Heat exchanger ： is part of the heat transfer of heat to the cold fluid equipment, also known as heat exchangers. Heat exchangers are chemical, oil, power, food and many other industrial sectors of the common equipment, occupies an important position in the production. In the chemical production of heat exchangers can be used as heaters, coolers, condensers, evaporators and reboilers, etc., more widely used.

Many types of heat exchangers, but according to the cold and hot fluid heat exchange principle and the way basically can be divided into three categories are: wall, mixed and regenerative. In the three types of heat exchangers, the middle wall heat exchanger is the most widely used.