Waste heat recovery system for slag drying machine of thermal power plant

Abstract

The utility model relates to the technical field of waste heat recovery systems, in particular to a waste heat recovery system for a slag dryer of a thermal power plant, which comprises the slag dryer, the top of the slag dryer is connected with a boiler, and an air supplement door is arranged on the slag dryer; the slag dryer is connected with a position A of a hot air recirculating air pipe through a recovery pipe, a hot air recirculating fan is arranged on the hot air recirculating air pipe, and the position A is located on the front side of the hot air recirculating fan and is close to an air inlet of the hot air recirculating fan; the hot air recirculating air pipe is connected with a position B of an air supply pipe for supplying air to the boiler furnace; the circulating fan can provide suction force to pump out air in the slag dryer; cooling air can enter the hearth in a controllable mode, the temperature of the cooling air can reach the temperature of air needed in the hearth, and the efficiency of the boiler is guaranteed.

Description

Technical Field

[0001] This utility model relates to the technical field of waste heat recovery systems, specifically a waste heat recovery system for a dry slag machine in a thermal power plant. Background Technology

[0002] Thermal power plant boilers generate heat energy through the combustion of raw coal, which is then used to heat the boiler water to produce superheated steam with a certain temperature and pressure for use by the steam turbine. After the raw coal combustion, a large amount of high-temperature ash is produced. This ash is collected in the boiler's cold ash hopper, cooled by a slag dryer, and then transported to the slag bin for solid waste treatment. Currently, a partial air intake damper is installed at the bottom of the horizontal section of the slag dryer. The negative pressure in the furnace allows outside cold air to enter the dryer through this damper to cool the high-temperature ash. The high-temperature air after cooling the ash enters the furnace through the cold ash hopper at the bottom of the furnace. However, this process has two drawbacks: firstly, it increases air leakage at the bottom of the boiler, resulting in a large amount of uncontrolled air entering the furnace, which is difficult to control and detect; secondly, because the cooling air (150℃) from the slag dryer is significantly lower than the hot secondary air (350℃), boiler efficiency is reduced, affecting the safe and economical operation of the boiler. Utility Model Content

[0003] The main objective of this invention is to provide a waste heat recovery system for a dry slag machine in a thermal power plant, in order to solve the problems of unorganized entry of cooling air from the dry slag machine into the furnace and the low temperature of the air entering the furnace, which leads to a reduction in boiler efficiency in the prior art.

[0004] To achieve the above objectives, this utility model provides a waste heat recovery system for a dry ash machine in a thermal power plant, including a dry ash machine, a boiler connected to the top of the dry ash machine, and a make-up air damper on the dry ash machine; the dry ash machine is connected to a hot air recirculation duct at point A via a recovery pipe, a hot air recirculation fan is installed on the hot air recirculation duct, point A is located in front of the hot air recirculation fan and close to the air inlet of the hot air recirculation fan; the hot air recirculation duct is connected to an air supply duct at point B that supplies air to the boiler furnace; the recirculation fan can provide suction force to extract the air from the dry ash machine.

[0005] Furthermore, an air preheater is installed on the air supply duct, with point B located in front of the air preheater and close to its inlet; a blower is installed at the front end of the air supply duct.

[0006] Furthermore, valve one is installed on the hot air recirculation duct, located in front of point A; valve two is installed on the recovery pipe.

[0007] Furthermore, the dry slag machine is equipped with a pressure gauge to detect its internal pressure; by reading the pressure gauge, the pressure inside the dry slag machine is ensured to be slightly lower than the pressure inside the furnace, preventing air from entering the furnace from the dry slag machine, and also preventing a large amount of air from entering the dry slag machine from the furnace.

[0008] Furthermore, a filter screen is installed at the connection point between the dry slag machine and the recovery pipe; the filter screen prevents large slag lumps from being sucked into the hot air recirculation fan, which could damage the fan.

[0009] This invention utilizes a recovery pipe to draw cooling air from the dry slag machine into the hot air recirculation duct. The cooling air is then heated to a specified temperature by the air preheater and recovered for use in the boiler. This recycling of cooling air reduces the consumption of hot air in the hot air recirculation duct, allowing the cooling air to enter the furnace in a controllable manner and ensuring that the temperature reaches the required temperature for the furnace, thus guaranteeing boiler efficiency. Attached Figure Description

[0010] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0011] Figure 1 This is a schematic diagram of the structure of an embodiment;

[0012] In the diagram: 1. Dry slag machine; 2. Boiler; 3. Hot air recirculation duct; 4. Hot air recirculation fan; 5. Air supply duct; 6. Filter screen; 7. Air preheater; 8. Valve 1; 9. Recovery pipe; 10. Valve 2; 11. Pressure gauge; 12. Make-up air damper; 13. Air supply fan. Detailed Implementation

[0013] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0014] like Figure 1 As shown in the embodiment of this utility model, a waste heat recovery system for a dry ash machine in a thermal power plant is provided, including a dry ash machine 1, a boiler 2 connected to the top of the dry ash machine 1, and multiple air supply doors 12 on the dry ash machine 1; the dry ash machine 1 is connected to point A of a hot air recirculation duct 3 via a recovery pipe 9, and a hot air recirculation fan 4 is installed on the hot air recirculation duct 3, with point A located in front of the hot air recirculation fan 4 and close to the air inlet of the hot air recirculation fan 4; the hot air recirculation duct 3 is connected to point B of an air supply pipe 5 that supplies air to the furnace of the boiler 2; the recirculation fan 4 can provide suction force to extract the air from the dry ash machine 1.

[0015] An air preheater 7 is installed on the air supply duct 5, and point B is located in front of the air preheater 7 and close to the inlet of the air preheater 7; a blower 13 is installed at the front end of the air supply duct 5.

[0016] A valve 18 is installed on the hot air recirculation duct 3, and the valve 18 is located on the front side of point A; a valve 20 is installed on the recovery pipe 9.

[0017] The dry slag machine 1 is equipped with a pressure gauge 11 for detecting its internal pressure. The pressure gauge 11 reads the internal pressure of the dry slag machine 1 to ensure that the internal pressure of the dry slag machine 1 is about 10 Pascals lower than the pressure inside the furnace, so as to prevent the air inside the dry slag machine 1 from entering the furnace and also to prevent a large amount of air inside the furnace from entering the dry slag machine.

[0018] A filter screen 6 is installed at the connection point between the dry slag machine 1 and the recovery pipe 9; the filter screen 6 prevents large slag lumps from being sucked into the hot air recirculation fan 4, which could damage the fan.

[0019] The working principle of the above embodiments is as follows:

[0020] The hot air recirculation fan 4 draws the cooling air from the dry slag machine 1 into the hot air recirculation duct 3, and finally heats the cooling air to the specified temperature through the air preheater 7 before recycling it into the boiler 2 for use.

[0021] This embodiment allows the cooling air from the dry slag machine to be controlled and recycled into the furnace, and the temperature can reach the required temperature of the air in the furnace, ensuring the boiler efficiency. The function of the hot air in the hot air recirculation duct is to increase the temperature of the cold air at the air preheater inlet, reduce condensation and low-temperature corrosion caused by the low temperature at the cold end of the air preheater, and the recycling of cooling air can reduce the consumption of hot air in the hot air recirculation duct.

[0022] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A waste heat recovery system for a dry ash machine in a thermal power plant, comprising a dry ash machine (1), wherein a boiler (2) is connected to the top of the dry ash machine (1), and a make-up air damper (12) is provided on the dry ash machine (1); characterized in that, The dry slag machine (1) is connected to point A of the hot air recirculation duct (3) via the recovery pipe (9). A hot air recirculation fan (4) is installed on the hot air recirculation duct (3). Point A is located in front of the hot air recirculation fan (4) and close to the air inlet of the hot air recirculation fan (4). The hot air recirculation duct (3) is connected to point B of the air supply duct (5) that supplies air to the furnace of the boiler (2).

2. The waste heat recovery system for dry slag machines in thermal power plants as described in claim 1, characterized in that, An air preheater (7) is provided on the air supply pipe (5), and point B is located on the front side of the air preheater (7) and close to the inlet of the air preheater (7); a blower (13) is provided at the front end of the air supply pipe (5).

3. The waste heat recovery system for dry slag machines in thermal power plants as described in claim 1, characterized in that, The hot air recirculation duct (3) is equipped with valve one (8), which is located in front of point A; the recovery pipe (9) is equipped with valve two (10).

4. The waste heat recovery system for dry slag machines in thermal power plants as described in claim 1, characterized in that, The dry slag machine (1) is equipped with a pressure gauge (11) for detecting its internal pressure.

5. The waste heat recovery system for dry slag machines in thermal power plants as described in claim 1, characterized in that, A filter screen (6) is provided at the connection point between the dry slag machine (1) and the recovery pipe (9).

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