Classification of heat exchange equipment in the chemical industry

Chemical heat exchange equipment is the equipment that realizes heat energy transfer in chemical reactants in the process of chemical production, so that heat is transferred from a fluid with a higher temperature to another fluid with a lower temperature.

In the production of chemical fertilizers, chemicals, and oil refining industries, various heat exchange processes are often carried out, especially the various chemical processes developed in recent years, which fully utilize the comprehensive utilization of heat energy, and various types of high-efficiency and energy-saving heat exchange equipment continue to Launched and applied to different cold exchange operation units. For example: heating or cooling, evaporation or condensation. Heat exchange equipment is the equipment that realizes heat energy transfer in the production process, that is, chemical reaction or physical reaction, so that heat is transferred from a fluid with a higher temperature to another fluid with a lower temperature.

According to different production processes, in order to achieve full utilization of heat and meet process parameters, heat exchange equipment can be heat exchangers (such as mutual heat exchange between two fluid media), condensers (such as water vapor condensation), heaters (such as high-temperature process Gas heating water), cooler (such as water or liquid ammonia as cold carrier), etc.

In chemical production, heat exchange equipment is not only used as a separate chemical equipment, but also often has heat exchange equipment or heat exchange parts attached to other equipment, such as reflux condenser in distillation equipment, heating in evaporation equipment, high and low temperature change The heat exchange of the catalyst in the furnace and the ammonia synthesis tower are all important and indispensable chemical operation equipment.

In the chemical production process, heat exchange equipment used for vapor-liquid, vapor-gas, gas-gas, and liquid-liquid can be divided into:

① Surface heat exchanger;

② Regenerative heat exchanger;

③ liquid indirect heat exchanger;

④ Direct contact heat exchanger.

The surface heat exchanger is that two fluids with different temperatures flow in the space separated by the wall, and pass through the wall

The heat conduction and fluid convection on the wall surface, heat exchange between the two fluids. Surface heat exchangers include shell and tube, casing and other types of heat exchangers.

The regenerative heat exchanger transfers heat from the high-temperature fluid to the low-temperature fluid by means of a heat storage body composed of solids. The heat storage body is in contact with the high-temperature fluid for a certain period of time, accepts and stores a certain amount of heat, and then contacts with the low-temperature fluid for a certain period of time. time, the heat is released to the cryogenic fluid. The regenerative heat exchanger is useful as a rotary heat exchanger on the convection section of the first-stage furnace, and the recovered flue gas temperature is used to preheat the combustion air; there are also valve-switching heat exchangers, etc.

The fluid connection indirect heat exchanger is a heat exchanger that connects two surface heat exchangers by a heat carrier circulating in it. The heat carrier circulates between the high-temperature fluid heat exchanger and the low-temperature fluid. Heater accepts heat and releases heat to low temperature fluid in low temperature fluid heat exchanger.

A direct contact heat exchanger is a device in which two fluids are in direct contact for heat exchange, such as a cold water tower, a gas condenser, etc. In addition, heat exchangers can also be divided into:

① Heater—Heats the fluid to the necessary temperature without a phase change in the heated fluid.

② Preheater—heat the fluid in advance to provide standard process parameters for subsequent operations;

③ Superheater—used to heat the fluid (process gas or steam) to superheated state;

④ Evaporator—used to heat the fluid to a temperature above the boiling point to evaporate the fluid, usually with a phase change.