A system for heating raw water by using waste heat of a dry slag machine of a coal-fired boiler

Abstract

The application provides a system for heating raw water by using waste heat of a dry slag machine of a coal-fired boiler, and the system comprises a raw water heat exchanger assembly, an upper wall heat exchanger assembly and a lower wall heat exchanger assembly; the raw water heat exchanger assembly is suspended and welded on the conveying assembly of the inclined section of the dry slag machine through a connecting rod; the upper wall heat exchanger assembly is arranged on the upper inner surface of the shell of the dry slag machine through wall welding; the lower wall heat exchanger assembly is arranged on the lower inner surface of the shell of the dry slag machine through wall welding; the upper ends of the upper wall heat exchanger assembly and the lower wall heat exchanger assembly are connected to the upper end of the raw water heat exchanger assembly through pipelines; the raw water heating system provided by the application absorbs the waste heat of the slag by using the flow of the raw water in the heat exchanger, realizes the recycling of the waste heat of the slag, and also plays a cooling role on the slag and the dry slag machine equipment, so that the input of cooling air can be reduced.

Description

Technical Field

[0001] This application relates to the field of waste heat recovery and utilization technology of coal-fired boiler ash drying machine, and in particular to a system for heating raw water using waste heat from coal-fired boiler ash drying machine. Technical Background

[0002] High-temperature slag is generated during the operation of coal-fired boilers in power plants. This high-temperature slag needs to be transported to the slag bin outside the boiler room. The slag dryer is the core equipment for slag conveying. The high-temperature slag is conveyed out through the conveyor chain of the slag dryer. Simultaneously, under the negative pressure of the boiler, ambient cold air enters the slag dryer in the opposite direction, allowing for thorough heat exchange with the high-temperature slag. This gradually cools the slag on the conveyor belt. Cold air entering from the side also cools the slag dryer casing, conveyor belt rollers, and conveyor chain. This air intake serves two purposes: firstly, it cools the slag in the equipment; secondly, the cold air absorbs radiant heat from the boiler and the slag, increasing its temperature, and can then enter the furnace to participate in combustion.

[0003] Although the introduction of cooling air can recover some heat from the slag, the temperature of the slag falling after boiler combustion is approximately 700-900℃. The cooling air can only recover a small amount of heat, resulting in a significant waste as a large portion of the heat remains unrecovered. Furthermore, the cooling air entering from the slag dryer is a "disordered" leak from the bottom of the furnace. If the air volume is too large, it will disrupt the combustion conditions within the furnace, raising the flame center position, increasing the reheat desuperheating water consumption, and raising the flue gas temperature. This leads to increased heat loss from incomplete combustion and flue gas, thereby affecting the safe and economical operation of the boiler equipment.

[0004] Therefore, recovering the waste heat of high-temperature slag and reducing energy waste is an urgent problem to be solved. It is imperative to develop a device that can recover the waste heat of the slag dryer and reduce the amount of cooling air used in the slag dryer. Summary of the Invention

[0005] This application provides a system for heating raw water using waste heat from a coal-fired boiler slag dryer. The system utilizes a heat exchanger installed inside the slag dryer to heat the raw water.

[0006] To achieve the above technical effects, this application provides a system for heating raw water using waste heat from a coal-fired boiler ash dryer, comprising: a boiler, an ash dryer, a conveying assembly, and a cleaning assembly. The ash dryer includes a horizontal section and an inclined section. The horizontal section is located directly below the ash well of the boiler. The conveying assembly is located inside the ash dryer, and the cleaning assembly is located below the conveying assembly.

[0007] It also includes: an electric air intake damper, a raw water heat exchanger assembly, an upper wall heat exchanger assembly, a lower wall heat exchanger assembly, a raw water tank, a raw water supply pump, and a raw water supply pipe;

[0008] The electric air inlet damper is located at the upper end of the inclined section of the dry slag machine; the raw water heat exchanger assembly is suspended and fixedly connected above the conveying assembly in the inclined section of the dry slag machine via a connecting rod; the upper wall heat exchanger assembly is fixedly arranged against the wall on the upper inner surface of the dry slag machine shell; the lower wall heat exchanger assembly is fixedly arranged against the wall on the lower inner surface of the dry slag machine shell; the upper ends of the upper wall heat exchanger assembly and the lower wall heat exchanger assembly are connected to the upper end of the raw water heat exchanger assembly via pipelines.

[0009] The raw water tank is equipped with a raw water supply pump, and the outlet main pipe of the raw water supply pump is connected to the raw water supply pipe. The raw water supply pipe is divided into two branches, which are respectively connected to the upper wall heat exchanger assembly and the lower wall heat exchanger assembly.

[0010] In a preferred embodiment, the raw water heat exchanger assembly includes a first upper header, a first lower header, and a first heat exchanger water pipe connected between the first upper header and the first lower header.

[0011] In a preferred embodiment, the upper wall heat exchanger assembly includes a second upper header, a second lower header, and a second heat exchanger water pipe connected between the second upper header and the second lower header; the lower wall heat exchanger assembly includes a third upper header, a third lower header, and a third heat exchanger water pipe connected between the third upper header and the third lower header; the two water flows of the raw water supply pipe are respectively connected to the second lower header of the upper wall heat exchanger assembly and the third lower header of the lower wall heat exchanger assembly.

[0012] In a preferred embodiment, the first lower header of the raw water heat exchanger assembly is connected to a raw water outlet pipe for the raw water to flow out after heat exchange.

[0013] In a preferred embodiment, the second upper header of the upper wall heat exchanger assembly and the third upper header of the lower wall heat exchanger assembly are both connected to the first upper header of the raw water heat exchanger assembly via pipelines.

[0014] In a preferred embodiment, the raw water outlet pipe is equipped with a pressure gauge, a thermometer, and a flow meter.

[0015] In a preferred embodiment, a heat exchanger soot blower extending to the inner side of the upper shell of the dry slag machine is installed, and the heat exchanger soot blower is controlled to start soot blowing by a timed soot blowing control unit.

[0016] In a preferred embodiment, the outlet header of the raw water supply pump is equipped with a pressure gauge, a thermometer, and a flow meter.

[0017] In a preferred embodiment, the check valve is provided at the outlet of the raw water supply pump.

[0018] In a preferred embodiment, the slag further includes: a slag crusher and a slag bin; the slag crusher is located directly below the farthest end of the conveying assembly; the slag bin is installed below the slag crusher and is used to collect the crushed slag.

[0019] In one preferred embodiment, the conveying assembly includes: a dry slag conveying chain and a first motor; the first motor is used to drive the dry slag conveying chain to rotate toward the slag bin, thereby realizing slag transportation.

[0020] In one preferred embodiment, the cleaning assembly includes a cleaning chain and a second motor, the second motor being used to drive the cleaning chain to rotate in the same direction as the dry slag conveying chain, thereby cleaning the bottom of the dry slag conveying chain.

[0021] In a preferred embodiment, two raw water supply pumps are connected in parallel in the raw water tank to provide water pressure to the raw water heating system.

[0022] The beneficial technical effects of this application are as follows: The raw water heating system provided by this application is equipped with a raw water heat exchanger assembly, an upper wall heat exchanger assembly and a lower wall heat exchanger assembly inside the slag dryer. The raw water is used to absorb the waste heat of the slag by flowing in the heat exchanger, realizing the recovery and utilization of waste heat of the slag, while also cooling the slag and the slag dryer equipment, which can reduce the introduction of cooling air. Attached Figure Description

[0023] Figure 1 A schematic diagram of a system for heating raw water using waste heat from a coal-fired boiler ash dryer.

[0024] Figure 2 This is a partially enlarged structural diagram of a system that uses waste heat from a coal-fired boiler slag dryer to heat raw water.

[0025] Figure 3 This is a partially enlarged structural diagram of a system that uses waste heat from a coal-fired boiler slag dryer to heat raw water.

[0026] Figure 4 A schematic diagram of a raw water heat exchanger assembly structure for a system that uses waste heat from a coal-fired boiler slag dryer to heat raw water.

[0027] Figure 5 This is a schematic diagram of a heat exchanger soot blower structure for a system that uses waste heat from a coal-fired boiler ash dryer to heat raw water.

[0028] Attached Figure Labels

[0029] 1. Boiler; 2. Dry slag machine; 3. Conveying assembly; 31. Dry slag conveying chain; 32. First motor; 4. Cleaning assembly; 41. Cleaning chain; 42. Second motor; 5. Electric air inlet damper; 6. Slag crusher; 7. Slag bin; 8. Raw water heat exchanger assembly; 81. First upper header; 82. First lower header; 83. First heat exchanger water pipe; 9. Upper wall heat exchanger assembly; 91. Second upper header; 92. Second lower header; 93. Second heat exchanger water pipe; 10. Lower wall heat exchanger assembly; 101. Third upper header; 102. Third lower header; 103. Third heat exchanger water pipe; 11. Heat exchanger soot blower; 12. Raw water tank; 13. Raw water feed pump; 131. Check valve; 14. Raw water feed pipe; 15. Raw water outlet pipe. Detailed Implementation

[0030] To make the purpose, technical solution, and advantages of this application clearer, the following will be combined with the appendix to this application. Figure 1-5 The technical solutions in this application are clearly and completely described. Obviously, the described embodiments are only some, not all, of the embodiments in this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] like Figure 1-3 As shown, this embodiment provides a system for heating raw water using the waste heat of a coal-fired boiler ash dryer, including: a boiler 1, an ash dryer 2, a conveying assembly 3, and a cleaning assembly 4. The ash dryer 2 includes a horizontal section and an inclined section. The horizontal section is located directly below the ash well of the boiler 1. The conveying assembly 3 is installed inside the ash dryer 2, and the cleaning assembly 4 is installed below the conveying assembly 3.

[0032] Includes: an electric air intake damper 5, a raw water heat exchanger assembly 8, an upper wall heat exchanger assembly 9, a lower wall heat exchanger assembly 10, a raw water tank 12, a raw water supply pump 13, and a raw water supply pipe 14.

[0033] The electric air inlet damper 5 is located at the upper end of the inclined section of the dry slag machine 2; the raw water heat exchanger assembly 8 is suspended and fixedly connected above the conveying assembly 3 in the inclined section of the dry slag machine 2 via a connecting rod; the upper wall heat exchanger assembly 9 is fixedly arranged against the wall on the upper inner surface of the outer shell of the dry slag machine 2; the lower wall heat exchanger assembly 10 is fixedly arranged against the wall on the lower inner surface of the outer shell of the dry slag machine 2; the upper ends of the upper wall heat exchanger assembly 9 and the lower wall heat exchanger assembly 10 are connected to the upper end of the raw water heat exchanger assembly 8 via pipelines.

[0034] The raw water tank 12 is equipped with a raw water supply pump 13. The outlet main pipe of the raw water supply pump 13 is connected to the raw water supply pipe 14. The raw water supply pipe 14 is divided into two paths, which are respectively connected to the upper wall heat exchanger assembly 9 and the lower wall heat exchanger assembly 10.

[0035] Preferably, the raw water heat exchanger assembly (8) is suspended and welded to the conveying assembly (3) on the inclined section of the dry slag machine (2) via a connecting rod, the upper wall heat exchanger assembly (9) is welded to the upper inner surface of the shell of the dry slag machine (2), and the lower wall heat exchanger assembly (10) is welded to the lower inner surface of the shell of the dry slag machine (2).

[0036] Preferably, the raw water heat exchanger assembly 8 includes a first upper header 81, a first lower header 82, and a first heat exchanger water pipe 83 connected between the first upper header 81 and the first lower header 82.

[0037] Preferably, the upper wall heat exchanger assembly 9 includes a second upper header 91, a second lower header 92, and a second heat exchanger water pipe 93 connected between the second upper header 91 and the second lower header 92; the lower wall heat exchanger assembly 10 includes a third upper header 101, a third lower header 102, and a third heat exchanger water pipe 103 connected between the third upper header 101 and the third lower header 102; the two water flows of the raw water supply pipe 14 are respectively connected to the second lower header 92 of the upper wall heat exchanger assembly 9 and the third lower header 102 of the lower wall heat exchanger assembly 10.

[0038] The structure of the raw water heat exchanger assembly 8 is as follows: Figure 4 As shown, the structures of the upper wall heat exchanger assembly 9 and the lower wall heat exchanger assembly 10 are similar to those of the raw water heat exchanger assembly 8.

[0039] Preferably, the first lower header 82 of the raw water heat exchanger assembly 8 is connected to a raw water outlet pipe 15 for the raw water to flow out after heat exchange.

[0040] Preferably, the second upper header 91 of the upper wall heat exchanger assembly 9 and the third upper header 101 of the lower wall heat exchanger assembly 10 are both connected to the first upper header 81 of the raw water heat exchanger assembly 8 via pipelines. Raw water flows from the second lower header 92 of the upper wall heat exchanger assembly 9 and the third lower header 102 of the lower wall heat exchanger assembly 10 through the second heat exchanger water pipe 93 and the third heat exchanger water pipe 103, respectively, and then reaches the second upper header 91 of the upper wall heat exchanger assembly 9 and the third upper header 101 of the lower wall heat exchanger assembly 10. After that, it flows through pipelines into the first upper header 81 of the raw water heat exchanger assembly 8, and then from the first upper header 81 of the raw water heat exchanger assembly 8 through the first heat exchanger water pipe 83 to the first lower header 82 of the raw water heat exchanger assembly 8, and finally flows out from the raw water outlet pipeline 15.

[0041] Preferably, the conveying assembly 3 includes: a dry slag conveying chain 31 and a first motor 32; the first motor 32 is used to drive the dry slag conveying chain 31 to rotate towards the slag bin, thereby realizing slag transportation.

[0042] Preferably, the cleaning assembly 4 includes a cleaning chain 41 and a second motor 42, the second motor 42 being used to drive the cleaning chain 41 to rotate in the same direction as the dry slag conveying chain 31, thereby cleaning the bottom of the dry slag conveying chain 31.

[0043] Preferably, the raw water outlet pipe 15 is equipped with a pressure gauge, a thermometer, and a flow meter. The pressure gauge is used to detect the water pressure and determine whether the operating pressure of the raw water heating system is normal. The thermometer is used to detect the temperature of the raw water after heat exchange. The flow meter detects the water flow rate and is used in conjunction with the thermometer to determine whether the cooling effect can be achieved.

[0044] Preferably, a heat exchanger soot blower 11 extending to the inner side of the upper outer shell of the dry slag machine 2 is installed. The heat exchanger soot blower 11 is controlled to start soot blowing by a timed soot blowing control unit. The heat exchanger soot blower 11 is used to blow soot onto the raw water heat exchanger assembly 8.

[0045] Preferably, the outlet header of the raw water supply pump 13 is equipped with a pressure gauge, a thermometer, and a flow meter.

[0046] Preferably, the outlet of the raw water supply pump 13 is provided with the check valve 131.

[0047] Preferably, it further includes: a slag crusher 6 and a slag bin 7; the slag crusher 6 is located directly below the farthest end of the conveying assembly 3; the slag bin 7 is installed below the slag crusher 6 and is used to collect the crushed slag.

[0048] Preferably, two raw water supply pumps 13 are connected in parallel in the raw water tank 12 to provide water pressure for the raw water heating system.

[0049] Working principle of this embodiment:

[0050] The slag falls from the slag well below boiler 1 into the dry slag conveyor chain 31 in the horizontal section of the dry slag machine 2. The dry slag is then transported by the conveyor chain 31 to the crusher 6 for crushing and finally falls into the slag bin 7. The temperature of the slag falling into boiler 1 is 700-900℃. During this process, air enters through the electric air inlet damper 5 under the negative pressure of the furnace, exchanges heat with the transported slag, and then participates in combustion within the furnace 1. The temperature of the air after heat exchange is 100-200℃.

[0051] Under the action of the raw water supply pump 13, raw water flows from the raw water tank 12 through the raw water supply pipe 14 to the second lower header 92 of the upper wall heat exchanger assembly 9 and the third lower header 102 of the lower wall heat exchanger assembly 10. After flowing through the second heat exchanger water pipe 93 and the third heat exchanger water pipe 103 respectively, it reaches the second upper header 91 of the upper wall heat exchanger assembly 9 and the third upper header 101 of the lower wall heat exchanger assembly 10. Then, it flows through the pipeline into the first upper header 81 of the raw water heat exchanger assembly 8, and then from the first upper header 81 of the raw water heat exchanger assembly 8 through the first heat exchanger water pipe 83 to the first lower header 82 of the raw water heat exchanger assembly 8. Finally, it flows out from the raw water outlet pipe 15.

[0052] When the raw water flows through the first heat exchanger pipe 83 of the raw water heat exchanger assembly 8, it exchanges heat with the transported slag. After absorbing heat from the hot air and radiant heat from the hot slag, the water temperature rises, thus heating the raw water while simultaneously reducing the temperature of the slag. During operation, the outer shell temperature of the slag dryer reaches approximately 80-100℃. As the raw water flows into the lower wall heat exchanger assembly 10 and the upper wall heat exchanger assembly 9, it not only reduces the temperature of the slag but also cools the slag dryer 2 equipment.

[0053] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A system for heating raw water using waste heat from a coal-fired boiler ash dryer, comprising: Boiler (1), slag dryer (2), conveying assembly (3), cleaning assembly (4), the slag dryer (2) includes a horizontal section and an inclined section, the horizontal section is located directly below the slag well of the boiler (1), the conveying assembly (3) is provided inside the slag dryer (2), and the cleaning assembly (4) is provided below the conveying assembly (3). Its features are, Includes: air intake electric damper (5), raw water heat exchanger assembly (8), upper wall heat exchanger assembly (9), lower wall heat exchanger assembly (10), raw water tank (12), raw water supply pump (13), and raw water supply pipe (14). The electric air intake damper (5) is located at the upper end of the inclined section of the dry slag machine (2); the raw water heat exchanger assembly (8) is suspended and fixedly connected above the conveying assembly (3) of the inclined section of the dry slag machine (2) by a connecting rod; the upper wall heat exchanger assembly (9) is fixedly arranged against the wall on the upper inner surface of the shell of the dry slag machine (2); the lower wall heat exchanger assembly (10) is fixedly arranged against the wall on the lower inner surface of the shell of the dry slag machine (2); the upper ends of the upper wall heat exchanger assembly (9) and the lower wall heat exchanger assembly (10) are connected to the upper end of the raw water heat exchanger assembly (8) through pipelines. The raw water tank (12) is equipped with the raw water supply pump (13), the outlet main pipe of the raw water supply pump (13) is connected to the raw water supply pipe (14), and the raw water supply pipe (14) is divided into two paths, which are respectively connected to the upper wall heat exchanger assembly (9) and the lower wall heat exchanger assembly (10). The raw water heat exchanger assembly (8) includes a first upper header (81), a first lower header (82), and a first heat exchanger water pipe (83) connected between the first upper header (81) and the first lower header (82). The upper wall heat exchanger assembly (9) includes a second upper header (91), a second lower header (92), and a second heat exchanger water pipe (93) connected between the second upper header (91) and the second lower header (92); the lower wall heat exchanger assembly (10) includes a third upper header (101), a third lower header (102), and a third heat exchanger water pipe (103) connected between the third upper header (101) and the third lower header (102); the two water flows of the raw water supply pipe (14) are respectively connected to the second lower header (92) of the upper wall heat exchanger assembly (9) and the third lower header (102) of the lower wall heat exchanger assembly (10); The first lower header (82) of the raw water heat exchanger assembly (8) is connected to a raw water outlet pipe (15) for the raw water to flow out after heat exchange; The second upper header (91) of the upper wall heat exchanger assembly (9) and the third upper header (101) of the lower wall heat exchanger assembly (10) are both connected to the first upper header (81) of the raw water heat exchanger assembly (8) via pipelines.

2. A system for heating raw water using waste heat from a coal-fired boiler ash dryer according to claim 1, characterized in that, The raw water outlet pipe (15) is equipped with a pressure gauge, a thermometer and a flow meter.

3. A system for heating raw water using waste heat from a coal-fired boiler ash dryer according to claim 1, characterized in that, The upper shell of the dry slag machine (2) is equipped with a heat exchanger soot blower (11) extending to its inner side, and the heat exchanger soot blower (11) is controlled to start soot blowing by a timed soot blowing control unit.

4. A system for heating raw water using waste heat from a coal-fired boiler ash dryer according to claim 1, characterized in that, The outlet header of the raw water supply pump (13) is equipped with a pressure gauge, a thermometer and a flow meter.

5. A system for heating raw water using waste heat from a coal-fired boiler ash dryer according to claim 1, characterized in that, The outlet of the raw water supply pump (13) is equipped with a check valve (131).

6. A system for heating raw water using waste heat from a coal-fired boiler ash dryer according to claim 1, characterized in that, Also includes: A slag crusher (6) and a slag bin (7); the slag crusher (6) is located directly below the farthest end of the conveying assembly (3); the slag bin (7) is installed below the slag crusher (6) and is used to hold the crushed slag.

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