Proper use of shell and tube heat exchangers
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(1) Before putting the system into operation, it is necessary to check whether the pressure gauges, thermometers and other related accessories, as well as the valves, are in good condition and complete. (2) Before feeding the medium in, first open the vent drain to remove gases. (3) Before using the heat exchanger, first open the valve for the cold liquid and the vent valve, and fill it with liquid. Once the liquid level reaches the specified position, slowly or in several steps open the valve for steam or other heating media; preheat the system first before applying heat, in order to avoid sudden temperature changes that could reduce the service life of the heat exchanger. (4) Regularly check the changes in temperature and pressure at the inlet and outlet of both the cold and hot working media; if any changes are detected, the cause must be identified immediately to resolve the fault. (5) Periodically analyze changes in the medium composition to determine whether there is a pipe leak, so as to seal or replace the pipe in a timely manner. (6) Periodically check the heat exchanger for leaks, any deformation of the casing, and signs of vibration; if any such issues are found, they should be resolved promptly. (7) Periodically discharge non-condensable gases and condensate, and remove fouling in a timely manner based on the decline in heat exchange efficiency, in order to improve it.
What exactly is the K value of a shell-and-tube cooler?
This depends on what fluids are present in the tube side and shell side, as well as their respective flow rates. Generally speaking, however, the K value for condensation heat transfer is higher than that for ordinary convection heat transfer. Taking an example I’ve worked on as reference, when water vapor condenses and is cooled by oil in a turbulent state, the value is roughly 10,000 W/(m2·K)
Thank you to the original poster for sharing; I’ve learned a lot from it. I have a question regarding vibrations in the heat exchanger; vibrations were detected in it after it had been in use for some time. What usually causes this kind of vibration? If the process conditions are not to be changed (for example, the shell-side flow rate is already fixed and the baffle plates have also been determined), how can vibration be reduced?