There are many structural types of evaporators, no matter which type, in the design and manufacture, the refrigerant vapor must leave the heat transfer surface quickly and maintain a reasonable liquid level, so as to effectively make full use of the heat transfer surface. A small amount of swallow steam generated when the refrigerant liquid is throttled can be separated from the liquid through the vapor-liquid separation equipment, and only the liquid separated from the vapor is sent to the evaporator to absorb heat, so as to improve the heat transfer effect of the evaporator.
If the liquid can vaporize and boil on the wet heating surface, the roots of the bubbles are small, the volume of the bubbles formed is not large, and the bubbles are easy to leave the heating surface and rise. If the liquid does not boil over the wetted heated surface, the bubbles that form will be larger in size and have larger roots, and the number of vaporized cores will be reduced. At this time, the bubbles generated will gather on the heating surface and develop along the heating surface to generate a vapor film, resulting in an increase in thermal resistance and a decrease in the heat release coefficient. Some commonly used refrigerant liquids have good wetting properties and therefore good heat release properties. Ammonia has better wetting properties than Freon.
The evaporator is one of the most commonly used wastewater evaporators in the process industry. The evaporator is to pass the secondary steam vaporized by the previous effect evaporator into the heating chamber of the latter effect evaporator as the heating steam of the latter effect evaporator. Evaporation makes full use of the latent heat of vaporization of the secondary steam of each effect, and is a relatively energy-saving evaporation operation.
The evaporator is used in the liquid syrup concentration process of the corn chemical plant. The raw steam is passed into the chemical wastewater evaporator to heat the liquid syrup, and the water in the liquid syrup is heated and evaporated to achieve the purpose of concentration. There are also many reports on the research and application of multi-effect evaporation at home and abroad, but there are many researches on conventional simulation and optimal design based on the solution of multi-effect evaporation design problems, while the solution based on the operation of chemical wastewater evaporators Process simulation and operational optimization problems are rarely studied.