On the issue of increasing evaporation volume through triple-effect evaporation
Thread Content
Currently, there is a three-effect evaporation system: the temperature in the first effect is around 83°C with a negative pressure of -0.06 Mpa; the temperature in the second effect is around 70°C with a negative pressure of -0.08 Mpa; and the temperature in the third effect is around 43°C with a negative pressure of -0.094 Mpa. Is it possible to control the temperature of the third effect and raise it, thereby increasing the evaporation rate?
Can you also reduce the pressure of the third effect?
As the temperature in the three-effect distillation column rises, the pressure in this column also increases. The amount of evaporation does not change much; it is possible to reduce the temperature by increasing the vacuum. Increasing the temperature difference between the heating medium and the cooling medium in the three-effect reboiler can raise the gas velocity, but this also increases the reflux rate, which may lead to an overload of the column. Moreover, it is not guaranteed that the quality of the product at the top of the column will remain satisfactory; it is best to carry out some calculations first
Increasing the evaporation capacity of the third effect can increase the heat transfer area, reduce the pressure or raise the evaporation pressure of the second effect (with the aim of increasing the temperature difference for heat transfer in the third effect)
In the case of evaporating saline wastewater, there are requirements regarding the temperature of the final evaporation stage. For devices already in operation on-site, the methods to increase the evaporation rate are to increase the heat exchange area and the heat exchange temperature difference. Of course, if the final evaporation rate in the evaporation of saline wastewater increases, the temperature will rise slightly.
Please try increasing the amount of steam used in the first stage.
Increasing the vacuum level, raising the temperature of the heat exchanger, and adjusting the flow rate to achieve better spraying of the liquid into chamber V all contribute to improving the evaporation efficiency
Let’s first consider the capacity of the vacuum pump; if a vacuum cannot be maintained and the temperature rises uncontrollably, that would reverse the order of priorities. After all, negative-pressure multi-effect evaporation is meant to save energy and reduce the risks associated with high temperatures of the medium
Moreover, it is easy to carry away the process medium from the top of the tower
Evaporation is mainly influenced by the heat transfer area and efficiency, as well as the vacuum level.