Triple-effect fall film evaporator

General introduction

Multi-effect falling film evaporator adopts the principle of falling film type evaporation. It heats up rare solution to boiling
point so that some moisture is boiled away; thus reaching to the aim of condensation. This machine unit adopts continuous production. It has the advantages of large condensing ratio (1/5-1/10), broad scope of viscidity (<400CP), good effect of heat transfer and large processing capacity etc.. It is suitable for evaporating the material that is heat sensitive, higher in consistency, large in viscidity and corrosive, also is suitable for condensing corn steep liquor and malt dust in the industry of starch, syrup and monosodium glutamate liquor in foodstuff, milk, sugar and lees filtrate.

This unit has bigger coefficient of heat transfer, so the temperature difference for heat transfer is little. It may assemble to
dual-effect, triple-effect, four-effect or five-effect evaporating system according to the properties of evaporating material and different evaporating objectives, as well as may make use of waste vapor on the top of pipe bundle or disc type drying machine and other low heat source (such as coagulated water vapor) to act as waste heat evaporator, which reduces steam consumption greatly and reaches the effect of saving energy. If waste heat vapor is supplied enough, it needn’t any live steam, thus getting remarkable economical benefit.

Structure and performance

Single-effect evaporator is composed by one heating room and one vapor-liquid separating room. This evaporator unit is composed by two or more evaporators, heat pump, various feeding and discharging pumps, vacuum device, test instrument, pipeline and valve. The heating room is mostly composed by crust, pipe bundling device and connection pipe. And vapor-liquid separating room is composed by crust and foam eliminator.

a.This machine unit feeds material continuously in downstream or in upstream or in mixed flow. If feeding in downstream, the flow direction of solution is the same as that of steam during heating. Raw material is preheated to boiling point by pre-heater and then reaches to the first effect. As the boiling point of solution in former effect is higher than that in latter effect, material will be overheating and evaporate by itself once entering to the latter effect, meanwhile, as the condensed water in former effect can also evaporate after coming into the latter effect, secondary stream will be produced more. If feeding in upstream, raw material is fed in the third effect. The first-effect material is discharged through the second-effect one. When feeding mixed material, raw material is fed by the third-effect material and is discharged by the second-effect one through the first effect.

b.Relying on the effect of heat-insulation compression, steam eject heating pump makes some secondary steam in the first effect improve its saturation temperature and return to the first-effect heating room to act as heating steam, thus, economic degree for producing steam is improved.

c.The static distribution panel makes material form film-like flow evenly and effectively after entering into feeding pipe from the top of heating room, so the coefficient of heat transfer is improved greatly; and temperature loss caused by static-pressure head may be omitted; therefore, the effect temperature difference is much large in the condition of the same falling film evaporator.

d.As solution stays for short time in evaporator, it is much suitable for evaporating heat-sensitive material.