A boiler flue gas desulfurization system

Abstract

The utility model discloses a kind of boiler flue gas desulfurization systems, including desulfurizer preparation device, its inlet is connected with salt mud discharge pipe and water supply pipe respectively, the slurry outlet of desulfurizer preparation device is connected to the lower part of absorption tower, for forming slurry pool in the lower part of absorption tower, slurry pool is connected with the liquid inlet end of first spraying mechanism by circulating pump, first spraying mechanism is arranged in the upper portion of absorption tower inner cavity;The flue gas inlet of absorption tower lower part is connected with boiler flue gas discharge line;The waste slurry discharge port of absorption tower bottom is connected with the import end of filter press device, the filtrate discharge port of filter press device is connected with the water supply pipe.The utility model can recycle and utilize the salt mud solid waste produced by alkali production system to realize the desulfurization of boiler flue gas.

Description

Technical Field

[0001] This utility model relates to the technical field of flue gas treatment equipment, and in particular to a boiler flue gas desulfurization system. Background Technology

[0002] In industrial alkali production systems, ammonia stripping towers require boilers to stably supply steam. Boiler combustion emits a large amount of exhaust gas, which contains sulfides. Direct emission of this gas will pollute the environment. Desulfurizing agents are usually prepared by purchasing limestone. However, limestone needs to be ground before use, and the amount of fresh water used is large, and wastewater requires additional treatment, resulting in high desulfurization costs for boiler flue gas. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, this utility model provides a boiler flue gas desulfurization system that can recycle and utilize the salt mud solid waste produced by the alkali production system to achieve desulfurization of boiler flue gas.

[0004] Technical Solution: To achieve the above objectives, this utility model provides a boiler flue gas desulfurization system, including a desulfurizing agent preparation device. The inlet of the desulfurizing agent preparation device is connected to a salt mud discharge pipe and a water supply pipe. The slurry outlet of the desulfurizing agent preparation device is connected to the lower part of the absorption tower to form a slurry pool at the lower part of the absorption tower. The slurry pool is connected to the inlet of a first spraying mechanism via a circulating pump. The first spraying mechanism is located in the upper part of the inner cavity of the absorption tower. The flue gas inlet at the lower part of the absorption tower is connected to the boiler flue gas discharge pipe. The waste slurry discharge port at the bottom of the absorption tower is connected to the inlet of a filter press device, and the filtrate discharge port of the filter press device is connected to the water supply pipe.

[0005] Furthermore, the flue gas inlet is located above the slurry tank, and an air inlet is provided at the bottom of the slurry tank. The air inlet is connected to the oxidation air system, which can form an oxidation zone in the upper middle part of the slurry tank.

[0006] Furthermore, the oxidation zone is equipped with multiple stirrers.

[0007] Furthermore, multiple first spray mechanisms are arranged longitudinally to form a longitudinal multi-level spray layer on the upper part of the absorption tower.

[0008] Furthermore, each of the first spray units is connected to the slurry pool at the bottom of the absorption tower via a separate circulating pump.

[0009] Furthermore, a second spraying mechanism is provided above the plurality of first spraying mechanisms, and the water inlet end of the second spraying mechanism is connected to the water supply pipe.

[0010] Furthermore, a defogging module is provided above the second spraying mechanism.

[0011] Furthermore, the demisting module is equipped with a rinsing mechanism, the water inlet of which is connected to the water supply pipe via a suction pump, and the slurry tank is equipped with a liquid level measuring device, which is electrically connected to the suction pump via a controller.

[0012] Beneficial Effects: This utility model discloses a boiler flue gas desulfurization system that utilizes salt mud solid waste from brine refining within the original alkali production system as raw material, and uses the original salt mud discharge filtration system as the treatment system for waste slurry after flue gas desulfurization. This not only reduces raw material costs but also eliminates the need for additional waste residue treatment equipment. The salt mud does not require grinding, reducing the cost of desulfurizing agent preparation, and the amount of fresh water used is also reduced. The waste liquid generated after waste residue filtration can be directly recycled, significantly reducing fresh water consumption. Overall, this system achieves the reuse of salt mud solid waste in boiler flue gas desulfurization, generating significant economic benefits. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of one embodiment of the boiler flue gas desulfurization system of this utility model. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings.

[0015] As attached Figure 1 The boiler flue gas desulfurization system includes a desulfurizing agent preparation device 1, whose inlet is connected to a salt mud discharge pipe 2 and a water supply pipe 3. The slurry outlet of the desulfurizing agent preparation device 1 is connected to the lower part of an absorption tower 5 to form a slurry pool 51 in the lower part of the absorption tower 5. The slurry pool 51 is connected to the liquid inlet of a first spraying mechanism 4 via a circulating pump. The first spraying mechanism 4 is arranged in the upper part of the inner cavity of the absorption tower 5. The flue gas inlet 52 at the lower part of the absorption tower 5 is connected to a boiler flue gas discharge pipe 6. The waste slurry discharge outlet at the bottom of the absorption tower 5 is connected to the inlet of a filter press 7. The filtrate discharge outlet of the filter press 7 is connected to the water supply pipe 3.

[0016] In industrial alkali production, the refining process of brine generates a large amount of salt mud solid waste, which is rich in calcium-based compounds. This salt mud solid waste is usually directly discharged into the supporting filter press system as waste residue. This solution recycles and utilizes the salt mud as a raw material for desulfurizing agents. Compared to limestone, its particles are finer and do not require grinding. Furthermore, it already contains a certain amount of moisture, resulting in relatively less fresh water consumption. This reduces energy and material consumption in the preparation of the desulfurizing agent, lowers the amount of fresh water used, and thus reduces costs.

[0017] The desulfurizing agent preparation device 1 employs a stirring device. By adding salt mud and an appropriate amount of water, the salt mud is diluted and stirred evenly to form a slurry, which can then be sprayed onto the sulfur-containing flue gas, thereby improving desulfurization efficiency. In this scheme, the prepared salt mud slurry is sprayed through a first spraying mechanism, forming an atomized spray zone in the upper and middle parts of the absorption tower. The boiler flue gas, after being dusted by a bag filter, is pressurized and sent to the lower part of the absorption tower. The atomized salt mud slurry moves downwards, while the pressurized flue gas moves upwards, creating a longitudinal convection that allows the sulfides in the flue gas to fully contact the calcium-based compounds in the salt slurry, achieving sulfur fixation and separation. Furthermore, this scheme first introduces the diluted salt mud slurry into the bottom of the absorption tower to form a slurry pool, and then uses a circulating extraction method to draw the slurry from the pool to the spraying mechanism for spraying. This ensures that the calcium-based compounds in the salt slurry are fully utilized.

[0018] The flue gas inlet 52 is located above the slurry tank 51, and an air inlet 53 is provided at the bottom of the slurry tank 51. The air inlet 53 is connected to the oxidation air system 8, which can form an oxidation zone in the upper middle part of the slurry tank 51. This scheme dilutes and atomizes the salt mud, so that fine droplets and calcium-based compound particles float in the atomized spray zone. By setting the flue gas inlet above the slurry tank 51, the flue gas rises into the atomized spray zone after entering the absorption tower. The droplets first react with the gaseous sulfur in the flue gas to form sulfurous acid. Subsequently, the sulfurous acid reacts with the suspended calcium-based compounds to form calcium sulfite, which falls into the slurry tank below with the droplets. By installing air inlets 53, an oxygen-rich environment is provided within the slurry tank. Unreacted calcium-based compounds dissolve back into the slurry and recirculate, while the generated calcium sulfite undergoes oxidation in the oxygen-rich environment, producing calcium sulfate precipitate. A sludge discharge pit is located at the center of the bottom of the slurry tank, with the waste slurry discharge outlet at its bottom. A waste slurry discharge pump removes the precipitated calcium sulfate sludge and sends it to the existing salt mud filter press system for filtration. The resulting filtrate can be directly recycled, further reducing the amount of fresh water used. The oxidation air is compressed air, sprayed directly into the slurry tank through a spray gun. The slurry has a long residence time in the tank, allowing sufficient time for oxidation to produce calcium sulfate precipitate, thus improving the desulfurization effect.

[0019] The oxidation zone is equipped with multiple agitators. These agitators are side-entry type, and the multiple agitators are evenly distributed to prevent sedimentation of the salt mud slurry, ensuring a uniform distribution of calcium-based compounds within the slurry. This guarantees that both the oxidation reaction in the tank and the absorption and neutralization reaction in the spray zone can proceed fully. Preferably, the agitators are positioned above the air inlet nozzle 53 to disperse the blown-in oxidation air, allowing it to diffuse quickly and thoroughly in the slurry, thereby improving oxidation efficiency.

[0020] Multiple first spray mechanisms 4 are longitudinally distributed to form a multi-stage spray layer on the upper part of the absorption tower 5. This increases the spray coverage area, enhances the contact between sulfides and calcium-based compounds in the flue gas, strengthens the desulfurization effect, and improves desulfurization efficiency. An efficiency-enhancing tray, made of alloy, is also installed below the lowest spray mechanism. This tray increases desulfurization efficiency and assists the spray mechanism and demister in removing most of the dust.

[0021] The first spraying mechanism 4 includes a main pipe and branch pipes. The branch pipes are arranged in pairs on both sides of the main pipe, and each branch pipe is evenly provided with several atomizing nozzles, which can achieve uniform spraying on the cross section of the absorption tower.

[0022] Each of the first spray units 4 is connected to the slurry pool at the bottom of the absorption tower 5 via a separate circulating pump. The spray units do not interfere with each other; if the spray volume decreases due to accidental blockage in one unit, it can be compensated for by increasing the flow rate of other spray units. This ensures the stability of the desulfurization effect.

[0023] A second spray mechanism 9 is provided above each of the multiple first spray mechanisms 4, and the water inlet of the second spray mechanism 9 is connected to the water supply pipe 3. This allows for rinsing of the multi-stage spray mechanisms below, preventing scaling.

[0024] A demisting module 10 is installed above the second spraying mechanism 9. It can remove slurry droplets entrained in the exhaust gas, ensuring the purification level of the final exhaust gas.

[0025] The demisting module 10 is equipped with a flushing mechanism 11. The water inlet of the flushing mechanism 11 is connected to the water supply pipe 3 via a suction pump. The slurry tank 51 is equipped with a liquid level measuring device, which is electrically connected to the suction pump via a controller. This allows for periodic flushing of the atomizing module 10, preventing clogging of the demister and stabilizing the liquid level in the slurry tank as supplemental water. This prevents the liquid level from being too high and submerging the flue gas inlet 52, or too low and causing the air inlet nozzle 53 to be exposed, thus ensuring stable desulfurization performance. Specifically, under normal circumstances, the flushing mechanism 11 performs periodic, quantitative flushing. When the liquid level in the slurry tank is detected to be too low, flushing can be triggered immediately to raise the liquid level.

[0026] The defogging module 10 includes a double-layer structure of primary ridge type and secondary tube bundle type, which has a better defogging effect, and each layer is equipped with a set of flushing nozzles to thoroughly clean the defogging device.

[0027] The above are merely preferred embodiments of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A boiler flue gas desulfurization system, characterized in that: The apparatus includes a desulfurizing agent preparation device (1), whose inlet is connected to a salt mud discharge pipe (2) and a water supply pipe (3) respectively. The slurry outlet of the desulfurizing agent preparation device (1) is connected to the lower part of the absorption tower (5) to form a slurry pool (51) in the lower part of the absorption tower (5). The slurry pool (51) is connected to the liquid inlet of the first spraying mechanism (4) through a circulating pump. The first spraying mechanism (4) is arranged in the upper part of the inner cavity of the absorption tower (5). The flue gas inlet (52) at the lower part of the absorption tower (5) is connected to the boiler flue gas discharge pipe (6). The waste slurry discharge port at the bottom of the absorption tower (5) is connected to the inlet of the filter press device (7). The filtrate discharge port of the filter press device (7) is connected to the water supply pipe (3).

2. The boiler flue gas desulfurization system according to claim 1, characterized in that: The flue gas inlet (52) is located above the slurry tank (51), and the bottom of the slurry tank (51) is provided with an air inlet nozzle (53). The air inlet nozzle (53) is connected to the oxidation air system (8) and can form an oxidation zone in the upper middle part of the slurry tank (51).

3. A boiler flue gas desulfurization system according to claim 2, characterized in that: The oxidation zone is equipped with multiple stirrers.

4. A boiler flue gas desulfurization system according to claim 2, characterized in that: Multiple first spraying mechanisms (4) are arranged longitudinally to form a longitudinal multi-level spraying layer on the upper part of the absorption tower (5).

5. A boiler flue gas desulfurization system according to claim 4, characterized in that: Each of the first spray units (4) is connected to the slurry pool at the bottom of the absorption tower (5) via a separate circulation pump.

6. A boiler flue gas desulfurization system according to claim 5, characterized in that: A second spraying mechanism (9) is provided above a plurality of first spraying mechanisms (4), and the water inlet end of the second spraying mechanism (9) is connected to the water supply pipe (3).

7. A boiler flue gas desulfurization system according to claim 6, characterized in that: A defogging module (10) is provided above the second spraying mechanism (9).

8. A boiler flue gas desulfurization system according to claim 7, characterized in that: The demisting module (10) is equipped with a rinsing mechanism (11). The water inlet of the rinsing mechanism (11) is connected to the water supply pipe (3) through a suction pump. The slurry tank (51) is equipped with a liquid level measuring device. The liquid level measuring device is electrically connected to the suction pump through a controller.

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