Semi-dry desulfurization ash recycling on-line treatment system and semi-dry desulfurization ash recycling on-line treatment method

Abstract

The invention discloses an online recycling treatment system and method for semi-dry desulfurization ash. The system at least comprises a decomposing furnace system (1), a high-temperature dust collecting system (2) and a hot material cooling system (3), wherein the decomposing furnace system (1) is used for carrying out high-temperature decomposition on desulfurized fly ash of the semi-dry desulfurization system to generate calcium oxide and sulfur dioxide enriched gas, and then sending the calcium oxide and sulfur dioxide enriched gas to the high-temperature dust collecting system (2) for separation; and the high-temperature dust collection system (2) cools the separated and collected calcium oxide through the hot material cooling system (3) and outputs the cooled calcium oxide. According to the method, the sulfur dioxide enriched gas with high added value is generated through on-line high-temperature decomposition of the semi-dry desulfurization ash, meanwhile, calcium oxide generated through decomposition serves as a desulfurizing agent to be recycled, the problem of solid waste desulfurization ash disposal of a traditional semi-dry desulfurization system is solved, and secondary pollution is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive utilization of by-products of semi-dry desulfurization, and specifically relates to an on-line disposal system and method for resource utilization of semi-dry desulfurization ash. Background Art

[0002] The combined process of semi-dry desulfurization and SCR denitrification is the mainstream technology for treating sintering and pellet flue gas in the steel industry at present, which has the advantages of high desulfurization and denitrification efficiency, relatively high flue gas discharge temperature, and no waste water generation. The process flow is as follows: flue gas to be treated → desulfurization reaction tower → bag filter → GGH heat exchanger (heating end) → flue gas heating system → SCR denitrification reactor → GGH heat exchanger (cooling end) → desulfurization and denitrification induced draft fan → chimney discharge.

[0003] Desulfurization ash is a by-product collected by the dust removal system after desulfurization in the semi-dry flue gas desulfurization process. Its components mainly include calcium sulfate (CaSO4), calcium sulfite (CaSO3), unreacted desulfurizer Ca(OH)2, etc. Among them, due to the unstable chemical properties of calcium sulfite (CaSO3), a high content of calcium sulfite (CaSO3) severely limits the comprehensive utilization of desulfurization ash, and it is generally only disposed of as solid waste, resulting in secondary pollution. At the same time, because desulfurization ash is mainly calcium-based salts with low added value, the comprehensive utilization must consider the disposal cost, and too complex disposal processes or too high energy consumption limit the popularization of the comprehensive utilization of desulfurization ash.

[0004] Patent CN114044534 B proposes a method for preparing calcium oxide by high-temperature decomposition of desulfurization ash, which uses high-temperature reduction and high-temperature oxidation methods to make desulfurization ash into CaO and SO2 products. However, its disposal process is cumbersome, the energy utilization rate is low, and the disposal cost is too high, making it difficult to promote and apply. Summary of the Invention

[0005] To overcome the above defects, the purpose of the present invention is to provide an on-line disposal system for resource utilization of semi-dry desulfurization ash while reducing disposal energy consumption and cost.

[0006] To achieve the above purpose, the on-line disposal system for resource utilization of semi-dry desulfurization ash of the present invention, the system at least includes a decomposition furnace system (1), a high-temperature dust collection system (2), a hot material cooling system (3), and a hot air heat exchange system (4);

[0007] Among them, the decomposition furnace system (1) is used to send the desulfurization ash of the semi-dry desulfurization system to the high-temperature dust collection system (2) for separation after high-temperature decomposition to generate calcium oxide and sulfur dioxide enrichment gas;

[0008] The separated calcium oxide collected by the high-temperature dust collection system (2) is output after being cooled by the hot material cooling system (3);

[0009] The described hot air heat exchange system (4) is used to heat exchange the sulfur dioxide enriched gas separated by the described high-temperature dust collection system (2); the sulfur dioxide enriched gas after heat exchange and temperature reduction is sent to the by-product preparation system, and the flue gas after heat exchange and temperature increase is sent back to the front flue of the SCR denitration reactor as a heat source for temperature increase.

[0010] Further, the calcium oxide cooled by the hot material cooling system (3) is output to the desulfurizer bin of the semi-dry desulfurization system.

[0011] Further, the cooling air of the hot material cooling system (3) is sent to the decomposition furnace system (1) as combustion-supporting air.

[0012] Further, the decomposition furnace system (1) is of the fluidized heating furnace or rotary kiln type, and the heating temperature is 800 - 1200 °C.

[0013] Further, the high-temperature dust collection system (2) is one of high-temperature ceramic filter tubes or high-efficiency cyclone dust collectors.

[0014] To achieve the above object, the semi-dry desulfurization ash resource-based online disposal method of the present invention is characterized in that the described method is completed by using the above system, and includes the following steps:

[0015] The desulfurization ash of the semi-dry desulfurization system is thermally decomposed by the decomposition furnace system (1) to generate calcium oxide and sulfur dioxide enriched gas, and is sent to the high-temperature dust collection system (2) for separation;

[0016] The calcium oxide collected by the high-temperature dust collection system (2) is cooled by the hot material cooling system (3) and then transported back to the desulfurizer bin of the semi-dry desulfurization system;

[0017] The sulfur dioxide enriched gas separated by the high-temperature dust collection system (2) is heat exchanged with a part of the flue gas led out after the dust collector of the semi-dry desulfurization system through the hot air heat exchange system (4);

[0018] The sulfur dioxide enriched gas after heat exchange and temperature reduction is sent to the by-product preparation system, and the flue gas after heat exchange and temperature increase is sent back to the front flue of the SCR denitration reactor as a heat source for temperature increase.

[0019] Further, it further includes the following steps: the cooling air of the hot material cooling system (3) is sent to the decomposition furnace system (1) as combustion-supporting air.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1), The semi-dry desulfurization ash resource-based online disposal system described in the present invention generates high-value sulfur dioxide enriched gas by online high-temperature decomposition of semi-dry desulfurization ash, and at the same time, the calcium oxide generated by decomposition is recycled as a desulfurizer, solving the problem of solid waste desulfurization ash disposal in the traditional semi-dry desulfurization system and avoiding secondary pollution.

[0022] 2), In the semi-dry desulfurized ash resource online disposal system of the present invention, the flue gas after desulfurization is heated by exchanging heat with the high-temperature enrichment gas, replacing the heating furnace required for heating in the traditional SCR denitration system, saving investment and realizing the comprehensive utilization of energy.

[0023] 3), The semi-dry desulfurized ash resource online disposal system of the present invention deeply combines the existing semi-dry desulfurization and SCR denitration processes, with little modification to the existing system, low investment and low energy consumption, and is suitable for industrialized and large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall process of the system of the present invention;

[0025] In the figure, 1 - decomposition furnace system, 2 - high-temperature dust collection system, 3 - hot material cooling system, 4 - hot air heat exchange system. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The embodiments of the present invention will be described in detail below with reference to the drawings.

[0027] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0028] The terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0029] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be directly connected, or indirectly connected through an intermediate medium, and may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0030] The present invention provides an on-line disposal system for resource utilization of semi-dry desulfurized ash. The system at least includes a decomposition furnace system (1), a high-temperature dust collection system (2), a hot material cooling system (3), and a hot air heat exchange system (4). The desulfurized ash of the semi-dry desulfurization system is thermally decomposed in the decomposition furnace system (1) to generate calcium oxide and sulfur dioxide-enriched gas, which is sent to the high-temperature dust collection system (2) for separation. The collected calcium oxide is cooled by the hot material cooling system (3) and then transported back to the desulfurizer bin of the semi-dry desulfurization system. The cooling air of the hot material cooling system (3) is sent to the decomposition furnace system (1) as combustion-supporting air. The sulfur dioxide-enriched gas separated by the high-temperature dust collection system (2) is heat-exchanged with a flue gas led out after the dust collector of the semi-dry desulfurization system through the hot air heat exchange system (4). The sulfur dioxide-enriched gas after heat exchange and temperature reduction is sent to the by-product preparation system, and the flue gas after heat exchange and temperature increase is sent back to the flue before the SCR denitration reactor as a heat source for temperature increase.

[0031] As an embodiment of the present invention, refer to Figure 1 , including a decomposition furnace system (1), a high-temperature dust collection system (2), a hot material cooling system (3), and a hot air heat exchange system (4). The desulfurized ash of the semi-dry desulfurization system is thermally decomposed in the decomposition furnace system (1) to generate calcium oxide and sulfur dioxide-enriched gas, which is sent to the high-temperature dust collection system (2) for separation. The collected calcium oxide is cooled by the hot material cooling system (3) and then transported back to the desulfurizer bin of the semi-dry desulfurization system. The cooling air of the hot material cooling system (3) is sent to the decomposition furnace system (1) as combustion-supporting air. The sulfur dioxide-enriched gas separated by the high-temperature dust collection system (2) is heat-exchanged with a flue gas led out after the dust collector of the semi-dry desulfurization system through the hot air heat exchange system (4). The sulfur dioxide-enriched gas after heat exchange and temperature reduction is sent to the by-product preparation system, and the flue gas after heat exchange and temperature increase is sent back to the flue before the SCR denitration reactor as a heat source for temperature increase.

[0032] The decomposition furnace system (1) can adopt the form of a fluidized bed heating furnace or a rotary kiln, and the heating temperature is 800 - 1200 °C.

[0033] The high-temperature dust collection system (2) can adopt one of the methods such as high-temperature ceramic filter tubes or high-efficiency cyclone dust collection.

[0034] The sulfur dioxide-enriched gas can be used as a raw material for preparing high-value-added products such as sulfuric acid, ammonium sulfate, and sulfur.

[0035] The present invention also provides an on-line disposal method for resource utilization of semi-dry desulfurized ash, as Figure 1As shown, it includes a precalciner system (1), a high-temperature dust collection system (2), a hot material cooling system (3), and a hot air heat exchange system (4). The desulfurization ash of the semi-dry desulfurization system is pyrolyzed at high temperature in the precalciner system (1) to generate calcium oxide and sulfur dioxide enriched gas, which is sent to the high-temperature dust collection system (2) for separation. The collected calcium oxide is cooled by the hot material cooling system (3) and then transported back to the desulfurizer bin of the semi-dry desulfurization system. The cooling air of the hot material cooling system (3) is sent to the precalciner system (1) as combustion-supporting air. The sulfur dioxide enriched gas separated by the high-temperature dust collection system (2) is exchanged heat with a part of the flue gas led out after the dust collector of the semi-dry desulfurization system through the hot air heat exchange system (4). The sulfur dioxide enriched gas after heat exchange and temperature reduction is sent to the by-product preparation system, and the flue gas after heat exchange and temperature increase is sent back to the flue before the SCR denitration reactor as a heat source for temperature increase.

[0036] In the description of this specification, specific features, structures, materials, or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0037] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A semi-dry desulfurized ash resource-based on-line disposal system, characterized in that: The described system at least includes a precalciner system (1), a high-temperature dust collection system (2), a hot material cooling system (3), and a hot air heat exchange system (4); Among them, the precalciner system (1) is used to send the desulfurized ash from the semi-dry flue gas desulfurization system to be decomposed at high temperature to generate calcium oxide and sulfur dioxide enriched gas, and then send it to the high-temperature dust collection system (2) for separation; The high-temperature dust collection system (2) outputs the collected calcium oxide after cooling by the hot material cooling system (3); The hot air heat exchange system (4) is used to exchange heat for the sulfur dioxide enriched gas separated by the high-temperature dust collection system (2); the sulfur dioxide enriched gas after heat exchange and temperature reduction is sent to the by-product preparation system, and the flue gas after heat exchange and temperature increase is sent back to the flue before the SCR denitration reactor as a heat source for temperature increase.

2. The semi-dry desulfurized ash resource-based online disposal system according to claim 1, characterized in that: The calcium oxide cooled by the hot material cooling system (3) is output to the desulfurizer bin of the semi-dry flue gas desulfurization system.

3. The semi-dry desulfurized ash resource-based online disposal system according to claim 1, characterized in that: The cooling air of the hot material cooling system (3) is sent to the precalciner system (1) as combustion-supporting air.

4. A semi-dry desulfurization ash resource-based online disposal system according to claim 1, characterized in that, The precalciner system (1) is of the type of fluidized bed heating furnace or rotary kiln, and the heating temperature is 800 - 1200 °C.

5. The on-line disposal system for resource utilization of semi-dry desulfurized ash according to claim 1, characterized in that, The high-temperature dust collection system (2) is one of high-temperature ceramic filter tubes or high-efficiency cyclone dust collectors.

6. An on-line disposal method for resource utilization of semi-dry desulfurized ash, characterized in that, The described method is completed by using the system as claimed in claim 1, and includes the following steps: The desulfurized ash of the semi-dry flue gas desulfurization system is decomposed at high temperature by the precalciner system (1) to generate calcium oxide and sulfur dioxide enriched gas, and is sent to the high-temperature dust collection system (2) for separation; The calcium oxide collected by the high-temperature dust collection system (2) is cooled by the hot material cooling system (3) and then transported back to the desulfurizer bin of the semi-dry flue gas desulfurization system; The sulfur dioxide enriched gas separated by the high-temperature dust collection system (2) is exchanged heat with a part of the flue gas led out after the dust collector of the semi-dry flue gas desulfurization system through the hot air heat exchange system (4); The sulfur dioxide enriched gas after heat exchange and temperature reduction is sent to the by-product preparation system, and the flue gas after heat exchange and temperature increase is sent back to the flue before the SCR denitration reactor as a heat source for temperature increase.

7. A semi-dry desulfurized ash resource-based online disposal method as described in claim 6, characterized in that, It further includes the following steps: The cooling air of the hot material cooling system (3) is sent to the precalciner system (1) as combustion-supporting air.

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