What are the characteristics of chemical machinery?

In the production of mechanical manufacturing technology, only the appearance and physical properties of the processed material have changed; In chemical production, substances have undergone chemical changes and become new substances. This has formed the characteristics of the chemical industry production process. For example, material changes often need to be completed at a certain temperature and pressure, so chemical production has the characteristics of high temperature, high pressure or vacuum.

Secondly, the types of substances contacted in the chemical production process are complex, not only corrosive substances, but also substances with combustion, explosion danger or toxicity. These in turn determine the characteristics of chemical machinery in materials and structure, making the varieties of materials used in chemical machinery very complicated. In particular, a large number of high-strength steel, high-alloy steel, non-ferrous metals and alloys and non-metallic materials are needed as structural materials or linings of equipment. In addition, when working under high pressure or vacuum, and when dealing with toxic or corrosive substances, the equipment must be reliably sealed to prevent liquid from leaking out, causing "running", "leakage", "dripping" and "leakage", affecting normal operation and endangering workers' health.

Heat transfer is carried out in heat transfer equipment such as heat exchanger, mass transfer is carried out in tower equipment, and materials are in a flowing state. Therefore, the structure of chemical equipment must consider the characteristics of these "transfer" processes and fluid flow conditions and the requirements of continuity, and strive to "transfer" quickly and in large quantities to improve efficiency. For example, many small tubes are installed in the heat exchanger, or fins are made on the outside of the tubes, or corrugated plates are used, and baffles are set in the heat exchanger to make the fluid flow zigzag or turbulent. In the tower equipment, a series of trays, packing rings or injection devices are placed to keep the fluid in a turbulent state. All these are aimed at improving heat and mass transfer and strengthening operation.