A heat exchanger is a device that transfers part of the heat from a hot fluid to a cold fluid, also known as a heat exchanger. Heat exchangers are general-purpose equipment in chemical, petroleum, power, food, and many other industrial sectors, playing an important role in production. In chemical production, heat exchangers can be used as heaters, coolers, condensers, evaporators, and reboilers, with even wider applications. There are many types of heat exchangers, but according to the principles and methods of heat exchange between the hot and cold fluids, they can basically be divided into three categories: shell-and-tube (or indirect), direct contact (or mixing), and regenerative (or storage) heat exchangers.