VACUUM CONDENSING PRACTICES

摘要

It is the boiling house where the sugar is finally produced. Creation of vacuum at evaporator/pans is necessary for achieving lower boiling point of sugar solutions in pans and steam economy in multiple effect evaporator. To control boiling conditions different type of equipments are used which condenses vapours, removes the non-condensable gasses from pans and evaporators. Condensing performance mainly depends on quantity of vapour, injection water supply, temperature of injection water, wastewater and vapour and volume of non-condensable gases per unit time. For fixed crush rate, vapour bleeding and massecuite boiling scheme average heat load to condenser remains same i.e., when injection water temperature is increased equal temperature rise in wastewater will be expected. According to C.G.M.Perk~(-3) the combination of individual counter current condenser with reciprocating/rotary dry air pump consumes least power. Other system either multijet or evacuating with aid of a water or steam jet require more energy. The system of counter current condenser are less sensitive with regards cooling water temperature than multijet-multispray condensers and is therefore multijet-multispray condensers are less suitable in cases where cooling water temperature is rather high.