Multiple effect evaporation water consumption

The filtrate is then concentrated to 60% of dry substance in multiple-effect evaporators economical in energy consumption ( 1 lb of water evaporated by 1/n lb of steam, where n is the number of effects). However, the temperature to which the liquor is exposed in the multiple-effect evaporators is much higher than in the single-effect, vacuum evaporators that are used in the final evaporation of refined liquor to afford finished-syrup concentration this exposure to high temperature causes, in the syrup liquor, formation of color and off-fla-... 

The principal measures of the performance of a steam-heated tubular evaporator are the capacity and the economy. Capacity is defined as the number of kilograms of water vaporized per hour. Economy is the number of kilograms vaporized per kilogram of steam fed to the unit. In a single-effect evaporator the economy is nearly always less than 1, but in multiple-effect equipment it may be considerably greater. The steam consumption, in kilograms per hour, is also important. It equals the capacity divided by the economy. 

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