A heat exchanger is a device that transfers part of the heat of a hot fluid to a cold fluid, also known as a heat exchanger. Heat exchangers play an important role in chemical, petroleum, power, food, and many other industrial productions. They can be used as heaters, coolers, condensers, evaporators, and reboilers in chemical production. .
It is suitable for heat exchangers with different media, different working conditions, different temperatures, and different pressures. The structure types are also different. The specific classification of heat exchangers is as follows:
I. Classification according to the principle of heat transfer 1. Partition wall heat exchangers: Partition wall heat exchangers are two fluids with different temperatures flowing in the space separated by the wall surface. The heat transfer through the wall surface and the convection of the fluid on the wall surface are the two fluids. Heat exchange between. Partition wall heat exchangers include shell and tube, sleeve and other types of heat exchangers. Partition wall heat exchanger is currently the most widely used heat exchanger.
2. Regenerative heat exchangers: Regenerative heat exchangers transfer heat from high-temperature fluids to low-temperature fluids through heat storage bodies composed of solid materials. After the heat medium reaches a certain temperature by heating the solid materials, the cold medium passes through. The solid material is heated to achieve the purpose of heat transfer. Regenerative heat exchangers include rotary and valve switching types.
3. Fluid connection indirect heat exchanger: The fluid connection indirect heat exchanger is a heat exchanger that connects two surface heat exchangers with a heat carrier circulating in them. The heat carrier is in a high temperature fluid heat exchanger and Circulation between low-temperature fluids, heat is received in high-temperature fluids, and heat is released to low-temperature fluids in low-temperature fluid heat exchangers.
4. Direct contact heat exchanger: Also known as a hybrid heat exchanger, this heat exchanger is a device in which two fluids are in direct contact and are mixed with each other for heat exchange, such as a cold water tower and a gas condenser.
5. Compound heat exchanger: Equipment that has two types of heat exchange methods: soda water surface indirect heat exchange and water-water direct mixed heat exchange. Compared with steam-water surface indirect heat exchange, it has higher heat exchange efficiency; compared with steam-water direct mixed heat exchange, it has higher stability and lower unit noise.
Second, classification according to use 1. Heaters Heaters heat the fluid to the necessary temperature, but the phase of the fluid does not change. 2. Preheater The preheater preheats the fluid in advance, and provides standard process parameters for process operations.
Heat exchanger heat exchanger 3, superheater Superheater is used to heat the fluid (process gas or steam) to a superheated state. 4. Evaporator The evaporator is used to heat the fluid to a temperature above the boiling point and cause the fluid to evaporate. Generally, there is a phase change.
3. According to the structure classification, it 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.