As for the tubular heat exchanger, what we want to introduce is the problems that should be considered in the design and selection of the tubular heat exchanger. In addition, there are also the design steps of the tubular heat exchanger. Therefore, Wuxi Rongyu chemical equipment technology also provides some technical support, in order to better introduce for everyone.

1. Problems to be considered in design and selection of tubular heat exchanger

According to the professional of Wuxi Rongyu chemical equipment technology, the main problems to be considered in the design and selection of tubular heat exchanger are as follows:

(1) Selection of cold and hot fluid flow channels

The general principles of selection are as follows:

a. The inside of the tube is not clean, easy to scale or corrosive fluid, because it can be convenient to clean the tube, so that the tube bundle and shell are damaged by corrosion.

b. There is a high pressure fluid in the pipe, which can protect the shell from pressure.

c. There is saturated steam in the shell side because it is clean and the condensate can be discharged easily. The higher surface heat transfer coefficient can be obtained when the fluid with small flow rate and high viscosity also goes through the shell side.

d. If the heat exchanger is of rigid structure, and the temperature difference of fluid is large, the heat stress can be reduced.

For the materials to be cooled, the shell side is generally selected, which is conducive to heat dissipation.

(2) Selection of flow rate

The velocity of the fluid not only affects the heat transfer coefficient of the heat exchanger, but also affects the fouling resistance. If the flow rate is too small, the pipeline will be blocked; if the flow rate is too high, the resistance of the fluid will be increased, so the appropriate flow rate should be selected.

(3) Selection of heat exchange tube specifications

The smaller the diameter of the heat exchange tube is, the greater the heat transfer coefficient per unit area is. Therefore, for clean fluid, the smaller diameter can be selected. However, if the fluid is not clean, the pipe diameter should be larger to prevent blockage. But the specification of heating pipe should not be too much.

(4) Selection of baffle

The spacing of baffles will affect the flow of the shell, so the spacing should not be too large to avoid affecting the heat transfer coefficient. However, if it is too large, it will not be conducive to manufacturing and maintenance. Generally speaking, the baffle spacing should be about 0.2-1 times of the shell inner diameter.

2. Design steps of tubular heat exchanger

(1) When the flow mode of heat exchanger is selected, the correction coefficient of temperature difference shall not be less than 0.8;

(2) The heat flux and average temperature difference are calculated, and then the total heat transfer coefficient is estimated;

(3) Select the appropriate fluid velocity, estimate the number of tube passes, and then determine the diameter, length and arrangement of heat exchange tubes.

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