OPERATION OF MILLS WITH LOW STEAM DEMAND: CHALLENGES AND SUCCESS IN EVAPORATOR STATION AND PAN HOUSE

IN THE PAST, development in process design in beet and cane sugar factories took place separately. One major difference between the cane and beet sugar industries is the energy supply situation. The cane sugar factories are self-sufficient in energy by burning bagasse, whereas the beet sugar factories need to buy their primary energy. With the introduction of cogeneration in the cane industry, several measures for efficient process designs proven in the beet sugar industry have been successfully transferred to cane sugar factories. In order to receive additional revenue from cogeneration, steam saving for the sugar process is mandatory. Now, plants with clearly less than 30% steam on cane for the plantation white process as well as approximately 40% steam on cane for the cane mill including a full refinery are operating successfully. Measures in designing steam efficient sugar mills are explained. Historically, sugar house operation was mainly oriented to the quality of the sugar produced as well as to the yield or molasses purity. Nowadays, the focus is also on the steam demand of the sugar house and steam savings for the overall process of sugar production from cane. One major challenge is the minimising of water addition during sugar house operation. Continuous boiling for A product plays an important part in terms of smooth operation and more efficient steam consumption. For operation of continuous pan boiling with vapour 4, falling film evaporators show reliable operation. Optimised arrangement of heaters supports the low-steam-demand strategy.