Heat exchanger is a kind of equipment that transfers part of heat from hot fluid to cold fluid, also known as heat exchanger. Heat exchanger plays an important role in chemical, petroleum, power, food and many other industrial production. It can be used as heater, cooler, condenser, evaporator and reboiler in chemical production.

It is applicable to heat exchanger with different medium, working condition, temperature and pressure, and its structure type is also different. The specific classification of heat exchanger is as follows:

Classification according to heat transfer principle

1. The wall to wall heat exchanger is a kind of heat exchange between two kinds of fluid with different temperature, which flows in the space separated by the wall, through heat conduction on the wall and convection on the wall. The wall to wall heat exchanger has shell and tube type, sleeve type and other types of heat exchanger. The wall to wall heat exchanger is the most widely used heat exchanger. 2. The regenerative heat exchanger transfers the heat from the high temperature fluid to the low temperature fluid through the heat storage body composed of solid materials. The hot medium first reaches a certain temperature by heating the solid materials, and then the cold medium is heated through the solid materials to achieve the purpose of heat transfer. Regenerative heat exchanger has rotary type, valve switching type and so on. 3. Fluid connection indirect heat exchanger fluid connection indirect heat exchanger is a heat exchanger that connects two surface heat exchangers with the circulating heat carrier. The heat carrier circulates between the high-temperature fluid heat exchanger and the low-temperature fluid, receives the heat in the high-temperature fluid, and releases the heat to the low-temperature fluid in the low-temperature fluid heat exchanger. 4. The direct contact heat exchanger is also known as the hybrid heat exchanger. This kind of heat exchanger is a kind of equipment that two kinds of fluids contact directly and mix with each other to exchange heat, such as cold water tower, gas condenser, etc. 5. The compound heat exchanger has two kinds of heat exchange equipment: the steam water surface indirect heat exchange and the water water direct mixed flow heat exchange. Compared with steam water surface indirect heat exchange, it has higher heat exchange efficiency, higher stability and lower unit noise compared with steam water direct mixed heat exchange.

Classification by use

1. The heater heats the fluid to the necessary temperature, but the heating fluid does not change phase.

2. Preheater preheater pre heats the fluid to provide standard process parameters for process operation.

3. Superheater superheater is used to heat the fluid (process gas or steam) to the superheated state.

4. The evaporator is used to heat the fluid to the temperature above the boiling point, so that the fluid evaporates, generally with phase change.