Cement plant waste heat recycling device

Abstract

The utility model relates to industrial waste heat recovery technical field especially cement plant production waste heat recycling device, including shell and tube heat exchanger, the left side of shell and tube heat exchanger is installed with filter box, the middle part welding of filter box inner chamber has the baffle, both sides of filter box inner chamber all are installed with metal filter screen, the top of filter box is installed with backflushing pipe subassembly. When the pressure difference is greater than threshold value, the PLC control box controls the first solenoid valve of front side to close, and the second solenoid valve of rear side opens, and the waste gas flows through from the rear side in the filter box and is filtered through the metal filter screen of rear side, and the high pressure gas pressure is reversed to blow the metal filter screen through the backflushing nozzle of front side and falls off the big particle dust adhered on the surface of filter screen, so this can filter the waste gas in advance, avoid the dust directly with the heat exchange tube in heat exchanger contact, prolongs the service life of heat exchange tube, and simultaneously can carry out the ash removal operation without stopping, guarantees production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of industrial waste heat recovery technology, specifically a device for recycling waste heat from cement plant production. Background Technology

[0002] Cement production is a systematic process that involves crushing, grinding, and calcining raw materials such as limestone and clay to produce clinker, which is then ground into finished cement products. The raw materials are calcined at high temperatures in a rotary kiln or vertical kiln to form cement clinker, which is then cooled. This process generates a large amount of high-temperature waste heat at the tail end of the rotary kiln, the cooler, and the outlet.

[0003] A search revealed that the announcement number is CN220567278U, and the name is "A Waste Heat Recycling Device for Cement Plants". It includes a recovery chamber with multiple air inlet pipes connected internally. Research and analysis showed that although it can improve the recovery and reuse of waste heat, reduce the difficulty of cleaning and maintenance for staff, reduce manpower efficiency, and facilitate production operations, it still has the following drawbacks to a certain extent.

[0004] For example, the above-mentioned device cannot filter dust from the exhaust gas before it enters the recovery chamber, resulting in a large number of flowing dust particles coming into direct contact with the heat exchange tubes inside the chamber. The cleaning rack rubs against the heat exchange tubes for a long time, causing the anti-corrosion and high-temperature resistant coating on the surface to peel off, which seriously affects the service life of the heat exchange tubes. Moreover, because the temperature of the exhaust gas is high, the temperature of the exhaust gas discharged after one heat exchange is still very high. The above-mentioned device can only recover the exhaust gas once, which results in incomplete utilization of waste heat and exhaust gas, and cannot maximize the utilization of exhaust gas waste heat, resulting in poor energy saving effect. In order to solve the above technical problems, we have designed a waste heat recycling device for cement plant production. Utility Model Content

[0005] The purpose of this utility model is to provide a waste heat recycling device for cement plant production, which has the advantages of extending the service life of heat exchange tubes, being able to automatically clean ash without stopping the machine, maximizing the utilization of waste heat from exhaust gas, and achieving better energy-saving effect. It solves the problems of shortening the service life of heat exchange tubes, low degree of automation, incomplete utilization of waste heat from exhaust gas, and poor energy-saving effect.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a waste heat recycling device for cement plant production, comprising a shell-and-tube heat exchanger, a filter box installed on the left side of the shell-and-tube heat exchanger, a partition welded to the middle of the inner cavity of the filter box, metal filter screens installed on both the front and rear sides of the inner cavity of the filter box, a backflush pipe assembly installed on the top of the filter box, a three-way pipe welded to both the left and right sides of the filter box, a first solenoid valve and a second solenoid valve respectively installed on the front and rear sides of the three-way pipe, a differential pressure sensor embedded in the top of the three-way pipe, a waste gas discharge pipe connected to the top right side of the shell-and-tube heat exchanger, a temperature sensor embedded in the top of the waste gas discharge pipe, a three-way electric valve installed on the right side of the waste gas discharge pipe, a finned tube heat exchanger connected to the right side of the three-way electric valve, a water storage tank connected to the right side of the finned tube heat exchanger, and a circulation pump installed at the bottom left side of the water storage tank.

[0007] Preferably, the backflush pipe assembly includes a high-pressure air pipe, with a third solenoid valve installed at the bottom of both the front and rear sides of the high-pressure air pipe, and backflush nozzles connected to both the left and right sides of the high-pressure air pipe, the bottom of which extends into the inner cavity of the filter box.

[0008] Preferably, a star-shaped ash discharge valve is installed on both the front and rear sides of the bottom of the filter box, and the air inlet pipe on the left side of the bottom of the shell and tube heat exchanger is fixedly connected to the tee pipe on the right side.

[0009] Preferably, the left and right sides of the shell-and-tube heat exchanger are respectively connected and installed with an air inlet pipe and an air outlet pipe, a water injection valve is installed on the right side of the top of the water storage tank, and a drain valve is installed at the bottom of the right side of the water storage tank.

[0010] Preferably, a circulation pipe is installed on the left side of the top of the water storage tank, and the left side of the circulation pipe is fixedly connected to the liquid outlet end at the top right side of the finned tube heat exchanger. The water outlet pipe of the circulation pump is fixedly connected to the liquid inlet end at the bottom right side of the finned tube heat exchanger.

[0011] Preferably, the connecting gas pipe at the top left side of the finned tube heat exchanger is fixedly connected to a three-way electric valve on its left side.

[0012] Preferably, the front side of the three-way electric valve is connected to an exhaust pipe, and the exhaust end at the bottom left side of the finned tube heat exchanger is connected to a connecting pipe, with the left side of the connecting pipe being fixedly connected to the exhaust pipe.

[0013] Preferably, a PLC control box is provided on the front side of the shell-and-tube heat exchanger. The output terminals of the PLC control box are electrically connected to the first solenoid valve, the second solenoid valve, the third solenoid valve, the three-way electric valve, and the circulating pump, respectively. The output terminals of the differential pressure sensor and the temperature sensor are both electrically connected to the PLC control box.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows: When the pressure difference exceeds the threshold, the PLC control box controls the first solenoid valve on the front to close and the second solenoid valve on the rear to open. The exhaust gas flows through the rear of the filter box and is filtered through the metal filter screen on the rear. The high-pressure air blows air in the opposite direction through the back-blowing nozzle on the front to blow off the large dust particles attached to the surface of the filter screen. This can filter the exhaust gas in advance, prevent dust from directly contacting the heat exchange tubes in the heat exchanger, extend the service life of the heat exchange tubes, and at the same time, it can perform dust removal operations without stopping the machine, ensuring production efficiency.

[0015] Preheated air is delivered to the cement raw material preheater to preheat the raw materials, reducing the heating burden on the raw materials. Temperature sensors detect the temperature of the exhaust gas. When the temperature is above 120℃, the right side of the three-way electric valve is opened and the front side is closed, allowing the exhaust gas to enter the finned tube heat exchanger to heat the water. After secondary heat exchange, the exhaust gas flows into the exhaust pipe through the connecting duct for discharge. When the temperature is below 120℃, the right side of the three-way electric valve is closed and the front side is opened, allowing the exhaust gas to be discharged directly from the exhaust pipe. This allows for secondary heat exchange and utilization of the exhaust gas, making waste heat utilization more thorough and achieving better energy-saving effects. Attached Figure Description

[0016] Figure 1 This is an axonometric view of the structure of this utility model; Figure 2 This is a left sectional axonometric view of the filter box of this utility model; Figure 3 This is a front axonometric view of a partial structure of this utility model; Figure 4 This is a rear axonometric view of the structure of this utility model.

[0017] In the diagram: 1. Shell-and-tube heat exchanger; 2. Air inlet duct; 3. Second solenoid valve; 4. Backflush assembly; 5. First solenoid valve; 6. Differential pressure sensor; 7. Filter box; 8. Rotary rotary valve; 9. T-junction; 10. PLC control box; 11. Connecting duct; 12. Finned tube heat exchanger; 13. Circulating pump; 14. Drain valve; 15. Water storage tank; 16. Water injection valve; 17. Circulating pipe; 18. Connecting air pipe; 19. Three-way electric valve; 20. Temperature sensor; 21. Exhaust duct; 22. Metal filter screen; 23. Baffle plate; 24. High-pressure air pipe; 25. Third solenoid valve; 26. Backflush nozzle; 27. Exhaust gas discharge pipe; 28. Air supply duct. Detailed Implementation

[0018] Please see Figures 1-4A waste heat recycling device for cement plant production includes a shell-and-tube heat exchanger 1. A filter box 7 is installed on the left side of the shell-and-tube heat exchanger 1. A baffle 23 is welded to the middle of the inner cavity of the filter box 7. Metal filter screens 22 with a pore size of 50-100 mesh are installed on both the front and rear sides of the inner cavity of the filter box 7. A backflush pipe assembly 4 is installed on the top of the filter box 7. A three-way pipe 9 is welded to both the left and right sides of the filter box 7. A first solenoid valve 5 and a second solenoid valve 3 are respectively installed on the front and rear sides of the three-way pipe 9. A differential pressure sensor is embedded in the top of the three-way pipe 9. The two detection ends of the differential pressure sensor 6 are respectively embedded in the three-way pipes 9 on both sides. The right side of the top of the shell-and-tube heat exchanger 1 is connected to the exhaust pipe 27. The top of the exhaust pipe 27 is embedded in the temperature sensor 20. The right side of the exhaust pipe 27 is connected to the three-way electric valve 19. The right side of the three-way electric valve 19 is connected to the finned tube heat exchanger 12. The right side of the finned tube heat exchanger 12 is connected to the water storage tank 15 (inner liner 304 stainless steel, insulation layer 50mm polyurethane). The bottom left side of the water storage tank 15 is connected to the circulation pump 13. Please see Figure 2 The backflush pipe assembly 4 includes a high-pressure air pipe 24. A third solenoid valve 25 is installed at the bottom of both the front and rear sides of the high-pressure air pipe 24. Backflush nozzles 26 are installed on both the left and right sides of the high-pressure air pipe 24. The bottom of the backflush nozzles 26 penetrates into the inner cavity of the filter box 7. The top of the high-pressure air pipe 24 is connected to an external compressed air pipeline. Please see Figure 1 and Figure 2 Star-shaped ash discharge valves 8 are installed on both the front and rear sides of the bottom of the filter box 7, and the air inlet pipe on the left side of the bottom of the shell and tube heat exchanger 1 is fixedly connected to the three-way pipe 9 on the right side. Please see Figure 1 and Figure 3 The shell-and-tube heat exchanger 1 is connected to the left and right sides by an air inlet pipe 2 and an air outlet pipe 28, respectively. The far end of the air outlet pipe 28 is connected to the cement raw material preheater. A water injection valve 16 is installed on the right side of the top of the water storage tank 15. The water injection valve 16 can easily add water to the water storage tank 15. A drain valve 14 is installed at the bottom right side of the water storage tank 15. The drain valve 14 can discharge the heated water for external use. Please see Figure 1 A circulation pipe 17 is installed on the left side of the top of the water storage tank 15. The left side of the circulation pipe 17 is fixedly connected to the liquid outlet end at the top right side of the finned tube heat exchanger 12. The water outlet pipe of the circulation pump 13 is fixedly connected to the liquid inlet end at the bottom right side of the finned tube heat exchanger 12. Please see Figure 4 The connecting pipe 18 at the top left side of the finned tube heat exchanger 12 is fixedly connected to the three-way electric valve 19 on the left side. Please see Figure 1 and Figure 3The front side of the three-way electric valve 19 is connected to the exhaust pipe 21, which is connected to the external exhaust pipe. The exhaust end of the bottom left side of the finned tube heat exchanger 12 is connected to the connecting pipe 11, and the left side of the connecting pipe 11 is fixedly connected to the exhaust pipe 21. Please see Figure 1 A PLC control box 10 is installed on the front side of the shell-and-tube heat exchanger 1. The output terminals of the PLC control box 10 are electrically connected to the first solenoid valve 5, the second solenoid valve 3, the third solenoid valve 25, the three-way electric valve 19, and the circulating pump 13, respectively. The output terminals of the differential pressure sensor 6 and the temperature sensor 20 are both electrically connected to the PLC control box 10.

[0019] In use, the high-temperature exhaust gas pipe is connected to the left-side T-connector 9. The two first solenoid valves 5 on the front side are opened, and the two second solenoid valves 3 on the rear side are closed. At this time, the exhaust gas flows through the front side of the filter box 7. The metal filter screen 22 on the front side filters the dust in the exhaust gas. The filtered exhaust gas flows into the shell-and-tube heat exchanger 1 through the right-side T-connector 9. Long-term filtration will cause the mesh of the metal filter screen 22 on the front side to become clogged. This will cause a pressure difference in the two T-connectors 9 (the pressure in the left T-connector 9 is higher, and the pressure in the right T-connector 9 is lower). At this time, the differential pressure sensor 6 in the two T-connectors 9 detects the pressure difference between the two sides. When the detected pressure difference is greater than the threshold, the sensor will detect the pressure difference. The information is transmitted to the PLC control box 10. The PLC control box 10 controls the two front first solenoid valves 5 to close and the two rear second solenoid valves 3 to open. The exhaust gas flows through the rear of the filter box 7 and is filtered by the rear metal filter screen 22. At the same time, the PLC control box 10 controls the front third solenoid valve 25 to open. At this time, the high-pressure air is blown through the front back-blowing nozzle 26 to the front metal filter screen 22, blowing off the large dust particles attached to the filter screen surface. Then, the front star-shaped dust discharge valve 8 can be opened to collect and reuse the blown-off dust, avoiding waste. This allows for pre-filtering of the exhaust gas and prevents dust from directly contacting the heat exchanger. The heat exchange tubes are in contact, extending their service life and allowing for dust removal without shutting down the machine, ensuring production efficiency. High-temperature exhaust gas flows in from the left side of the bottom of the shell-and-tube heat exchanger 1 and flows out from the right side of the top. The air undergoing heat exchange flows in through the inlet pipe 2 and flows out through the outlet pipe 28. The preheated air is then transported to the cement raw material preheater to preheat the raw materials, reducing the heating burden on them. The exhaust gas after heat exchange flows through the exhaust pipe 27 and then through the three-way electric valve 19. At this time, the temperature sensor 20 detects the temperature of the exhaust gas. When the temperature of the exhaust gas after heat exchange exceeds 120°C, the PLC control box 10 controls the three-way electric valve 19 to open the right-side channel and close the front channel. The exhaust gas enters the finned tube heat exchanger 12 through the connecting pipe 18. At this time, the circulating pump 13 is controlled to work to transport water from the water storage tank 15 to the finned tube heat exchanger 12. Secondary heat exchange occurs inside the finned tube heat exchanger 12, where the exhaust gas heats the water. After secondary heat exchange, the exhaust gas flows into the exhaust pipe 21 through the connecting pipe 11 for discharge. When the temperature sensor 20 detects that the temperature of the exhaust gas after the first heat exchange is lower than 120°C, the PLC control box 10 closes the right channel of the three-way electric valve 19 and opens the front channel, allowing the exhaust gas to be discharged directly from the exhaust pipe 21. This allows for secondary heat exchange and utilization of the exhaust gas, making waste heat utilization more thorough and energy-saving.

[0020] In summary, the waste heat recycling device in this cement plant, through the coordinated use of shell-and-tube heat exchanger 1, second solenoid valve 3, backflush pipe assembly 4, first solenoid valve 5, differential pressure sensor 6, filter box 7, three-way pipe 9, PLC control box 10, finned tube heat exchanger 12, circulating pump 13, three-way electric valve 19, temperature sensor 20, and metal filter screen 22, solves the problems of shortened heat exchange tube lifespan, low automation level, incomplete utilization of waste heat from exhaust gas, and poor energy-saving effect.

Claims

1. A waste heat recycling device for cement plant production, comprising a shell-and-tube heat exchanger (1), characterized in that: A filter box (7) is installed on the left side of the shell-and-tube heat exchanger (1). A baffle plate (23) is welded to the middle of the inner cavity of the filter box (7). Metal filter screens (22) are installed on both the front and rear sides of the inner cavity of the filter box (7). A backflush pipe assembly (4) is installed on the top of the filter box (7). A three-way pipe (9) is welded to both the left and right sides of the filter box (7). A first solenoid valve (5) and a second solenoid valve (3) are installed on the front and rear sides of the three-way pipe (9), respectively. A three-way pipe (9) is embedded in the top of the three-way pipe (9). A differential pressure sensor (6) is installed. The right side of the top of the shell-and-tube heat exchanger (1) is connected to a waste gas discharge pipe (27). A temperature sensor (20) is embedded in the top of the waste gas discharge pipe (27). A three-way electric valve (19) is installed on the right side of the waste gas discharge pipe (27). A finned tube heat exchanger (12) is connected to the right side of the three-way electric valve (19). A water storage tank (15) is connected to the right side of the finned tube heat exchanger (12). A circulating pump (13) is installed at the bottom left side of the water storage tank (15).

2. The waste heat recycling device for cement plant production according to claim 1, characterized in that: The backflush pipe assembly (4) includes a high-pressure air pipe (24), and a third solenoid valve (25) is installed at the bottom of both the front and rear sides of the high-pressure air pipe (24). Backflush nozzles (26) are connected to both the left and right sides of the high-pressure air pipe (24), and the bottom of the backflush nozzles (26) extends into the inner cavity of the filter box (7).

3. The waste heat recycling device for cement plant production according to claim 1, characterized in that: The filter box (7) is equipped with star-shaped ash discharge valves (8) on both the front and rear sides of the bottom. The air inlet pipe on the left side of the bottom of the shell and tube heat exchanger (1) is fixedly connected to the three-way pipe (9) on the right side.

4. The waste heat recycling device for cement plant production according to claim 1, characterized in that: The shell-and-tube heat exchanger (1) is connected to the left and right sides respectively by an air inlet pipe (2) and an air outlet pipe (28). A water injection valve (16) is installed on the right side of the top of the water storage tank (15), and a drain valve (14) is installed at the bottom right side of the water storage tank (15).

5. A waste heat recycling device for cement plant production according to claim 1, characterized in that: A circulation pipe (17) is installed on the left side of the top of the water storage tank (15). The left side of the circulation pipe (17) is fixedly connected to the liquid outlet end at the top right side of the finned tube heat exchanger (12). The water outlet pipe of the circulation pump (13) is fixedly connected to the liquid inlet end at the bottom right side of the finned tube heat exchanger (12).

6. The waste heat recycling device for cement plant production according to claim 1, characterized in that: The connecting pipe (18) at the top left side of the finned tube heat exchanger (12) is fixedly connected to the three-way electric valve (19) on the left side.

7. A waste heat recycling device for cement plant production according to claim 1, characterized in that: The front side of the three-way electric valve (19) is connected to an exhaust pipe (21), and the exhaust end of the bottom left side of the finned tube heat exchanger (12) is connected to a connecting pipe (11). The left side of the connecting pipe (11) is fixedly connected to the exhaust pipe (21).

8. A waste heat recycling device for cement plant production according to claim 1, characterized in that: A PLC control box (10) is provided on the front side of the shell-and-tube heat exchanger (1). The output terminals of the PLC control box (10) are electrically connected to the first solenoid valve (5), the second solenoid valve (3), the third solenoid valve (25), the three-way electric valve (19), and the circulating pump (13), respectively. The output terminals of the differential pressure sensor (6) and the temperature sensor (20) are both electrically connected to the PLC control box (10).

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