The influence of the structure of chemical wastewater evaporator on the heat transfer of the evapora

There are many types of chemical waste water evaporators. No matter which type, we must make sure that the refrigerant vapor can leave the heat transfer surface quickly and maintain a reasonable liquid level height in the design and manufacture, so as to make full use of the heat transfer surface effectively. A small amount of swallow steam generated during the throttling of refrigerant liquid can be separated from the liquid through the vapor-liquid separation equipment. Only the separated liquid is sent to the evaporator for heat absorption, so as to improve the heat transfer effect of the evaporator.

If the liquid can vaporize and boil on the wetted heating surface, the root of the bubble is small, and the volume of forming the bubble is small, and the bubble is easy to leave the heating surface and rise. If the liquid can not vaporize and boil on the wetted heating surface, the volume of the formed bubbles is larger, the root is larger, and the number of vaporized cores will be reduced. At this time, the generated bubbles will gather on the heating surface, and along the heating surface, they will generate vapor film, which will increase the thermal resistance and reduce the heat release coefficient. Some commonly used refrigerant liquids have good wettability, so they have good exothermic properties. Ammonia has better wettability than Freon.

In the evaporator, when the refrigerant liquid at the refrigerant side is mixed with lubricating oil, the oil is very dry at low temperature, which is easy to adhere to the heat transfer surface to form an oil film and is not easy to be discharged, thus increasing the heat transfer resistance; at the same time, the formation of an oil film will prevent the refrigerant liquid from wetting the heat transfer surface, reducing the heat transfer efficiency, and in serious cases, it will make the refrigerant completely not absorb external heat and lose its refrigeration function Use.

Water, salt water and air are the common cooling medium in the refrigeration plant. The heat release intensity is not only related to their physical properties, but also related to the external factors such as the flow speed, the shape of the flow velocity and the flow path. When the flow velocity is large, the geometry of the flow velocity and the flow path are reasonable, the heat release coefficient increases, but the corresponding power consumption and infrastructure costs also increase. The most suitable flow rate and the layout of the fluid passage can be determined only by technical and economic analysis and comparison.