Shell and tube heat exchanger

Shell and tube heat exchanger is also called tubular heat exchanger. It is a wall heat exchanger with the wall surface of the tube bundle enclosed in the shell as the heat transfer surface. The heat exchanger has the advantages of simple structure, low cost, wide flow section and easy to clean scale; However, the heat transfer coefficient is low and the floor area is large. It can be made of various structural materials (mainly metal materials) and can be used under high temperature and high pressure. It is a widely used type.

Shell and tube heat exchangers include fixed tube plate steam water heat exchanger, shell and tube steam water heat exchanger with expansion joint, floating head steam water heat exchanger, U-shaped shell and tube steam water heat exchanger, wave joint shell and tube steam water heat exchanger, segmented water water heat exchanger, etc. The main control parameters of shell and tube heat exchanger are heating area, hot water flow, heat exchange, heat medium parameters, etc.

Shell and tube heat exchanger is composed of shell, heat transfer tube bundle, tubesheet, baffle (baffle) and tube box. The shell is mostly cylindrical, with a tube bundle inside, and both ends of the tube bundle are fixed on the tube plate. There are two kinds of cold and hot fluids for heat exchange. One flows in the pipe, which is called pipe side fluid; The other one flows outside the tube, which is called shell side fluid. In order to improve the heat transfer coefficient of the fluid outside the tube, several baffles are usually installed in the shell. The baffle can increase the fluid velocity on the shell side, force the fluid to cross the tube bundle several times according to the specified distance, and enhance the degree of fluid turbulence. The heat exchange tubes can be arranged in equilateral triangles or squares on the tubesheet. The equilateral triangle arrangement is compact, the degree of fluid turbulence outside the tube is high, and the heat transfer coefficient is large; Square arrangement is convenient for cleaning outside the pipe, which is suitable for fluids easy to scale.

The main control parameters of shell and tube heat exchanger are heating area, hot water flow, heat exchange, heat medium parameters, etc.

Each time the fluid passes through the tube bundle is called a tube side; Each pass through the shell is called a shell pass. The simple single shell side and single tube side heat exchanger is called 1-1 heat exchanger for short. In order to improve the fluid velocity in the pipe, diaphragms can be set in the pipe boxes at both ends to divide all pipes into several groups. In this way, the fluid only passes through part of the tube at a time, so it goes back and forth many times in the tube bundle, which is called multi tube pass. Similarly, in order to improve the flow rate outside the pipe, a longitudinal baffle can also be installed in the shell to force the fluid to pass through the shell space many times, which is called multi shell side. Multi tube pass and multi shell pass can be used together.