Composition and advantages of shell-and-tube heat exchangers
The shell-and-tube heat exchanger is mainly composed of shell, tube bundle, baffle plate, tube sheet and head. The shell is mostly round, with parallel tube bundles or spiral tubes inside. The tube bundles are installed in the shell, and the two ends are fixed on the tube sheet. The head is connected with flanges at both ends of the shell with bolts. Two fluids for heat transfer in shell-and-tube heat exchangers:
(1) A kind of flow in a pipe, the stroke of which is called a pipe;
(2) A kind of flow outside the tube, whose stroke is called shell stroke;
(3) The wall of the bundle is the heat transfer surface. The types of pipes are different, and the process is generally 16 mm 20 mm or 25 mm in diameter.
(4) The wall thickness is generally 1 mm, 1.5 mm, 2 mm and 2.5 mm.
(5) Its main advantages are large heat transfer area per unit volume, compact structure and good heat transfer effect. Strong structure, and can choose a wide range of structural materials, so strong adaptability, greater flexibility in operation. Compared with other types of heat exchangers, shell-and-tube heat exchangers have the disadvantage of low heat transfer efficiency. For example, for water-water heat transfer, the K value range of traditional shell-and-tube heat exchangers is generally 1150-2230W/
High Heat Exchange Efficiency of Shell-and-Tube Heat Exchangers
The diameter of the imported heat exchanger is as low as 8 mm and the wall thickness is only 0.6 mm. It has greatly improved the efficiency of heat transfer and has been gradually promoted in the domestic market this year. Shell-and-tube heat exchanger and helical tube bundle design can increase the turbulence effect and heat transfer efficiency to a limited extent. The asymmetric design of inner shell and tube can reach 4.6 times. This asymmetric design determines its wide application in the field of steam-water heat transfer. The heat transfer efficiency can reach 14 000 w/m2.k, which greatly improves the production efficiency and saves the cost. At the same time, as shell-and-tube heat exchangers are mostly metal structures, with the introduction of the new GMP, stainless steel 316L as the main heat exchanger will become the necessary choice for beverage, food and pharmaceutical industries.