Flue gas flow boosting system and method for a desulfurization wastewater evaporation tower

Abstract

The application discloses a flue gas flow lifting system and method of a desulfurization wastewater evaporation tower, and the system comprises a hot primary air flow guide pipe, a concentric multi-point uniform distribution air extractor and an air inlet adjusting valve; the concentric multi-point uniform distribution air extractor comprises an inner cylinder, an outer cylinder, an upper ring plate and a lower ring plate; the inner cylinder is located on the inner side of the outer cylinder; the upper ring plate and the lower ring plate are connected to the top and the bottom of the outer cylinder respectively, 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 a high-temperature flue gas extraction port, and the bottom is a mixed flue gas discharge port; the sidewall of the outer cylinder is provided with a hot primary air inlet; the concentric multi-point uniform distribution air extractor is installed on an air preheater bypass flue, and is located upstream of the desulfurization wastewater evaporation tower; one end of the hot primary air flow guide pipe is connected to the hot primary air inlet on the outer cylinder, and the other end is connected to a hot primary air main pipe; and the air inlet adjusting valve is installed on the hot primary air flow guide pipe. The application can lift the flue gas flow according to the requirement.

Description

Technical Field

[0001] This invention relates to a flue gas flow rate enhancement system and method for a desulfurization wastewater drying tower, belonging to the technical field of zero discharge of desulfurization wastewater from coal-fired power plants. Background Technology

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

[0003] In the zero-discharge process for desulfurization wastewater from coal-fired boilers, the conventional technical route is to use the heat of the boiler flue gas to evaporate the desulfurization wastewater, and then spray the wastewater into the main flue of the air preheater outlet or into a separately installed bypass flue of the air preheater. Because spraying into the main flue outlet may bring serious flue corrosion risks, it is generally recommended to build a new bypass flue and equip it with an independent drying tower to evaporate the desulfurization 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 rotary air preheater commonly used in current coal-fired power plants has a three-compartment structure, including a flue gas compartment, a primary air compartment, and a secondary air compartment. The flue gas compartment is connected to the main inlet flue and the outlet flue. One end of the air preheater bypass flue is connected to the main inlet flue and the other end is connected to the main outlet flue. The primary air compartment is connected to the cold primary air header and the outlet primary air header. The secondary air compartment is connected to the cold secondary air header and the outlet primary air header.

[0005] The desulfurization wastewater evaporation system based on the air preheater flue gas bypass uses the differential pressure on the air preheater flue gas side to drive high-temperature flue gas into the evaporation tower. Because the differential pressure on the air preheater flue gas side changes with the unit load and the degree of blockage, it is difficult to adjust the amount of flue gas entering the evaporation tower. Especially when the differential pressure on the air preheater flue gas side is small, it may cause insufficient flue gas flow into the desulfurization wastewater evaporation tower, resulting in problems such as the desulfurization wastewater not being dried in time and wastewater sticking to the wall and causing corrosion. Summary of the Invention

[0006] To address the problem of insufficient flue gas flow capacity in traditional air preheater bypass flue desulfurization wastewater drying towers, this invention provides a flue gas flow enhancement system and method for desulfurization wastewater drying towers.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A flue gas flow enhancement system for a desulfurization wastewater drying tower, wherein one end of the air preheater bypass flue 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, and the desulfurization wastewater drying tower is located on the air preheater bypass flue, including a hot primary air diversion pipe, a concentric multi-point uniformly distributed air ejector and an air inlet regulating valve.

[0009] The concentric multi-point uniformly distributed exhaust fan 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, forming a sealed annular cavity 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 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.

[0010] The concentric multi-point uniformly 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 uniformly distributed air extractor is located upstream of the desulfurization wastewater drying 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.

[0011] The aforementioned concentric multi-point uniformly distributed exhaust fan is installed on the bypass flue of the air preheater upstream of the desulfurization wastewater drying tower via a high-temperature flue gas extraction port and a mixed flue gas discharge port. This means the bypass flue of the air preheater upstream of the desulfurization wastewater drying tower is divided into two sections: a first bypass inlet flue and a 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 exhaust fan. One end of the second bypass inlet flue is connected to the mixed flue gas discharge port on the concentric multi-point uniformly distributed exhaust fan, and the other end is connected to the flue gas inlet of the desulfurization wastewater drying tower. The bypass flue of the air preheater downstream of the desulfurization wastewater drying tower is connected at one end to the flue gas outlet of the desulfurization wastewater drying tower, and at the other end to the main outlet flue of the air preheater.

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

[0013] In this application, the terms "connection" and "connection" of pipelines refer to both connection and interconnection.

[0014] The flue gas flow enhancement system of the desulfurization wastewater drying tower introduced hot primary air through a hot primary air diversion pipe and mixed it with the flue gas in the bypass flue of the air preheater through a concentric multi-point uniformly distributed air extractor to enhance the flue gas flow and ensure the desulfurization wastewater drying effect. The size of the hot primary air can be adjusted according to the engineering practice, making it flexible and controllable.

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

[0016] To balance the increase in flow rate and the uniformity of the mixed flue gas, each hot primary air nozzle is angled downwards, and the injection direction is all directed towards the axis of the inner cylinder. More preferably, the axis of each hot primary air nozzle forms an angle of 30–45° with the axis of the inner cylinder.

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

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

[0019] For ease of installation, the top of the outer cylinder is lower than the top of the inner cylinder.

[0020] To facilitate installation, the flue gas flow enhancement system of the aforementioned desulfurization wastewater drying tower also includes a mixing cylinder, which is connected to the bottom of the outer cylinder and serves as the outlet for mixed flue gas.

[0021] Installation flanges can be installed at the high-temperature flue gas extraction port and the mixed flue gas discharge port of the concentric multi-point uniformly distributed exhaust fan for easy installation.

[0022] A method for increasing the flue gas flow rate of a desulfurization wastewater drying tower is implemented using the aforementioned flue gas flow rate increasing system for the desulfurization wastewater drying tower: hot primary air is introduced into a sealed annular cavity between the outer and inner cylinders through a hot primary air inlet pipe, and is injected into the bypass flue of the air preheater through a hot primary air nozzle. The hot primary air is injected into the flue gas from all sides and mixes with the flue gas to increase the flue gas flow rate. The flow rate of the mixed flue gas is adjusted by regulating the opening of the inlet regulating valve.

[0023] To balance the flow rate increase with the uniformity of mixing and ensure the effective evaporation of desulfurization wastewater, the hot primary air is injected at a 30-45° angle to the axis of the air preheater bypass flue, pointing towards the axis of the air preheater bypass flue. This allows for a significant flow rate increase with a smaller amount of hot primary air, while ensuring the uniformity of the mixed gas.

[0024] As is common sense, the direction from upstream to downstream is the direction of material flow, where materials flow from upstream to downstream.

[0025] Any techniques not mentioned in this invention are based on existing technologies.

[0026] The flue gas flow rate enhancement system for the desulfurization wastewater drying tower of this invention introduces hot primary air through a hot primary air inlet pipe and mixes it with the flue gas in the bypass flue of the air preheater through a concentric multi-point uniformly distributed air extractor to enhance the flue gas flow rate, ensuring the desulfurization wastewater drying effect. Furthermore, the size of the hot primary air can be adjusted according to engineering practice. The system is simple in structure, flexible, controllable, adaptable, and has low modification costs. Moreover, the structural design of the concentric multi-point uniformly distributed air extractor balances the flow rate enhancement effect and the mixing uniformity of the mixed flue gas. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the installation location of the flue gas flow enhancement system for the desulfurization wastewater drying tower of the present invention;

[0028] Figure 2 for Figure 1 Schematic diagram of the elevation structure of the concentric multi-point uniformly distributed air ejector;

[0029] Figure 3 for Figure 1 Cross-sectional view of the elevation structure of the concentric multi-point uniformly distributed air ejector;

[0030] In the diagram: 1 is the hot primary air intake pipe, 2 is the concentric multi-point uniformly 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 header, 5 is the desulfurization wastewater drying tower, 6 is the high-temperature flue gas extraction port of the concentric multi-point uniformly distributed air extractor, 7 is the mixed flue gas discharge port of the concentric multi-point uniformly distributed air extractor, 8 is the hot primary air interface of the concentric multi-point uniformly distributed air extractor, and 9 is the hot primary air nozzle of the concentric multi-point uniformly distributed air extractor. Detailed Implementation

[0031] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0032] The directional terms used in this application, such as up / down, left / right, horizontal, vertical, top / bottom, etc., are all based on the appendix. Figure 3 The relative orientations or positional relationships shown should not be construed as an absolute limitation on this application.

[0033] Example 1

[0034] like Figure 1 As shown, a flue gas flow enhancement system for a desulfurization wastewater drying tower is provided. One end of the air preheater bypass flue 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 desulfurization wastewater drying tower is located on the air preheater bypass flue and includes a hot primary air diversion pipe, a concentric multi-point uniformly distributed air extractor, and an air inlet regulating valve.

[0035] like Figure 2-3As shown, the concentric multi-point uniformly 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 evenly distributed around 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;

[0036] The concentric multi-point uniformly 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 uniformly distributed air extractor is located upstream of the desulfurization wastewater drying 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 flue gas flow enhancement system of the desulfurization wastewater drying tower introduced hot primary air through a hot primary air diversion pipe and mixed it with the flue gas in the bypass flue of the air preheater through a concentric multi-point uniformly distributed air extractor to enhance the flue gas flow and ensure the desulfurization wastewater drying effect. The size of the hot primary air can be adjusted according to the engineering practice, making it flexible and controllable.

[0038] Example 2

[0039] Based on Example 1, the following improvements were made: To improve the uniformity of the mixed flue gas, the inner and outer cylinders are concentrically arranged. To balance the flow rate increase and the uniformity of the mixed flue gas, each hot primary air nozzle is angled downwards, and the injection direction is directed towards the axis of the inner cylinder. In this example, the axis of each hot primary air nozzle forms a 40° angle with the axis of the inner cylinder (experimentally verified, it can also be 30°, 35°, or 45°), and the interval between two adjacent hot primary air nozzles is 8 cm.

[0040] Example 3

[0041] Based on Example 2, the following improvements were made: To further enhance the flow rate increase, the bottom of the annular cavity has a tapered structure. For ease 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 connected to a mixing cylinder, serving as the outlet for the mixed flue gas. Figure 2-3 As shown, the high-temperature flue gas extraction port, mixed flue gas discharge port, and hot primary air inlet of the concentric multi-point uniformly distributed exhaust fan are each equipped with mounting flanges for easy installation.

[0042] A method for increasing the flue gas flow rate of a desulfurization wastewater drying tower is implemented using the aforementioned flue gas flow rate increasing system for the desulfurization wastewater drying tower: hot primary air is introduced into a sealed annular cavity between the outer and inner cylinders through a hot primary air inlet pipe, and is injected into the bypass flue of the air preheater through a hot primary air nozzle; the hot primary air is injected into the flue gas at a 40° angle to the axis of the bypass flue of the air preheater and in the direction of the axis of the bypass flue of the air preheater, mixing 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 of the air inlet regulating valve.

[0043] The above-mentioned flue gas flow enhancement system and method for the desulfurization wastewater drying tower 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 uniformly distributed air extractor to enhance the flue gas flow and ensure the desulfurization wastewater drying effect. The size of the hot primary air can be adjusted according to the engineering practice. The structure is simple, flexible, controllable, adaptable, and has low modification cost. Furthermore, the structural design of the concentric multi-point uniformly distributed air extractor takes into account both the flow enhancement effect and the mixing uniformity of the mixed flue gas.

Claims

1. A flue gas flow rate boosting system for a desulfurization wastewater drying tower, wherein one end of an air preheater bypass flue 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, and the desulfurization wastewater drying tower is located on the air preheater bypass flue, characterized in that: Includes hot primary air duct, concentric multi-point uniformly distributed air extractor and air inlet regulating valve; The concentric multi-point uniformly distributed exhaust fan 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, forming a sealed annular cavity 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 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 uniformly 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 uniformly distributed air extractor is located upstream of the desulfurization wastewater drying 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 for the desulfurization wastewater drying tower according to claim 1, characterized in that: The inner and outer cylinders are set concentrically.

3. The flue gas flow rate boosting system for the desulfurization wastewater drying tower according to claim 1 or 2, characterized in that: Each hot primary air nozzle is set at an angle downwards, and the spray direction is all pointing towards the axis of the inner cylinder.

4. The flue gas flow rate boosting system for the desulfurization wastewater drying tower according to claim 1 or 2, characterized in that: The axis of each hot primary air nozzle forms an angle of 30 to 45 degrees with the axis of the inner cylinder.

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

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

7. The flue gas flow rate boosting system for the desulfurization wastewater drying 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 for the desulfurization wastewater drying 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 the outlet for mixed flue gas.

9. A method for increasing the flue gas flow rate of a desulfurization wastewater drying tower, comprising the flue gas flow rate increasing system of the desulfurization wastewater drying tower as described in any one of claims 1-8, characterized in that: Hot primary air is introduced into the sealed annular cavity between the outer and inner cylinders through a hot primary air inlet pipe, and is injected into the bypass flue of the air preheater through a hot primary air nozzle. Hot primary air is injected into the flue gas from all sides and mixes 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 of the air inlet regulating valve.

10. The method for increasing the flue gas flow rate of the desulfurization wastewater drying tower according to claim 9, characterized in that: Hot primary air is injected into the flue gas at an angle of 30-45° to the axis of the air preheater bypass flue and in the direction of the axis of the air preheater bypass flue.

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