Budem naozaj velmi vdacny
Summary
After all necessary calculations I could claim, that this evaporation line has been encountering some serious defects in the way of its running. In the concrete it concerned the way of heating the third evaporator with superheated steam, what has been causing blockage of almost one third of its heat transfer surface. As a treatment I suggested to cool the superheated steam with water under pressure to saturation temperature before entering the evaporator. Expected increase of heat duty in evaporator III is more than 21 %.
Next very important suggestion was lowering the level of solution in tubes of the first two evaporators what allowed me to increase the heat-load by 12 % in average. After comparing maximal heat duties in particular evaporators I came to conclusion that the existing equipment was not designed correctly, in the concrete size of heating surface in the third evaporator is too small considering options for heat transfer in first two evaporators.
After application of suggested precautions discussed in former text I assume increase in performance of whole device, measured as increase of amount of evaporated water, more than 16 %.
In case that new performance will not be sufficient, the best solution is believed to be making investment into a new evaporation line.