Triple-effect Forced Circulation Evaporator for Flue Gas Wastewater Treatment

A multiple-effect evaporator is a combination of multiple sets of single-effect evaporators, the characteristic is that the exhaust steam from the previous effect is reused in the aftereffect as heating source. There are double-effect, triple-effect, four-effect and even more effects, which are selected according to the working conditions.

Forced circulation evaporator, the material inside is pressurized by a forced circulation pump into heating chamber, then flows into the separation chamber to be vapor-liquor separated. The liquor phase material keeps circulating between heating chamber and separation chamber until reached a certain concentration, and the vapor separated is discharged from the top of the separation chamber. It is especially for concentration and crystallization of material which is of greater viscosity, producing scaling or crystals. And it can be designed as single-effect and multiple-effect according to specific requirements.

Application Scope

Forced circulation evaporator has been widely used for concentration of water solution and organic solution in food processing, pharmaceutical industry, chemical industry and environmental protection industry, especially for material which are of greater viscosity, producing scaling and crystals, eg. Various fruit pulps (tomato paste), organic salts (ammonium sulfate, sodium chloride, calcium chloride, magnesium sulfate and etc), maltodextrin, starch and etc.

Main Principle

In the multiple-effect evaporator, the Effect I is heated by the live steam, and the exhaust steam from Effect I flows to Effect II and acts as the heating source, thus the live steam consumption is reduced. The total temperature difference between the heating temperature in Effect I and the boiling point in last effect, is distributed in each effect, the temperature difference between effects decreases as the amount of effect increases.

The water evaporated forms exhaust steam (called as secondary steam) is reused by multiple times, the live steam consumption is reduced, so as to achieve the purpose of energy saving.  

Forced circulation evaporator adopts a forced circulation pump forcing the liquor material to pass through the heat exchange tubes at velocity of 2～5m/s. And the high velocity of material inside the heat exchange tubes is able to avoid scaling produced on the surface of the heat exchange tubes by the boiling products. 

System Configuration

The forced circulation evaporator could be designed as single-effect and multiple-effect according to specific requirments, and it consists of heating chamber, seporation chambers (crystallizer), forced circulation pumps, vacuum pump, material delivery pumps, operation platsform and electrical control system.