Shell and tube heat exchanger tube diameter

The smaller the diameter of the heat exchanger, the more compact and cheaper it is, and a better ratio of convective heat transfer coefficient to resistance coefficient can be obtained. However, the smaller the pipe diameter, the greater the pressure drop of the heat exchanger. In the case of meeting the allowable pressure drop, 19 pipes are generally recommended. For fluids that are prone to fouling, in order to facilitate cleaning, a tube with an outer diameter of 25 is used. For process fluids with gas-liquid two-phase flow, a larger pipe diameter is generally used. For example, reboilers, boilers, and heat exchange tubes mostly use pipe diameters of 32 and 51.