, and a thermal modification outlet. The first oxidant inlet is used to provide a first oxidant to the combustion unit; the fuel inlet is used to provide carbon-containing solid waste to the combustion unit; and the thermal modification outlet is used to discharge the thermally modified products and carbon encapsulated in second-size particles.

[0080] According to an embodiment of the present invention, when the thermal modification unit and the molten combustion unit are arranged in a separate structure, the molten combustion unit further includes: a second oxidant inlet, a molten combustion inlet, a slag outlet, and a gas outlet. The second oxidant inlet is used to provide a second oxidant to the molten combustion unit; the molten combustion inlet is connected to the thermal modification outlet and is used to receive the thermally modified products and second-size encapsulated carbon discharged from the thermal modification unit; the slag outlet is used to discharge the slag within the molten combustion unit; and the gas outlet is used to discharge carbon dioxide within the molten combustion unit.

[0081] According to an embodiment of the present invention, when the thermal modification unit and the melting combustion unit are arranged in a separate structure, the thermal modification unit includes any one of a fluidized bed, a bubbling bed, or a flow pipeline reactor; the melting combustion unit includes any one of a gas flow bed, a rotary kiln, or a cupola furnace.

[0082] The following combination Figure 2 The carbon-containing solid waste treatment device is described in detail in the embodiments of the present invention using the carbon-containing solid waste treatment method.

[0083] according to Figure 2The carbon-containing solid waste treatment method shown employs a separate structure arrangement for the thermal modification unit and the melting combustion unit. Before thermal modification, the carbon-containing solid waste is introduced into the thermal modification unit via a fuel inlet, and a first oxidant is introduced into the unit via a first oxidant inlet. The carbon-containing solid waste includes exposed carbon and coated carbon. The oxygen equivalent ratio of the first oxidant is set to 0.1-0.5. During thermal modification, the carbon-containing solid waste within the thermal modification unit undergoes thermal modification under the first oxidant conditions. This thermal modification includes a first thermal modification of a first proportion of exposed carbon in the carbon-containing solid waste under the first oxidant conditions, and a second thermal modification of coated carbon of a first particle size under the first oxidant conditions.

[0084] The first and second thermal modification changes within the thermal modification unit are specifically manifested as follows:

[0085] Under the first oxidant condition, a first proportion of exposed carbon in carbonaceous solid waste comes into contact with oxygen in the first oxidant and combusts / gasifies. During the combustion / gasification reaction, a first heat of reaction is released and thermally modified products are generated, including activated carbon and combustible gas. The first heat of reaction released by the first thermal modification change can maintain the first reaction temperature of the thermal modification change (800℃-950℃). Combustible gas with the first reaction temperature is released from the pores of the exposed carbon, opening the pores of the exposed carbon and breaking the carbon chains on the surface of the exposed carbon, thereby destroying the graphitization structure of the surface. This enables the transformation of exposed carbon with dense pores and a high degree of graphitization into activated carbon with loose pores, a large specific surface area, and a low degree of graphitization, improving the reactivity of exposed carbon and solving the problem of the difficulty in burning exposed carbon.

[0086] As for the second thermal modification, the first-size coated carbon changes from a solid state to a fluidized state under the first oxidant condition. The fluidized first-size coated carbon rubs and collides with each other in the thermal modification unit and breaks down to form second-size coated carbon. At the same time, the first-size coated carbon uses the first reaction heat released by the first thermal modification change of the exposed carbon under the first oxidant condition to heat the second-size coated carbon to the first reaction temperature, thereby improving the sensible heat capacity of the second-size coated carbon so that it can be melted and burned in the subsequent process.

[0087] Continue as Figure 2 As shown, the thermal modification outlet is connected to the molten combustion inlet of the molten combustion unit, and is used to receive the thermally modified product generated after the first modification of exposed carbon and the second-size coated carbon formed by crushing the first-size coated carbon after the second modification.

[0088] After the thermally modified product and the carbon coated with the second particle size enter the melting combustion unit, a second oxidant is introduced into the melting combustion unit through the second oxidant inlet to provide the second oxidant conditions, so that the thermally modified product and the carbon coated with the second particle size undergo a melting combustion reaction. The melting combustion reaction includes: the thermally modified product undergoing a first melting combustion reaction under the second oxidant conditions, and the carbon coated with the second particle size undergoing a second melting combustion reaction under the second oxidant conditions. The oxygen equivalent ratio of the second oxidant in the second oxidant conditions is 0.6-0.85.

[0089] The first and second melting combustion reactions occurring within the melting combustion unit are specifically manifested as follows:

[0090] Under the second oxidant conditions, the thermally modified product comes into contact with and mixes with oxygen in the second oxidant (oxygen equivalent ratio of 0.6-0.85), and then burns rapidly. The combustion is completed within a few seconds (6-60s), realizing the transformation of activated carbon in the thermally modified product into carbon dioxide. At the same time, the second reaction heat released during the melting combustion process maintains the first melting combustion reaction at the second reaction temperature (1300℃-1600℃). The second reaction temperature in the melting combustion unit can be used to melt the inorganic components present in the activated carbon to generate slag.

[0091] For the second encapsulated carbon, the first reaction heat generated by the first melting and combustion reaction of the thermally modified product under the second oxidant conditions, at 1300℃-1600℃, melts and opens the slag shell (inorganic component slag shell) on the outer surface of the second-sized encapsulated carbon, exposing the carbon encapsulated inside the inorganic component. The exposed carbon comes into contact with the second oxidant and burns at the second reaction temperature to generate carbon dioxide, while the inorganic component melts and burns to form slag, thus achieving the decarburization treatment of the encapsulated carbon.

[0092] The carbon dioxide and slag produced after the first and second melting combustion reactions are discharged from the melting combustion unit through the gas outlet and slag outlet, respectively. The discharged slag can be utilized for high value.

[0093] In embodiments of the present invention, a thermal modification unit is used to improve the reactivity of exposed carbon, solving the problem of carbon's poor reactivity in exposed carbon. Based on this, a melting combustion unit is then used to achieve rapid combustion of the thermally modified products of exposed carbon. Combustion can be organized using only simple air distribution, eliminating the need for additional burners and other structures, thus reducing the use of burners. For coated carbon, the thermal modification unit first thermally breaks down coated carbon of a first particle size into coated carbon of a second particle size. Then, the melting combustion unit uses the high temperature (above 1300°C) generated by the thermally modified products to melt and open the inorganic outer shell of the second-size coated carbon, exposing the carbon inside. The exposed carbon rapidly combusts into carbon dioxide under high-temperature conditions, solving the problem of difficult carbon removal from coated carbon. In these embodiments, the thermal modification unit and the melting combustion unit achieve rapid removal and decarbonization of exposed and coated carbon from carbon-containing solid waste. The resulting slag can be used as a high-value product, realizing the resource utilization of the inorganic components in the slag.

[0094] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for treating carbonaceous solid waste, comprising: After a first proportion of exposed carbon in carbon-containing solid waste undergoes a first thermal modification under a first oxidant condition, it generates a thermally modified product and produces a first heat of reaction. The first heat of reaction is used to maintain a first reaction temperature. The thermally modified product includes activated carbon and combustible gas. The carbon in carbon-containing solid waste with a first particle size undergoes a second thermal modification under the first reaction temperature and the first oxidant condition, and is then thermally crushed to form carbon with a second particle size. After the thermally modified product undergoes a first melting and combustion reaction under the second oxidant condition, it generates slag and carbon dioxide, and produces a second heat of reaction, which is used to maintain the second reaction temperature. After the carbon encapsulated by the second particle size undergoes a second melting and combustion reaction under the second oxidant conditions at the second reaction temperature, slag and carbon dioxide are generated. Wherein, the oxygen equivalent ratio of the first oxidant is 0.15-0.5, and the oxygen equivalent ratio of the second oxidant is 0.6-0.85; the first reaction temperature is 800℃-950℃, and the second reaction temperature is 1300℃-1600℃; The carbon-containing solid waste comes from gasification ash, carbon-containing steel slag, aluminum and graphite carbon-containing solid waste generated from aluminum smelting, and the exposed carbon refers to carbon adhering to the surface of inorganic components, while the encapsulated carbon refers to carbon being encapsulated by inorganic components.

2. The method according to claim 1, wherein: The first proportion of exposed carbon accounts for 20%-70% of the total mass of exposed carbon in the carbon-containing solid waste.

3. The method according to claim 1, wherein, The duration of the first thermal modification change of the first proportion of exposed carbon under the first oxidant conditions is 1-10 min.

4. The method according to claim 1, wherein, The duration of the first melt combustion reaction of the thermally modified product under the second oxidant condition is 6-60 seconds.

5. The method according to claim 1, wherein, The first oxidant includes at least one of the following: Air, air-rich air, or pure oxygen; The second oxidant includes at least one of the following: Air, air-rich air, or pure oxygen.

6. The method according to claim 1, wherein, The combustible gas includes at least one of hydrogen, carbon monoxide, and methane.

7. The method according to any one of claims 1-6, wherein, The carbon-containing solid waste treatment method is performed by a carbon-containing solid waste treatment device, which includes: A thermal modification unit is used to perform thermal modification changes on carbon-containing solid waste under a first oxidant condition. The thermal modification changes include: a first proportion of exposed carbon in the carbon-containing solid waste undergoes a first thermal modification change under the first oxidant condition to generate a thermally modified product and generate a first heat of reaction, which is used to maintain a first reaction temperature. The thermally modified product includes activated carbon and combustible gas. A first-size encapsulated carbon in the carbon-containing solid waste undergoes a second thermal modification change under the first oxidant condition using the first reaction temperature, and is then thermally broken down to form a second-size encapsulated carbon. A melting combustion unit, connected to the thermal modification unit, is used to receive the thermally modified product and the second-size encapsulated carbon, and to undergo a melting combustion reaction under a second oxidant condition, wherein the melting combustion reaction includes: After the thermally modified product undergoes a first melting and combustion reaction under the second oxidant condition, it generates slag and carbon dioxide, and produces a second heat of reaction, which is used to maintain the second reaction temperature. After the carbon encapsulated by the second particle size undergoes a second melting and combustion reaction under the second oxidant conditions at the second reaction temperature, slag and carbon dioxide are generated.

8. The method according to claim 7, wherein, The thermal modification unit and the melting combustion unit can be arranged as an integrated structure or as separate structures.

9. The method according to claim 8, wherein, When the thermal modification unit and the melting combustion unit are arranged in a separate structure, the thermal modification unit further includes: A first oxidant inlet is provided for supplying a first oxidant to the thermal modification unit; A fuel inlet for supplying the carbonaceous solid waste to the thermal modification unit; A thermally modified outlet is used to discharge the thermally modified product and the second-size encapsulated carbon.

10. The method according to claim 9, wherein, When the thermal modification unit and the melting combustion unit are arranged in a separate structure, the melting combustion unit further includes: The second oxidant inlet is used to supply a second oxidant to the melting combustion unit; The melting and combustion inlet is connected to the thermal modification outlet and is used to receive the thermally modified product and the second-size encapsulated carbon discharged from the thermal modification unit. A slag outlet is used to discharge the slag from the molten combustion unit; and The vent is used to discharge carbon dioxide from the molten combustion unit.

11. The method according to claim 9, wherein, The thermal modification unit includes either a fluidized bed or a flow tubular reactor.

12. The method according to claim 11, wherein, The fluidized bed is a bubbling bed.

13. The method according to claim 10, wherein, The melting and combustion unit includes any one of a fluidized bed, a rotary kiln, or a cupola furnace.

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