SDA sodium-based semi-dry desulfurization ash recycling system
By designing the SDA sodium-based semi-dry desulfurization ash recycling and reuse system, the desulfurization ash is treated with coagulant, flocculant and decolorizer to generate high-purity sodium sulfate, which solves the problem of desulfurization ash occupying space and environmental pollution, and realizes resource utilization and harmless treatment.
Patent Information
- Application Number
- CN202421651630.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-12
- Publication Date
- 2025-04-18
- Estimated Expiration
- 2034-07-12
AI Technical Summary
In the prior art, the desulfurization ash produced by the SDA sodium-based semi-dry desulfurization process lacks effective disposal means, resulting in solid waste occupying space and causing environmental pollution problems.
A SDA sodium-based semi-dry desulfurization ash recycling and reuse system was designed. The desulfurization ash was treated with coagulant, flocculant and decolorizing through spiral loading, dissolution, mixing, decomposition, etc., and the desulfurization ash was used to treat the desulfurization ash with coagulant, flocculant and decolorizing agent to generate a high-purity sodium sulfate mother liquor, and finally, the industrial sodium sulfate crystallization was obtained by evaporating the salt separation.
The harmless treatment and resource utilization of desulfurization ash has been achieved, environmental pollution has been reduced, the environmental protection burden of enterprises has been reduced, and an economical and reasonable treatment route has been provided.
Smart Images
Figure CN222766003U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the treatment of byproduct desulfurization ash in a flue gas desulfurization system, in particular to an SDA sodium-based semi-dry desulfurization ash recovery and reuse system. Background Art
[0002] At present, most of the flue gas desulfurization systems of coking enterprises in my country adopt the SDA (rotary spray drying) semi-dry desulfurization process. The flue gas of the coke oven (240-270℃) is connected to the semi-dry desulfurization tower through the flue gas pipeline. The flue gas enters the tower body from the flue gas distributor on the top of the desulfurization tower, and fully contacts with the atomized desulfurizer in the tower, and quickly completes the physical and chemical reactions (absorbing SO2 and evaporating and drying at the same time), so as to achieve the purpose of removing SO2 and other acidic media. The powdery flue gas with SO2 removed and dried leaves the desulfurization tower and enters the dust collector through the flue gas pipeline. The dry particulate matter in the flue gas is first filtered and collected by the filter bag. The dust layer filtered by the dust filter bag further removes SO2 from the flue gas, and at the same time adsorbs sticky components such as tar. After the flue gas after dust removal enters the denitrification purification and waste heat recovery, the flue gas is transported by the induced draft fan to the coke oven chimney to meet the emission standards. While desulfurizing the flue gas, a large amount of solid waste by-product - desulfurization ash is also generated. Currently, there is a lack of effective disposal methods for sodium-based desulfurization ash. Directly piling it up on site not only takes up space, but also brings a series of environmental pollution problems. Therefore, seeking an economically reasonable desulfurization ash treatment route has become an environmental problem that companies need to solve urgently.
[0003] The chemical principles of flue gas desulfurization are as follows:
[0004] Main reaction: Na2CO3+SO2+1 / 2O2=Na2SO4+CO2
[0005] Side reaction: Na2CO3+SO3=Na2SO4+CO22HCL+Na2CO3=2NaCl+CO2+H2O
[0006] According to the above reaction equation, the desulfurization ash produced by SDA sodium-based semi-dry desulfurization mainly consists of sodium sulfate, sodium chloride and unreacted sodium carbonate, etc., in addition to some insoluble substances such as coke powder and tar. Converting and purifying the valuable components in the desulfurization ash, turning waste into treasure, can eliminate environmental risks of enterprises and reduce their environmental burden. Summary of the invention
[0007] The utility model aims at the problem of how to comprehensively utilize desulfurization ash, a solid waste byproduct generated by flue gas desulfurization, and provides a SDA sodium-based semi-dry desulfurization ash recovery and reuse system.
[0008] The utility model adopts the following technical scheme: an SDA sodium-based semi-dry desulfurization ash recovery and reuse system, including a spiral feeder, a dissolving tank, a first-stage lifting pump, a feed buffer tank, a second-stage lifting pump, a mixing tank, an impurity removal tank, a decolorization sedimentation tank, a discharge tank, a discharge pump, a third-stage lifting pump, a fourth-stage lifting pump and a fifth-stage lifting pump, wherein the dissolving tank, the feed buffer tank, the mixing tank, the impurity removal tank and the discharge tank are all provided with agitators, the dissolving tank and the feed buffer tank are connected by a first-stage lifting pump and a pipeline, the feed buffer tank and the mixing tank are connected by a second-stage lifting pump and a pipeline, the mixing tank and the impurity removal tank are connected by a third-stage lifting pump and a pipeline, the impurity removal tank and the decolorization sedimentation tank are connected by a fourth-stage lifting pump and a pipeline, the decolorization sedimentation tank and the discharge tank are connected by a fifth-stage lifting pump and a pipeline, and the discharge tank is connected with a discharge pump.
[0009] The desulfurized ash is fed to the dissolving tank by a spiral feeder and dissolved with the production condensate water to form a desulfurized ash mother liquor. The first-stage lifting pump then pumps the desulfurized ash mother liquor to the feed buffer tank. After buffering, the desulfurized ash mother liquor is pumped to the mixing tank by the second-stage lifting pump. A coagulant is added to the mixing tank. The desulfurized ash mother liquor is then pumped to the impurity removal tank by the third-stage lifting pump. A flocculant is added to the impurity removal tank. The desulfurized ash mother liquor is then pumped to the decolorization sedimentation tank by the fourth-stage lifting pump. A decolorizer is added to the decolorization sedimentation tank. The desulfurized ash mother liquor is then pumped to the discharge tank by the fifth-stage lifting pump. Concentrated sulfuric acid is added to the discharge tank. After the reaction, the mother liquor in the discharge tank is a qualified mother liquor, that is, the components in the mother liquor are basically sodium sulfate, and there is a small amount of sodium chloride. Insoluble substances such as coke powder and tar are settled in the decolorization sedimentation tank after the action of coagulants and flocculants. Sodium carbonate reacts with concentrated sulfuric acid to convert into sodium sulfate. The qualified mother liquor in the discharge tank is discharged by the discharge pump, and the qualified mother liquor is sent to the phenol-cyanide wastewater concentrated water pool in the factory area, where it is evaporated, separated and crystallized to produce qualified industrial sodium sulfate. The sludge produced after sedimentation in the decolorization sedimentation tank is discharged by the sludge pump.
[0010] In the above-mentioned SDA sodium-based semi-dry desulfurization ash recovery and reuse system, a filter tube is also provided in the decolorization sedimentation tank. A filter tube is provided in the decolorization sedimentation tank, and the desulfurization ash mother liquor enters the decolorization sedimentation tank after being filtered through the filter tube.
[0011] The utility model recycling and reuse system obtains high-purity sodium sulfate mother liquor from desulfurization ash through the steps of dissolution, decolorization, purification, and impurity removal, providing support for the subsequent comprehensive resource utilization of sodium-based semi-dry desulfurization ash. Qualified high-purity sodium sulfate mother liquor can produce qualified industrial sodium sulfate products after treatment, ultimately achieving harmless treatment of SDA sodium-based semi-dry desulfurization ash. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 It is a structural schematic diagram of the utility model system.
[0013] In the figure: 1-screw feeder, 2-dissolving tank, 3-first-stage lifting pump, 4-feeding buffer tank, 5-second-stage lifting pump, 6-mixing tank, 7-impurity removal tank, 8-decolorization sedimentation tank, 9-discharging tank, 10-discharging pump, 11-third-stage lifting pump, 12-fourth-stage lifting pump, 13-fifth-stage lifting pump. DETAILED DESCRIPTION
[0014] A SDA sodium-based semi-dry desulfurization ash recovery and reuse system, comprising a spiral feeder 1, a dissolving tank 2, a primary lift pump 3, a feed buffer tank 4, a secondary lift pump 5, a mixing tank 6, a de-impurity tank 7, a decolorization sedimentation tank 8, a discharging tank 9, a discharging pump 10, a tertiary lift pump 11, a quaternary lift pump 12 and a quintuple lift pump 13, wherein the dissolving tank 2, the feed buffer tank 4, the mixing tank 6, the de-impurity tank 7 and the discharging tank 9 are all provided with a stirrer, and the dissolving tank 2 and the feed buffer tank are provided with a stirrer. 4 are connected through a first-stage lifting pump 3 and a pipeline, the feed buffer tank 4 and the mixing tank 6 are connected through a second-stage lifting pump 5 and a pipeline, the mixing tank 6 and the impurity removal tank 7 are connected through a third-stage lifting pump 11 and a pipeline, the impurity removal tank 7 and the decolorization sedimentation tank 8 are connected through a fourth-stage lifting pump 12 and a pipeline, a filter tube is also provided in the decolorization sedimentation tank 8, the decolorization sedimentation tank 8 and the discharge tank 9 are connected through a fifth-stage lifting pump 13 and a pipeline, and the discharge tank 9 is connected with a discharge pump 10.
[0015] The utility model feeds the desulfurized ash produced by the coke oven flue gas desulfurization device to the dissolving tank 2 through the spiral negative pressure pipeline of the spiral feeder 1 to dissolve with the production condensed water to dissolve into the desulfurized ash mother liquor, and the first-stage lifting pump 3 pumps the desulfurized ash mother liquor to the feeding buffer tank 4, and the desulfurized ash mother liquor is pumped to the mixing tank 6 by the second-stage lifting pump 5 after buffering, and the coagulant is added to the mixing tank 6, and the desulfurized ash mother liquor is pumped to the impurity removal tank 7 by the third-stage lifting pump 11, and the flocculant is added to the impurity removal tank 7, and the desulfurized ash mother liquor is pumped to the decolorization sedimentation tank 8 by the fourth-stage lifting pump 12, and the desulfurized ash mother liquor is decolorized. A filter tube is provided in the color precipitation tank 8. The desulfurized ash mother liquor is filtered through the filter tube and enters the decolorization precipitation tank 8. A decolorant is added to the decolorization precipitation tank 8. The desulfurized ash mother liquor is then pumped to the discharge tank 9 by the five-stage lifting pump 13. Concentrated sulfuric acid is added to the discharge tank 9. After the reaction, the mother liquor in the discharge tank 9 is a qualified mother liquor, that is, the components in the mother liquor are basically sodium sulfate, and there is a small amount of sodium chloride. The insoluble substances such as coke powder and tar are precipitated in the decolorization precipitation tank 8 after the action of coagulants and flocculants. Sodium carbonate reacts with concentrated sulfuric acid and turns into sodium sulfate. The qualified mother liquor in the discharge tank 9 is discharged by the discharge pump 10, and the qualified mother liquor produced is sent to the concentrated water pool of phenol-cyanide wastewater in the factory area, and the qualified product industrial sodium sulfate is produced by evaporation, salt separation and crystallization. The sludge produced after sedimentation in the decolorization precipitation tank 8 is discharged by the sludge pump.
[0016] Due to the different particle size distribution, hydrophilicity and charge of the insoluble matter in the desulfurization ash, the corresponding coagulation reaction mechanism is also different. The realization of solid-liquid separation involves three processes: destabilization, aggregation and sedimentation of colloidal particles. Through the action of coagulants and flocculants, the zeta potential of charged colloidal particles can be reduced or eliminated, thereby reducing the repulsive energy peak between them, exerting the attractive potential energy, promoting the aggregation between particles, and increasing their sedimentation performance; for hydrophilic organic colloids or high molecular substances, the aggregation stability between them is broken by destroying their hydration. In the utility model, the coagulant is PAC (polyaluminum chloride), the flocculant is PAM (polyacrylamide), and the decolorant is activated carbon.
[0017] The utility model can help enterprises in the power, coking, steel and other industries to effectively solve the environmental pollution problem caused by the accumulation of desulfurization ash on site through the comprehensive utilization pretreatment of SDA sodium-based semi-dry desulfurization ash resources, and has important significance for the protection of the atmospheric environment, water environment and soil environment. The phenol-cyanide wastewater treatment station in the factory and the reuse unit salt crystallization treatment device and sludge treatment device are combined to reduce engineering investment and land occupation.
Claims
1. A SDA sodium-based semi-dry desulfurization ash recovery and reuse system, characterized by: The invention comprises a screw feeder (1), a dissolving tank (2), a first-stage lifting pump (3), a feed buffer tank (4), a second-stage lifting pump (5), a mixing tank (6), a decolorizing tank (7), a decolorizing sedimentation tank (8), a discharging tank (9), a discharging pump (10), a third-stage lifting pump (11), a fourth-stage lifting pump (12) and a fifth-stage lifting pump (13), wherein the dissolving tank (2), the feed buffer tank (4), the mixing tank (6), the decolorizing tank (7) and the discharging tank (9) are all provided with a stirrer, and the dissolving tank (2) and the feed buffer tank are provided with a stirrer. (4) are connected via a first-stage lifting pump (3) and a pipeline, the feed buffer tank (4) and the mixing tank (6) are connected via a second-stage lifting pump (5) and a pipeline, the mixing tank (6) and the impurity removal tank (7) are connected via a third-stage lifting pump (11) and a pipeline, the impurity removal tank (7) and the decolorization sedimentation tank (8) are connected via a fourth-stage lifting pump (12) and a pipeline, the decolorization sedimentation tank (8) and the discharge tank (9) are connected via a fifth-stage lifting pump (13) and a pipeline, and the discharge tank (9) is connected with a discharge pump (10).
2. The SDA sodium-based semi-dry desulfurization ash recovery and reuse system according to claim 1 is characterized by: A filter tube is also provided in the decolorization sedimentation tank (8).