Flow equalizing device for flue gas at outlet of desulfurization wastewater drying tower and raw flue gas

Abstract

The utility model discloses a flow equalizing device for flue gas at an outlet of a desulfurization wastewater drying tower and raw flue gas, and relates to the technical field of zero emission of desulfurization wastewater of a coal-fired unit. The device comprises a flow-equalizing distribution pipe, flow-equalizing distribution branch pipes, an air preheater and a drying tower, the flow equalizing distribution pipe is located in an air preheater outlet flue of the air preheater, and a plurality of flow equalizing distribution branch pipes are arranged on the flow equalizing distribution pipe at intervals. An air preheater outlet flue is connected with a plurality of air preheater outlet flue branch pipes, and a drying tower outlet flue of the drying tower is inserted into the air preheater outlet flue and connected with the right end of the flow equalizing distribution pipe. The flue work amount in a conventional scheme can be effectively reduced, the problems of contamination and blockage of a heat exchange pipe of a low-temperature economizer at an inlet of a dust remover due to uneven diversion of wet flue gas of desulfurization waste water are solved, the flue gas waste heat utilization effect is improved, and the economical efficiency of a unit is improved.

Description

Technical Field

[0001] This utility model relates to the field of zero discharge technology for desulfurization wastewater from coal-fired power units, and more specifically, it is a device suitable for mixing and equalizing the flue gas at the outlet of the desulfurization wastewater drying tower of a coal-fired power unit with the raw flue gas from the boiler. Background Technology

[0002] Coal-fired power units are major producers of industrial wastewater, with desulfurization wastewater accounting for a significant proportion of this industrial wastewater. As environmental protection requirements become increasingly stringent, the state has set higher standards for wastewater discharge from coal-fired power units. The "Action Plan for High-Quality Development of Environmental Protection Equipment Manufacturing Industry (2022-2025)" explicitly proposes promoting the research and application of zero-discharge technology for desulfurization wastewater from coal-fired power plants, listing it as a key development direction. The "Guidelines for Feasible Technologies for Pollution Prevention and Control in Thermal Power Plants" points out that the core of achieving near-zero wastewater discharge in thermal power plants is to achieve zero discharge of desulfurization wastewater. Some local environmental policies even explicitly require that coal-fired power units must simultaneously construct zero-discharge desulfurization wastewater treatment devices.

[0003] Driven by policy, zero-discharge technologies for desulfurization wastewater have flourished, with the "concentration + drying" technology route becoming a mainstream solution and being applied in numerous coal-fired power plant projects. Concentration schemes vary, all aiming to increase wastewater concentration and reduce the amount of wastewater requiring drying. Drying schemes primarily employ desulfurization wastewater drying towers. High-temperature flue gas from the air preheater inlet or high-temperature air from the hot secondary air system is drawn into the drying tower and mixed with concentrated desulfurization wastewater that has been atomized and sprayed into the tower. The mixed gas is then sent to the air preheater outlet flue, where it is combined with the boiler's raw flue gas and fed into subsequent dust collectors and other flue gas purification equipment, thus achieving zero discharge of desulfurization wastewater.

[0004] There are two methods for connecting the flue gas from the outlet of a conventional desulfurization wastewater drying tower to the boiler's original flue gas duct. One method is to distribute the flue gas from the drying tower outlet to multiple branch pipes at the dust collector inlet via pipelines. The other method is to connect it to the boiler's air preheater outlet flue gas duct using a single main pipe (for single-row air preheater units) or two main pipes (for double-row air preheater units). Both methods are used in coal-fired units. The former method results in a longer drying tower outlet flue gas duct, limited space, and the need for compensators on the pipeline to prevent excessive thermal displacement. This method involves a larger pipeline project and is more expensive. The latter method connects the drying tower outlet flue gas directly to the air preheater outlet. The flue and pipes are relatively short, which can save on some piping work. However, because the cross-section of the air preheater outlet flue is relatively wide, after the dryer tower outlet flue is inserted into the air preheater outlet flue, most of the wet flue gas with high relative humidity of desulfurization wastewater flows into one or two flue branch pipes near the dryer tower interface. This causes the humidity of the flue gas in the branch pipe to increase. When the unit is equipped with a low-temperature economizer at the dust collector inlet, the wet flue gas with high relative humidity condenses after cooling. The small droplets after condensation and the dust in the flue gas adhere to the heat exchange tubes of the low-temperature economizer, causing fouling and blockage of the low-temperature economizer, affecting the heat exchange effect of the low-temperature economizer, and thus affecting the economic efficiency of the unit.

[0005] Therefore, it is necessary to develop a flow equalization device that can ensure uniform distribution of wet flue gas from desulfurization wastewater entering each branch pipe of the air preheater outlet flue while reducing the amount of engineering work required for the desulfurization wastewater drying tower flue, thus avoiding the problem of fouling and clogging of the low-temperature economizer and improving the economic efficiency of the unit. Utility Model Content

[0006] The primary objective of this invention is to address the issues of large flue gas volume and limited layout space in existing desulfurization wastewater drying tower outlet flue gas to boiler raw flue gas schemes. This invention saves on pipeline engineering and reduces power plant construction costs.

[0007] The second objective of this invention is to solve the problem of fouling and blockage of the heat exchange tubes of the low-temperature economizer caused by uneven distribution of wet flue gas from the desulfurization wastewater drying tower in the existing desulfurization wastewater drying tower outlet flue gas into the boiler raw flue gas scheme. This invention improves the utilization effect of flue gas waste heat and enhances the economic efficiency of the power plant.

[0008] To achieve the above objectives, the technical solution of this utility model is as follows: a device for equalizing the flow of flue gas at the outlet of a desulfurization wastewater drying tower with the original flue gas, characterized in that: it includes a flow equalization distribution pipe, flow equalization distribution branch pipes, an air preheater, and a drying tower; the flow equalization distribution pipe is located in the air preheater outlet flue of the air preheater, the diameter of the flow equalization distribution pipe gradually decreases from right to left, and multiple flow equalization branch pipes are spaced apart on the flow equalization distribution pipe;

[0009] The air preheater outlet flue is connected to multiple air preheater outlet flue branch pipes, and the flow distribution branch pipe corresponds one-to-one with the air preheater outlet flue branch pipe.

[0010] The drying tower outlet flue is inserted into the air preheater outlet flue and connected to the right end of the flow distribution pipe.

[0011] In the above technical solution, the flow distribution pipe slopes from right to left with a gradient of not less than 0.003.

[0012] In the above technical solution, the flow distribution pipe includes multiple steel pipes connected sequentially from right to left with gradually decreasing diameters, and the steel pipes are connected to the flow distribution branch pipes.

[0013] In the above technical solution, adjacent steel pipes are connected by reducers, and the leftmost steel pipe is connected to an elbow; the reducers are eccentric reducers, and the bottoms of multiple reducers are flush.

[0014] In the above technical solution, the windward side of the top of the flow distribution pipe is provided with wear-resistant angle steel.

[0015] The above technical solution also includes an interface device, the left end of which is connected to the rightmost steel pipe, and the right end of which is connected to the outlet flue of the drying tower.

[0016] In the above technical solution, the inner diameter of the interface device is 10mm larger than the outer diameter of the outlet flue of the drying tower, and the interface device is provided with multiple rings of sealing teeth, the height of which is 3mm.

[0017] In the above technical solution, the outlet flue of the drying tower is inserted 200mm into the outlet flue of the air preheater.

[0018] In the above technical solution, an expansion gap is reserved between the interface device and the wall panel of the air preheater outlet flue.

[0019] The above technical solution also includes a fixed bracket and a guide bracket. Both the fixed bracket and the guide bracket are pipe clamp structures. The fixed bracket is installed in the middle of the flow distribution pipe, and the guide bracket is installed at both ends of the flow distribution pipe. The fixed bracket and the guide bracket are rooted in the inner support rod or diagonal brace of the air preheater outlet flue.

[0020] Compared with the prior art, this utility model has the following advantages:

[0021] 1) This utility model can effectively reduce the amount of flue engineering in conventional schemes, avoid the problem of uneven distribution of desulfurization wastewater and wet flue gas leading to fouling and blockage of the heat exchange tubes of the low-temperature economizer at the dust collector inlet, improve the utilization effect of flue gas waste heat, and improve the economic efficiency of the unit.

[0022] 2) This utility model minimizes the leakage of flue gas from the sealing tooth position without affecting the relative thermal displacement between the interface device and the outlet flue of the drying tower; a certain expansion gap is reserved between the interface sleeve and the wall plate of the air preheater outlet flue to ensure that the interface sleeve and the wall plate do not get stuck when the unit is running normally.

[0023] 3) The reducer of this utility model adopts an eccentric reducer, and the bottom is flush during installation; the flow distribution pipe is sloped along the flue gas flow direction from the outlet flue of the drying tower, with a slope of not less than 0.003, so as to ensure that the liquid droplets condensed in the outlet flue of the drying tower flow into the outlet flue of the air preheater by gravity and do not accumulate in the flow distribution pipe.

[0024] 4) The wear-resistant angle steel of this utility model serves to protect the flow distribution pipe from being washed away by dust in the flue gas.

[0025] 5) The fixed bracket and guide bracket of this utility model ensure the stability of the flow distribution pipe in the air preheater outlet flue and prevent the flow distribution pipe from being swayed by the flue gas; wherein the fixed bracket is installed in the middle position of the flow distribution pipe and the guide bracket is installed at both ends of the flow distribution pipe to ensure that the flow distribution pipe can expand freely to both sides with the middle position as the dead point. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of this utility model.

[0027] Figure 2 for Figure 1 A schematic diagram of direction A in the middle.

[0028] Figure 3 for Figure 1 A schematic diagram at point BB.

[0029] Figure 4 for Figure 1 A schematic diagram at point CC.

[0030] Figure 5 This diagram shows the connection between the interface device and the outlet flue of the drying tower.

[0031] Figure 6 This is a schematic diagram of a fixed bracket.

[0032] Figure 7 This is a schematic diagram of a guide bracket.

[0033] Figure 8 The diagram shows the flow field simulation results of this utility model.

[0034] Figure 9 The diagram shows the process simulation results of a single desulfurization wastewater flue connected to the outlet flue of an air preheater.

[0035] Among them, 110-flow distribution pipe, 111-steel pipe, 112-reducer, 113-elbow, 120-flow distribution branch pipe, 130-wear-resistant angle steel, 200-air preheater, 210-air preheater outlet flue, 211-internal support rod, 212-diagonal brace, 213-wall panel, 220-air preheater outlet flue branch pipe, 300-drying tower, 310-drying tower outlet flue, 400-interface device, 410-sealing tooth, 420-expansion gap, 510-fixed bracket, 520-guide bracket. Detailed Implementation

[0036] The following detailed description, in conjunction with the accompanying drawings, illustrates the implementation of this utility model. However, these descriptions do not constitute a limitation of the present utility model and are merely illustrative. Furthermore, the advantages of this utility model will become clearer and easier to understand through this description.

[0037] Referring to the accompanying drawings, a device for equalizing the flow of flue gas at the outlet of a desulfurization wastewater drying tower with the original flue gas is characterized by comprising a flow equalization distribution pipe 110, flow equalization distribution branch pipes 120, an air preheater 200, and a drying tower 300; the flow equalization distribution pipe 110 is located within the air preheater outlet flue 210 of the air preheater 200, and the diameter of the flow equalization distribution pipe 110 gradually decreases from right to left (i.e., along the flow direction of the flue gas from the drying tower outlet flue), and multiple flow equalization branch pipes 120 are spaced apart on the flow equalization distribution pipe 110;

[0038] The air preheater outlet flue 210 is connected to multiple air preheater outlet flue branch pipes 220, and the flow distribution branch pipe 120 corresponds one-to-one with the air preheater outlet flue branch pipe 220.

[0039] The drying tower outlet flue 310 of the drying tower 300 is inserted into the air preheater outlet flue 210 and connected to the right end of the flow distribution pipe 110.

[0040] like Figure 3 As shown, the flow distribution pipe 110 slopes from right to left (i.e., along the flue gas flow direction from the outlet flue of the drying tower) with a slope of not less than 0.003.

[0041] The flow distribution pipe 110 includes a plurality of steel pipes 111 connected sequentially from right to left (i.e., along the flue gas flow direction from the outlet flue of the drying tower) with gradually decreasing pipe diameters. The steel pipes 111 are connected to the flow distribution branch pipe 120.

[0042] Adjacent steel pipes 111 are connected by reducers 112, and the leftmost steel pipe 111 is connected to an elbow 113; the reducers 112 are eccentric reducers, and the bottoms of multiple reducers 112 are flush; the elbow 113 corresponds to the branch pipe 220 of the air preheater outlet flue.

[0043] like Figure 2 As shown, the top windward surface of the flow distribution pipe 110 is provided with a wear-resistant angle steel 130, and the thickness of the wear-resistant angle steel 130 is not less than 10mm.

[0044] like Figure 3 As shown, it also includes an interface device 400, the left end (air outlet side) of which is connected to the rightmost steel pipe 111, and the right end (air inlet side) of which is connected to the drying tower outlet flue 310.

[0045] like Figure 5 As shown, the inner diameter of the interface device 400 is 10mm larger than the outer diameter of the drying tower outlet flue 310. The interface device 400 is provided with multiple rings of sealing teeth 410, and the height of the sealing teeth 410 is 3mm. The drying tower outlet flue 310 is inserted into the air preheater outlet flue 210 by 200mm. The leakage of flue gas from the sealing teeth 410 position is minimized without affecting the relative thermal displacement between the interface device 400 and the drying tower outlet flue 310.

[0046] An expansion gap 420 is reserved between the interface device 400 and the wall plate 213 of the air preheater outlet flue 210 to ensure that the interface device 400 and the wall plate 213 of the air preheater outlet flue 210 do not get stuck during normal operation of the unit. The expansion gap is calculated based on the length of the flow distribution pipe 110 and the temperature of the flue gas at the air preheater outlet and a certain margin is reserved.

[0047] like Figure 4 , Figure 6-7 As shown, it also includes a fixed bracket 510 and a guide bracket 520. Both the fixed bracket 510 and the guide bracket 520 are pipe clamp structures. The fixed bracket 510 is installed in the middle of the flow distribution pipe 110, and the guide bracket 520 is installed at both ends of the flow distribution pipe 110. The fixed bracket 510 and the guide bracket 520 are rooted on the inner support rod 211 and the diagonal brace 212 of the air preheater outlet flue 210.

[0048] In actual use, steel pipe 111, reducer 112, and elbow 113 are welded together, and steel pipe 111 is welded to interface device 400. Along the flue gas flow from the outlet flue of the drying tower, the diameter of the flow distribution pipe 110 gradually decreases. The diameter of the flow distribution pipe 110 and the diameter of the flow distribution branch pipe 120 are calculated according to the average distribution of the desulfurization wastewater flue gas volume and corrected by numerical simulation.

[0049] Numerical simulations were performed using CFD software on the proposed scheme and the scheme of connecting a single desulfurization wastewater flue to the air preheater outlet flue, respectively. The simulation results are as follows: Figure 8 and Figure 9 As shown; Figure 8In the text, Velocity Magnitude (m / s) represents the flow velocity (meters per second), and pathlines-2 represents the pathlines-2. Figure 9 In this context, Particle ID is the particle identifier, and pathlines-1 is the pathline-1.

[0050] As can be seen from the numerical simulation results in the figure, such as Figure 9 As shown, when a single desulfurization wastewater flue is connected to the air preheater outlet flue, most of the wet flue gas from the desulfurization wastewater flows into the flue branch pipe immediately adjacent to the interface; for example... Figure 8 As shown, by adopting the present invention, the wet flue gas from the desulfurization wastewater is basically evenly distributed into the branch pipe 220 of the air preheater outlet flue, which has a significant effect on reducing the relative humidity of the flue gas in the branch pipe 220 of the air preheater outlet flue and avoiding fouling and blockage of the low-temperature economizer.

[0051] All other unspecified parts belong to the prior art.

Claims

1. A device for equalizing the flow of flue gas from the outlet of a desulfurization wastewater drying tower with the original flue gas, characterized in that: It includes a flow distribution pipe (110), flow distribution branch pipes (120), an air preheater (200), and a drying tower (300); the flow distribution pipe (110) is located in the air preheater outlet flue (210) of the air preheater (200), the diameter of the flow distribution pipe (110) gradually decreases from right to left, and multiple flow distribution branch pipes (120) are arranged at intervals on the flow distribution pipe (110); The air preheater outlet flue (210) is connected to multiple air preheater outlet flue branch pipes (220), and the flow distribution branch pipe (120) corresponds one-to-one with the air preheater outlet flue branch pipe (220); The drying tower outlet flue (310) of the drying tower (300) is inserted into the air preheater outlet flue (210) and connected to the right end of the flow distribution pipe (110).

2. The device for equalizing the flow of flue gas from the outlet of a desulfurization wastewater drying tower with the original flue gas according to claim 1, characterized in that: The flow distribution pipe (110) slopes from right to left with a gradient of not less than 0.

003.

3. The device for equalizing the flow of flue gas from the outlet of a desulfurization wastewater drying tower with the original flue gas according to claim 2, characterized in that: The flow distribution pipe (110) includes a plurality of steel pipes (111) connected sequentially from right to left with gradually decreasing diameters, and the steel pipes (111) are connected to the flow distribution branch pipe (120).

4. The device for equalizing the flow of flue gas from the outlet of a desulfurization wastewater drying tower with the original flue gas according to claim 3, characterized in that: The adjacent steel pipes (111) are connected by reducers (112), and the leftmost steel pipe (111) is connected to the elbow (113); the reducers (112) are eccentric reducers, and the bottoms of multiple reducers (112) are flush.

5. The device for equalizing the flow of flue gas from the outlet of a desulfurization wastewater drying tower with the original flue gas according to claim 1, characterized in that: The top windward side of the flow distribution pipe (110) is provided with a wear-resistant angle steel (130).

6. The device for equalizing the flow of flue gas from the outlet of a desulfurization wastewater drying tower with the original flue gas according to claim 4, characterized in that: It also includes an interface device (400), the left end of which is connected to the rightmost steel pipe (111), and the right end is connected to the outlet flue (310) of the drying tower.

7. The device for equalizing the flow of flue gas from the outlet of a desulfurization wastewater drying tower with the original flue gas according to claim 6, characterized in that: The inner diameter of the interface device (400) is 10 mm larger than the outer diameter of the outlet flue (310) of the drying tower. The interface device (400) is provided with multiple rings of sealing teeth (410), and the height of the sealing teeth (410) is 3 mm.

8. The device for equalizing the flow of flue gas from the outlet of a desulfurization wastewater drying tower with the original flue gas according to claim 6, characterized in that: The outlet flue (310) of the drying tower is inserted 200mm into the outlet flue (210) of the air preheater.

9. The device for equalizing the flow of flue gas from the outlet of a desulfurization wastewater drying tower with the original flue gas according to claim 7, characterized in that: An expansion gap (420) is reserved between the interface device (400) and the wall panel (213) of the air preheater outlet flue (210).

10. The device for equalizing the flow of flue gas from the outlet of a desulfurization wastewater drying tower with the original flue gas according to claim 1, characterized in that: It also includes a fixed bracket (510) and a guide bracket (520), both of which are pipe clamp structures. The fixed bracket (510) is installed in the middle of the flow distribution pipe (110), and the guide bracket (520) is installed at both ends of the flow distribution pipe (110). The fixed bracket (510) and the guide bracket (520) are rooted in the inner support rod (211) or diagonal brace (212) of the air preheater outlet flue (210).

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