Multiple Effect Evaporator (MEE)
The Multiple Effect Evaporator (MEE) is an apparatus for efficiently using the heat from steam to evaporate water. In a multiple-effect evaporator, water is boiled in a sequence of vessels, each held at a lower pressure than the last. Because the boiling temperature of water decreases as pressure decreases, the vapor boiled off in one vessel can be used to heat the next, and only the first vessel (at the highest pressure) requires an external source of heat. While in theory, evaporators may be built with an arbitrarily large number of stages, evaporators with more than four stages are rarely practical except in systems where the liquor is the desired product such as in chemical recovery systems where up to seven effects are used.
Multiple-effect evaporation commonly uses sensible heat in the condensate to preheat liquor to be flashed. In practice, the design of liquid flow paths can be somewhat complicated in order to extract the most recoverable heat and obtain the highest evaporation rates from the equipment.
We can supply multiple-effect evaporation from two effects to six effects. Our MEE system capacity ranges from up to 300 KLD. We can also supply multiple effect evaporators with Thermo compressors to get good steam economy & reduce the cost.
Application
MEE is used in the ZLD Plant, After the 3rd Stage RO Plant, RO Reject Water TDS becomes very high. For every High TDS water, we cannot dispose of this water anywhere. Evaporation is the only option for this kind of high TDS water.
Vertical Thin Film Dryer (VTFD)
The vertical thin film dryer consists of a cylindrical, vertically arranged body with a heating jacket and a rotor inside. The rotor is equipped with rows of pendulum blades all over the length of the dryer. The hinged blades spread the wet feed product in a thin product layer across the heated wall and mix the product layer material intensively. Thus, the volatile components evaporate continuously from the product layer at high evaporation rates. The hinged blades are designed with a minimum gap to prevent product fouling on the heating surface, but they are never in contact with the heated wall.
The product enters the dryer at its top. After having been heated to the boiling point, evaporation starts. In the slurry zone first solids form, and with progressing evaporation of the volatiles and continued shearing by the hinged blades the paste breaks up to powder. The final solid product is discharged by gravity via a suitable airlock at the bottom of the dryer.