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March 16th, 2010 at 10:01 am

what an evaporator does

As mentioned previously, the object of evaporation can be to concentrate a solution containing the desired product or to retrieve the solvent. Sometimes both may be carried out. Design Evaporator consists of three main elements: efficient use of energy, vapor-liquid separation and heat transfer.

In most cases the solvent is water, heat supplied from condensation of steam and the heat is transferred from the indirect heat transfer through metal surfaces. For evaporators be efficient, selected and used equipment must be able to make several things:

1. transfer of large amounts of heat for the solution with a minimum amount of metal surface. This requirement, more than all other factors, determines the type, size and cost of the evaporator.
2. to achieve the specified separation of liquid and vapor and do so with the simplest of devices available. Separation may be important for several reasons: the value of the product otherwise loss; pollution; fouling equipment downstream they contacted the steam; corrosion of this same downstream equipment. Inadequate Separation can also cause problems of pumping or inefficient operation due to undesired recirculation.
3. to make efficient use of energy. This can take many forms. Evaporator performance often are evaluated on the basis of steam economics-pounds of solvent evaporated per pound of steam used. The heat is needed to increase the temperature of the feed from the specified starting value to the boiling liquid, to provide the energy needed to separate the solvent liquid feed and to vaporize solvent. The largest increase in the economy of energy you can reuse the solvent vaporized as heating medium. This may be achieved in various ways to be discussed later. Energy efficiency can be increased for the exchange of heat between the feed enter and leave residues or condensation.
4. meeting the conditions imposed by the liquid is evaporated or solution be concentrated. Factors that should be considered include the quality of the product, Salting and sizing, corrosion, foaming, degradation of the product, holdup, and the need for specific types of construction.
Today many types of evaporators are in use in a wide variety of applications. There is no set rule regarding the selection of types evaporator. In many fields of different types are used in a satisfactory manner for identical services. The final selection and design often can result from tradition or previous experience. The wide variation of the characteristics of the solution expand operation evaporator and design by heat transfer simple A separate art.

Tags: Condensation, Corrosion, Downstream Equipment, Economy, Efficient Use, Elements, Energy Efficiency, Evaporation, Evaporator, heat transfer, Inadequate Separation, Indirect Heat, Liquid Feed, Liquid Separation, Metal Surface, Metal Surfaces, Pollution, Solvent, Steam, Water Heat


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