What is a heat exchanger?
Today Murphy experts will share some basic knowledge of heat exchanger.
1. Definition of heat exchanger
The heat exchanger is a heat exchange device that transfers part of the heat of the hot fluid to the cold fluid, so that the temperature of the fluid reaches the index specified in the process flow.
2. Function
The main function is to ensure the specific temperature required by the process for the medium, and also to improve energy utilization, recover waste heat, waste heat and low-level heat energy.
3. Application
The heat exchanger has a wide range of applications. It is general-purpose equipment widely used in industries such as chemical industry, oil refining, power, atomic energy, light industry, food pharmacy and machinery manufacturing. The heat exchanger can be a separate device, such as a heater, a cooler, and a condenser; it can also be a component of certain process equipment, such as a heat exchanger in an ammonia synthesis tower.
Various classifications of heat exchangers
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:
(1) Heat exchangers are classified according to heat transfer principles
1. Surface type heat exchanger: The surface type heat exchanger is two fluids with different temperatures flowing in the space separated by the wall surface. The heat conduction between the wall surface and the fluid convection on the wall surface, and the two fluids exchange heat. Surface heat exchangers include shell and tube, sleeve and other types of heat exchangers.
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: The direct contact heat exchanger is a device that directly contacts two fluids for heat exchange, such as a cold water tower and a gas condenser.
(2) Classification of heat exchangers by use
1. Heater: The heater heats the fluid to the necessary temperature, but the phase of the fluid does not change.
2. Pre-heater: The pre-heater heats the fluid in advance, and provides standard process parameters for the process operation.
3. Super-heater: The super-heater 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 its fluid to evaporate. Generally, there is a phase change.
(3) Classification by heat exchanger structure
It can be divided into: floating head heat exchanger, fixed tube plate heat exchanger, U-shaped tube plate heat exchanger, and plate heat exchanger and so on.
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