Reasons for the decrease in heat transfer efficiency of water oil cooler
The water oil cooler is a type of condenser commonly used in vacuum depressurization overhead systems. Since the circulating water temperature for cooling is usually 30 to 32 ° C, the conventional water cooler (bow baffle, floating head type) has a small temperature difference of cross heat transfer, and when the temperature reaches 40 ° C or less after cooling, the circulating water The temperature rise is too small, causing excessive consumption of circulating water, which has been less used in recent years.
A specially designed water cooler - surface condenser (hydraulic system cooler) is used abroad. Due to the special structure of the surface condenser, the pressure drop of the process stream is lower, the heat transfer coefficient is larger, and in particular, it has a certain reverse heat transfer effect, which can achieve a lower temperature after cooling, and the temperature rise of the circulating water is larger, Significantly reduce circulating water consumption. In recent years, it has been widely used in domestic vacuum distillation systems for large-scale atmospheric and vacuum distillation units.
The main reasons for the decrease in heat transfer efficiency of water coolers are as follows:
Cooling water flow is reduced;
The cooling water inlet and outlet temperature is high;
The impurities in the shell side block the water cooler tube or scale, which causes the heat exchange efficiency of the water cooler to decrease;
The impurities of the tube are adsorbed on the tube wall, resulting in a decrease in heat exchange efficiency;
The internal leakage of the water cooler causes the heat exchange efficiency to decrease;
When the water cooler is used, it does not exhaust according to the normal operation, resulting in a decrease in heat exchange efficiency.