Water quenching heat energy utilization system for lead-zinc volatile kiln slag

Abstract

The utility model discloses a water quenching heat energy utilization system for lead-zinc volatile kiln slag. The water quenching heat energy utilization system comprises a hot water conveying pipeline, a filter, a CO2 transcritical cycle heat pump, an air conveying pipeline, a cylindrical dryer and a material conveying device, a water inlet of the filter is connected with a water outlet of the water quenching pool through a hot water conveying pipeline, and a water outlet of the filter is connected with a water inlet of the CO2 transcritical cycle heat pump through a pipeline, so that normal-temperature air entering the CO2 transcritical cycle heat pump is heated by utilizing heat energy of hot water discharged from the water quenching pool; an air outlet of the CO2 transcritical cycle heat pump is connected with a feeding port of the cylinder dryer through an air conveying pipeline so that wet zinc leaching residues entering the cylinder dryer can be pre-dried through hot air, a discharging port of the cylinder dryer is connected with the material conveying device, and the material conveying device is connected with a material inlet of the lead-zinc volatilization kiln. The wet zinc leaching residues are preheated and dried through heat energy carried by hot water generated through water quenching, the energy utilization rate is increased, and fossil energy consumption is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of non-ferrous metal smelting technology, specifically a water quenching thermal energy utilization system for lead-zinc volatile kiln slag. Background Technology

[0002] Lead-zinc volatilization kiln smelting is one of the important methods for treating zinc leaching residue. A mixture of zinc leaching residue and coke enters the lead-zinc volatilization kiln from the material inlet at the kiln tail. It exchanges heat and mass with compressed air entering from the kiln head. During this process, volatile valuable metals such as lead and zinc in the zinc leaching residue leave the volatilization kiln with the flue gas and are collected through a dust collection process. The kiln slag after the reaction leaves the volatilization kiln from the material outlet at the kiln head. The kiln slag containing residual carbon is treated by water quenching to obtain raw materials for cement production.

[0003] The moisture content of the feed material in a lead-zinc volatilization kiln can be close to 20%. A large amount of coal char needs to be consumed in the volatilization kiln for moisture evaporation and heating to meet the reaction conditions, resulting in high coal char consumption and production costs. The kiln slag temperature is around 1000℃. After water quenching, the slag temperature drops to around 100℃, and the water temperature in the quenching tank rises to around 60℃. Currently, a large amount of hot water at around 60℃ generated during the water quenching process has not been effectively utilized, resulting in a large amount of heat being directly lost to the environment through the cooling tower, wasting valuable waste heat resources and causing thermal pollution to the environment. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a water quenching thermal energy utilization system for lead-zinc volatile kiln slag. This system uses the heat energy carried by the hot water generated during water quenching to preheat and dry the wet zinc leaching slag, thereby improving energy utilization during the production process and reducing fossil energy consumption.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A water quenching thermal energy utilization system for lead-zinc volatile kiln slag includes a hot water delivery pipeline, a filter, a CO2 transcritical cycle heat pump, an air delivery pipeline, a cylindrical dryer, and a material conveying device.

[0007] The filter's inlet is connected to the drain outlet of the water quenching tank via a hot water delivery pipe. The filter's outlet is connected to the inlet of a CO2 transcritical cycle heat pump via a pipe, thereby utilizing the heat energy of the hot water discharged from the water quenching tank to heat the ambient temperature air entering the CO2 transcritical cycle heat pump. The CO2 transcritical cycle heat pump's outlet is connected to the feed inlet of a cylindrical dryer via an air delivery pipe, thereby pre-drying the wet zinc leaching residue entering the cylindrical dryer with hot air. The cylindrical dryer's outlet is connected to a material conveying device, which is connected to the material inlet of the lead-zinc volatilization kiln.

[0008] Furthermore, it also includes a hot water pump, the inlet of which is connected to the drain outlet of the water quenching tank via a hot water delivery pipe, and the outlet of which is connected to the inlet of the filter via a hot water delivery pipe.

[0009] Furthermore, the CO2 transcritical cycle heat pump includes an evaporator, the inlet of which is connected to the outlet of a filter via a pipe, the cold medium inlet of which is connected to a throttling device via a pipe, the throttling device being connected to the cold medium outlet of a cooler via a pipe, the hot medium inlet of which is connected to the outlet of a compressor, the air inlet of which is connected to the outside air, and the air outlet of which is connected to the feed inlet of a cylindrical dryer via an air delivery pipe.

[0010] The compressor inlet is connected to the gas outlet of the gas-liquid separator, the gas inlet of the gas-liquid separator is connected to the heat medium outlet of the evaporator, and the water outlet of the evaporator is connected to a water collection device.

[0011] Furthermore, the throttling device is an electronic expansion valve, a thermostatic expansion valve, or a capillary tube.

[0012] Furthermore, a fan is installed inside the air delivery duct.

[0013] Furthermore, the material conveying device is a conveyor belt.

[0014] Furthermore, the temperature of the hot water discharged from the water quenching tank is 50-60℃, and the temperature of the hot air is 100-110℃.

[0015] Furthermore, the evaporation temperature of the evaporator is 0–20°C.

[0016] Furthermore, the cooling pressure of the cooler is 8-15 MPa, and the temperature of the cooling medium outlet of the cooler is 40°C.

[0017] Furthermore, the outlet temperature of the compressor is 100–115°C, and the subcooling of the compressor is 0–60°C.

[0018] Compared with the prior art, this utility model has the following technical effects:

[0019] This invention utilizes a CO2 transcritical cycle heat pump to heat ambient air using the heat energy carried by the hot water generated during the water quenching process. This converts the ambient air into hot air, which is then used to pre-dry the wet zinc leaching residue entering the cylindrical dryer. This pre-drying process reduces the moisture content and increases the temperature of the zinc leaching residue. The dried zinc leaching residue, along with coke, is then transported to the lead-zinc volatilization kiln. This reduces energy consumption due to moisture evaporation and heat absorption from the zinc leaching residue during production, lowers coke consumption during the lead-zinc volatilization kiln smelting process, and reduces heat loss from the water quenching hot water. This improves energy utilization efficiency and significantly enhances the energy efficiency of the lead-zinc volatilization kiln, achieving energy conservation and significant economic benefits. It also promotes green manufacturing. Attached Figure Description

[0020] Figure 1 : Flowchart of the water quenching heat energy utilization system for lead-zinc volatile kiln slag of this utility model;

[0021] Figure 2 : A schematic diagram of the CO2 transcritical cycle heat pump system of this utility model;

[0022] Figure 3 The relationship between the efficiency of water quenching heat energy recovery and the improvement of energy efficiency of lead-zinc volatilization kilns.

[0023] In the diagram: 1. Evaporator; 2. Gas-liquid separator; 3. Compressor; 4. Cooler; 5. Throttling device. Detailed Implementation

[0024] The specific content of this utility model will be further explained in detail below with reference to the embodiments.

[0025] like Figure 1 As shown, a water quenching thermal energy utilization system for lead-zinc volatilization kiln slag includes a hot water conveying pipeline, a filter, a CO2 transcritical cycle heat pump, an air conveying pipeline, a cylindrical dryer, and a material conveying device. The filter's inlet is connected to the drain outlet of the water quenching tank via the hot water conveying pipeline; the filter's outlet is connected to the CO2 transcritical cycle heat pump's inlet via a pipeline; the CO2 transcritical cycle heat pump's outlet is connected to the cylindrical dryer's inlet via the air conveying pipeline; the cylindrical dryer's outlet is connected to the material conveying device; and the material conveying device is connected to the lead-zinc volatilization kiln's material inlet.

[0026] Hot water stored in the water quenching tank is transported to a filter via a hot water pipeline to remove solid residues, resulting in filter residue hot water. This prevents volatile kiln slag from condensing on the heat exchanger surface of the CO2 transcritical cycle heat pump, which would increase thermal resistance and thus affect heat exchange efficiency and economic benefits. The filter residue hot water then enters the CO2 transcritical cycle heat pump and exchanges heat with the ambient air entering the pump, converting the ambient air into hot air at 100-110°C. The hot water is then discharged as cold water, which can be recycled back into the water quenching tank or centrally discharged. Air is transported to the cylindrical dryer through an air conveying pipe to preheat and dry the wet zinc leaching residue entering the dryer. Coal char and the dry zinc leaching residue discharged from the outlet of the cylindrical dryer are transported by a material conveying device to the inside of the lead-zinc volatilization kiln. The kiln slag after reaction is discharged from the material outlet of the lead-zinc volatilization kiln and is cooled by water quenching in a water quenching tank. The room temperature water in the water quenching tank is heated to hot water at 50-60°C and circulated repeatedly to realize the recovery and utilization of the heat energy carried by the water quenching hot water, thereby reducing the amount of coal char used and reducing fossil energy consumption.

[0027] like Figure 2 As shown, the CO2 transcritical cycle heat pump includes an evaporator 1. The inlet of the evaporator 1 is connected to the outlet of the filter through a pipe, thereby transporting the hot water from the filter residue to the evaporator 1. The cold medium inlet of the evaporator 1 is connected to a throttling device 5 through a pipe. The throttling device 5 is connected to the cold medium outlet of the cooler 4 through a pipe. The hot medium inlet of the cooler 4 is connected to the outlet of the compressor 3. The inlet of the compressor 3 is connected to the gas outlet of the gas-liquid separator 2. The gas inlet of the gas-liquid separator 2 is connected to the hot medium outlet of the evaporator 1. The outlet of the evaporator 1 is connected to a water collection device. The air inlet of the cooler 4 is connected to the outside air. The air outlet of the cooler 4 is connected to the feed inlet of the cylindrical dryer through an air conveying pipe.

[0028] After the hot water from the filter residue is transported to evaporator 1, it exchanges heat with the liquid low-pressure, low-temperature CO2 inside evaporator 1. The hot water turns into cold water and is discharged from the outlet of evaporator 1, entering the water collection device. Then it is either centrally discharged or circulated into the water quenching tank. The liquid CO2 absorbs heat and vaporizes, becoming medium-temperature, low-pressure CO2, which enters gas-liquid separator 2. Gas-liquid separator 2 can prevent liquid slugging in compressor 3 and facilitate oil return from compressor. The medium-temperature, low-pressure CO2 enters compressor 3 and is compressed to a transcritical state. The high-pressure, high-temperature transcritical CO2 enters cooler 4 and exchanges heat with the ambient air entering cooler 4, releasing heat and liquefying, becoming high-pressure, low-temperature CO2. The high-pressure, low-temperature CO2 enters throttling device 5, and after throttling and depressurization, it becomes low-pressure, low-temperature CO2. The low-pressure, low-temperature CO2 is circulated back into evaporator 1 to exchange heat with the hot water. At the same time, the ambient air is heated to 100-110°C hot air, and then transported to the cylindrical dryer through the air conveying pipeline to preheat and dry the wet zinc leaching residue.

[0029] Preferably, the hot water delivery pipeline is connected to a hot water pump, which pressurizes the hot water discharged from the water quenching tank and pumps it into the filter.

[0030] Preferably, the throttling device 5 is an electronic expansion valve, a thermostatic expansion valve, or a capillary tube.

[0031] Preferably, the material conveying device is a conveyor belt.

[0032] Preferably, the air delivery duct is equipped with a fan for pressurizing the hot air.

[0033] Preferably, the evaporation temperature of the evaporator 1 is 0 to 20°C.

[0034] Preferably, the cooling pressure of the cooler 4 is 8-15 MPa, and the temperature of the cold medium outlet of the cooler 4 is 40°C.

[0035] Preferably, the outlet temperature of the compressor 3 is 100-115°C, and the subcooling of the compressor 3 is 0-60°C.

[0036] Preferably, the drum dryer can be in a counter-current configuration. Specifically, the drum dryer is a rotating cylinder with an inclined angle. The wet zinc leaching residue moves from the high end to the low end of the cylinder. At the same time, an air conveying pipe is connected to the low end of the drum dryer, and hot air moves from the low end to the high end of the cylinder. This causes the wet zinc leaching residue and the hot air to move towards each other. Through heat and mass exchange between the hot air and the wet zinc leaching residue with a moisture content of 20-27% and a temperature of 5-30°C, the wet zinc leaching residue is preheated and dried, transforming it into dry zinc leaching residue with a moisture content of 5-20% and a temperature of 50-80°C.

[0037] A method for utilizing the water quenching heat energy of lead-zinc volatile kiln slag includes the following steps:

[0038] Step 1: Hot water at 50-60°C stored in the water quenching tank is transported to the filter through a hot water delivery pipeline to filter out solid residues in the hot water and obtain filter residue hot water.

[0039] Step 2: The hot water from the filter residue enters the evaporator 1 and exchanges heat with the liquid low-pressure low-temperature CO2 inside the evaporator 1. The hot water turns into cold water and is discharged from the outlet of the evaporator 1, entering the water collection device. The liquid CO2 absorbs heat and vaporizes, turning into medium-temperature low-pressure CO2.

[0040] Step 3: Medium-temperature low-pressure CO2 passes through gas-liquid separator 2 and enters compressor 3, where it is compressed to a transcritical state. The high-pressure, high-temperature transcritical CO2 enters cooler 4 and exchanges heat with ambient air entering cooler 4, releasing heat and liquefying into high-pressure, low-temperature CO2. The ambient air is heated to 100-110°C and transported to a cylindrical dryer through an air conveying pipeline to preheat and dry the wet zinc leaching residue, obtaining dry zinc leaching residue. The dry zinc leaching residue and coke are transported together by a material conveying device to a lead-zinc volatilization kiln for production.

[0041] Step 5: High-pressure low-temperature CO2 enters the throttling device 5, and after throttling and pressure reduction, it becomes low-pressure low-temperature CO2;

[0042] Step 6: Low-pressure, low-temperature CO2 is recirculated into evaporator 1 to exchange heat with hot water.

[0043] Repeating steps 1 to 6, using a CO2 transcritical cycle heat pump, the heat energy carried by the water-quenched hot water is used to heat the ambient air. Then, the wet zinc leaching residue is preheated and dried using the hot air. This achieves the recovery and utilization of water-quenched heat energy, improves heat utilization efficiency, reduces the amount of coal coke used, reduces fossil energy consumption, and achieves the goal of energy conservation.

[0044] Figure 3 This embodiment demonstrates the relationship between the efficiency of water quenching heat energy recovery and the improvement of energy efficiency in lead-zinc volatilization kilns during actual use. It can be seen that the improvement of energy efficiency in lead-zinc volatilization kilns is directly proportional to the efficiency of water quenching heat energy recovery, indicating that the water quenching heat energy utilization system proposed in this embodiment can effectively improve the energy efficiency of the lead-zinc volatilization kiln production process.

Claims

1. A water quenching thermal energy utilization system for lead-zinc volatile kiln slag, characterized in that, This includes hot water delivery pipelines, filters, CO2 transcritical cycle heat pumps, air delivery pipelines, cylindrical dryers, and material conveying devices. The filter's inlet is connected to the drain outlet of the water quenching tank via a hot water delivery pipe. The filter's outlet is connected to the inlet of a CO2 transcritical cycle heat pump via a pipe, thereby utilizing the heat energy of the hot water discharged from the water quenching tank to heat the ambient temperature air entering the CO2 transcritical cycle heat pump. The CO2 transcritical cycle heat pump's outlet is connected to the feed inlet of a cylindrical dryer via an air delivery pipe, thereby pre-drying the wet zinc leaching residue entering the cylindrical dryer with hot air. The cylindrical dryer's outlet is connected to a material conveying device, which is connected to the material inlet of the lead-zinc volatilization kiln.

2. The water quenching thermal energy utilization system for lead-zinc volatile kiln slag according to claim 1, characterized in that, It also includes a hot water pump, whose inlet is connected to the drain of the water quenching tank via a hot water delivery pipe, and whose outlet is connected to the inlet of the filter via a hot water delivery pipe.

3. The water quenching thermal energy utilization system for lead-zinc volatile kiln slag according to claim 1 or 2, characterized in that, The CO2 transcritical cycle heat pump includes an evaporator (1), the inlet of the evaporator (1) is connected to the outlet of the filter through a pipe, the cold medium inlet of the evaporator (1) is connected to a throttling device (5) through a pipe, the throttling device (5) is connected to the cold medium outlet of the cooler (4) through a pipe, the hot medium inlet of the cooler (4) is connected to the outlet of the compressor (3), the air inlet of the cooler (4) is connected to the outside air, and the air outlet of the cooler (4) is connected to the feed inlet of the cylindrical dryer through an air conveying pipe. The inlet of the compressor (3) is connected to the gas outlet of the gas-liquid separator (2), the gas inlet of the gas-liquid separator (2) is connected to the heat medium outlet of the evaporator (1), and the water outlet of the evaporator (1) is connected to a water collection device.

4. The water quenching thermal energy utilization system for lead-zinc volatile kiln slag according to claim 3, characterized in that, The throttling device (5) is an electronic expansion valve, a thermal expansion valve, or a capillary tube.

5. The water quenching thermal energy utilization system for lead-zinc volatile kiln slag according to claim 1 or 2, characterized in that, The air delivery duct is equipped with a fan.

6. The water quenching thermal energy utilization system for lead-zinc volatile kiln slag according to claim 1 or 2, characterized in that, The material conveying device is a conveyor belt.

7. The water quenching thermal energy utilization system for lead-zinc volatile kiln slag according to claim 1 or 2, characterized in that, The hot water discharged from the water quenching tank has a temperature of 50-60℃, and the hot air temperature has a temperature of 100-110℃.

8. The water quenching thermal energy utilization system for lead-zinc volatile kiln slag according to claim 3, characterized in that, The evaporator (1) has an evaporation temperature of 0 to 20°C.

9. The water quenching thermal energy utilization system for lead-zinc volatile kiln slag according to claim 3, characterized in that, The cooling pressure of the cooler (4) is 8-15 MPa, and the temperature of the cold medium outlet of the cooler (4) is 40°C.

10. The water quenching thermal energy utilization system for lead-zinc volatile kiln slag according to claim 3, characterized in that, The outlet temperature of the compressor (3) is 100-115°C, and the subcooling of the compressor (3) is 0-60°C.

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