Method for multi-stage recovery and comprehensive utilization of industrial waste heat of high-purity quartz sand

Abstract

The invention discloses a method for multi-stage recovery and comprehensive utilization of industrial waste heat of high-purity quartz sand, and relates to the technical field of high-purity quartz sand production.The method comprises the specific steps that cooling return water, hot steam and high-temperature waste water in a high-purity quartz sand production line are subjected to unified collection, conveying and heat preservation treatment; the heat is conveyed to a heating area or a closed heat preservation unit room for heat dissipation through control; the heat exchanger is used for heating the pure water through the emitted waste heat, and the pure water is conveyed to work sections such as flotation and acid pickling for production. According to the invention, the waste heat generated by the high-purity quartz sand production line is comprehensively reutilized, the problem of high energy consumption of high-purity quartz sand production is relieved, the problems of poor heating effect of pure water in winter by conventional air energy and heating of factory areas in winter are solved, and the energy-saving and green production process of the high-purity quartz sand industrial line is further supplemented.

Description

Technical Field

[0001] The present invention relates to the technical field of high-purity quartz sand production, and in particular to a method for multi-stage recovery and comprehensive utilization of industrial waste heat of high-purity quartz sand. Background Art

[0002] Current high-purity quartz sand production processes generally consume high amounts of energy. Calcination, water quenching, pickling, flotation, drying, magnetic separation, chlorination roasting, and sand making processes generate significant amounts of low- and medium-temperature waste heat (steam, cooling water, high-temperature wastewater, hot materials, etc.) ranging from 35°C to 300°C. Existing technologies lack a systematic recovery mechanism. Pure water heating (50-65°C) in the flotation process and pickling insulation (80-120°C) require additional natural gas and electricity consumption, with energy costs accounting for over 25% of total production costs. Traditional hot pure water preparation systems face seasonal switching challenges, relying on gas-fired boilers (thermal efficiency ≤85%) in winter and air energy (COP ≈ 3.5) in summer, preventing cross-process energy synergy. Furthermore, workshop heating systems operate independently and are not linked to the heat demands of the production process. In traditional processes, this waste heat is typically discharged through cooling towers, cooling circulating water tanks, or directly into the environment, resulting in energy waste and environmental damage. Existing waste heat recovery technologies are primarily targeted at a single process section, lacking the coordinated integration of waste heat from multiple sections and failing to achieve multi-stage utilization based on temperature differences in waste heat, resulting in low energy efficiency. Given this situation, high-purity quartz sand production lines urgently need a comprehensive waste heat utilization process that is energy-efficient, environmentally friendly, cost-effective, and efficient. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand, which can alleviate the problem of high energy consumption in the production of high-purity quartz sand, solve the problem of poor winter pure water heating effect and factory heating of conventional air energy, and further supplement an energy-saving and green production process for the high-purity quartz sand industrial line.

[0004] The purpose of the present invention can be achieved through the following technical solutions: A method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand comprises the following steps: Step 1: Collect, transport and insulate the cooling return water used for equipment cooling in the high-purity quartz sand production line; Step 2: The hot steam generated in each section of the high-purity quartz sand production line is collected, transported and insulated through the induced draft system device; Step 3: Concentrate, precipitate, collect, transport and heat-insulate the high-temperature wastewater generated in each section of the high-purity quartz sand production line; Step 4: The cooling return water, hot steam and high-temperature wastewater from each section in steps 1, 2 and 3 are transported in batches to the heating area requiring heating and the sealed insulation unit room for heat dissipation, thereby continuously raising the specific ambient temperature; Step 5: Use a heat exchanger to replace the waste heat emitted in step 4 through medium heat, and combine with electric auxiliary heating equipment to heat up part of the production pure water, and then keep it warm and store it; Step 6. The hot pure water in the insulated hot water tank is transported to the flotation, pickling and other sections for production water; the cooling return water generated during the production process of each section is heat-dissipated and circulated to the production line for cooling water; the hot steam and high-temperature wastewater generated in each section are condensed and heat-dissipated by the heat dissipation device, and then discharged to the wastewater treatment system for treatment.

[0005] As a further solution of the present invention: in step 1: Equipment includes calciners, drying furnaces, high gradient magnetic separators, chlorination roasters, sand making machines and all other equipment that requires cooling water treatment; The initial temperature of cooling water is 25-30℃, and the cooling return water temperature is 35-55℃.

[0006] As a further solution of the present invention: in step 1: Collection means collecting the cooling return water from each section into the insulation water tank: Transportation refers to transporting the cooling return water of each section from the insulation water tank to the heat dissipation system through pumps and pipelines; Insulation treatment refers to the coordinated treatment of cooling return water from each work section through insulated pipes and insulated water tanks to minimize heat consumption during transportation and storage; the insulation material can be selected from one or more of polyurethane foam, polystyrene foam, asbestos, rubber and plastic sponge, glass wool, rock wool, aluminum foil (auxiliary material), and tin foil.

[0007] As a further solution of the present invention: in step 2: The sources of hot steam include overflow hot steam from flotation machine tanks, exhaust hot steam from flotation wastewater, evaporation water vapor from flotation (concentrate, middlings, tailings), overflow hot steam from water quenching tanks, hot steam evaporated during quartz transportation and drying, hot steam during pickling operations (acid and sand removal), hot gas evaporated from water during drying, and heat-released evaporation from dissolution of reagents (lime, sulfuric acid, caustic soda, etc.). The temperature of the hot steam is 80-100°C.

[0008] The induced draft system includes dust hoods, pipelines, fans, spray towers, water tanks, flow meters, thermometers, liquid level gauges and other facilities. Each facility has the characteristics of heat preservation, acid resistance, corrosion resistance and high temperature resistance.

[0009] As a further solution of the present invention: in step 2: collecting means collecting the hot steam from each section through the induced draft system; Transportation refers to transporting the hot steam from each section to the heat dissipation area through fans and pipelines; Insulation treatment refers to the coordinated treatment of hot gases through insulated pipes and insulated water tanks to minimize heat consumption during transportation and storage; the insulation material can be selected from one or more of polyurethane foam, polystyrene foam, asbestos, rubber and plastic sponge, glass wool, rock wool, aluminum foil (auxiliary material), and tin foil.

[0010] As a further solution of the present invention: in step three: The sources of high-temperature wastewater include flotation high-temperature wastewater, water quenching high-temperature wastewater, and pickling high-temperature wastewater. The temperature of high-temperature wastewater is 45-85°C.

[0011] As a further solution of the present invention: in step three: The concentration sedimentation process is to remove the mud and sand brought in by the flotation, pickling and water quenching sections in advance by relying on one or more equipment such as the desludging hopper, sedimentation collection tank, sedimentation collection water tank and sedimentation tank, so as to facilitate the subsequent transportation of high-temperature wastewater. Collection refers to the collection of overflow high-temperature wastewater after concentration and sedimentation in each section into an insulated water tank; Transportation refers to transporting high-temperature wastewater from each section from the insulation water tank to the cooling system through pumps and pipelines; Insulation treatment refers to the coordinated treatment of high-temperature wastewater generated in each work section through insulated pipes and insulated water tanks to minimize heat consumption during transportation and storage; the insulation material can be selected from one or more of polyurethane foam, polystyrene foam, asbestos, rubber and plastic sponge, glass wool, rock wool, aluminum foil (auxiliary material), and tin foil.

[0012] As a further solution of the present invention: in step 4: Heat dissipation includes heating heat dissipation within the factory area and heat dissipation within the sealed and insulated unit room; Heating areas include workshop production areas, office areas, auxiliary supporting areas and areas that require heating in winter; Heating and cooling methods include hot air heating system, radiator system, and water floor heating system; The heat dissipation methods in the sealed and insulated unit room include one or more of cooling tower heat dissipation, steam radiator heat dissipation, plate heat exchanger heat dissipation, gas-liquid heat exchanger, and air source heat pump radiator; The building materials of the walls, floors, roofs and other areas in the sealed and insulated unit room must be insulated and resistant to high temperatures of 50°C. The insulation building materials can be one or more of rubber-plastic sponge insulation layer, polyurethane foam wall interlayer, glass wool, rock wool, etc. The enclosed and insulated unit room includes a heat dissipation system, a transfer system, a heating system, a conveying system, and an insulation system.

[0013] As a further solution of the present invention: in step 5: the heat exchanger equipment can be one or more of a hot air heat exchanger, an air source heat pump water heater, an air source water heater, an air energy pure heater, and a gas-liquid heat exchanger, and the closed environment temperature must be controlled to be >25°C; The electric auxiliary heating is an auxiliary heating device, which is mainly used to reheat the hot pure water <65℃ to 90℃ after being heated by the heat exchanger, which is beneficial for the subsequent pickling and insulation hot water; The medium can be one or more of heat-conducting air, heat-conducting oil, heat-conducting water or heat-conducting solid; The insulated hot water tank must be able to withstand high temperatures of 90°C and be anti-pollution, and the hot water temperature must not drop by more than 2°C after 24 hours.

[0014] As a further solution of the present invention: in step six: The temperature of the water used in the flotation process is 50-60°C, and the temperature of the water used in the pickling process is 80-90°C. The cooling return water inlet temperature is 25~30℃. After being cooled by the heat dissipation device, the cooling return water meets the circulating cooling water temperature requirements and can be reused as cooling water for equipment in various production workshops. The temperature of hot steam and high-temperature wastewater is less than 25°C after condensation and heat dissipation treatment by the heat dissipation device; the wastewater after condensation and heat dissipation treatment contains acidic substances such as HF and HCl, and the wastewater must be treated to meet the standards before it can be discharged to local sewage treatment.

[0015] Beneficial effects of the present invention: To address the issue of waste heat recovery and reuse in high-purity quartz sand production lines, a set of process methods suitable for the multi-stage recovery and comprehensive utilization of waste heat from the high-purity quartz sand industry has been developed. Based on traditional technologies, the collection and utilization of waste heat from high-purity quartz sand production lines has been optimized and improved. The large amount of medium- and low-temperature waste heat generated in processes such as calcination and water quenching, pickling, flotation, drying, magnetic separation, chlorination roasting, and sand making has been synergistically integrated to establish a systematic recovery mechanism. Based on the different properties of waste heat, suitable collection, transportation, and energy conversion methods are adopted to improve energy utilization. Furthermore, the energy consumption issues of pure water heating and pickling insulation in the flotation process have been resolved, effectively reducing production energy costs. The heating system uses a single energy-saving heating method throughout the year, enabling cross-process energy collaboration. This allows for a linkage between workshop heating and production waste heat, improving the energy utilization of the production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below with reference to the accompanying drawings.

[0017] Figure 1 The present invention is a flow chart of a method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0019] Example 1 See Figure 1 As shown: the calcining furnace, drying furnace, high gradient magnetic separator, chlorination roasting furnace, sand making machine bearing cooling return water 45-55 ℃, magnetic pole cooling return water 40-50 ℃, material cooling return water 50-65 ℃ in the high purity quartz sand production line are collected and put into the insulation hot water tank. The temperature of the hot water tank is about 50-55 ℃; the hot water is then transported to the radiators of each workshop for primary waste heat utilization through a high temperature resistant clean water pump; the heating return water temperature is 35-40 ℃, which can be returned to the cooling tower in the closed insulation unit room for secondary heat dissipation. After heat dissipation, the low temperature water can be used as circulating cooling water for production equipment; the hot air replaced by the cooling tower can be used for heat replacement by the air source heat pump to heat pure water, and the ambient temperature of the closed insulation unit room is 200-300℃. The temperature is not lower than 20℃, and the pure water is heated by air source heat pump. After heating, the temperature of the pure water is 55℃ and it is transported to the insulated water tank for storage; the insulated water tank uses a high-temperature resistant clean water pump to transfer most of the pure water for direct use in flotation production, and the water temperature for flotation production is 50℃; the insulated water tank uses a high-temperature resistant clean water pump to transfer a small amount of pure water for secondary heating in combination with electric auxiliary heating, and the temperature can be raised to 80℃ for pickling and insulation use; during the transportation process, the transportation pipeline can be treated with polyurethane foaming agent + aluminum foil wrapping for transportation insulation treatment, and the insulated water tank is made of internal HDPE + rubber and plastic sponge material filling + 304 stainless steel shell material, and the walls, floors and roofs of the closed insulated unit room are added with polyurethane foam interlayer insulation.

[0020] Example 2 See Figure 1As shown: the hot steam overflowing from the flotation machine tank in the high-purity quartz sand production line, the hot steam discharged from the flotation wastewater, the evaporated water vapor from flotation (concentrate, middlings, tailings), the hot steam overflowing from the water quenching tank, the evaporated hot water vapor from drying the material after water quenching, the hot steam during the pickling operation (acid discharge, sand discharge), the hot gas evaporated from the water during the drying process, and the heat evaporated water vapor from the lime in the wastewater treatment are respectively connected to the dust collecting hood of the induced draft system for absorption, and the hot steam temperature is 80-100℃; the hot steam is collected through the insulation pipeline by the fan and transported to the steam radiator in the closed insulation unit room for heat dissipation; the hot steam generated in each section is condensed by the heat dissipation device and discharged to the wastewater treatment system for treatment; ensuring the closed insulation unit room environment The ambient temperature is not lower than 20℃, and the air source heat pump is used to heat the pure water. After heating, the pure water temperature is 55℃ and is transported to the insulated water tank for storage; the insulated water tank uses a high-temperature resistant clean water pump to transfer most of the pure water for direct use in flotation production, and the flotation production water temperature is 50℃; the insulated water tank uses a high-temperature resistant clean water pump to heat a small amount of pure water in combination with electric auxiliary heating for secondary heating, which can raise the temperature to 80℃ for pickling and insulation use; during the transportation process, the delivery pipeline can be treated with polyurethane foaming agent + aluminum foil wrapping for transportation insulation treatment, and the insulated water tank is made of internal HDPE + rubber and plastic sponge material filling + 304 stainless steel shell material, and the walls, floors and roofs of the closed insulated unit room are added with polyurethane foam interlayer insulation.

[0021] Example 3 See Figure 1 As shown: the high-temperature wastewater discharged from flotation at 45-55℃, the high-temperature wastewater discharged from water quenching at 40-80℃, and the high-temperature wastewater discharged from pickling at 70-80℃ in the high-purity quartz sand production line are concentrated and precipitated respectively through a desludging bucket + sedimentation collection tank, and the overflow clarified high-temperature wastewater is uniformly collected and put into an insulated hot water tank. The temperature of the hot water tank is approximately 60℃; the high-temperature wastewater is then transported to the plate heat exchanger in the closed insulated unit room through a high-temperature resistant, wear-resistant, and acid-resistant water pump for heat dissipation. After heat dissipation, the low-temperature wastewater is uniformly discharged to the wastewater treatment system for treatment; the hot air replaced by the heat exchanger can be used for heat replacement by the air source heat pump to heat pure water, and the ambient temperature of the closed insulated unit room is not lower than 20℃ , use air source heat pump to heat pure water, the pure water temperature after heating is 55 ℃, and it is transported to the insulated water tank for storage; the insulated water tank uses a high-temperature resistant clean water pump to transfer most of the pure water for direct use in flotation production water, and the flotation production water temperature is 50 ℃; the insulated water tank uses a high-temperature resistant clean water pump to heat a small amount of pure water combined with electric auxiliary heating for secondary heating, which can raise the temperature to 80 ℃ for pickling and insulation use; during the transportation process, the delivery pipeline can be treated with polyurethane foaming agent + aluminum foil wrapping for transportation insulation treatment, and the insulated water tank with stainless steel shell material is filled with internal HDPE + rubber and plastic sponge material, and the walls, floors and roofs of the closed insulation unit room are added with polyurethane foam interlayer insulation.

[0022] Example 4 See Figure 1 As shown: Combining Examples 1-3 to obtain this example, The cooling return water used for equipment cooling in the high-purity quartz sand production line is collected, transported and insulated; the hot steam generated in each section of the high-purity quartz sand production line is collected, transported and insulated through the induced draft system device; the high-temperature wastewater generated in each section of the high-purity quartz sand production line is concentrated, precipitated, collected, transported and insulated; the cooling return water, hot steam and high-temperature wastewater of each section are controlled by valves to transport the heat in batches to the heating area requiring heating and the closed insulated unit room for heat dissipation, thereby continuously improving the specific ambient temperature; the waste heat emitted in step 4 is replaced by medium heat through a heat exchanger, and some pure water for production is heated and stored insulated in combination with electric auxiliary heating equipment; the hot pure water in the insulated hot water tank is transported to the flotation, pickling and other sections for production water; the cooling return water generated in the production process of each section is heat-dissipated and circulated to the production line cooling water; the hot steam and high-temperature wastewater generated in each section are condensed and heat-dissipated by the heat dissipation device and then discharged to the wastewater treatment system for treatment.

[0023] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand, characterized in that: The following steps are involved: Step 1: Collect, transport and insulate the cooling return water used for equipment cooling in the high-purity quartz sand production line; Step 2: The hot steam generated in each section of the high-purity quartz sand production line is collected, transported and insulated through the induced draft system device; Step 3: Concentrate, precipitate, collect, transport and heat-insulate the high-temperature wastewater generated in each section of the high-purity quartz sand production line; Step 4: The cooling return water, hot steam and high-temperature wastewater from each section in steps 1, 2 and 3 are controlled by valves to transport the heat in batches to the heating area requiring heating and the sealed insulation unit room for heat dissipation; Step 5: Use a heat exchanger to replace the waste heat emitted in step 4 through medium heat, and combine with electric auxiliary heating equipment to heat up part of the production pure water, and then keep it warm and store it; Step 6: The hot pure water stored in the heat preservation is transported to each section for production water; the cooling return water generated during the production process of each section is heat-dissipated and then circulated to the production line for cooling water; The hot steam and high-temperature wastewater generated in each process section are condensed and dissipated through the heat dissipation device and then discharged to the wastewater treatment system for treatment.

2. The method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand according to claim 1, characterized in that: In step one: Equipment includes calcining furnaces, drying furnaces, high gradient magnetic separators, chlorination roasters, sand making machines and other equipment requiring cooling water treatment; The initial temperature of cooling water is 25-30℃, and the cooling return water temperature is 35-55℃.

3. The method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand according to claim 2, characterized in that: In step one: Collection means collecting the cooling return water from each section into the insulation water tank: Transportation refers to transporting the cooling return water of each section from the insulation water tank to the heat dissipation system through pumps and pipelines; Insulation treatment refers to the coordinated treatment of cooling return water from each work section through insulation pipes and insulation water tanks.

4. The method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand according to claim 1, characterized in that: In step 2: The sources of hot steam include overflow hot steam in the flotation machine tank, exhaust hot steam from flotation wastewater, evaporation water vapor from flotation, overflow hot steam in the water quenching tank, hot steam evaporated during quartz transportation and drying, hot steam during pickling operation, hot gas evaporated from water during drying, and evaporation water vapor released by dissolution of reagents; The temperature of the hot steam is 80-100°C.

5. The method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand according to claim 4, characterized in that: In step 2: Collection means collecting the hot steam from each section through the induced draft system; Transportation refers to transporting the hot steam from each section to the heat dissipation area through fans and pipelines; Insulation treatment refers to the coordinated treatment of cooling return water from each work section through insulation pipes and insulation water tanks.

6. The method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand according to claim 1, characterized in that: In step three: The sources of high-temperature wastewater include flotation high-temperature wastewater, water quenching high-temperature wastewater, and pickling high-temperature wastewater. The temperature of high-temperature wastewater is 45-85°C.

7. The method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand according to claim 6, characterized in that: In step three: The concentration sedimentation process refers to the use of one or more equipment in the desludging hopper, sedimentation collection tank, sedimentation collection tank, and sedimentation tank to remove the mud and sand brought in by the flotation, pickling and water quenching sections in advance; Collection refers to the collection of overflow high-temperature wastewater after concentration and sedimentation in each section into an insulated water tank; Transportation refers to transporting high-temperature wastewater from each section from the insulation water tank to the cooling system through pumps and pipelines; Insulation treatment refers to the coordinated treatment of high-temperature wastewater generated in each work section through insulated pipes and insulated water tanks.

8. The method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand according to claim 1, characterized in that: In step four: Heat dissipation includes heating heat dissipation within the factory area and heat dissipation within the sealed and insulated unit room; Heating areas include workshop production areas, office areas, auxiliary supporting areas and areas that require heating in winter; Heating and cooling methods include hot air heating system, radiator system, and water floor heating system; The heat dissipation methods in the sealed and insulated unit room include one or more of cooling tower heat dissipation, steam radiator heat dissipation, plate heat exchanger heat dissipation, gas-liquid heat exchanger, and air source heat pump radiator.

9. The method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand according to claim 1, characterized in that: In step 5: The heat exchanger equipment is one or more of a hot air heat exchanger, an air source heat pump water heater, an air source water heater, an air energy pure heater, and an air-liquid heat exchanger, and the closed environment temperature must be controlled to be >25°C; The electric auxiliary heating equipment is used to reheat the hot pure water <65℃ after being heated by the heat exchanger to 90℃; The medium is one or more of heat-conducting air, heat-conducting oil, heat-conducting water or heat-conducting solid.

10. The method for multi-stage recovery and comprehensive utilization of industrial waste heat from high-purity quartz sand according to claim 1, characterized in that: In step six: The cooling return water inlet temperature is 25~30℃. After being cooled by the heat dissipation device, the cooling return water meets the circulating cooling water temperature requirements and can be reused as cooling water for equipment in various production workshops. The temperature of hot steam and high-temperature wastewater is less than 25℃ after condensation and heat dissipation treatment by the heat dissipation device.

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