High-efficiency desulfurization process for reducing use amount of high-calcium desulfurization agent

Abstract

The invention belongs to the technical field of desulfurization, and particularly relates to an efficient desulfurization process for reducing the use amount of a high-calcium-method desulfurizer. Which comprises a high-calcium method flue gas desulfurization system and a CFB flue gas desulfurization system, and comprises the steps of high-calcium method flue gas desulfurization system desulfurization ash, high-calcium method flue gas desulfurization system circulation ash, CFB flue gas desulfurization system reutilization and CFB flue gas desulfurization system desulfurization waste ash outsourcing treatment. A cross-process circulation path from high-calcium flue gas desulfurization ash to CFB flue gas desulfurization system reutilization is provided for the first time. Analysis finds that the activity of the residual desulfurizer in the high-calcium flue gas desulfurization ash is high (the content of effective calcium hydroxide is high), the residual desulfurizer is used as an auxiliary desulfurizer of a CFB flue gas desulfurization system, an in-plant two-stage circulation system is formed, and the traditional mode that waste ash is directly discarded in a single process is broken through.

Description

Technical Field

[0001] The invention belongs to the technical field of desulfurization, and in particular relates to a high-efficiency desulfurization process that reduces the usage of a high-calcium desulfurizer. Background Art

[0002] With the continuous advancement of industrialization, the steel industry has carried out large-scale new construction and renovation of ultra-low emission treatment facilities in recent years to promote energy conservation and carbon reduction. Currently, desulfurization processes for flue gas treatment in the steel industry are mainly divided into wet, semi-dry, and dry methods. Among them, high-calcium desulfurization in dry desulfurization uses highly active calcium hydroxide (Ca(OH)2) as a desulfurizer. In the dry desulfurization system, it reacts with SO2 in the flue gas to produce solid products such as calcium sulfite (CaSO3) and calcium sulfate (CaSO4). The basic reaction is: Ca(OH)2 + SO2 → CaSO3 + H2O 2CaSO3 + O2 → 2CaSO4 This method is widely used for flue gas treatment in small and medium-sized boilers due to its simple operation, low investment, and zero wastewater discharge. This method overcomes the difficult byproduct disposal drawbacks of sodium-based desulfurization methods and is suitable for a wider desulfurization temperature range. However, it suffers from low desulfurizer utilization efficiency and high desulfurization byproduct production. Under normal operating conditions, the desulfurizer utilization rate in high-calcium desulfurization methods is 30%. Unreacted desulfurizer remains after the reaction, reacting with pollutants in the flue gas and producing desulfurization ash. Disposal of desulfurization ash as solid waste is difficult, resulting in wasted desulfurizer and a large amount of desulfurization ash to be disposed of, leading to high operating costs. According to incomplete statistics, domestic production of dry desulfurization ash exceeded 10 million tons in 2017, and desulfurization ash production is expected to increase significantly in the future. Therefore, it is crucial to further explore methods for utilizing ultra-low-activity desulfurization ash and disposing of waste ash for use in other production industries to broaden the resource utilization of dry desulfurization ash.

[0003] To solve the above problems, the present application proposes a high-efficiency desulfurization process that reduces the amount of high-calcium desulfurizer used. Summary of the Invention

[0004] The present invention proposes an efficient desulfurization process that reduces the usage of high-calcium desulfurizer, realizes resource recycling of desulfurization ash in the plant, effectively utilizes the desulfurizer, and reduces outsourcing disposal costs.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A high-efficiency desulfurization process that reduces the use of high-calcium desulfurizer includes a high-calcium flue gas desulfurization system and a CFB flue gas desulfurization system. The steps include: desulfurization ash from the high-calcium flue gas desulfurization system → recycling ash from the high-calcium flue gas desulfurization system → reuse in the CFB flue gas desulfurization system → outsourcing the desulfurization waste ash from the CFB flue gas desulfurization system for disposal.

[0006] As a preferred embodiment, the high calcium flue gas desulfurization system includes a No. 1 desulfurization tower, a No. 1 waste ash bin, a No. 2 desulfurization tower, and a No. 2 waste ash bin. A waste ash discharge port and a discharge pipeline are provided on the side of the conical hopper of the No. 1 waste ash bin. A No. 1 manual plug-in valve, a No. 1 observation port, and a No. 1 variable frequency star feeder are provided on the discharge pipeline. The waste ash from the No. 1 waste ash bin enters the No. 1 waste ash circulation pneumatic conveying pipeline through the No. 1 plug-in valve and the No. 1 variable frequency star feeder, and is transported to the No. 1 desulfurization tower for circulation desulfurization. A waste ash discharge port and a discharge pipeline are arranged on the side of the cone hopper of the No. 2 waste ash silo. The discharge pipeline is provided with a No. 2 manual plug-in valve, a No. 2 observation port and a No. 2 variable frequency star feeder. The waste ash from the No. 2 waste ash silo enters the No. 2 waste ash circulating pneumatic conveying pipeline through the No. 2 plug-in valve and the No. 2 variable frequency star feeder and is transported to the No. 2 desulfurization tower for circulating desulfurization. The waste ash in the No. 1 waste ash silo comes from the No. 1 desulfurization and dust removal system, and the waste ash in the No. 2 waste ash silo comes from the No. 2 desulfurization and dust removal system.

[0007] Preferably, valve No. 3 and valve No. 4 are provided on the pneumatic conveying pipeline to control the direction of pneumatic conveying. When valve No. 3 is opened and valve No. 4 is closed, pneumatic conveying is provided to the No. 1 desulfurization waste ash circulation. When valve No. 3 is closed and valve No. 4 is opened, pneumatic conveying is provided to the No. 2 desulfurization waste ash circulation.

[0008] Preferably, the pneumatic conveying pipeline is connected to the Roots blower outlet pneumatic conveying pipeline, and the Roots blower of the standby feeding system in the high calcium flue gas desulfurization system is used as the air supply device for waste ash conveying. There are No. 1 shut-off valve and No. 2 shut-off valve on the Roots blower outlet pneumatic conveying pipeline to control the direction of pneumatic conveying. When the No. 1 shut-off valve is opened and the No. 2 shut-off valve is closed, pneumatic conveying is provided to the standby feeding system. When the No. 1 shut-off valve is closed and the No. 2 shut-off valve is opened, pneumatic conveying is provided to the waste ash circulation system.

[0009] Preferably, the CFB flue gas desulfurization system includes a CFB desulfurization tower and a CFB dust collector. The waste ash in the No. 1 waste ash bin and the No. 2 waste ash bin is discharged into the transfer vehicle through the bottom ash discharge port. The transfer vehicle transfers the waste ash to the CFB flue gas desulfurization system and transports it to the CFB desulfurization tower through the conveying device to participate in the desulfurization reaction.

[0010] Among them, the by-products after the reaction in the CFB desulfurization tower enter the CFB dust collector with the flue gas, and after separation by the bag dust collector, enter the bottom chute and re-enter the CFB flue gas desulfurization system for recycling. The final product with lower activity is transported to the CFB waste ash bin through the ash conveying system and is outsourced for disposal as the final desulfurization waste ash.

[0011] As a preferred method, the activity of waste ash is released in stages according to different process characteristics: a circulation device is added to the high-calcium flue gas desulfurization system to activate the residual activity of waste ash for secondary desulfurization by extending the residence time (controlling the bag differential pressure to 800-1200Pa) and increasing the flue gas temperature (90℃→100℃); low-activity waste ash is transferred to the CFB flue gas desulfurization system, and the strong turbulent environment of the fluidized bed is used to fully tap the remaining reaction potential, thereby realizing "step-by-step extraction" of waste ash activity.

[0012] Among them, the waste ash circulation volume (2h / d→20h / d) and the dust removal blowing frequency are dynamically adjusted to establish the optimal operating window for the synergistic desulfurization of "desulfurizer + circulating ash".

[0013] The present invention has the following advantages: 1. Innovation of multi-level recycling model This is the first time a cross-process recycling pathway has been proposed: "reuse of high-calcium FGD ash in the CFB FGD system." Analysis revealed that the residual desulfurizer in high-calcium FGD ash is highly active (high in effective calcium hydroxide). This ash can be used as a supplementary desulfurizer in the CFB FGD system, forming a "two-stage in-plant recycling" system and breaking away from the traditional practice of directly discarding waste ash from a single process.

[0014] 2. Waste ash active gradient activation technology The activity of waste ash is released in stages according to different process characteristics: a circulation device is added to the high-calcium flue gas desulfurization system to activate the residual activity of the waste ash for secondary desulfurization by extending the residence time (controlling the bag differential pressure to 800-1200Pa) and increasing the flue gas temperature (90℃→100℃); the low-activity waste ash is transferred to the CFB flue gas desulfurization system, and the strong turbulent environment of the fluidized bed is used to fully tap the remaining reaction potential, thereby achieving "tiered extraction" of waste ash activity.

[0015] 3. System collaborative optimization and innovation 3.1. Thermal synergy: coordinate with upstream units to increase the inlet flue gas temperature and optimize the thermal activation conditions of the desulfurizer; 3.2. Operational coordination: Dynamically adjust the waste ash circulation volume (2h / d → 20h / d) and the frequency of dust removal injection to establish the optimal operating window for the coordinated desulfurization of "desulfurizer + circulating ash"; 3.3. Solid waste conversion: The desulfurization ash from the high calcium flue gas desulfurization system is converted from terminal solid waste to CFB flue gas desulfurization raw material, reducing 33.68 tons / year of final solid waste.

[0016] 4. Closed-loop control of resources and costs Building a "closed loop of calcium resources": The high-calcium powder saved by the high-calcium flue gas desulfurization system (760 tons / year) and the quicklime saved by the CFB flue gas desulfurization system (258.89 tons / year) form a synergistic energy-saving mechanism, while reducing the amount of waste ash disposal and achieving a dual reduction in materials and costs (annual comprehensive cost reduction of 2.4192 million yuan).

[0017] Through process coupling and system optimization, desulfurization waste ash is transformed from a "processing burden" to an "alternative resource", creating a new resource utilization paradigm of "graded circulation-cross-system utilization-calcium resource closed loop" for dry desulfurization waste ash. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a process flow chart of the present invention; Figure 2 This is a schematic structural diagram of the high calcium flue gas desulfurization system of the present invention; Figure 3 This is a schematic structural diagram of the CFB flue gas desulfurization system of the present invention.

[0019] In the figure, 1-No. 1 desulfurization tower; 2-No. 1 waste ash silo; 3-No. 2 waste ash silo; 4-No. 2 desulfurization tower; 5-No. 1 manual plug-in valve; 6-No. 1 variable frequency star feeder; 7-No. 2 manual plug-in valve; 8-No. 2 variable frequency star feeder cabin; 9-No. 3 valve; 10-No. 4 valve; 11-No. 1 shut-off valve; 12-No. 2 shut-off valve; 13-CFB desulfurization tower; 14-CFB dust collector. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of the present invention more clearly apparent, the present invention will be described in further detail below with reference to the accompanying drawings. It is hereby stated that any directional terms such as "up," "down," "left," "right," "front," "back," "inside," and "outside" that appear or will appear herein are based solely on the accompanying drawings and are not intended to limit the present invention.

[0021] Example 1 like Figure 1 and Figure 2As shown, the high calcium flue gas desulfurization system of the present application includes a No. 1 desulfurization tower 1, a No. 1 waste ash bin 2, a No. 2 waste ash bin 3, and a No. 2 desulfurization tower 4. A waste ash discharge port and a discharge pipeline are provided on the side of the cone bucket of the No. 1 waste ash bin 2. A No. 1 manual plug-in valve 5, a No. 1 observation port, and a No. 1 variable frequency star feeder 6 are provided on the discharge pipeline; the waste ash from the No. 1 waste ash bin 2 enters the No. 1 waste ash circulation pneumatic conveying pipeline through the No. 1 plug-in valve 5 and the No. 1 variable frequency star feeder 6, and is transported to the No. 1 desulfurization tower 1 for circulation desulfurization. Sulfur; a waste ash discharge port and a discharge pipeline are provided on the side of the cone hopper of the No. 2 waste ash silo 3, and a No. 2 manual plug-in valve 7, a No. 2 observation port, and a No. 2 variable frequency star feeder 8 are provided on the discharge pipeline; the waste ash in the No. 2 waste ash silo 3 enters the No. 2 waste ash circulation pneumatic conveying pipeline through the No. 2 plug-in valve 7 and the No. 2 variable frequency star feeder 8, and is transported to the No. 2 desulfurization tower 4 for circulating desulfurization; the waste ash in the No. 1 waste ash silo 2 comes from the No. 1 desulfurization and dust removal system, and the waste ash in the No. 2 waste ash silo 3 comes from the No. 2 desulfurization and dust removal system.

[0022] Among them, there are valve No. 3 9 and valve No. 4 10 on the pneumatic conveying pipeline to control the direction of pneumatic conveying. When valve No. 3 9 is opened and valve No. 4 10 is closed, pneumatic conveying is provided to the No. 1 desulfurization waste ash circulation; when valve No. 3 9 is closed and valve No. 4 10 is opened, pneumatic conveying is provided to the No. 2 desulfurization waste ash circulation.

[0023] Among them, the pneumatic conveying pipeline is connected to the Roots blower outlet pneumatic conveying pipeline, and the Roots blower of the standby feeding system in the high calcium flue gas desulfurization system is used as the air supply device for waste ash transportation. There are No. 1 shut-off valve 11 and No. 2 shut-off valve 12 on the Roots blower outlet pneumatic conveying pipeline to control the direction of pneumatic conveying. When the No. 1 shut-off valve 11 is opened and the No. 2 shut-off valve 12 is closed, pneumatic conveying is provided to the standby feeding system. When the No. 1 shut-off valve 11 is closed and the No. 2 shut-off valve 12 is opened, pneumatic conveying is provided to the waste ash circulation system.

[0024] Example 2 like Figure 1 and Figure 3 As shown, the CFB flue gas desulfurization system includes a CFB desulfurization tower 13 and a CFB dust collector 14. The waste ash in the No. 1 waste ash bin 2 and the No. 2 waste ash bin 3 is discharged to the transfer vehicle through the bottom ash discharge port. The transfer vehicle transfers the waste ash to the CFB flue gas desulfurization system and is transported to the CFB desulfurization tower 13 through a conveying device to participate in the desulfurization reaction. Among them, the by-products after the reaction in the CFB desulfurization tower 13 enter the CFB dust collector 14 with the flue gas, and after separation by the bag dust collector, enter the bottom chute and re-enter the CBF desulfurization system for recycling. Finally, the products with lower activity are transported to the CFB waste ash bin through the ash conveying system and are outsourced for disposal as the final desulfurization waste ash.

[0025] Example 3 like Figure 3As shown, the present invention is applied to a specific embodiment. On April 19, 2024, a high-calcium flue gas desulfurization project of an environmental protection company was put into trial operation. At the initial start-up, problems such as high desulfurization agent usage and low utilization rate were shown; waste ash still contained high activity, large amounts of solid waste were generated, and treatment was difficult. The reasons were analyzed as follows: 1. The inlet flue gas temperature is low, which is not conducive to the volume expansion of the desulfurizer and reduces the desulfurization efficiency; 2. The contact time between the desulfurizer and the flue gas is short, the reaction is not sufficient, and the activity cannot be released; 3. Waste ash is not fully utilized, resulting in large amounts of solid waste and difficulty in treatment.

[0026] To address this situation, we need to find ways to reduce material consumption, conserve resources, improve desulfurizer utilization, and rationally utilize waste ash activity. Based on the fact that the desulfurizers in the CFB flue gas desulfurization system and the high-calcium flue gas desulfurization system are essentially the same, and by analyzing and comparing the reaction efficiencies of high-calcium flue gas desulfurization and CFB flue gas desulfurization, as well as the residual desulfurizer active ingredient content in the generated waste ash, we found that a model of high-calcium flue gas desulfurization system ash circulation + CFB flue gas desulfurization recirculation can be formed to solve the problem. Therefore, the following production process improvements were made: 1. Technical transformation 1.1. Add a desulfurization ash circulation device to re-desulfurize the desulfurization ash with high activity after desulfurization, fully release and utilize the activity of the desulfurization ash, convert the original solid waste into an auxiliary desulfurization agent, and reduce the discharge and treatment volume of solid waste; 1.2. Gradually increase the desulfurization ash circulation volume and circulation time to explore the best desulfurization mode with desulfurizer + circulating ash. The desulfurization ash circulation start time is increased from the initial 2 hours / day to 20 hours / day, and the desulfurization ash activity test is carried out in a timely manner.

[0027] 2. Operation control: 2.1. Negotiate with upstream units to increase the inlet flue gas temperature (from 90°C to above 100°C) so that the desulfurizer can be better thermally activated in a high-temperature environment, increase the surface area, and achieve better desulfurization effect.

[0028] 2.2. By controlling the spraying frequency in each chamber of the dust collector, the differential pressure of the dust collector bag is maintained at 800-1200Pa, the residence time of the desulfurizer + circulating ash in the bag is prolonged, and the flue gas is subjected to secondary desulfurization in the process of passing through the dust collector, thereby reducing the consumption of desulfurizer and the amount of solid waste generated.

[0029] 2.3. The low-activity circulating ash produced in the high-calcium flue gas desulfurization process is used in the CFB flue gas desulfurization system as an auxiliary desulfurizer again. After the activity is fully utilized by the circulating fluidized bed desulfurization, it is outsourced for disposal as the final solid waste.

[0030] Through the above improvements, the following results can be achieved: 1. Improved flue gas desulfurization efficiency using high calcium method (data indicators are derived from laboratory testing of the calcium hydroxide content in incoming high calcium powder and desulfurization ash, which increased from 30% to 50%) 2. The high calcium flue gas desulfurization method reduces the consumption of high calcium powder and the purchase cost of desulfurizer.

[0031] It is known that the consumption of high calcium powder in 2024 is 1900t Effective desulfurization agent content of high calcium powder entering the site: 1900t×0.9=1710t When the utilization rate is 30%, the actual consumption of high calcium powder is: 1710t×0.3=513t That is, the actual effective use of high calcium powder for reaction in 2024 is 513t Derivation: When the utilization rate is 50%, the actual consumption of high calcium powder is: 513 / 0.5=1026t Combined with 90% high calcium powder When the utilization rate is 50%, the annual storage volume of high calcium powder is: 1026 / 0.9=1140t Therefore, the annual saving of high calcium powder storage volume is: 1900-1140=760t Annual cost savings: 2950×760=2242000 yuan 3. Reduce the purchase cost of quicklime for CFB flue gas desulfurization After the high calcium flue gas desulfurization ash is recycled and mixed with CFB flue gas desulfurization, the desulfurizer activity utilization is calculated as 30%, and the theoretical effective calcium hydroxide amount that can be provided is: 1026×0.3=308t 308t calcium hydroxide converted to required CaO: 308×(56 / 74)=233t Assuming the CaO content in the quicklime for CFB flue gas desulfurization is 90%, the amount of quicklime required is: 233 / 0.9=258.89t Reduce procurement costs: 258.89 × 530 = 137,211.7 yuan 4. Save desulfurization ash disposal costs ① When the original high calcium method flue gas desulfurization reaction efficiency is 30%, 513 tons of calcium hydroxide reacts and the amount of calcium sulfate produced is: (136 / 74) × 513 = 942.81 tons Desulfurization ash production: 1900-513+942.81=2329.81t Disposal cost calculated based on a unit price of RMB 120 per ton: 2329.81 × 120 = RMB 279,577.2 ② When the reaction efficiency of high-calcium flue gas desulfurization is 50%, the high-calcium flue gas desulfurization circulating desulfurization ash is used in CFB flue gas desulfurization and mixed desulfurization, resulting in an increase in CFB flue gas desulfurization ash. It is known that at this time, 1140t of high-calcium powder is stored, and 513t of high-calcium powder is used for high-calcium flue gas desulfurization. The amount of product after the reaction of this part of high-calcium powder is: (136 / 74)×513=943.92t.

[0032] The amount of waste ash from high-calcium flue gas desulfurization is: 1140-513+943.92=1570.92t.

[0033] In CFB flue gas desulfurization, 30% of the active ingredients can be utilized: 1026×0.3=307.8t.

[0034] The amount of this part converted into calcium sulfate: (136 / 74)×307.8=565.69t.

[0035] After the high calcium flue gas desulfurization ash is recycled in the CFB flue gas desulfurization cycle, the total amount of desulfurization ash produced is: 1570.92-307.8+565.69=1828.81t.

[0036] Under the original flue gas volume conditions, CFB flue gas desulfurization does not use high-calcium flue gas desulfurization ash, and uses the same 307.8t of calcium hydroxide. The required amount of calcium oxide is: (56 / 74)×307.8=232.93t.

[0037] To meet the demand for this part of calcium oxide, the amount of quicklime that needs to be purchased is 232.93 / 0.9=258.81t.

[0038] The amount of waste ash generated for disposal by this procurement department is: 258.81-232.93+565.69=591.57t.

[0039] The increase in CFB flue gas desulfurization ash caused by mixed desulfurization is: 1828.81-591.57=1237.24.

[0040] In summary, after waste ash resource utilization, the total annual waste ash reduction is: 1570.92-1237.24=333.68t Savings on desulfurization ash disposal costs: 120×333.68 yuan = 40041.6 yuan.

[0041] Ultimately, the following economic benefits and production improvements can be achieved: 1. The high calcium flue gas desulfurization efficiency and the reaction utilization rate of the desulfurizer are increased from 30% to 50%.

[0042] 2. The original flue gas flow rate of the high-calcium flue gas desulfurization system is 450,000 Nm³ / h, the SO2 inlet concentration is 90 mg / Nm³, and the SO2 outlet concentration is <35 mg / Nm³. Under the same original flue gas conditions, the desulfurizer consumption is reduced by 760t / a, and the high-calcium powder procurement cost is reduced by RMB 2.242 million / a.

[0043] 3. High-calcium flue gas desulfurization ash is transported to the CFB flue gas desulfurization system, where it is mixed with the CFB flue gas desulfurizer and recycled. Under the same flue gas flow rate of 550,000 Nm³ / h and SO₂ concentration of 800 mg / Nm³, the CFB flue gas desulfurization system reduces quicklime consumption by 258.89 tons / year, reducing quicklime procurement costs by 137,200 yuan / year.

[0044] 4. The original high-calcium flue gas desulfurization ash production was 2,330.92 t / a, and the CFB flue gas desulfurization ash production was 10,800 t / a. After the high-calcium flue gas desulfurization ash was transported to the CFB flue gas desulfurization for recycling, the amount of high-calcium flue gas desulfurization ash and CFB flue gas desulfurization ash reduced by 333.68 t / a. The unit price of desulfurization ash disposal was 120 yuan / ton, reducing the desulfurization ash disposal cost by 40,000 yuan / a.

[0045] 5. The comprehensive benefits of the project implementation will reduce the operating costs by RMB 2.4192 million per year.

[0046] 4. Operation effect comparison: Through this method, the following results were achieved: 1. The reaction utilization rate of desulfurizer in high calcium flue gas desulfurization system is increased from 30% to 50%.

[0047] 2. The original flue gas flow rate of the high-calcium flue gas desulfurization system is 450,000 Nm³ / h, the SO2 inlet concentration is 90 mg / Nm³, and the SO2 outlet concentration is <35 mg / Nm³. Under the same original flue gas conditions, the desulfurizer consumption is reduced by 760 tons / a, and the high-calcium powder procurement cost is reduced by RMB 2.242 million / a.

[0048] 3. High-calcium flue gas desulfurization ash is transported to the CFB flue gas desulfurization system, where it is mixed with the CFB flue gas desulfurizer and recycled. Under the same flue gas flow rate of 550,000 Nm³ / h and SO₂ concentration of 800 mg / Nm³, the CFB flue gas desulfurization system reduces quicklime consumption by 258.89 tons / year, reducing quicklime procurement costs by 137,200 yuan / year.

[0049] 4. The original high-calcium flue gas desulfurization ash production was 2,330.92 tons / a, and the CFB flue gas desulfurization ash production was 10,800 tons / a. After the high-calcium flue gas desulfurization ash was transported to the CFB flue gas desulfurization recycling, the high-calcium flue gas desulfurization ash and CFB flue gas desulfurization ash were reduced by 333.68 tons / a. The unit price of desulfurization ash disposal was 120 yuan / ton, reducing the desulfurization ash disposal cost by 40,000 yuan / a.

[0050] 5. The comprehensive benefits of the project implementation will reduce the operating costs by RMB 2.4192 million per year.

[0051] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An efficient desulfurization process for reducing the amount of high-calcium desulfurizer used, characterized by: It includes a high-calcium flue gas desulfurization system and a CFB flue gas desulfurization system. The steps include desulfurization ash from the high-calcium flue gas desulfurization system → recycling ash from the high-calcium flue gas desulfurization system → reuse in the CFB flue gas desulfurization system → outsourcing of desulfurization waste ash from the CFB flue gas desulfurization system for disposal.

2. The high-efficiency desulfurization process for reducing the amount of high-calcium desulfurizer used according to claim 1, characterized in that: The high calcium flue gas desulfurization system comprises a No. 1 desulfurization tower (1), a No. 1 waste ash bin (2), a No. 2 waste ash bin (3), and a No. 2 desulfurization tower (4). A waste ash discharge port and a discharge pipeline are provided on the side of the cone hopper of the No. 1 waste ash bin (2). A No. 1 manual plug valve (5), a No. 1 observation port, and a No. 1 variable frequency star feeder (6) are provided on the discharge pipeline. The waste ash in the No. 1 waste ash bin (2) enters the No. 1 waste ash circulation pneumatic conveying pipeline through the No. 1 plug valve (5) and the No. 1 variable frequency star feeder (6), and is transported to the No. 1 desulfurization tower (1) for circulation desulfurization. A waste ash discharge port and a discharge pipeline are provided on the side of the cone hopper of the No. 2 waste ash bin (3), and a No. 2 manual plug-in valve (7), a No. 2 observation port, and a No. 2 variable frequency star feeder (8) are provided on the discharge pipeline; the waste ash in the No. 2 waste ash bin (3) enters the No. 2 waste ash circulation pneumatic conveying pipeline through the No. 2 plug-in valve (7) and the No. 2 variable frequency star feeder (8), and is transported to the No. 2 desulfurization tower (4) for circulation desulfurization; the waste ash in the No. 1 waste ash bin (2) comes from the No. 1 desulfurization and dust removal system, and the waste ash in the No. 2 waste ash bin (3) comes from the No. 2 desulfurization and dust removal system.

3. The high-efficiency desulfurization process for reducing the usage of high-calcium desulfurizer according to claim 2, characterized in that: There are valve No. 3 (9) and valve No. 4 (10) on the pneumatic conveying pipeline to control the direction of pneumatic conveying. When valve No. 3 (9) is opened and valve No. 4 (10) is closed, pneumatic conveying is provided to the No. 1 desulfurization waste ash circulation. When valve No. 3 (9) is closed and valve No. 4 (10) is opened, pneumatic conveying is provided to the No. 2 desulfurization waste ash circulation.

4. The high-efficiency desulfurization process for reducing the usage of high-calcium desulfurizer according to claim 2, characterized in that: The pneumatic conveying pipeline is connected to the Roots blower outlet pneumatic conveying pipeline, and the Roots blower of the standby feeding system of the high calcium flue gas desulfurization system is used as the air supply device for conveying the desulfurization ash. A No. 1 shut-off valve (11) and a No. 2 shut-off valve (12) are provided on the Roots blower outlet pneumatic conveying pipeline to control the direction of the pneumatic conveying. When the No. 1 shut-off valve (11) is opened and the No. 2 shut-off valve (12) is closed, pneumatic conveying is provided to the standby feeding system. When the No. 1 shut-off valve (11) is closed and the No. 2 shut-off valve (12) is opened, pneumatic conveying is provided to the waste ash circulation system.

5. The high-efficiency desulfurization process for reducing the usage of high-calcium desulfurizer according to claim 2, characterized in that: The CFB flue gas desulfurization system includes a CFB desulfurization tower (13) and a CFB dust collector (14). The waste ash in the No. 1 waste ash bin (2) and the No. 2 waste ash bin (3) is discharged to a transfer vehicle through the bottom ash discharge port. The transfer vehicle transfers the waste ash to the CFB flue gas desulfurization system and transports it to the CFB desulfurization tower (13) through a conveying device to participate in the desulfurization reaction.

6. The high-efficiency desulfurization process for reducing the usage of high-calcium desulfurizer according to claim 2, characterized in that: The by-products after the reaction in the CFB desulfurization tower (13) enter the CFB dust collector (14) along with the flue gas, are separated by the bag filter, enter the bottom chute and re-enter the CBF desulfurization system for recycling. The final product with low activity is transported to the CFB waste ash bin through the ash conveying system and is disposed of externally as the final desulfurization waste ash.

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