Views: 77 Author: Site Editor Publish Time: 2019-12-17 Origin: Site
Heat exchanger is a device used to transfer heat from hot fluid to cold fluid to meet the specified process requirements. It is an industrial application of convective heat transfer and heat conduction. Heat exchanger is a general equipment in chemical industry, petroleum, power, food and many other industrial sectors, which plays an important role in production. According to its operation process, the heat exchanger can be divided into three categories: dividing wall type, hybrid type and regenerative type.
This type of heat exchanger is made of installing jacket on the outer wall of the container, and the structure is simple, but its heating surface is limited by the wall of the container and the heat transfer coefficient is not high. In order to improve the heat transfer coefficient and make the liquid in the kettle heat evenly, the agitator can be installed in the kettle. When cooling water or a non-phase-change heating agent is introduced into the jacket, a spiral baffle or other measures for increasing the turbulence can also be arranged in the jacket so as to improve the heat transfer coefficient on one side of the jacket. In order to supplement the defect of the heat transfer surface, it is also possible to install the coil pipe inside the kettle.
This type of heat exchanger is a device for carrying out regenerative heat exchange. The interior is equipped with solid fillers to store heat. The heat transfer is carried out in two stages. In the first stage, the hot gas passes through the fire grid and transmits the heat to the fire grid and stores it. In the second stage, the cold gas is heated through the fire grid, receiving the heat saved by the fire grid. These two stages are carried out alternately. Usually, two heat accumulators are used alternately, and when the hot gas enters a heat accumulator, the cold gas enters the other heat accumulator.
Regenerative heat exchanger is often used in metallurgical industry, such as steelmaking. It is also used in chemical industries, such as air preheaters or combustors in gas furnaces and regenerative cracking furnaces in artificial oil plants. Regenerative heat exchanger is generally used in situations where the requirement of medium mixing is low.
The hybrid heat exchanger relies on the direct contact of cold and hot fluid for heat transfer. The heat transfer mode avoids the thermal resistance of the heat transfer partition wall and the dirt on both sides of the heat transfer partition wall, so long as the contact condition between the fluid is good, a large heat transfer rate is achieved. Where the fluid is allowed to mix with each other, mixed heat exchanger can be used, such as gas washing and cooling, circulating water cooling, steam-water mixing heating, steam condensation and so on. It is widely used in chemical and metallurgical enterprises, power engineering, air conditioning engineering and many other production departments.
