Improving Cogeneration in Sugar Factories by Superheated Steam Drying of Bagasse

摘要

The typical cogeneration system in sugar factories uses moist bagasse as the fuel for the boiler,which generates high-pressure steam required by the backpressure turbine to produce power output.Exhaust steam from back-pressure turbine is used for heating duty in the evaporation unit.Because the steam is superheated,it must be mixed with cooling water to produce saturated steam.Combustion of moist bagasse in the typical system is inefficient because substantial thermal energy is required to evaporate moisture in bagasse.In this paper,an investigation is made into the improvement of the typical system by using superheated steam dryer,in which superheated steam from the turbine exhaust is in direct contact with moist bagasse.It is found that the improved system reduces bagasse consumption and increase power plant efficiency.Furthermore,the improved system recovers water that would be lost with flue gases in the typical system.