The heat exchangers for different media, different working conditions, different temperatures and different pressures have different structural types. The specific classification of heat exchangers is as follows:
First, according to the principle of heat transfer
1. The partition wall heat exchanger is a two-fluid heat exchanger in which the two fluids with different temperatures flow in a space separated by the wall surface, and the heat conduction between the wall surface and the fluid convect on the wall surface, and the two fluids exchange heat. The wall-mounted heat exchangers have shell-and-tube, sleeve and other types of heat exchangers. The wall-mounted heat exchanger is currently the most widely used heat exchanger. 2. The regenerative heat exchanger of the regenerative heat exchanger transfers heat from the high temperature fluid to the low temperature fluid through a regenerator composed of solid matter, and the heat medium first passes through the solid material to reach a certain temperature, and then the cold medium passes through the solid. The substance is heated to achieve the purpose of heat transfer. The regenerative heat exchanger has a rotary type, a valve switching type, and the like. 3, fluid connection indirect heat exchanger fluid connection indirect heat exchanger, is a heat exchanger that connects two surface heat exchangers from the heat carrier circulating therein, the heat carrier in the high temperature fluid heat exchanger and low temperature The fluid circulates between the high temperature fluids and the low temperature fluid heat exchangers to release the heat to the low temperature fluids. 4. The direct contact heat exchanger is also called a hybrid heat exchanger. The heat exchanger is a device in which two fluids are in direct contact and mixed with each other for heat exchange, for example, a cold water tower, a gas condenser, and the like. 5. The complex heat exchanger has both steam-water indirect heat transfer and water-water direct mixed-flow heat exchange. Compared with indirect heat exchange of steam surface, it has higher heat exchange efficiency; it has higher stability and lower unit noise than direct mixed heat exchange of steam and water.
Second, by purpose
1. The heater heater heats the fluid to the necessary temperature, but the heating fluid does not undergo a phase change. 2. The preheater preheater preheats the fluid to provide standard process parameters for the process operation.
2. The superheater superheater is used to heat the fluid (process gas or steam) to an overheated state. 4. The evaporator evaporator is used to heat the fluid to reach a temperature above the boiling point, causing the fluid to evaporate, generally with a change in phase. 
Third, by structure
Can be divided into: floating head heat exchanger, fixed tube plate heat exchanger, U-shaped tube plate heat exchanger, plate heat exchanger and so on.