The heat transfer capacity of the floating-head heat exchanger is insufficient; seeking guidance!
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I hope everyone can give some advice! I am involved in the management of equipment transfer between factories, and I have encountered a difficult problem recently. The introduction is as follows; first, thank you all! It is a floating-head heat exchanger with one unit in operation and one as standby; the gas-phase material flows through the shell side while the water-phase material is used to heat the tube side. Last Tuesday, on May 26th, the unit was switched to standby mode, and it was found that its heat exchange capacity was insufficient. The specific issue was that the temperature at the water-phase outlet was about 10 degrees lower than normal. On June 1st this week, the heat exchanger was opened for inspection of the tube box and floating head, and no signs of short circuit in the water phase were detected. The tube bundle was removed and no obvious defects were found. After reinstalling it, the heat exchange capacity remained insufficient
There are many reasons for insufficient heat exchange capacity. It is recommended to carefully verify the operating parameters such as flow rate, temperature, and pressure in the heat exchanger thermodynamic calculation sheet. Shell side flow, temperature, pressure. Medium concentrations in the tube side and shell side, and whether the phases are consistent with those specified in the thermodynamic calculations (medium viscosity, specific heat, thermal conductivity, and density all affect heat transfer efficiency). Additionally, an inspection of the inside of the heat exchanger is also necessary, such as checking whether there is scaling on the inner walls of the tubes and whether the baffle plates are properly installed
Since there is no leakage from the partition plates, then consider the issue of scaling on the heat exchange tubes (what kind of water? ) Is the exhaust from the switching operation manager thorough?
Since the original poster did not provide more detailed information, let me analyze it: First of all, it is only mentioned that the water temperature rises to an unacceptable level when switching to the backup device. If both the original operating device and the backup device are identical, and the operating parameters of the original device are normal (under the same operating conditions), then there can be only one reason: dirt buildup on the backup device. Furthermore, if the backup equipment has been in operation for a short period of time and the water quality meets the standards, with dirt not being an issue, then one of the assumptions underlying the above analysis must be incorrect. It may be that the operating conditions are different, resulting in the water outlet temperature not meeting the requirements, or there may be issues with the standby equipment itself (I wonder if similar problems have occurred before when this standby equipment was put into use?) ), or there is a problem with the instrument. In any case, there are many possibilities; to solve the problem, it’s better to describe the situation on site in more detail to facilitate analysis.
It’s probably tube fouling; try high-pressure water cleaning.
1. It may be due to scale buildup on the pipe wall. 2. Is the inflow and outflow of water different from before?