Can the heat exchanger be used in this way? ? ?
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Operation of the heat exchanger: 1. Both the tube side and the shell side are in operation simultaneously; 2. The tube side is in operation while the shell side is shut off; 3. The shell side is in operation while the tube side is shut off. Are all three of these methods considered normal ways of operation? (1 is obviously not a normal method.) Are 2 and 3 allowed? Why? Everyone is welcome to discuss!
It can be used this way in general, but why go to the trouble?
Generally, plate heat exchangers are not permitted; however, ordinary heat exchangers are acceptable, as the tube side and the shell side are tested for pressure separately.
Generally, when one side is shut down and the other is put into use, it depends on whether the process requirements permit it; if it affects those requirements, such a practice will definitely not be adopted.
Investment should be made simultaneously; otherwise, it loses its meaning. Increases loss.
This post was last edited by ylb913 on 2015-6-23 at 15:41. 1. Gases are better, but liquids are incompressible; the pressure increase resulting from heating them is enormous! 2. There are two ways to cut off flow: one is to simply allow the system to come to a stop without any issues, and the other is to close the inlet valve or the outlet valve. 3. It’s somewhat better to cut out the inlet and outlet valves while the system is hot; it’s not possible to do so once the system is filled with liquid when it’s cold. 4. Floating heads and U-tube types are acceptable; fixed tube sheets are subject to limitations due to the temperature difference between the tube side and the shell side. It’s a bit better if the shell side is retained; if the tube side is retained, the shell side gets cold. 5. Requirements regarding temperature and the material of the heat exchange tubes: for example, in a waste heat boiler where the tubes are made of 20G material and the temperature inside the boiler exceeds 1000 degrees (in the tube side), it’s fine to have water walls; however, if there is no water, the boiler will dry out and the tubes will be damaged.
Shell-and-tube heat exchangers should be used strictly within their designed range (the design conditions of the equipment are based on the process conditions); it is absolutely not permissible to change these conditions arbitrarily. In fixed-tube-sheet heat exchangers, the temperature difference between the tube side and the shell side metals is often quite severe; deviations from this acceptable range can lead to serious equipment failures. Severe consequences can arise from situations such as feeding water into a waste heat boiler after it has been dry-heated, introducing cold material into a reboiler after heating it with steam first, or liquid leaking above the level of the heat exchange tubes in a horizontal waste heat boiler with fixed tube sheets; these issues can result in equipment damage at the least, and safety accidents at the worst.
This approach cannot be used for tubular heat exchangers with a poor pressing design.