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.
Introduction to Surface Coolers and Their Applications
A surface cooler (table cooler) is an efficient heat exchange device widely used in central air conditioning, industrial refrigeration, and ventilation systems. It operates by circulating chilled water or refrigerant through copper tubes, exchanging heat with air via aluminum fins to lower air temperature and remove moisture. Compact in structure and highly efficient, surface coolers are applied in the following scenarios:
- Commercial Buildings: Such as malls, hotels, and offices for air conditioning and dehumidification.
- Industrial Settings: Such as electronics and pharmaceutical plants to control temperature and humidity.
- Data Centers: To maintain a constant temperature and humidity for server operations.
- Hospitals: For precise temperature and humidity control in operating rooms and wards.
- Transportation: In air conditioning systems for subways and train stations.
Surface coolers enable energy-efficient and precise environmental control, meeting diverse needs across various applications.
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.
What is a heat pump and how does it work?
A heat pump is a device that transfers heat from one place to another, typically to heat or cool a building. It works by using a refrigerant to absorb heat from a colder area (like the outside air, ground, or water) and release it into a warmer area (like inside a home).
How it works:
- Evaporation: The refrigerant, a special fluid, absorbs heat from a low-temperature source (e.g., outdoor air) in the evaporator coil. This causes the refrigerant to evaporate into a gas.
- Compression: The gaseous refrigerant is compressed by a compressor, which increases its temperature and pressure, making it very hot.
- Condensation: The hot gas flows into the condenser coil, where it releases its heat to the indoor space (for heating) or outside (for cooling). As it loses heat, the refrigerant condenses back into a liquid.
- Expansion: The liquid refrigerant passes through an expansion valve, which reduces its pressure and temperature, preparing it to absorb heat again in the evaporator.
Key points:
- Reversible: Most heat pumps can switch modes to either heat or cool a space by reversing the refrigerant flow.
- Efficiency: They’re highly efficient because they move heat rather than generate it, often using less energy than traditional heaters or air conditioners.
- Types: Common types include air-source, ground-source (geothermal), and water-source heat pumps, depending on the heat source.
For example, in winter, an air-source heat pump extracts heat from cold outdoor air to warm your home. In summer, it reverses to act like an air conditioner, removing heat from indoors.
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.
The practice of the United States imposing excessive tariffs is wrong
The United Nations Industrial Development Organization published an article on its website on the 18th stating that the United States' excessive imposition of tariffs is wrong and will pose huge risks to world economic growth and industrial development, weaken the potential of developing countries and least developed countries to fully participate in global trade, and offset their efforts to modernize their industries and diversify their economies.
The article points out that imposing tariffs will drive up industrial production costs, reduce economic efficiency, offset trade dividends, weaken competitiveness, ultimately endanger global employment, and bring the heaviest blow to the most vulnerable countries in the economy. The imposition of tariffs will also impact the trade of key industries and disrupt the global industrial chain. Protectionism will reduce employment and economic opportunities, slow down the industrialization process, and hinder poverty reduction efforts. Imposing tariffs will not only impact countries with already fragile economies, but also affect the countries implementing tariffs themselves, and will exacerbate geopolitical tensions and uncertainty. The imposition of tariffs by the United States is not based on facts and will not have the expected effect.
Application of waste heat recovery refrigeration in the chemical industry
During the chemical production process, a large amount of waste heat is generated, such as heat dissipation from reaction vessels and exhaust gas from distillation towers. The refrigeration system driven by industrial waste heat can recover and convert this waste heat into cold energy, which can be used for cooling, crystallization, separation and other processes of chemical products. For example, in urea production, the high-temperature gas discharged from the synthesis tower is recovered through a heat exchanger to drive an absorption refrigeration system, providing cooling capacity for the crystallization of urea solution and improving product quality and production efficiency.
The research and development prospects of new technologies for waste heat recovery
Efficient heat exchanger technology: Developing heat exchangers with higher heat transfer efficiency, lower resistance, and smaller volume, such as plate heat exchangers and heat pipe heat exchangers designed with new materials and optimized structures, to improve the efficiency and economy of industrial heat recovery.
Intelligent control system: Develop an intelligent industrial heat recovery control system using technologies such as the Internet of Things, big data, and artificial intelligence. By monitoring and analyzing the thermal parameters in the production process in real-time, automatically adjusting the operating status of the heat recovery equipment, optimizing the control of heat recovery, and improving the stability and energy utilization efficiency of the system.
New energy storage technology: Research and apply new energy storage technologies such as phase change energy storage materials and thermochemical energy storage to solve the problems of industrial waste heat discontinuity and instability. By storing heat during the generation of waste heat and releasing it when needed, flexible utilization of waste heat can be achieved, improving the overall performance of the heat recovery system.