CRYSTALLIZATION WITH DOUBLE-EFFECT EVAPOR ATION

An obvious advantage of continuous evaporating crystallizers with stir ring systems is the possibility to operate at very low temperature dif ferences. This enables the design of equipment for a crystallization s cheme providing a double-effect evaporation: The vapour from the evapo rating crystallizers for raw sugar and after-product is the heating me dium for the white sugar evaporating crystallizer. Model calculations are introduced and the consequences of such lay-outs for the evaporati ng station and the power plant of a sugar factory are described. Accor dingly, the sole production of white sugar of EEC quality 2 results in operational steam requirements of 15.3 kg/100 kg beet. Just in time f or the 1994 beet campaign such lay-outs and equipment for a crystalliz ation with double-effect evaporation have been installed in the sugar factories of Gustrow and Klein Wanzleben. Gustrow sugar factory has al ready started operation during the 1994 beet campaign. The report give s a survey of the operating conditions and results.