High-efficiency recovery and utilization process and device of waste heat from yellow phosphorus production based on multi-stage exchange

Abstract

The present invention relates to the field of waste heat recovery technology, specifically to a process and apparatus for efficiently recycling waste heat from yellow phosphorus production based on multi-stage exchange. The process and apparatus comprise a recovery chamber and an external combustion engine that directly utilizes the waste heat from high-temperature flue gas to generate electricity. A cleaning machine and a heat exchanger are located within the recovery chamber. In this multi-stage exchange-based process and apparatus, as the scraper reciprocates, a connecting rod drives a piston plate to pressurize the outer casing, pushing external gas into a liquid storage tank and forcing the heat exchange fluid to circulate within the heat exchange tubes. This reduces the need for additional delivery pumps and avoids additional energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat recovery, and in particular to a process and device for efficiently recovering and utilizing waste heat from yellow phosphorus production based on multi-stage exchange. Background Art

[0002] Efficient waste heat recovery and utilization from yellow phosphorus production is achieved through tail gas purification, combustion heat conversion, and cascade utilization. After dust removal and alkaline washing to remove acid, the yellow phosphorus tail gas enters a dedicated boiler for combustion. The high-temperature flue gas passes through a corrosion-resistant heat exchanger to generate steam, which drives a steam turbine for power generation or directly provides heat for production. The system utilizes a segmented anti-corrosion design, low-temperature heat pipe heat exchange technology, and a waste liquid recovery device, increasing waste heat utilization to over 80% and reducing carbon dioxide emissions by over 10,000 tons annually.

[0003] Patent application number CN202223576262.1 discloses a yellow phosphorus production fume collection device, which includes a heating furnace and a recovery device body. The recovery device body includes an induced draft device, a dust removal device, and a waste heat recovery device. The two ends of the induced draft device are respectively connected to the heating furnace and the dust removal device. The dust removal device is internally provided with a first dust removal chamber and a second dust removal chamber. The waste heat recovery device includes a recovery chamber, which is internally provided with clean water and superconducting rods. A return air duct is provided above the recovery chamber. The superconducting rods extend through the recovery chamber to the interior of the return air duct to heat the return air. This device effectively purifies yellow phosphorus fume, facilitating its subsequent treatment.

[0004] However, the cleaning devices of traditional yellow phosphorus production waste heat recovery systems generally rely on external power (such as motors or air pumps) to drive the cleaning mechanism, which not only increases energy consumption and operating costs, but also causes dust accumulation on the surface of the heat exchange tubes due to intermittent cleaning, increases thermal resistance, and significantly reduces heat exchange efficiency after long-term operation. In addition, the heat exchange fluid circulation needs to rely on an independent delivery pump to maintain flow, which consumes a lot of additional electricity. The pump body is prone to failure under high temperature and high dust conditions, and maintenance costs increase.

[0005] In view of this, we propose a process and device for efficient recovery and utilization of waste heat from yellow phosphorus production based on multi-stage exchange. Summary of the Invention

[0006] The purpose of the present invention is to provide a process and device for efficiently recovering and utilizing waste heat from yellow phosphorus production based on multi-stage exchange. When the external combustion engine absorbs heat, the power generated by the rotation of the internal flywheel can drive a cleaning machine to clean the heat exchanger and simultaneously provide power for the flow of heat exchange fluid inside the heat exchanger, so as to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above objectives, the present invention provides the following technical solutions:

[0008] A highly efficient recovery and utilization device for waste heat from yellow phosphorus production based on multi-stage exchange includes a recovery chamber and an external combustion engine that directly utilizes waste heat from high-temperature flue gas to generate electricity. A cleaning machine and a heat exchanger are provided inside the recovery chamber.

[0009] This setting uses the power of the internal flywheel rotating when the external combustion engine absorbs heat to drive the cleaning machine to clean the heat exchanger, and at the same time provides power for the flow of heat exchange fluid inside the heat exchanger;

[0010] The cleaning machine includes a reciprocating screw, a scraper, and a push frame. The reciprocating screw can rotate together with the flywheel inside the external combustion engine, thereby driving the scraper and the push frame to move back and forth inside the recovery chamber.

[0011] The heat exchanger includes a liquid storage tank, a heat exchange tube, an outer casing, a piston plate, and an air outlet pipe. When the scraper arranged on the outside of the heat exchange tube moves, it also drives the piston plate to move back and forth inside the outer casing, and cooperates with the air inlet valve and air outlet valve on the outer casing to push the external gas into the liquid storage tank through the air outlet pipe to complete the pressurization work, thereby promoting the movement of the heat exchange liquid in the heat exchange tube.

[0012] This setting will scrape off the flue gas ash on the heat exchange tubes to prevent the increase of thermal resistance, maintain the heat exchange efficiency, and force the heat exchange fluid to circulate in the heat exchange tubes, reducing the investment in additional delivery pumps and avoiding additional energy consumption.

[0013] In the technical solution of the present invention, the recovery cabin includes a cabin body, a guide plate welded on the inner wall of the cabin body and an L-shaped inner partition, an ash discharge bin for removing accumulated ash, and an outwardly protruding bin body integrally formed on the front and rear side walls of the cabin body. A number of regularly distributed jacks are provided on the outer side walls of the front and rear ends of the cabin body, and the openings on the upper right top surface and the left side wall of the cabin body are provided for the smoke generated during yellow phosphorus production to pass through.

[0014] In the technical solution of the present invention, the ash discharge bin includes a bin body fixedly connected to the outer wall of the bin body by bolts, a baffle slidably connected to the inside of the bin body, a number of regularly distributed telescopic rods and a spring sleeved on the outside of the telescopic rods, and a number of regularly distributed ash discharge grooves are opened on the bottom surface of the bin body.

[0015] In the technical solution of the present invention, both ends of the telescopic rod are respectively clamped and fixed on the inner side wall of the cabin body and the longitudinal wall of the baffle, and the elastic force provided by the spring pushes the baffle to move toward the cabin body.

[0016] This setting allows dust to be discharged from the cabin through an independent space and ensures that the internal environment of the cabin is sealed during discharge.

[0017] In the technical solution of the present invention, the cleaning machine also includes ring teeth, a rotating shaft arranged parallel to the reciprocating screw, shaft teeth fixed on the outer wall of the rotating shaft and meshing with the ring teeth, a pulley clamped to the rotating shaft and the end of the reciprocating screw, and a synchronous belt sleeved between the two pulleys.

[0018] In the technical solution of the present invention, the ring gear is clamped and fixed to the outside of the flywheel inside the external combustion engine, the rotating shaft and the reciprocating screw are both rotatably connected to the inner wall of the cabin, and the top protrusion of the scraper cross plate is sleeved on the outside of the reciprocating screw.

[0019] In the technical solution of the present invention, accordion covers are also clamped on the front and rear sides of the horizontal plate at the top of the scraper, and the other end of the accordion cover is clamped on the inner wall of the convex bin body. A pair of accordion covers are both arranged below the inner partition, and the push frame is welded and fixed to the bottom end of the scraper.

[0020] This setting utilizes the power generated by the flywheel of the external combustion engine, allowing the scraper to remove dust from the surface of the internal structure of the heat exchanger in real time during its forward and backward movement, ensuring long-term stability of the heat exchange efficiency.

[0021] In the technical solution of the present invention, the heat exchanger also includes a liquid outlet pipe clamped to a port on one side of the heat exchange tube and several connecting rods clamped and fixed to the outer wall of the piston plate, and the other end of the connecting rod is clamped and fixed to the outer wall of the push frame.

[0022] In the technical solution of the present invention, the bottom end pipe of the liquid storage tank is clamped and fixed to the other side port of the heat exchange tube, and the outer casing is clamped and fixed to the outer wall of the cabin body. The outer wall of the outer casing is clamped with an air inlet valve and an air outlet valve. One end of the air outlet pipe is clamped to the outside of the air outlet valve on the top surface of the outer casing, and the other end extends to the interior of the liquid storage tank.

[0023] This setting converts the power generated by the external combustion engine into mechanical energy, and after the external gas is pushed into the liquid storage tank, the heat exchange fluid is forced to circulate in the heat exchange tube, reducing the investment in additional delivery pumps and avoiding the generation of additional energy consumption.

[0024] On the other hand, the present invention also provides a process for efficiently recovering and utilizing waste heat from yellow phosphorus production based on multi-stage exchange, using the above-mentioned device for efficiently recovering and utilizing waste heat from yellow phosphorus production based on multi-stage exchange, comprising the following steps:

[0025] S1. First, when yellow phosphorus is produced, the flue gas enters the interior of the cabin, causing the temperature inside the cabin to rise. The heat source continuously heats the working fluid in the closed cylinder inside the external combustion engine, causing it to expand due to the heat, pushing the piston in the power external combustion engine cylinder outward. The piston drives the crankshaft to rotate through the connecting rod. The flywheel on the crankshaft relies on inertia to store kinetic energy and maintain a stable speed.

[0026] S2. Simultaneously, the crankshaft drives the displacement piston to push the expanded gas to the cold end. After the gas dissipates heat and contracts at the cold end, the inertial force of the flywheel pulls the piston back to compress the gas, causing it to return to the hot end and be reheated, forming a continuous cycle. In this process, the rotational kinetic energy of the flywheel drives the generator through the output shaft, thereby realizing the conversion of thermal energy into electrical energy.

[0027] S3. When the flywheel of the external combustion engine rotates, the ring gear rotates accordingly, and the meshing shaft gear drives the rotating shaft to rotate, which in turn causes the pulley on the outside of the rotating shaft to rotate. After being transmitted by the synchronous belt, it drives the pulley on the outside of the reciprocating screw to rotate together with it;

[0028] S4. After the reciprocating screw rotates, it drives the scraper to move back and forth on the outside of the heat exchange tube. After the scraper scrapes the dust on the heat exchange tube, the push frame that moves with the scraper drives the dust to move toward the baffle.

[0029] S5. After the push frame squeezes the baffle, the telescopic rod contracts, and the baffle is pushed forward, allowing the accumulated dust to fall from the ash discharge chute. In the subsequent backward movement of the push frame, the elastic force of the spring pushes the baffle backward, and resets it;

[0030] S6. As the scraper moves back and forth, the piston plate is driven to move inside the outer casing through the connecting rod, and the external air is sucked into the outer casing through the air inlet valve and the air outlet valve, and then discharged into the interior of the liquid storage tank through the air outlet pipe outside the air outlet valve, thereby completing the pressurization work inside the liquid storage tank;

[0031] S7. Subsequently, the heat exchange liquid in the liquid storage tank will flow in the heat exchange tube, and when the liquid level in the liquid storage tank drops, the liquid storage tank can be filled up through the external liquid supply device.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. This multi-stage heat exchange-based process and device for efficiently recovering waste heat from yellow phosphorus production uses an external combustion engine to directly utilize the waste heat from high-temperature flue gas to generate electricity. Simultaneously, the flywheel's rotational power drives the reciprocating screw and scrapers of the cleaning machine, enabling real-time removal of dust from the heat exchange tube surface. This integrated design eliminates the need for additional energy consumption, solving the problem of the cleaning device's reliance on external power in traditional waste heat recovery systems. This significantly reduces operating costs and ensures long-term stable heat exchange efficiency.

[0034] 2. This multi-stage exchange-based process and device for efficiently recovering and utilizing waste heat from yellow phosphorus production uses a connecting rod to drive a piston plate to pressurize the outer casing during reciprocating motion of the scraper, pushing external gas into the liquid storage tank and forcing the heat exchange liquid to circulate within the heat exchange tubes, reducing the need for additional delivery pumps and avoiding additional energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1It is a schematic diagram of the overall structure of the present invention;

[0036] Figure 2 It is a schematic cross-sectional view of the overall structure of the present invention;

[0037] Figure 3 Schematic diagram of the structure of the recovery cabin in the present invention;

[0038] Figure 4 It is a schematic cross-sectional view of the structure of the recovery cabin in the present invention;

[0039] Figure 5 It is a schematic cross-sectional view of the structure of the ash discharge bin in the present invention;

[0040] Figure 6 It is a structural schematic diagram of the external combustion engine in the present invention;

[0041] Figure 7 It is a schematic cross-sectional view of the structure of the cleaning machine of the present invention;

[0042] Figure 8 For the present invention Figure 7 A magnified schematic diagram of part A;

[0043] Figure 9 Schematic diagram of the structure of the heat exchanger in the present invention;

[0044] Figure 10 It is a partial structural schematic diagram of the heat exchanger in the present invention;

[0045] Description of reference numerals:

[0046] 100, recovery cabin; 110, cabin body; 111, socket; 120, deflector; 130, inner partition; 140, ash discharge bin; 141, bin body; 1410, ash discharge chute; 142, baffle; 143, telescopic rod; 144, spring; 150, protruding bin body;

[0047] 200, external combustion engine;

[0048] 300, cleaning machine; 310, ring gear; 320, shaft gear; 330, rotating shaft; 340, reciprocating screw; 350, pulley; 360, synchronous belt; 370, scraper; 380, accordion cover; 390, push frame;

[0049] 400, heat exchanger; 410, liquid storage tank; 420, heat exchange tube; 430, liquid outlet pipe; 440, outer casing; 441, ventilation groove; 450, piston plate; 460, connecting rod; 470, outlet pipe. DETAILED DESCRIPTION

[0050] The following will provide a clear and complete description of the technical solutions of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0051] See also Figures 1-10 As shown, this embodiment provides a technical solution:

[0052] The highly efficient yellow phosphorus production waste heat recovery and utilization device, based on multi-stage exchange, includes a recovery chamber 100 and an external combustion engine 200 that directly utilizes the waste heat from high-temperature flue gas to generate electricity. A cleaning machine 300 and a heat exchanger 400 are installed within the recovery chamber 100. When the external combustion engine 200 absorbs heat, the power generated by the rotation of the internal flywheel drives the cleaning machine 300 to clean the heat exchanger 400 and simultaneously provides power for the flow of heat exchange fluid within the heat exchanger 400.

[0053] See also Figure 2-Figure 5 As shown, the recovery chamber 100 includes a chamber body 110, a guide plate 120 welded to the inner wall of the chamber body 110, an L-shaped inner partition 130, an ash discharge bin 140 for removing accumulated ash, and an outwardly protruding chamber body 150 integrally formed on the front and rear side walls of the chamber body 110. A number of regularly distributed sockets 111 are provided on the outer side walls of the front and rear ends of the chamber body 110, and the openings on the upper right top surface and the left side wall of the chamber body 110 are used for the passage of smoke generated during yellow phosphorus production.

[0054] Specifically, the ash discharge bin 140 includes a bin body 141 fixedly connected to the outer wall of the cabin body 110 by bolts, a baffle 142 slidably connected to the inside of the bin body 141, a number of regularly distributed telescopic rods 143 and a spring 144 mounted on the outside of the telescopic rods 143. The bottom surface of the bin body 141 is provided with a number of regularly distributed ash discharge grooves 1410.

[0055] Furthermore, both ends of the telescopic rod 143 are respectively clamped and fixed on the inner side wall of the chamber body 141 and the longitudinal wall of the baffle 142 , and the elastic force provided by the spring 144 pushes the baffle 142 to move toward the chamber body 110 .

[0056] Furthermore, the cabin 110 is used to provide a placement area for the external combustion engine 200, the cleaning machine 300 and the heat exchanger 400, and limits the flow area of ​​the flue gas during yellow phosphorus production through the guide plate 120 and the inner partition 130. The convex cabin 150 provides a placement area for the internal structure of the cleaning machine 300. The ash discharge trough 1410 on the cabin 141 is used to provide an area for dust discharge. When the baffle 142 moves forward, the telescopic rod 143 contracts, and the baffle 142 is pushed forward, allowing the accumulated dust to fall from the ash discharge trough 1410. In the subsequent process of the push frame 390 moving backward, the elastic force of the spring 144 pushes the baffle 142 backward and resets it. This setting allows dust to be discharged from the cabin 110 through an independent space and ensures the closed environment of the internal environment of the cabin 110 during discharge.

[0057] See also Figure 6 As shown, the external combustion engine 200 includes a closed cylinder, a piston sliding in the cylinder, a connecting rod moving with the piston, a crankshaft arranged at the end of the connecting rod, and a flywheel outside the crankshaft. The working principle of the external combustion engine 200 is to continuously heat the working medium in the closed cylinder, such as hydrogen / helium, through an external heat source, so that it expands due to heat and drives the power piston to move outward. The piston drives the crankshaft to rotate through the connecting rod. The flywheel on the crankshaft relies on inertia to store kinetic energy and maintain a stable speed, helping the engine to pass the dead point; at the same time, the crankshaft drives the displacement piston to push the expanded gas to the cold end. After the gas dissipates heat and shrinks at the cold end, the inertial force of the flywheel pulls the piston back to compress the gas, causing it to return to the hot end for reheating, forming a continuous cycle. This configuration uses the rotational kinetic energy of the flywheel to drive the generator through the output shaft to achieve the conversion of thermal energy into electrical energy.

[0058] See also Figure 7-Figure 8 As shown, the cleaning machine 300 includes a reciprocating screw 340, a scraper 370, and a push frame 390. The reciprocating screw 340 can rotate together with the flywheel inside the external combustion engine 200, thereby driving the scraper 370 and the push frame 390 to move back and forth inside the recovery cabin 100.

[0059] Specifically, the cleaning machine 300 also includes a ring gear 310, a rotating shaft 330 arranged parallel to the reciprocating screw 340, a shaft tooth 320 fixed on the outer wall of the rotating shaft 330 and meshing with the ring gear 310, a pulley 350 clamped to the end of the rotating shaft 330 and the reciprocating screw 340, and a synchronous belt 360 sleeved between the two pulleys 350.

[0060] Furthermore, the ring gear 310 is clamped and fixed to the outside of the flywheel inside the external combustion engine 200, the rotating shaft 330 and the reciprocating screw 340 are both rotatably connected to the inner wall of the cabin 110, and the top protrusion of the scraper 370 cross plate is sleeved on the outside of the reciprocating screw 340.

[0061] Furthermore, an accordion cover 380 is clamped on the front and rear sides of the top horizontal plate of the scraper 370, and the other end of the accordion cover 380 is clamped on the inner wall of the convex bin body 150. A pair of accordion covers 380 are both arranged below the inner partition 130, and the push frame 390 is welded and fixed to the bottom end of the scraper 370.

[0062] Furthermore, after the flywheel of the external combustion engine 200 rotates, the ring gear 310 rotates accordingly, and the meshing shaft teeth 320 drives the rotating shaft 330 to rotate, thereby causing the pulley 350 on the outside of the rotating shaft 330 to rotate. After being transmitted by the synchronous belt 360, the pulley 350 on the outside of the reciprocating screw 340 is driven to rotate together with it. After the reciprocating screw 340 rotates, it drives the scraper 370 to move back and forth on the outside of the heat exchange tube 420. After the scraper 370 scrapes off the accumulated dust on the heat exchange tube 420, the push frame 390 that moves with the scraper 370 drives the accumulated dust to move toward the baffle 142. This setting utilizes the power generated by the flywheel of the external combustion engine 200, and allows the scraper 370 to remove the dust on the surface of the internal structure of the heat exchanger 400 in real time during the back and forth movement, thereby ensuring long-term stability of the heat exchange efficiency.

[0063] See also Figure 9-10 As shown, the heat exchanger 400 includes a liquid storage tank 410, a heat exchange tube 420, an outer casing 440, a piston plate 450, and an air outlet pipe 470. When the scraper 370 arranged on the outside of the heat exchange tube 420 moves, the flue gas ash on the heat exchange tube 420 is scraped off to prevent the thermal resistance from increasing and maintain the heat exchange efficiency. At the same time, it drives the piston plate 450 to move back and forth inside the outer casing 440, and cooperates with the air inlet valve and the air outlet valve on the outer casing 440 to push the external gas from the air outlet pipe 470 into the liquid storage tank 410 to complete the pressurization work, thereby promoting the movement of the heat exchange liquid in the heat exchange tube 420.

[0064] Specifically, the heat exchanger 400 also includes a liquid outlet pipe 430 clamped to a port on one side of the heat exchange tube 420 and several connecting rods 460 clamped and fixed to the outer wall of the piston plate 450, and the other end of the connecting rod 460 is clamped and fixed to the outer wall of the push frame 390.

[0065] Furthermore, the bottom end pipe of the liquid storage tank 410 is clamped and fixed to the other side port of the heat exchange tube 420, and the outer casing 440 is clamped and fixed to the outer wall of the cabin body 110. The outer casing 440 has an air inlet valve and an air outlet valve clamped on the outer wall. One end of the air outlet pipe 470 is clamped to the outside of the air outlet valve on the top surface of the outer casing 440, and the other end extends to the interior of the liquid storage tank 410.

[0066] Furthermore, while the scraper 370 moves back and forth, the piston plate 450 is driven to move inside the outer frame 440 through the connecting rod 460, and the external gas is sucked into the outer frame 440 through the air inlet valve and the air outlet valve, and then discharged into the interior of the liquid storage tank 410 through the air outlet pipe 470 outside the air outlet valve, thereby completing the pressurization work inside the liquid storage tank 410. A ventilation groove 441 is provided on one side wall of the outer frame 440, which is used for gas circulation to maintain the internal and external air pressure of the outer frame 440 when the piston plate 450 moves; this setting converts the power generated by the external combustion engine 200 into mechanical energy, and after the external gas is pushed into the liquid storage tank 410, the heat exchange fluid is forced to circulate in the heat exchange tube 420, reducing the investment in additional delivery pumps and avoiding the generation of additional energy consumption.

[0067] The present invention also provides a process for efficiently recovering and utilizing waste heat from yellow phosphorus production based on multi-stage exchange, and the process comprises the following steps:

[0068] S1. First, when yellow phosphorus is produced, smoke enters the interior of the cabin 110, causing the temperature inside the cabin 110 to rise. The heat source continuously heats the working fluid in the closed cylinder of the external combustion engine 200, causing it to expand due to the heat, pushing the piston in the cylinder of the power external combustion engine 200 outward. The piston drives the crankshaft to rotate through the connecting rod. The flywheel on the crankshaft relies on inertia to store kinetic energy and maintain a stable speed.

[0069] S2. Simultaneously, the crankshaft drives the displacement piston to push the expanded gas to the cold end. After the gas dissipates heat and contracts at the cold end, the inertial force of the flywheel pulls the piston back to compress the gas, causing it to return to the hot end and be reheated, forming a continuous cycle. In this process, the rotational kinetic energy of the flywheel drives the generator through the output shaft, thereby realizing the conversion of thermal energy into electrical energy.

[0070] S3. When the flywheel of the external combustion engine 200 rotates, the ring gear 310 rotates accordingly, and the meshing shaft gear 320 drives the rotating shaft 330 to rotate, which in turn causes the pulley 350 on the outer side of the rotating shaft 330 to rotate. After being transmitted by the synchronous belt 360, the pulley 350 on the outer side of the reciprocating screw 340 rotates together with it;

[0071] S4. After the reciprocating screw 340 rotates, it drives the scraper 370 to move back and forth outside the heat exchange tube 420. The scraper 370 scrapes the dust accumulated on the heat exchange tube 420. The push frame 390, which moves with the scraper 370, drives the dust to move toward the baffle 142.

[0072] S5: After the push frame 390 squeezes the baffle 142, the telescopic rod 143 contracts, pushing the baffle 142 forward, allowing the accumulated dust to fall from the dust discharge chute 1410. In the subsequent backward movement of the push frame 390, the elastic force of the spring 144 pushes the baffle 142 backward, thereby resetting the baffle.

[0073] S6: As the scraper 370 moves forward and backward, the piston plate 450 is driven to move inside the outer casing 440 via the connecting rod 460. External air is sucked into the outer casing 440 through the air inlet valve and the air outlet valve, and then discharged into the liquid storage tank 410 through the air outlet pipe 470 outside the air outlet valve, thereby completing the pressurization of the liquid storage tank 410.

[0074] S7. Subsequently, the heat exchange liquid in the liquid storage tank 410 will flow in the heat exchange tube 420. When the liquid level in the liquid storage tank 410 drops, the liquid storage tank 410 can be filled up through the external liquid supply device.

[0075] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to make and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the description and its equivalents.

Claims

1. A yellow phosphorus production waste heat recovery and utilization device based on multi-stage exchange, comprising a recovery chamber and an external combustion engine that directly utilizes the waste heat of high-temperature flue gas to generate electricity, characterized by: A cleaning machine and a heat exchanger are provided inside the recovery cabin. When the external combustion engine absorbs heat, the power generated by the rotation of the internal flywheel can drive the cleaning machine to clean the heat exchanger and at the same time provide power for the flow of heat exchange fluid inside the heat exchanger. The cleaning machine includes a reciprocating screw, a scraper, and a push frame. The reciprocating screw can rotate together with the flywheel inside the external combustion engine, thereby driving the scraper and the push frame to move back and forth inside the recovery chamber; the push frame is welded and fixed to the bottom end of the scraper; The heat exchanger includes a liquid storage tank, a heat exchange tube, an outer casing, a piston plate, and an air outlet pipe. When the scraper arranged on the outside of the heat exchange tube moves, it scrapes off the flue gas ash on the heat exchange tube to prevent the increase of thermal resistance and maintain the heat exchange efficiency. At the same time, it drives the piston plate to move back and forth inside the outer casing, and cooperates with the air inlet valve and air outlet valve on the outer casing to push the external air from the air outlet pipe into the liquid storage tank to complete the pressurization work, thereby promoting the movement of the heat exchange liquid in the heat exchange tube. The recovery chamber includes a chamber body, a guide plate welded to the inner wall of the chamber body, an L-shaped inner partition, an ash discharge bin for removing accumulated ash, and an outwardly protruding chamber body integrally formed on the front and rear side walls of the chamber body. The outer side walls of the front and rear ends of the chamber body are each provided with a plurality of regularly distributed jacks. The openings provided on the upper right top surface and the left side wall of the chamber body allow the fumes generated during yellow phosphorus production to pass through. The ash discharge bin includes a bin body fixedly connected to the outer wall of the bin body by bolts, a baffle slidably connected to the inside of the bin body, a plurality of regularly distributed telescopic rods, and a spring sleeved on the outside of the telescopic rods. The bottom surface of the bin body is provided with a plurality of regularly distributed ash discharge grooves. The two ends of the telescopic rod are respectively clamped and fixed on the inner side wall of the cabin body and the longitudinal wall of the baffle, and the elastic force provided by the spring pushes the baffle to move toward the cabin body.

2. The yellow phosphorus production waste heat recovery and utilization device based on multi-stage exchange according to claim 1 is characterized in that: The cleaning machine also includes ring teeth, a rotating shaft arranged parallel to the reciprocating screw, shaft teeth fixed on the outer wall of the rotating shaft and meshing with the ring teeth, a pulley clamped on the rotating shaft and the end of the reciprocating screw, and a synchronous belt sleeved between the two pulleys.

3. The yellow phosphorus production waste heat recovery and utilization device based on multi-stage exchange according to claim 2 is characterized in that: The ring gear is fixedly connected to the outside of the flywheel inside the external combustion engine, the rotating shaft and the reciprocating screw are both rotatably connected to the inner wall of the cabin, and the top protrusion of the scraper cross plate is sleeved on the outside of the reciprocating screw.

4. The yellow phosphorus production waste heat recovery and utilization device based on multi-stage exchange according to claim 3 is characterized in that: The front and rear sides of the scraper horizontal plate are also clamped with accordion covers, and the other end of the accordion cover is clamped on the inner side wall of the convex warehouse body. A pair of accordion covers are both arranged below the inner partition.

5. The yellow phosphorus production waste heat recovery and utilization device based on multi-stage exchange according to claim 4 is characterized in that: The heat exchanger also includes a liquid outlet pipe clamped to a port on one side of the heat exchange tube and a plurality of connecting rods clamped and fixed to the outer side wall of the piston plate, and the other end of the connecting rod is clamped and fixed to the outer side wall of the push frame.

6. The yellow phosphorus production waste heat recovery and utilization device based on multi-stage exchange according to claim 5 is characterized in that: The bottom end pipe of the liquid storage tank is clamped and fixed to the other side port of the heat exchange tube, and the outer casing is clamped and fixed to the outer wall of the cabin body. The outer wall of the outer casing is clamped with an air inlet valve and an air outlet valve. One end of the air outlet pipe is clamped to the outside of the air outlet valve on the top surface of the outer casing, and the other end extends to the interior of the liquid storage tank.

7. A process for recovering waste heat from yellow phosphorus production based on multi-stage exchange, using the device for recovering waste heat from yellow phosphorus production based on multi-stage exchange according to claim 6, characterized in that: The following steps are involved: S1. First, when yellow phosphorus is produced, the flue gas enters the interior of the cabin, causing the temperature inside the cabin to rise. The heat source continuously heats the working fluid in the closed cylinder inside the external combustion engine, causing it to expand due to the heat, pushing the power piston in the cylinder of the external combustion engine outward. The power piston drives the crankshaft to rotate through the connecting rod. The flywheel on the crankshaft relies on inertia to store kinetic energy and maintain a stable speed. S2. Simultaneously, the crankshaft drives the displacement piston to push the expanded gas to the cold end. After the gas dissipates heat and contracts at the cold end, the inertial force of the flywheel pulls the power piston back to compress the gas, causing it to return to the hot end and be reheated, forming a continuous cycle. In this process, the rotational kinetic energy of the flywheel drives the generator through the output shaft, thereby realizing the conversion of thermal energy into electrical energy. S3. When the flywheel of the external combustion engine rotates, the ring gear rotates accordingly, and the meshing shaft gear drives the rotating shaft to rotate, which in turn causes the pulley on the outside of the rotating shaft to rotate. After being transmitted by the synchronous belt, it drives the pulley on the outside of the reciprocating screw to rotate together with it; S4. After the reciprocating screw rotates, it drives the scraper to move back and forth on the outside of the heat exchange tube. After the scraper scrapes the dust on the heat exchange tube, the push frame that moves with the scraper drives the dust to move toward the baffle. S5. After the push frame squeezes the baffle, the telescopic rod contracts, and the baffle is pushed forward, allowing the accumulated dust to fall from the ash discharge chute. In the subsequent backward movement of the push frame, the elastic force of the spring pushes the baffle backward, and resets it; S6. As the scraper moves back and forth, the piston plate is driven to move inside the outer casing through the connecting rod, and the external air is sucked into the outer casing through the air inlet valve and the air outlet valve, and then discharged into the interior of the liquid storage tank through the air outlet pipe outside the air outlet valve, thereby completing the pressurization work inside the liquid storage tank; S7. Subsequently, the heat exchange liquid in the liquid storage tank will flow in the heat exchange tube, and when the liquid level in the liquid storage tank drops, the liquid storage tank can be filled up through the external liquid supply device.

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