Flue gas flow increasing system and method of desulfurization wastewater evaporation drying tower

Abstract

The invention discloses a flue gas flow increasing system and method for a desulfurization wastewater evaporation drying tower. The system comprises a hot primary air drainage pipe, concentric multi-point uniformly-distributed air extractors and an air inlet adjusting valve. The concentric multipoint uniform distribution air extractor comprises an inner cylinder body, an outer cylinder body, an upper annular plate and a lower annular plate, the inner cylinder is positioned on the inner side of the outer cylinder; the upper annular plate and the lower annular plate are respectively connected to the top and the bottom of the outer barrel, so that a sealed annular cavity is formed between the outer barrel and the inner barrel; hot primary air nozzles distributed along the periphery are arranged on the lower annular plate; the top of the inner cylinder is a high-temperature flue gas extraction port, and the bottom of the inner cylinder is a mixed flue gas exhaust port; a hot primary air inlet is formed in the side wall of the outer barrel; the concentric multi-point uniformly-distributed air extractor is mounted on a bypass flue of the air preheater and is positioned at the upstream of the desulfurization wastewater evaporation tower; one end of the hot primary air drainage pipe is connected with a hot primary air inlet in the outer barrel, and the other end is connected with a hot primary air mother pipe; the air inlet adjusting valve is installed on the hot primary air drainage pipe. The flue gas flow can be increased according to needs.

Description

Technical Field

[0001] The present invention relates to a flue gas flow rate boosting system and method for a desulfurized wastewater evaporation tower, belonging to the technical field of zero discharge of desulfurized wastewater in coal-fired power plants. Background Art

[0002] Currently, the vast majority of coal-fired power plants use the "limestone-gypsum wet desulfurization process" to desulfurize flue gas. Driven by environmental protection policies, wet desulfurized wastewater has become the focus of treatment.

[0003] In the zero-discharge process of desulfurized wastewater from coal-fired boilers, the conventional technical route is to evaporate the desulfurized wastewater using the heat of the boiler flue gas. The desulfurized wastewater is sprayed into the main flue at the outlet of the air preheater or into a separately arranged bypass flue of the air preheater. Since spraying into the outlet main flue may bring serious risks of flue corrosion, generally, a new bypass flue is selected and an independent evaporation tower is equipped to evaporate the desulfurized wastewater. The pollutants in the wastewater are discharged in the form of dry ash, and the salt crystal particles enter the dust collector or ash hopper.

[0004] The currently commonly used rotary air preheater in coal-fired power plants has a three-compartment structure, including a flue gas compartment, a primary air compartment, and a secondary air compartment. The inlet of the flue gas compartment is connected to the inlet main flue, and the outlet is connected to the outlet main flue. One end of the bypass flue of the air preheater is connected to the inlet main flue, and the other end is connected to the outlet main flue. The inlet of the primary air compartment of the air preheater is connected to the cold primary air header, and the outlet is connected to the hot primary air header. The inlet of the secondary air compartment is connected to the cold secondary air header, and the outlet is connected to the hot primary air header.

[0005] The desulfurized wastewater evaporation system based on the flue gas bypass of the air preheater uses the differential pressure on the flue gas side of the air preheater to drive high-temperature flue gas into the evaporation tower. Since the differential pressure on the flue gas side of the air preheater changes with the unit load and blockage degree, it is difficult to adjust the flue gas volume entering the evaporation tower. Especially when the differential pressure on the flue gas side of the air preheater is small, it may cause insufficient flue gas flow rate entering the desulfurized wastewater evaporation tower, resulting in problems such as untimely evaporation of desulfurized wastewater and corrosion of the wastewater sticking to the wall. Summary of the Invention

[0006] In order to solve the problem of insufficient flue gas flow capacity of the desulfurized wastewater evaporation tower in the traditional air preheater bypass flue, the present invention provides a flue gas flow rate boosting system and method for a desulfurized wastewater evaporation tower.

[0007] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] A flue gas flow rate lifting system for a desulfurization wastewater evaporation tower, wherein one end of an air preheater bypass flue is connected to an inlet main flue of the air preheater, and the other end is connected to an outlet main flue of the air preheater. The desulfurization wastewater evaporation tower is arranged on the air preheater bypass flue, and comprises a hot primary air drainage pipe, a concentric multi-point uniformly distributed exhauster and an air inlet regulating valve;

[0009] The concentric multi-point uniformly distributed exhauster includes an inner cylinder, an outer cylinder, an upper ring plate and a lower ring plate; the outer diameter of the inner cylinder is smaller than the inner diameter of the outer cylinder, and the inner cylinder is located inside the outer cylinder; the upper ring plate and the lower ring plate are respectively connected to the top and bottom of the outer cylinder, so that a sealed annular cavity is formed between the outer cylinder and the inner cylinder; the lower ring plate is provided with hot primary air nozzles distributed along the periphery; the top of the inner cylinder is used as a high-temperature smoke extraction port, and the bottom is used as a mixed smoke exhaust port; the side wall of the outer cylinder is provided with a hot primary air inlet;

[0010] The concentric multi-point evenly distributed vacuum pump is installed on the bypass flue of the air preheater through the high-temperature flue gas extraction port and the mixed flue gas exhaust port, and the concentric multi-point evenly distributed vacuum pump is located upstream of the desulfurization wastewater evaporation tower; one end of the hot primary air drainage pipe is connected to the hot primary air inlet on the outer cylinder, and the other end is connected to the hot primary air main pipe; the air inlet regulating valve is installed on the hot primary air drainage pipe.

[0011] The above-mentioned concentric multi-point uniformly distributed exhauster is installed on the bypass flue of the air preheater upstream of the desulfurization wastewater evaporation tower through the high-temperature flue gas extraction port and the mixed flue gas exhaust port, that is, the bypass flue of the air preheater upstream of the desulfurization wastewater evaporation tower is divided into two sections: the first bypass inlet flue and the second bypass inlet flue, one end of the first bypass inlet flue is connected to the main inlet flue of the air preheater, and the other end is connected to the high-temperature flue gas extraction port on the concentric multi-point uniformly distributed exhauster; one end of the second bypass inlet flue is connected to the mixed flue gas exhaust port on the concentric multi-point uniformly distributed exhauster, and the other end is connected to the flue gas inlet on the desulfurization wastewater evaporation tower. The bypass flue of the air preheater downstream of the desulfurization wastewater evaporation tower is connected to the flue gas outlet on the desulfurization wastewater evaporation tower at one end, and connected to the outlet main flue of the air preheater at the other end.

[0012] The air inlet of the hot primary air nozzle is connected to the annular cavity, and the air nozzle on the hot primary air nozzle is located outside the annular cavity and points to the axis of the inner cylinder.

[0013] The connection and communication of pipelines in this application both refer to being connected and communicating.

[0014] The flue gas flow rate increasing system of the above-mentioned desulfurization wastewater drying tower introduces hot primary air through the hot primary air drainage pipe, and mixes it with the flue gas in the air preheater bypass flue through concentric multi-point evenly distributed vacuum pumps to increase the flue gas flow rate, thereby ensuring the desulfurization wastewater drying effect, and the size of the hot primary air can be adjusted according to engineering practice, which is flexible and controllable.

[0015] To improve the uniformity of the mixed flue gas, the inner cylinder and the outer cylinder are concentrically arranged, that is, the axes of the inner cylinder and the outer cylinder coincide.

[0016] To balance the flow rate improvement effect and the uniformity of the mixed flue gas, each hot primary air nozzle is arranged obliquely downward, and the injection directions all point to the axis of the inner cylinder. Further preferably, the axes of each hot primary air nozzle and the axial direction of the inner cylinder form an angle of 30-45°.

[0017] To further improve the uniformity of the mixed flue gas, each hot primary air nozzle is evenly distributed along the periphery of the lower ring plate.

[0018] To further improve the flow rate improvement effect, the bottom of the annular cavity is of a tapered structure.

[0019] To facilitate installation, the top of the outer cylinder is lower than the top of the inner cylinder.

[0020] To facilitate installation, the flue gas flow rate improvement system of the above-mentioned desulfurized waste water evaporation tower further includes a mixing cylinder, and the mixing cylinder is docked at the bottom of the outer cylinder and serves as the mixed flue gas discharge port.

[0021] Installation flanges can be provided at the high-temperature flue gas extraction ports and the mixed flue gas discharge ports of the concentric multi-point evenly distributed air extractors to facilitate installation.

[0022] A method for improving the flue gas flow rate of a desulfurized waste water evaporation tower is realized by using the above-mentioned flue gas flow rate improvement system of the desulfurized waste water evaporation tower: the hot primary air is introduced into the sealed annular cavity between the outer cylinder and the inner cylinder through the hot primary air diversion pipe, and is sprayed into the air preheater bypass flue through the hot primary air nozzles. The hot primary air is sprayed into the flue gas from all around the flue gas and mixed with the flue gas to increase the flue gas flow rate, and the flow rate of the mixed flue gas is adjusted by adjusting the opening degree of the air inlet regulating valve.

[0023] To balance the flow rate improvement effect and the mixing uniformity and ensure the desulfurized waste water evaporation effect, the hot primary air is sprayed into the air preheater bypass flue at an angle of 30-45° with the axial direction of the air preheater bypass flue and pointing to the axis of the air preheater bypass flue. In this way, a significant flow rate improvement effect can be obtained with less hot primary air, and at the same time, the uniformity of the mixed gas is ensured.

[0024] As common knowledge, in the direction from upstream to downstream, that is, the direction of material flow, the material flows from upstream to downstream.

[0025] For the technologies not mentioned in the present invention, reference is made to the prior art.

[0026] The flue gas flow rate boosting system of the desulfurized waste water evaporation tower of the present invention introduces hot primary air through a hot primary air diversion pipe and mixes it with the flue gas in the bypass flue of the air preheater through a concentric multi-point evenly distributed air extractor to boost the flue gas flow rate, ensure the evaporation effect of the desulfurized waste water, and can adjust the size of the hot primary air according to the actual engineering situation. The structure is simple, flexible, controllable, has good adaptability, and low transformation cost; further through the structural design of the concentric multi-point evenly distributed air extractor, both the flow rate boosting effect and the mixing uniformity of the mixed flue gas are taken into account. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the installation position of the flue gas flow rate boosting system of the desulfurized waste water evaporation tower of the present invention;

[0028] Figure 2 is Figure 1 the elevation structure schematic diagram of the concentric multi-point evenly distributed air extractor in

[0029] Figure 3 is Figure 1 the elevation structure sectional view of the concentric multi-point evenly distributed air extractor in

[0030] In the figure: 1 is the hot primary air diversion pipe, 2 is the concentric multi-point evenly distributed air extractor, 21 is the outer cylinder, 22 is the inner cylinder, 23 is the upper ring plate, 3 is the air inlet regulating valve, 4 is the hot primary air main pipe, 5 is the desulfurized waste water evaporation tower, 6 is the high-temperature flue gas extraction port of the concentric multi-point evenly distributed air extractor, 7 is the mixed flue gas discharge port of the concentric multi-point evenly distributed air extractor, 8 is the hot primary air interface of the concentric multi-point evenly distributed air extractor, and 9 is the hot primary air nozzle of the concentric multi-point evenly distributed air extractor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] In order to better understand the present invention, the content of the present invention will be further clarified below in conjunction with embodiments, but the content of the present invention is not limited to the following embodiments.

[0032] The up-down, left-right, horizontal, vertical, top-bottom and other orientation words in this application are all based on the relative orientation or positional relationship shown in the attached Figure 3 drawings, and should not be construed as an absolute limitation to this application.

[0033] Embodiment 1

[0034] As Figure 1 shown, a flue gas flow rate boosting system of a desulfurized waste water evaporation tower, one end of the bypass flue of the air preheater is connected to the inlet main flue of the air preheater, and the other end is connected to the outlet main flue of the air preheater. The desulfurized waste water evaporation tower is arranged on the bypass flue of the air preheater, and includes a hot primary air diversion pipe, a concentric multi-point evenly distributed air extractor and an air inlet regulating valve;

[0035] As Figure 2-3As shown in the figure, the concentric multi-point evenly distributed air extractor includes an inner cylinder, an outer cylinder, an upper ring plate and a lower ring plate; the outer diameter of the inner cylinder is smaller than the inner diameter of the outer cylinder, and the inner cylinder is located inside the outer cylinder; the upper ring plate and the lower ring plate are respectively connected to the top and bottom of the outer cylinder, so that a sealed annular cavity is formed between the outer cylinder and the inner cylinder; the lower ring plate is provided with evenly distributed hot primary air nozzles along the perimeter; the top of the inner cylinder serves as the high-temperature flue gas extraction port, and the bottom serves as the mixed flue gas discharge port; the side wall of the outer cylinder is provided with a hot primary air inlet.

[0036] The concentric multi-point evenly distributed air extractor is installed on the bypass flue of the air preheater through the high-temperature flue gas extraction port and the mixed flue gas discharge port, and the concentric multi-point evenly distributed air extractor is located upstream of the desulfurized waste water evaporation tower; one end of the hot primary air diversion pipe is connected to the hot primary air inlet on the outer cylinder, and the other end is connected to the hot primary air main pipe; the air inlet regulating valve is installed on the hot primary air diversion pipe.

[0037] The above-mentioned flue gas flow rate boosting system of the desulfurized waste water evaporation tower introduces hot primary air through the hot primary air diversion pipe and mixes it with the flue gas in the bypass flue of the air preheater through the concentric multi-point evenly distributed air extractor to boost the flue gas flow rate, ensure the evaporation effect of the desulfurized waste water, and can adjust the size of the hot primary air according to the actual situation of the project, which is flexible and controllable.

[0038] Embodiment 2

[0039] On the basis of Embodiment 1, the following further improvements are made: in order to improve the uniformity of the mixed flue gas, the inner cylinder and the outer cylinder are concentrically arranged. In order to balance the flow rate boosting effect and the uniformity of the mixed flue gas, each hot primary air nozzle is arranged obliquely downward, and the jet direction points to the axis of the inner cylinder. In this example, the axis of each hot primary air nozzle forms an angle of 40° with the axial direction of the inner cylinder (verified by experiments, it can also be 30°, 35°, 45°), and the interval between adjacent two hot primary air nozzles is 8 cm.

[0040] Embodiment 3

[0041] On the basis of Embodiment 2, the following further improvements are made: in order to further improve the flow rate boosting effect, the bottom of the annular cavity is of a tapered structure. For the convenience of installation, the top of the outer cylinder is lower than the top of the inner cylinder, and the bottom of the outer cylinder is butted with a mixing cylinder, which serves as the mixed flue gas discharge port. As Figure 2-3 As shown in the figure, installation flanges are respectively arranged at the high-temperature flue gas extraction port, the mixed flue gas discharge port and the hot primary air inlet of the concentric multi-point evenly distributed air extractor for easy installation.

[0042] A method for increasing the flue gas flow rate of a desulfurized wastewater evaporation tower is realized by using the above-mentioned flue gas flow rate increasing system of the desulfurized wastewater evaporation tower: The hot primary air is introduced into the sealed annular cavity between the outer cylinder and the inner cylinder through the hot primary air diversion pipe, and is sprayed into the bypass flue of the air preheater through the hot primary air nozzle; The hot primary air is sprayed into the flue gas at an angle of 40° with the axis of the bypass flue of the air preheater and in a direction pointing to the axis of the bypass flue of the air preheater, and is mixed with the flue gas to increase the flue gas flow rate. The flow rate of the mixed flue gas is adjusted by adjusting the opening degree of the air inlet regulating valve.

[0043] The above-mentioned flue gas flow rate increasing system and method of the desulfurized wastewater evaporation tower introduce hot primary air through the hot primary air diversion pipe, and mix it with the flue gas in the bypass flue of the air preheater through the concentric multi-point evenly distributed air extractor to increase the flue gas flow rate, ensure the evaporation effect of the desulfurized wastewater, and can adjust the size of the hot primary air according to the actual situation of the project. The structure is simple, flexible, controllable, has good adaptability, and low transformation cost; Further, through the structural design of the concentric multi-point evenly distributed air extractor, the flow rate increase effect and mixing uniformity of the mixed flue gas are taken into account.

Claims

1. A flue gas flow rate boosting system for a desulfurized wastewater evaporation tower, one end of a bypass flue of an air preheater is connected to an inlet main flue of the air preheater, and the other end is connected to an outlet main flue of the air preheater. The desulfurized wastewater evaporation tower is arranged on the bypass flue of the air preheater, and is characterized in that: It includes a hot primary air diversion pipe, a concentric multi-point evenly distributed air extractor, and an air inlet regulating valve; The concentric multi-point evenly distributed air extractor includes an inner cylinder, an outer cylinder, an upper ring plate, and a lower ring plate; the outer diameter of the inner cylinder is smaller than the inner diameter of the outer cylinder, and the inner cylinder is located inside the outer cylinder; the upper ring plate and the lower ring plate are respectively connected to the top and bottom of the outer cylinder, so that a sealed annular cavity is formed between the outer cylinder and the inner cylinder; the lower ring plate is provided with hot primary air nozzles distributed along the perimeter; the top of the inner cylinder serves as a high-temperature flue gas extraction port, and the bottom serves as a mixed flue gas discharge port; the side wall of the outer cylinder is provided with a hot primary air inlet; The concentric multi-point evenly distributed air extractor is installed on the bypass flue of the air preheater through the high-temperature flue gas extraction port and the mixed flue gas discharge port, and the concentric multi-point evenly distributed air extractor is located upstream of the desulfurized waste water evaporation tower; one end of the hot primary air diversion pipe is connected to the hot primary air inlet on the outer cylinder, and the other end is connected to the hot primary air main pipe; the air inlet regulating valve is installed on the hot primary air diversion pipe.

2. The flue gas flow rate boosting system of the desulfurized wastewater evaporation tower according to claim 1, wherein: The inner cylinder and the outer cylinder are concentrically arranged.

3. The flue gas flow rate boosting system of the desulfurized wastewater evaporation tower according to claim 1 or 2, characterized in that: Each hot primary air nozzle is arranged obliquely downward, and the jet direction points to the axis of the inner cylinder.

4. The flue gas flow rate boosting system of the desulfurized wastewater evaporation tower according to claim 1 or 2, characterized in that: The axis of each hot primary air nozzle forms an angle of 30-45° with the axial direction of the inner cylinder.

5. The flue gas flow rate boosting system of the desulfurized wastewater evaporation tower according to claim 1 or 2, characterized in that: Each hot primary air nozzle is evenly distributed along the perimeter of the lower ring plate.

6. The flue gas flow rate boosting system of the desulfurized wastewater evaporation tower according to claim 1 or 2, characterized in that: The bottom of the annular cavity is of a tapered structure.

7. The flue gas flow rate boosting system of the desulfurized wastewater evaporation tower according to claim 1 or 2, characterized in that: The top of the outer cylinder is lower than the top of the inner cylinder.

8. The flue gas flow rate boosting system of the desulfurized wastewater evaporation tower according to claim 1 or 2, characterized in that: It also includes a mixing cylinder, which is connected to the bottom of the outer cylinder and serves as a mixed flue gas discharge port.

9. A method for increasing the flue gas flow rate of a desulfurized wastewater evaporation tower, which uses the flue gas flow rate increasing system of the desulfurized wastewater evaporation tower described in any one of claims 1-8, characterized in that: The hot primary air is introduced into the sealed annular cavity between the outer cylinder and the inner cylinder through the hot primary air diversion pipe, and is sprayed into the bypass flue of the air preheater through the hot primary air nozzles. The hot primary air is sprayed into the flue gas from all around the flue gas to mix with the flue gas to increase the flue gas flow rate, and the flow rate of the mixed flue gas is adjusted by adjusting the opening degree of the air inlet regulating valve.

10. The method for increasing the flue gas flow rate of the desulfurized wastewater evaporation tower according to claim 9, characterized in that: The hot primary air is sprayed into the flue gas at an angle of 30-45° with the axial direction of the bypass flue of the air preheater and pointing to the axis of the bypass flue of the air preheater.

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