The general understanding of the outer half-tube reactor is that there are physical or chemical reaction vessels. Through the structural design and parameter configuration of the vessels, the heating, evaporation, cooling and low-speed mixing functions required by the process can be realized.
　　External half-tube reactor is widely used in petroleum, chemical industry, rubber, pesticide, dyestuff, medicine and food. It is used to complete pressure vessel of sulfurization, nitration, hydrogenation, alkylation, polymerization and condensation, such as reactor, reaction pot, decomposition pot, polymerization kettle, etc. Its material is generally carbon-manganese steel, stainless steel, zirconium, nickel-based (Harrington, Monel, Inkon-nickel) alloy and its alloy. It's a composite material.