Sugar factories dry their pressed pulp in so-called high-temperature driers
. High-temperature drying operates by evaporation, the pressed pulp being d
ried in direct contact with a mixture of combustion and boiler exhaust gase
s and fresh air. This method represents the State Of the art in the drying
of molassed pressed pulp. Other methods, such as steam drying and low-tempe
rature drying, have been employed for many years alongside of high-temperat
ure drying, but have not replaced it.
Sudzucker's Warburg factory conducted a comprehensive measuring program dur
ing the 1999/2000 campaign to determine the factors influencing energy requ
irements. The rate of water evaporation and dry substance level of the mola
ssed pressed pulp were found to be the major factors impacting on specific
primary energy consumption and the temperature of the mixture of gases at t
he entrance of the drum. The specific energy consumption and drum entrance
temperature rose as the rate of water evaporation and the dry substance con
tent increased, and also with increasing dry substance content of the molas
sed pressed pulp at a constant rate of water evaporation.