How to economically choose an air heat exchanger? - Xia Xiefang, General Manager of Pioneer Drying Co., Ltd.

Air heat exchangers are the most important auxiliary equipment for drying equipment. Drying technology involves the chemical, pharmaceutical, light industry, food processing, wood, minerals and other industries. There are various kinds of materials handled by the drying equipment. The air heat exchanger must meet the requirements of various drying materials for hot air. Drying processing is an energy-intensive operation. The most basic method to reduce energy consumption is to select an efficient heat exchange device. How to economically choose an air heat exchanger is of great significance.

Air heat exchangers mainly include heat pipe heat exchangers, coal-fired hot air furnaces, steam heat exchangers, and electric heaters. We must choose the air heat exchanger economically and rationally according to the actual needs of production. First, the air heat exchanger should be selected according to the type and quality requirements of the dry materials. The hot air temperature, humidity, and cleanliness can all have a great effect on the quality of the product. Second, the heat source used by the equipment is economically available. The heat sources used in different heat exchange equipments are different, and the air heat exchangers should be selected according to the economical efficiency and difficulty of the heat source. Third, convenient operation and control. The operation and control of equipment is a prerequisite for ensuring the quality of product processing. Fourth, safe and reliable. For flammable, explosive or easily oxidized materials, use appropriate heat exchange equipment. Fifth, the selected equipment should meet the environmental protection requirements.

The heat pipe heat exchanger is a kind of heat exchange device that encloses the working substance in the pipe to perform physical phase change or chemical reaction repeatedly to transfer heat. The working fluid of the heat pipe can choose different liquids according to the needs, but each working fluid has its suitable working temperature range. The heat pipe heat exchanger has the advantages of recovering waste heat, preheating air, etc., and has many types and functions, so it is widely used in the drying industry.

Coal-fired hot-blast stoves are coal-fired hot air ovens. Most of them use indirect heat exchange to heat the air. The indirect heat transfer is characterized by a high degree of cleanliness of the hot gas obtained and no change in humidity during the heat exchange process. The coal-fired hot blast stove has the advantages of high output temperature, large calorific value and high thermal efficiency, and can be used together with various drying equipments.

The steam heat exchanger is an indirect heat exchange device and consists of a plurality of heat discharge pipes. When steam is used as a heat medium, steam passes through the tubes and air is taken between the fins outside the tubes. Due to the different materials of the fins and the winding patterns of the fins, many specifications have been made and serialized.

The electric heater has the characteristics of simple structure, high mechanical strength, high thermal efficiency, safety, reliability, easy installation, and easy temperature control automation. However, electricity is a high-grade energy source and has a high operating cost. It is not suitable for use in materials drying systems with low added value.