CN206631430U - Lime stone gypsum wet flue gas desulfurizing device - Google Patents

Abstract

The utility model discloses a limestone-gypsum wet flue gas desulfurization device. The pre-washing tower is connected with the desulfurization tower through a flue gas pipe. It is a two-layer perforated tray, including the upper tray and the lower tray; the demister is connected to the backwash pump, the ammonia absorption layer is connected to the ammonia absorption pump, the top of the desulfurization tower is connected to the chimney through the flue gas pipe, and the bottom of the desulfurization tower The desulfurization tower discharge pump is connected to the pre-washing tower, the bottom of the pre-washing tower is connected to the centrifuge through the pre-washing tower discharge pump, the centrifuge is connected to the vibrating fluidized bed through a screw feeder, and the top of the vibrating fluidized bed is connected to the cyclone dust collector. The design is compact, saving investment and space. The spray layers of the desulfurization tower are arranged up and down to reduce the secondary carryover of flue gas; there is no sewage and other waste discharge; ammonia escape is reduced to 2 to 5 PPM, and its by-product is ammonium sulfate, which can be used Make fertilizer.

Description

Limestone-gypsum wet flue gas desulfurization plant

technical field

The utility model belongs to the technical field of flue gas desulfurization equipment, in particular to a limestone-gypsum wet flue gas desulfurization device.

Background technique

Flue gas desulfurization (FGD) is an effective desulfurization method widely used in industry. According to the form of sulfide absorbent and by-products, desulfurization technology can be divided into three types: dry method, semi-dry method and wet method. The dry desulfurization process mainly uses solid absorbents to remove SO ₂ in the flue gas. Generally, fine limestone powder is sprayed into the furnace to decompose it into CaO by heat, absorb SO ₂ in the flue gas, and generate CaSO ₃ , which is combined with fly ash Collect together in the dust collector or discharge through the chimney. Wet flue gas desulfurization is to use the gas-liquid reaction of liquid absorbent under ionic conditions to remove SO ₂ in the flue gas. The equipment used in the system is simple, the operation is stable and reliable, and the desulfurization efficiency is high. The biggest advantage of dry desulfurization is that there is no discharge of waste water and waste acid in the treatment, which reduces secondary pollution; the disadvantage is that the desulfurization efficiency is low and the equipment is huge. Wet desulfurization uses liquid absorbent to wash flue gas to remove SO ₂ . The equipment used is relatively simple, easy to operate, and high desulfurization efficiency; but the temperature of flue gas after desulfurization is lower, and the corrosion of equipment is more serious than dry method. The spraying effect of the existing desulfurization tower is not ideal, and it cannot be adjusted according to the _SO2 concentration, which increases the treatment cost and is incomplete. Because of incomplete treatment, secondary pollutants will be discharged, and the beneficial ammonia content is high. Therefore, how to develop a new type of limestone-gypsum wet flue gas desulfurization device has important practical significance.

Utility model content

Aiming at the technical problem in the prior art that the spraying effect of the desulfurization tower is not ideal, resulting in the discharge of secondary pollutants, the purpose of this utility model is to provide a limestone-gypsum wet flue gas desulfurization device.

The technical scheme that the utility model takes is:

Limestone-gypsum wet flue gas desulfurization device, including pre-washing tower, pre-washing tower oxidation fan, desulfurization tower, centrifuge, screw feeder, vibrating vulcanized bed, cyclone dust collector, chimney, said pre-washing tower passes flue gas The pipeline is connected to the desulfurization tower. The inside of the desulfurization tower is equipped with a mist eliminator and an ammonia absorption layer from top to bottom. The ammonia absorption layer is set as two layers of perforated trays, and the upper tray is set as an inverted arc-shaped plate with holes at the bottom. , the lower tray is arranged as an inverted trapezoidal plate tangentially along the upper tray, and the side walls of the inverted trapezoidal plate are equidistantly provided with taper holes; the demister is connected to the backwash pump, the ammonia absorption layer is connected to the ammonia absorption pump, and the desulfurization tower The top is connected to the chimney through the flue gas pipe, the bottom of the desulfurization tower is connected to the pre-washing tower through the desulfurization tower discharge pump, the bottom of the pre-washing tower is connected to the centrifuge through the pre-washing tower discharge pump, and the centrifuge passes through the screw feeder and vibration The fluidized bed is connected, and the top of the vibrating fluidized bed is connected to the cyclone dust collector.

Further, the demister is provided with multiple layers of demisting blades along the air inlet direction, and each layer of demisting blades is arranged in a circular arrangement along the central axis of the desulfurization tower in a gradually expanding diameter. When the flue gas flow rate is higher than the critical speed, the large liquid droplets in the high-speed flue gas impact the liquid film accumulated on the blade, causing small liquid droplets to splash, and the multi-layer demister blades can effectively capture the splashed small liquid droplets And the small droplets carried by the high-speed flue gas weaken the secondary carry of the flue gas.

Furthermore, the defogging blades are arranged as a hollow honeycomb structure with a hexagonal cross-section, and the defogging blades are arranged at equal intervals along the longitudinal direction as airflow gaps formed by trapezoidal partitions, and concave holes are arranged at both ends of the trapezoidal partitions. Zigzag barb. The setting of the concave barb and the airflow gap can absorb the splashed liquid droplets from both horizontal and vertical directions, so that the gas can flow from bottom to top along the airflow gap, and the trapezoidal partition has a certain bending degree to ensure the air flow During the process, the water droplets flow down along the wall, and the gas flows upward along the air gap, which can effectively realize the gas-liquid separation process.

Further, the hollow position of each layer of defogging blades is provided with support plates, the support plates are arranged at equal intervals in the longitudinal direction to form a roof shape, and the support plates are uniformly provided with flow guide holes. The supporting plate plays a supporting role. The diversion holes on the supporting plate improve the demisting efficiency of the plate type mist eliminator. The ridge-like structure design can reduce resistance and is used in the separation of flue gas and liquid droplets in the flue gas desulfurization system.

Further, the sides of the pre-washing tower and the desulfurization tower are both provided with circulation pumps, and the pipelines at both ends of the circulation pump are respectively connected to the upper and lower ends of the tower body. The sediment at the bottom of the pre-washing tower and the desulfurization tower is circulated back to the top through the circulation pump for secondary desulfurization, which improves the desulfurization rate.

Further, the side wall of the pre-washing tower is provided with a flue gas inlet, and the top of the pre-washing tower is provided with a washing spray pipe, and the washing spray pipes are arranged in a spiral ring facing the direction of the airflow.

Further, butterfly-shaped spray holes are provided on the lower wall of the washing spray pipe at an angle of 45°, and adjacent spray holes are arranged at equal intervals.

The butterfly-shaped spray holes on the spray pipe at an angle of 45° expand the staggered angle of the adjacent two layers of spray pipes, and the area affected by the lower spray pipes on the smoothness and uniformity will not be the same as the upper spray pipes on the smoothness and uniformity The affected areas of the degree overlap, thereby improving the uniformity of spraying, strengthening the gas-liquid mixing effect, and improving the efficiency of flue gas desulfurization.

Further, the convex surface of the upper tray of the ammonia absorption layer faces the airflow, and the concave surface faces the spray liquid. The gas-liquid contact area is increased, and the desulfurization project with high utilization rate of absorbent and adaptability to flue gas conditions with high concentration of SO ₂ is improved.

The beneficial effects of the utility model are:

The equipment of the utility model is compact in design, saving investment and space. The gas is preliminarily treated by the pre-washing tower. The structure of the demister and the ammonia absorption layer in the desulfurization tower is novel. The spray layer is arranged up and down. The multi-layered demister blades can effectively capture the splashed small droplets and high-speed flue gas. The small droplets carried can weaken the secondary carry of flue gas; adjust according to the SO ₂ concentration, even in the case of high SO ₂ concentration, it can reduce the treatment cost, and there is no sewage and other waste discharge; the ammonia escape is reduced to 2~ 5 ppm. The desulfurization products are discharged into the regeneration tank, and the regenerated sodium-based desulfurizer is returned to the desulfurization tower for recycling to reduce the treatment cost. The by-product is ammonium sulfate, which can be used as fertilizer.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the utility model.

Fig. 2 is a structural schematic diagram of the ammonia absorbing layer in the utility model.

Fig. 3 is a structural schematic diagram of the demister in the utility model.

Fig. 4 is a structural schematic diagram of the defogging blade in the utility model.

Among them, 1. Pre-washing tower; 2. Pre-washing tower oxidation fan; 3. Demister; 4. Ammonia absorption layer; 5. Desulfurization tower; 6. Pre-washing tower discharge pump; 7. Desulfurization tower discharge pump; 8. Centrifuge; 9. Screw feeder; 10. Vibrating vulcanized bed; 11. Cyclone dust collector; 12. Ammonia absorption pump; 13. Backwash pump; 14. Chimney; 15. Upper tray; 16. Lower tower plate; 17, defogging blade; 18, support plate; 19, trapezoidal partition.

detailed description

Further illustrate the utility model below in conjunction with accompanying drawing.

Limestone (lime) wet desulfurization technology has been widely used in the field of wet FGD because the absorbent is cheap and easy to obtain. The reaction mechanism with limestone as absorbent is:

Absorption: SO ₂ (g)→SO ₂ (L)+H ₂ O→H ⁺ +HSO ₃ ^- →H ⁺ +SO ₃ ^2-

Dissolution: CaCO ₃ (s)+H ⁺ →Ca ²⁺ +HCO ₃ ^-

Neutralization: HCO ₃ ^- +H ⁺ →CO ₂ (g)+H ₂ O

Oxidation: HSO ₃ ^- +1/2O ₂ →SO ₃ ^2- +H+

SO ₃ ^2- +1/2O ₂ →SO ₄ ^2-

Crystallization: Ca ₂ ++SO ₃ ^2- +1/2H ₂ O→CaSO ₃ ·1/2H ₂ O(s)

The process is characterized by high desulfurization efficiency (>95%), high utilization rate of absorbent (>90%), can adapt to high _- concentration SO2 flue gas conditions, low calcium-sulfur ratio (generally <1.05), and comprehensive utilization of desulfurized gypsum Wait.

Process operation reaction principle

The ammonia-ammonia sulfate method uses a certain concentration of ammonia water as an absorbent to wash the SO ₂ in the flue gas in the desulfurization tower to achieve the purpose of flue gas purification. By oxidizing NH ₄ HSO ₃ in the absorption liquid to (NH ₄ ) ₂ SO ₄ , a desulfurization by-product that can be used as agricultural fertilizer is formed. The response of the whole process is as follows:

2NH ₄ OH+SO ₂ =(NH ₄ ) ₂ SO ₃ +H ₂ O

(NH ₄ ) ₂ SO ₃ +SO ₂ +H ₂ O＝2NH ₄ HSO ₃

NH ₄ HSO ₃ +NH ₃ =(NH ₄ ) ₂ SO ₃

(NH ₄ ) ₂ SO ₃ +1/2O ₂ ＝(NH ₄ ) ₂ SO ₄

Example 1

As shown in Figure 1 and Figure 2, the limestone-gypsum wet flue gas desulfurization plant includes a pre-washing tower, a pre-washing tower oxidation fan, a desulfurization tower, a centrifuge, a screw feeder, a vibrating vulcanized bed, a cyclone dust collector, and a chimney , the pre-washing tower is connected to the desulfurization tower through the flue gas pipeline, and the interior of the desulfurization tower is respectively provided with a demister and an ammonia absorption layer from top to bottom, the ammonia absorption layer is set as two layers of perforated trays, and the upper tray is set as The inverted circular arc-shaped plate with holes at the bottom, the lower tray is arranged as an inverted trapezoidal plate tangentially along the upper tray, and the side walls of the inverted trapezoidal plate are provided with tapered holes at equal intervals; the demister is connected to the backwash pump, and the ammonia absorption layer It is connected to the ammonia absorption pump, the top of the desulfurization tower is connected to the chimney through the flue gas pipe, the bottom of the desulfurization tower is connected to the pre-washing tower through the desulfurization tower discharge pump, and the bottom of the pre-washing tower is connected to the centrifuge through the pre-washing tower discharge pump. The centrifuge is connected with the vibrating fluidized bed through a screw feeder, and the top of the vibrating fluidized bed is connected with a cyclone dust collector.

The specific operation process is: the flue gas to be treated is passed into the pre-washing tower, ammonia water or waste ammonia is pumped into the desulfurization tower through the circulation pump on the side of the desulfurization tower, and the process water is pumped into the desulfurization tower through the ammonia absorption pump and backwash pump. In the ammonia absorption layer and demister inside the desulfurization tower, the flue gas to be treated first enters the pre-washing tower, and is sprayed through the spray pipes arranged in a spiral ring in the pre-washing tower, which is harmful to the pollutants in the flue gas. Substances are initially removed, and the liquid at the bottom of the pre-washing tower is sprayed and dropped from the top again through the side circulation pump to achieve the initial desulfurization efficiency; the flue gas pretreated by the pre-washing tower is passed through the bottom of the desulfurization tower, _In the process of flue gas passing upwards, the ammonia absorption layer absorbs SO2 and related harmful components in the gas, and the demister will impact the large droplets in the high-speed flue gas on the liquid film accumulated on the blade, resulting in small droplets Splashing, and the multi-layer demisting blades can effectively capture the small droplets splashed and the small droplets carried by the high-speed flue gas, reducing the secondary carry of the flue gas. The desulfurization product is discharged into the regeneration tank, and Ca(OH) ₂ solution is used for reduction and regeneration, and the regenerated sodium-based desulfurizer is returned to the desulfurization tower for recycling, reducing the treatment cost. The slurry treated by the desulfurization tower is transported to the centrifuge through the desulfurization tower discharge pump, the slurry treated by the pre-washing tower is transported to the centrifuge through the pre-wash tower discharge pump, and the centrifugal liquid enters the vibration through the screw feeder. Fluidized bed, the solid matter treated by the vibrating fluidized bed is bagged, and the gas components are discharged into the desulfurization tower through the cyclone dust collector. The gas desulfurized by the desulfurization tower is discharged into the atmosphere through the chimney.

Example 2

On the basis of Example 1, different from Example 1, as shown in Figure 3 and Figure 4, the mist eliminator is provided with multi-layer defogging blades along the air intake direction, and each layer of defogging blades is along the center of the desulfurization tower. The shafts are arranged in an annular arrangement with gradually expanding diameters. When the flue gas flow rate is higher than the critical speed, the large liquid droplets in the high-speed flue gas impact the liquid film accumulated on the blade, causing small liquid droplets to splash, and the multi-layer demister blades can effectively capture the splashed small liquid droplets And the small droplets carried by the high-speed flue gas weaken the secondary carry of the flue gas.

The defogging blades are arranged as a hollow honeycomb structure with a hexagonal cross-section, and the defogging blades are arranged at equal intervals along the longitudinal direction as airflow gaps formed by trapezoidal partitions, and concave-shaped barbs are provided at both ends of the trapezoidal partitions. The setting of the concave barb and the airflow gap can absorb the splashed liquid droplets from both horizontal and vertical directions, so that the gas can flow from bottom to top along the airflow gap. Because the trapezoidal partition has a certain bending degree, the air flow is guaranteed. During the process, the water droplets flow down along the wall, and the gas flows upward along the airflow gap, which can effectively realize the gas-liquid separation process.

The hollow position of each layer of defogging blades is provided with a support plate, and the support plates are arranged at equal intervals in the longitudinal direction to form a roof shape, and the support plates are uniformly provided with flow guide holes. The support plate plays a supporting role. The guide holes on the support plate improve the demisting efficiency of the plate demister. The ridge-like structure design can reduce resistance and is used in the separation of flue gas and liquid droplets in the flue gas desulfurization system.

Example 3

On the basis of Example 1, different from Example 1, the sides of the pre-washing tower and the desulfurization tower are equipped with circulating pumps, and the pipelines at both ends of the circulating pump are respectively connected to the upper and lower ends of the tower body. The sediment at the bottom of the pre-washing tower and the desulfurization tower is circulated back to the top through the circulation pump for secondary desulfurization, which improves the desulfurization rate.

The side wall of the pre-washing tower is provided with a flue gas inlet, and the top of the pre-washing tower is provided with a washing spray pipe, and the washing spray pipes are arranged in a spiral ring facing the direction of the airflow.

Butterfly-shaped spray holes are set on the lower wall of the washing spray pipe at an angle of 45°, and adjacent spray holes are arranged at equal intervals.

The butterfly-shaped spray holes on the spray pipe at an angle of 45° expand the staggered angle of the adjacent two layers of spray pipes, and the area affected by the lower spray pipes on the smoothness and uniformity will not be the same as the upper spray pipes on the smoothness and uniformity The affected areas of the degree overlap, thereby improving the uniformity of spraying, strengthening the gas-liquid mixing effect, and improving the efficiency of flue gas desulfurization.

The convex surface of the upper tray of the ammonia absorbing layer faces the airflow, and the concave surface faces the spray liquid. The gas-liquid contact area is increased, and the desulfurization project with high utilization rate of absorbent and adaptability to flue gas conditions with high concentration of SO ₂ is improved.

The above description is not a limitation of the present utility model. It should be pointed out that for those of ordinary skill in the art, some changes, modifications, additions or replacements can also be made without departing from the essential scope of the present utility model. , These improvements and modifications should also be regarded as the protection scope of the present utility model.

Claims (8)

1. wet desulfurization of flue gas by limestone-gypsum method device, it is characterised in that including prewashing tower, prewashing tower oxidation fan, desulfurization Tower, centrifuge, screw(-type) feeder, vibration vulcanization bed, cyclone dust collectors, chimney, the prewashing tower pass through flue and desulfurization Tower connects, and the inside of desulfurizing tower is respectively arranged with demister and ammonia absorbed layer from top to bottom, ammonia absorbed layer be arranged to two layers it is porous Column plate, upper strata column plate are arranged to the rounding arc of bottom opening, and descending trays are arranged to inverted trapezoidal along upper strata column plate is tangent Plate, the side wall of inverted trapezoidal plate equidistantly open up taper hole；Demister connects with backwashing pump, and ammonia absorbed layer connects with ammonia absorption pump, The top of desulfurizing tower is connected by flue with chimney, and the bottom of desulfurizing tower is connected by desulfurizing tower slurry pump with prewashing tower, Prewashing tower bottom is connected by prewashing tower slurry pump with centrifuge, and centrifuge is connected by screw(-type) feeder with vibration vulcanization bed, Vibrate vulcanization bed top connection cyclone dust collectors.

2. wet desulfurization of flue gas by limestone-gypsum method device according to claim 1, it is characterised in that the demister along Airintake direction is provided with multilayer demisting blade, the annular arrangement of central shaft of the every layer of demisting blade along desulfurizing tower diametrically flaring Set.

3. wet desulfurization of flue gas by limestone-gypsum method device according to claim 2, it is characterised in that the demisting blade is set It is set to the hexagonal hollow honeycomb body structure in section, the gas that demisting blade is formed along longitudinal spaced set for trapezoidal dividing plate Gap is flowed, the both ends of trapezoidal dividing plate are provided with concave shape barb.

4. wet desulfurization of flue gas by limestone-gypsum method device according to claim 2, it is characterised in that every layer of demisting leaf The hollow position of piece is provided with supporting plate, and supporting plate longitudinal direction spaced set forms ridge, has been uniformly arranged and led in supporting plate Discharge orifice.

5. wet desulfurization of flue gas by limestone-gypsum method device according to claim 1, it is characterised in that the prewashing tower and de- The sidepiece of sulphur tower is provided with circulating pump, and the both ends pipeline of circulating pump is respectively communicated with the upper and lower ends in tower body.

6. wet desulfurization of flue gas by limestone-gypsum method device according to claim 1, it is characterised in that the side of the prewashing tower Wall is provided with smoke inlet, is provided with wash spray pipe at the top of prewashing tower, wash spray pipe in face of the direction of air-flow helically Ring-type is arranged.

7. wet desulfurization of flue gas by limestone-gypsum method device according to claim 6, it is characterised in that the wash spray pipe Lower wall surface in 45° angle open up butterfly spray apertures, adjacent spray apertures are equidistantly arranged.

8. wet desulfurization of flue gas by limestone-gypsum method device according to claim 1, it is characterised in that the ammonia absorbed layer The convex surface of upper strata column plate is met to air-flow, and concave surface is met to spray liquid.