Heating medium: The heat exchanger transfers heat to the drying medium (such as air, nitrogen, etc.) to increase its temperature. The hot drying medium comes into full contact with the sludge and transfers heat to the sludge through convection, conduction, and other means, causing the water in the sludge to absorb heat and evaporate into steam, thereby achieving the drying of the sludge.
Recycling waste heat: During the sludge drying process, a large amount of exhaust gas containing heat is generated. The heat exchanger can cool the exhaust gas and recover the heat from it. The recovered heat can be used to preheat fresh air or drying medium entering the dryer, as well as for other process links that require thermal energy, thereby improving the energy utilization efficiency of the entire drying system and reducing energy consumption.
Removing moisture: During the sludge drying process, the heat exchanger can not only heat the drying medium, but also condense the water vapor in the drying medium into liquid water through cooling, thereby achieving dehumidification of the drying medium. Dehumidification of the drying medium is beneficial for improving its ability to absorb moisture from sludge and enhancing the drying effect. For example, in some sludge drying systems that use circulating drying media, by setting up cooling heat exchangers to dehumidify the circulating air, the drying speed of sludge can be increased by 20% -30%.
Application of Heat Pump Heat Exchanger in Food Drying Field
Provide a drying heat source: Heat pump heat exchangers can raise the temperature of environmental heat or waste heat, providing a stable heat source for the food drying process. For example, in the process of drying fruits and vegetables, a heat pump drying system can heat the air to a suitable temperature (such as 50-70 ℃), allowing the moisture in the fruits and vegetables to slowly evaporate at a lower temperature. This not only preserves the nutritional content and flavor of the food, but also improves the drying efficiency. Compared with traditional hot air drying methods, it can save a lot of energy.
Recycling of Waste Heat from Drying Exhaust Gas: The exhaust gas emitted during the food drying process contains a certain amount of heat and moisture, which can be cooled by a heat pump heat exchanger to recover the heat and condense the moisture in the exhaust gas. The recovered heat can be used to preheat fresh air or other process steps, reducing energy consumption during the drying process. Taking mushroom drying as an example, recovering exhaust heat through a heat pump heat exchanger can reduce drying energy consumption by 20% -30%.
Application of Heat Pump Heat Exchanger in Drying Chemical Materials
Heating of drying medium: In the drying process of chemical materials, it is necessary to heat the drying medium (such as air, nitrogen, etc.) to a certain temperature to improve the drying efficiency. Heat pump heat exchangers can elevate the temperature of thermal energy or industrial waste heat in the environment and use it to heat drying media. For example, when drying pesticide intermediates, a heat pump heat exchanger is used to heat the air and raise the air temperature to 60-80 ℃, providing the required heat for the drying process. Compared with traditional electric or gas heating methods, it can significantly reduce the drying cost.
Recycling of waste heat from drying exhaust gas: The exhaust gas emitted during the drying process of chemical materials usually contains a certain amount of heat and moisture. If directly discharged, it will cause energy waste and environmental pollution. A heat pump heat exchanger can cool dry exhaust gas, recover its heat, and condense the moisture in the exhaust gas, achieving the goal of waste heat recovery and energy conservation and emission reduction. The recovered heat can be used to preheat fresh drying media or other processes, improving energy utilization efficiency.
The role of heat pump heat exchangers in the chemical industry
1. Maintain reaction temperature: Many chemical reactions require specific temperature ranges to ensure reaction rate and product quality. The heat pump heat exchanger can adjust the temperature inside the reaction vessel to timely remove or supplement the required heat generated by the reaction, so that the reaction can proceed under stable temperature conditions. For example, in the polyester synthesis reaction, it is necessary to strictly control the reaction temperature at around 200-250 ℃. The heat pump heat exchanger can accurately adjust the temperature of the reaction kettle to ensure the smooth progress of the reaction.
2. Recycling reaction waste heat: Some chemical reactions are exothermic reactions, and if the large amount of waste heat generated is not utilized, it will not only cause energy waste, but also may cause thermal pollution to the environment. Heat pump heat exchangers can recover the heat from high-temperature hot water or steam discharged from the reaction kettle, raise it to a higher temperature level, and use it for other processes that require heat, such as preheating reactants, heating process water, etc., thereby improving the energy utilization efficiency of the entire chemical production process.
What industrial fields are heat pump heat exchangers used in?
Process heating in industrial production: In some industrial production processes that do not require particularly high temperature but require a large amount of heat energy, such as food processing, textile printing and dyeing, wood drying, etc., heat pump heat exchangers can use industrial waste heat or environmental heat energy to provide the required heat for the production process, achieving energy recovery and energy conservation and emission reduction.
Industrial wastewater waste heat recovery: Many industrial production processes generate a large amount of wastewater, which often contains a certain amount of heat. Heat pump heat exchangers can extract heat from wastewater and use it to preheat production water or other processes that require thermal energy, reducing energy consumption and production costs for enterprises.
Dryer Exhaust Heat Recovery Exchanger Technical Overview
1. Exchanger Types
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Plate Heat Exchanger
Compact structure with high heat transfer efficiency, suitable for low-temperature exhaust (<200°C) with minimal corrosiveness. Easy to clean, ideal for small to medium-sized dryers. -
Rotary Wheel Exchanger
Transfers heat via a rotating wheel, suitable for high-flow, low-temperature-difference exhaust recovery. High efficiency, best for large-scale drying systems, but requires more space.
2. Design Considerations
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Exhaust Characteristics
Evaluate exhaust temperature (typically 80–200°C), flow rate, humidity, and dust content. Corrosive gases require resistant materials (e.g., stainless steel). -
Heat Recovery Efficiency
Efficiency ranges from 50%–80%, depending on temperature difference and heat transfer area. Balance efficiency with pressure drop to maintain exhaust performance. -
Maintenance and Cost
Plate exchangers are easy to disassemble and clean, with low maintenance costs. Rotary wheel exchangers suit continuous operation but have higher initial costs.
3. Application Scenarios
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Plate Heat Exchanger: Used in small to medium dryers, such as in food or textile industries, for recovering low-temperature exhaust to preheat fresh air.
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Rotary Wheel Exchanger: Applied in large industrial dryers, like paper or chemical material drying, for handling high-flow exhaust.
U-tube heat exchanger
A U-tube heat exchanger is a common shell-and-tube device named for its U-shaped tube bundle, widely used in chemical, petroleum, and energy industries. It consists of U-tubes, a shell, and tube sheets, with hot fluid flowing inside the tubes and cold fluid in the shell, facilitating heat transfer. The U-shape allows tubes to expand freely, accommodating high temperatures and pressures while reducing thermal stress. Advantages include simple design, easy maintenance, and high heat transfer efficiency, ideal for clean or moderately corrosive fluids. However, tube cleaning is challenging, and it requires more space. U-tube heat exchangers excel in steam condensation and liquid heating processes.
microchannel heat exchanger
A microchannel heat exchanger is a highly efficient, compact device used in refrigeration, air conditioning, automotive, and renewable energy sectors. Its core feature is a microscale channel structure that greatly increases the heat transfer area, enhancing efficiency. Compared to traditional heat exchangers, it’s smaller, lighter, and offers superior heat transfer with less refrigerant, making it energy-saving and eco-friendly. Typically made of aluminum alloy, it’s corrosion-resistant and easy to process. Common designs include parallel-flow and cross-flow, ideal for high heat flux scenarios. Despite higher manufacturing costs, its efficiency and compactness make it popular, especially for EV battery cooling and data center thermal management.
graphite heat exchanger
A graphite heat exchanger is a type of heat transfer equipment made from graphite, widely used in industries like chemical processing, pharmaceuticals, and metallurgy for handling corrosive media. Graphite offers excellent corrosion resistance, high-temperature stability, and good thermal conductivity, making it ideal for harsh environments involving acids, alkalis, and other aggressive substances.
Graphite heat exchangers come in various designs, including tubular, plate, and block types. Tubular designs suit high-temperature and high-pressure conditions, plate types offer high heat transfer efficiency, and block types are compact and easy to maintain. They work by transferring heat from one medium to another through graphite, while maintaining the chemical stability of the media.
Advantages include:
- Corrosion resistance: Suitable for diverse chemical environments.
- High thermal conductivity: Efficient heat transfer.
- Long lifespan: Durable graphite material.
Drawbacks include graphite’s brittleness, which limits mechanical shock resistance, and relatively high manufacturing costs. Graphite heat exchangers are commonly used in applications like chlor-alkali production and sulfuric acid processing, making them ideal for complex chemical processes.
Heat exchanger for cooling solar inverters
Solar inverters generate a large amount of heat during operation. If this heat is not dissipated in a timely manner, the internal temperature of the inverter will continue to rise, leading to a decrease in device performance, shortened lifespan, and even causing malfunctions. Therefore, based on solar inverters with different heat exchangers, we provide you with suitable cooling solutions.
Air cooled heat exchangers use air as a cooling medium and force air to flow over the surface of the heat exchanger through a fan to achieve heat exchange.
Design selection: We determine the size, heat dissipation area, and fan air volume and pressure of the air-cooled heat exchanger based on the power size, heating power, and operating environment of the inverter. Generally speaking, compact plate fin air-cooled heat exchangers can be used for small solar inverters, which have the characteristics of small size and high heat dissipation efficiency; Large inverters can use tube and strip air-cooled heat exchangers, which have a large heat dissipation area and can meet high-power heat dissipation requirements.
Liquid cooled heat exchangers use liquid as the cooling medium, which circulates inside the heat exchanger, absorbs the heat generated by the inverter, and then dissipates the heat to the external environment through the radiator.
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