According to the characteristics of energy transfer or conversion in the process of waste heat utilization, the domestic industrial waste heat recovery technology can be divided into heat exchange technology, heat work conversion technology and waste heat refrigeration heating technology.
Heat exchange technology
The heat exchange technology is the most direct and efficient economic method. Under the form of no residual heat energy, the residual heat energy is directly transmitted to the energy consumption process of the process through the heat exchange equipment, thereby reducing the primary energy consumption. The main utilization methods include partition wall heat exchange, waste heat boiler, regenerative heat exchange, and heat pipe heat transfer.
The use of thermal power conversion technology can improve the grade of waste heat, and is another important technology for industrial waste heat. According to the classification of working fluids, it can be divided into steam turbine power generation with water as working fluid and organic working fluid with low boiling point working fluid. At present, the main purpose is to use water as a working medium, and a low temperature steam turbine composed of a waste heat boiler + a steam turbine or an expander to generate electricity.
Compared with the traditional compression refrigeration unit, the absorption type and adsorption refrigeration system can utilize cheap energy, low-grade heat energy to avoid power consumption, and has remarkable power-saving effect, and has been widely popularized and applied.
The absorption type waste heat refrigeration unit has high refrigeration efficiency and is suitable for large-scale heat recovery. The adsorption refrigeration system is simple in structure, noise-free and pollution-free. It can be used in bumpy and turbulent occasions, and is more suitable for small heat recovery or for cogeneration systems.
The heat pump consumes a part (electric energy, mechanical energy, high-temperature heat energy) as compensation, and the heat of the low-temperature residual heat source is “pumped” to the high-temperature heat medium through the thermal cycle of the refrigerator. The heat pump technology is often used to recover slightly higher than the ambient temperature (30). ~60 ° C) waste heat, to achieve energy saving and consumption reduction purposes.