The general term of machines and equipment used in the production of chemical industry.

In chemical production, in order to process raw materials into finished products of certain specifications, a series of chemical processes, such as raw material pretreatment, chemical reaction, separation and refining of reaction products, are often required. The machinery used to achieve these processes is often classified as chemical equipment.

Chemical equipment can generally be divided into two categories: ¢Ù Chemical machinery. It refers to the machinery whose main action parts are motion, such as various filters, crushers, centrifugal separators, rotary kilns, mixers, rotary dryers and fluid conveying machinery. ¢Ú Chemical equipment. It refers to machinery whose main functional parts are static or have little movement, such as various vessels (tanks, tanks, kettles, etc.), ordinary kilns, towers, reactors, heat exchangers, ordinary dryers, evaporators, reactors, electrolyzers, crystallization equipment, mass transfer equipment, adsorption equipment, fluidization equipment, ordinary separation equipment, ion exchange equipment, etc.

The division of chemical machinery is not strict. Some fluid conveying machinery (such as pumps, fans and compressors) are often called chemical machinery in the chemical sector, but they are also general machinery in various industrial production. The design and manufacture of modern chemical equipment, in addition to relying on the development of mechanical engineering and material engineering, is also closely related to the development of chemical technology and chemical engineering. The quality, output and cost of chemical products, to a large extent, depend on the perfection of chemical equipment, and the characteristics of chemical machinery must be able to adapt to the special conditions such as high temperature, high pressure, high vacuum, ultra-low pressure, flammability, explosion and strong corrosivity that are often encountered in the chemical process. Modern chemical industry requires chemical machinery: ¢Ù It has the safety and reliability of continuous operation. ¢Ú It has sufficient mechanical strength under certain operating conditions (such as temperature, pressure, etc.). ¢Û It has excellent corrosion resistance. ¢Ü Good sealing performance. ¢Ý High efficiency and low energy consumption. Pressure vessel refers to the equipment with specific process function and withstanding certain pressure in industrial production, which is called [1] pressure vessel. Storage and transportation vessels, reaction vessels, heat exchangers and separation vessels are all pressure vessels.

In order to distinguish from ordinary vessels (atmospheric vessels), only vessels that meet the following three conditions at the same time are called pressure vessels: (1) The maximum working pressure (Pw) (Note 1) is greater than or equal to 0.1Mpa (excluding the hydrostatic pressure, the same below); (2) The internal diameter (non cambered section refers to its maximum size) is greater than or equal to 0.15 m, and the volume (V) (Note 2) is greater than or equal to 0.25 m3; (3) The containing medium is liquefied gas or liquid with the maximum working temperature higher than or equal to the standard boiling point Pressure vessels are widely used.