Shell-and-tube heat exchanger design and selection steps
1. Process calculation:
1> Calculate the amount of heat to be transferred according to the type of fluid, the flow rate of the cooling fluid, the temperature of the inlet and outlet, and the working pressure.
2> Select the material of the tube and the housing according to the corrosiveness and other characteristics of the fluid. According to the processing characteristics of the material, the flow rate, pressure, temperature of the fluid, the temperature of the heat exchange tube and the shell, the amount of heat to be transferred, the cost of the product, and the ease of maintenance and cleaning, etc., which type of shell-and-tube type is used. Heater.
3> Establish the fluid flow space, that is, determine what medium is in the tube and shell, respectively. 4> Determine the flow direction of the two fluids participating in the heat exchanger, so that the cocurrent, countercurrent or crossflow. And calculate the effective average temperature difference of the fluid.
5> Select the heat transfer coefficient K based on experience and estimate the required heat transfer area A.
6>According to the calculation of heat transfer area A, referring to the standard series of shell-and-tube heat exchangers in China, the basic parameters of the heat exchanger (tube diameter, number of tubes, number of tubes, tube length, tube arrangement, baffle) are preliminarily determined. Structural parameters and arrangement of components, etc., structural parameters such as housing diameter).
7> Calculate the heat transfer coefficient and calculate the resistance drop according to the determined standard series size. After the zui, heat exchangers or mechanical design are selected according to the standard.
2, mechanical design calculation mechanical design calculations include: (1) calculation of shell and tube wall thickness (2) tube and tube sheet connection structure design (3) shell and tube sheet connection structure design (4) tube sheet thickness calculation (5) Structural design of components such as baffles and support plates (6) Stress calculation of heat exchange tubes and shells under combined temperature and fluid pressure (7) Tube pull-off force and stability check (8) Whether expansion joints are required, if necessary, select the expansion joint structure and perform the relevant calculations.
(9) Selection of take-over, take-over flange, container flange, support, etc. and design of opening reinforcement
