A coal-fired boiler primary and secondary air hot water air heater device

Abstract

The utility model provides a kind of coal-fired boiler primary air and secondary air hot water air heater device, it is related to coal-fired boiler field.The coal-fired boiler primary air and secondary air hot water air heater device, including the low-temperature coal economizer circulation line for heating, the water outlet end of low-temperature coal economizer circulation line is connected and has heat source inlet pipe through, the water inlet end of low-temperature coal economizer circulation line is connected and has heat source return pipe through, between heat source inlet pipe and heat source return pipe and be connected with primary air fan air heater and air supply fan air heater, the coal-fired boiler primary air and secondary air hot water air heater device, by the heat absorbed by low-temperature coal economizer, utilize low-temperature coal economizer circulation line to be delivered to air heater, by air heater to the air of primary air fan and air supply fan is heated, improve downstream air preheater heat exchange equipment's cold end comprehensive exhaust smoke temperature, to be able to realize the reasonable use of heat, simultaneously, flow regulating valve is connected and set in air heater and heat source inlet pipe connection place, different warm air heater can be passed into different flow heat source, and then targeted adjustment device can be carried out.

Description

Technical Field

[0001] This utility model relates to the field of coal-fired boiler technology, specifically to a primary and secondary air hot water heater device for a coal-fired boiler. Background Technology

[0002] With the transformation of generating units for flexible peak shaving, the peak load of the units has been further reduced. During low-load or low-temperature operation, the comprehensive temperature of the cold end of the air preheater heat transfer elements is far below the required 148℃, leading to frequent blockages in the air preheater heat transfer elements, which can severely affect the unit's output. Currently, there are two solutions to increase the average wall temperature of the cold end of the air preheater: air heaters and hot air recirculation. Hot air recirculation introduces hot secondary air from the air preheater outlet into the fan inlet, increasing the air temperature at the fan inlet and the exhaust gas temperature at the air preheater outlet. Since the hot air is recirculated, it is equivalent to increasing the air volume of the air preheater, which can lead to a decrease in hot air temperature and boiler efficiency. Therefore, to reduce the impact of hot air recirculation on boiler efficiency, the recirculation air volume generally does not exceed 5% of the secondary air volume. Because the hot air contains fly ash, the hot air recirculation scheme carries the risk of fan blade wear. Furthermore, fly ash contains a small amount of ammonium bisulfate, which can deposit on the fan blades at extremely low temperatures. Hot air recirculation causes reduced boiler efficiency, fan blade wear, and scaling.

[0003] Steam heaters are currently a widely used and effective means of increasing the average wall temperature of the cold end of an air preheater. Steam heaters use auxiliary steam to increase the inlet air temperature of the air preheater. This method requires the consumption of auxiliary steam, which will increase the unit's coal consumption.

[0004] Existing patent CN205579622U describes a natural circulation indirect low-temperature economizer, located at the tail end of a boiler flue. An air preheater is also installed within the boiler flue, connected to an air inlet channel. The economizer includes a heat absorption section and a heat release section. The heat absorption section is located downstream of the air preheater within the boiler flue, while the heat release section is located within the air inlet channel. The heat release section is connected to the heat absorption section via a circulation pipe, which includes an ascending pipe and a descending pipe, and contains a heat transfer medium. This technical solution utilizes recovered flue gas waste heat to heat the cold air entering the air preheater, increasing the wall temperature of the cold section and protecting the air preheater. It can replace conventional steam-heated air heaters, saving gas consumption. The increased air temperature entering the furnace cavity leads to a corresponding increase in the flue gas temperature at the air preheater outlet, enhancing the efficiency of flue gas waste heat utilization. Simultaneously, it effectively reduces exhaust gas temperature, utilizing flue gas waste heat and improving the overall operating efficiency of the power plant. However, the return heat source heats each heater evenly, but different heaters have different heating temperature requirements, so a heater that can be adjusted according to the needs is needed. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a primary and secondary air hot water heater device for coal-fired boilers, which solves the problem mentioned in the background technology that the heater cannot be adjusted according to needs.

[0006] Technical solution

[0007] To achieve the above objectives, this utility model is implemented through the following technical solution: a primary and secondary air hot water heater device for a coal-fired boiler, comprising a low-temperature economizer circulation pipeline for heating, wherein the outlet end of the low-temperature economizer circulation pipeline is connected to and penetrates a heat source inlet pipe, and the inlet end of the low-temperature economizer circulation pipeline is connected to and penetrates a heat source return pipe, wherein a primary air fan heater and a blower heater are connected in parallel between the heat source inlet pipe and the heat source return pipe, and both the heat source inlet pipe and the heat source return pipe are connected to and penetrated by a pressurizing component to accelerate the flow rate of the heat source, the primary air fan heater and the blower heater are collectively referred to as heaters, and a flow regulating valve is connected and penetrated at the connection between the heater and the heat source inlet pipe.

[0008] Furthermore, the resistance of the heater is 300 ≤ Pa.

[0009] Furthermore, the connection ends of the heat source inlet pipe and the heat source return pipe are both provided with isolation parts.

[0010] Furthermore, the pressurization component consists of two pressurization valves connected in parallel.

[0011] Furthermore, a return pipe is connected between the heat source inlet pipe and the heat source return pipe relative to the heater, and the return pipe is simultaneously connected to a flow regulating valve that controls its flow rate.

[0012] Furthermore, the heater includes a flow channel for accommodating gas flow, the flow channel being connected and communicating with the air outlets of the primary air fan and the blower, and a spiral finned tube being arranged inside the flow channel perpendicular to the gas flow direction, the liquid inlet end and liquid outlet end of the spiral finned tube being connected and communicating with the heat source inlet pipe and the heat source return pipe, respectively.

[0013] Furthermore, a temperature sensor is installed at the outlet of the low-temperature economizer circulation pipeline, and a temperature sensor is installed at the outlet of each air heater.

[0014] The beneficial effects of this utility model are as follows:

[0015] 1. The primary and secondary air hot water heater system for this coal-fired boiler uses the heat absorbed by the low-temperature economizer to be transported to the heater via the low-temperature economizer circulation pipeline. The heater heats the exhaust air from the primary air fan and the blower, thereby increasing the overall flue gas temperature at the cold end of the downstream air preheater heat exchange equipment. This enables the rational use of heat. At the same time, a flow regulating valve is installed at the connection between the heater and the heat source inlet pipe, which allows for the supply of different flow rates of heat source to different heaters, thus enabling targeted adjustments to the device.

[0016] 2. The primary and secondary air-hot water heater device for this coal-fired boiler, by setting the heater resistance to 300 ≤ Pa, can avoid increasing the load on the fan due to the addition of heaters. The heater includes a flow channel for accommodating gas flow, which is connected and communicates with the air outlets of the primary air fan and the blower. The interior of the flow channel is equipped with a spiral finned tube perpendicular to the gas flow direction. The joint end of the spiral finned tube is located on the outside of the flow channel and is insulated by an insulation cover. By placing the joint on the outside of the flow channel, the projected area of ​​the spiral finned tube in the flow channel can be reduced, thereby reducing the resistance of the heater. Attached Figure Description

[0017] Figure 1 This is a flowchart of the present utility model;

[0018] Figure 2 This is a schematic diagram of the connection of the heater of this utility model.

[0019] The components include: 1. Low-temperature economizer circulation pipeline; 2. Heat source inlet pipe; 3. Heat source return pipe; 4. Primary air fan heater; 5. Supply air fan heater; 6. Pressure boosting component; 7. Flow regulating valve; 8. Isolation section; 601. Pressure boosting valve; 901. Flow channel; 902. Spiral finned tube; 10. Temperature sensor one; 11. Temperature sensor two; 12. Return pipe. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] See Figure 1-2A primary and secondary air hot water heater device for a coal-fired boiler includes a low-temperature economizer circulation pipe 1 for heating. The outlet of the low-temperature economizer circulation pipe 1 is connected to and penetrates a heat source inlet pipe 2. The inlet of the low-temperature economizer circulation pipe 1 is connected to and penetrates a heat source return pipe 3. A primary air fan heater 4 and a blower heater 5 are connected in parallel between the heat source inlet pipe 2 and the heat source return pipe 3. A pressurization component 6 is connected to and penetrates both the heat source inlet pipe 2 and the heat source return pipe 3. The air heater 5 is collectively referred to as the air heater. The air heater is connected to the heat source inlet pipe 2 and is connected to a flow regulating valve 7. The heat absorbed by the low-temperature economizer is transported to the air heater through the low-temperature economizer circulation pipe 1. The air heater heats the air output of the primary air fan and the blower, thereby achieving the rational use of heat. At the same time, the flow regulating valve 7 is installed at the connection between the air heater and the heat source inlet pipe 2, which allows different flow rates of heat source to be supplied to different air heaters, thereby enabling targeted adjustment of the device.

[0022] The resistance of the air heater is ≤300Pa. By limiting the resistance of the air heater, the increased load on the fan due to the addition of the air heater can be avoided. The air heater includes a flow channel 901 that accommodates the gas flow. The flow channel 901 is connected and connected to the air outlets of the primary air fan and the supply air fan respectively. A spiral finned tube 902 is arranged inside the flow channel 901 perpendicular to the gas flow direction. The joint end of the spiral finned tube 902 is located outside the flow channel 901 and is insulated by a heat insulation cover. By placing the joint outside the flow channel 901, the projected area of ​​the spiral finned tube 902 located inside the flow channel 901 can be reduced, thereby reducing the resistance of the air heater. The liquid inlet end and liquid outlet end of the spiral finned tube 902 are connected and connected to the heat source inlet pipe 2 and the heat source return pipe 3 respectively.

[0023] Both the heat source inlet pipe 2 and the heat source return pipe 3 are equipped with an isolation section 8. When the air temperature is high, closing the isolation section 8 can seal the heat source outside the heater, cut off the flow of heat source, and stop the heater from working.

[0024] The pressurization unit 6 consists of two parallel pressurization valves 601, which can pump the heat source to different primary air fan heaters 4 and supply air fan heaters 5.

[0025] Temperature sensor 10 is installed at the outlet of the low-temperature economizer circulation pipeline 1, and temperature sensor 21 is installed at the outlet of each air heater. The flow regulating valve 7 is controlled by the temperature difference between temperature sensor 10 and temperature sensor 211, so that the corresponding air heater can be kept at a suitable temperature.

[0026] A return pipe 12 is connected between the heat source inlet pipe 2 and the heat source return pipe 3 relative to the heater. The return pipe 12 is also connected to the flow regulating valve 7 that controls its flow rate. Other flow regulating valves 7 are adjusted so that the total flow rate supplied by the booster component 6 remains unchanged. The flow rate is balanced by increasing and decreasing the flow regulating valves 7 at the return pipe 12.

[0027] It should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0028] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A primary and secondary air hot water heater device for a coal-fired boiler, comprising a low-temperature economizer circulation pipeline (1) for heating, characterized in that: The outlet end of the low-temperature economizer circulation pipeline (1) is connected to and penetrates a heat source inlet pipe (2), and the inlet end of the low-temperature economizer circulation pipeline (1) is connected to and penetrates a heat source return pipe (3). The heat source inlet pipe (2) and the heat source return pipe (3) are connected in parallel by a primary air blower heater (4) and a blower heater (5). Both the heat source inlet pipe (2) and the heat source return pipe (3) are connected to and pass through a pressurizing component (6) to accelerate the flow rate of the heat source. The primary air blower heater (4) and the blower heater (5) are collectively referred to as heaters. A flow regulating valve (7) is connected to and passes through the connection between the heater and the heat source inlet pipe (2).

2. The coal-fired boiler primary and secondary air hot water heater device according to claim 1, characterized in that: The resistance of the heater is ≤300Pa.

3. The coal-fired boiler primary and secondary air hot water heater device according to claim 2, characterized in that: The connection ends of the heat source inlet pipe (2) and the heat source return pipe (3) are both provided with isolation parts (8).

4. A coal-fired boiler primary and secondary air hot water heater device according to any one of claims 1-3, characterized in that: The booster unit (6) consists of two booster valves (601) connected in parallel.

5. The coal-fired boiler primary and secondary air hot water heater device according to claim 4, characterized in that: The heat source inlet pipe (2) and the heat source return pipe (3) are connected to a return pipe (12) relative to the heater, and the return pipe (12) is simultaneously connected to a flow regulating valve (7) that controls its flow rate.

6. The coal-fired boiler primary and secondary air hot water heater device according to claim 5, characterized in that: The heater includes a flow channel (901) for accommodating gas flow. The flow channel (901) is connected to and communicates with the air outlets of the primary air fan and the blower. The interior of the flow channel (901) is provided with a spiral fin tube (902) perpendicular to the gas flow direction. The liquid inlet and liquid outlet of the spiral fin tube (902) are connected to and communicate with the heat source inlet pipe (2) and the heat source return pipe (3), respectively.

7. The coal-fired boiler primary and secondary air hot water heater device according to claim 6, characterized in that: Temperature sensor 1 (10) is installed at the outlet of the low-temperature economizer circulation pipeline (1), and temperature sensor 2 (11) is installed at the outlet of each heater.

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