To increase the efficiency in sugar and ethanol industries by using a decanter centrifuge : a feasibility study made in the Dominican Republic

Abstract: This Bachelor Degree Project is a study about possible improvements of the efficiency at sugar mills and ethanol distilleries by using a decanter centrifuge. The report handles background, purpose and result including conclusions and discussions. The implementation of the decanter at site is fully described, including problems and solutions during the project. With the increased use of ethanol as a bio fuel, the question about bio ethanol’s energy balance have become of more importance. As a part of the project a study about the energy balance have been carried out. In our research we did only find one (more or less) accepted investigation concerning ethanol energy balance from sugar cane. All other found information about the subject refers to this single assessment which is quite remarkable. The sugar and ethanol production processes are almost similar until after the clarifier step. The clarifier is a gravitational settling tank where the juice is clarified and then sent to evaporation (sugar process) or fermentation (ethanol process). The by-product called molasses still contains some sugar and is therefore sent to a rotating vacuum filter to extract the remaining sugar. Rotating vacuum filters has high energy consumption, is dirty, creates a lot of smell and needs a lot of space. The objective with the study was to investigate the possibilities to replace the rotating vacuum filter with a decanter centrifuge and achieve better efficiency in the production. A decanter is a centrifuge that separates solids from liquids. The decanter is based on the simple theory that solids fall to the bottom due to the force of gravity. The decanter centrifuge works with this principle but the difference is that the gravity force has been replaced by a centrifugal force. The result of our test gives a good indication that the decanter is a good investment. The payback time is short and the investment gives many positive side effects such as less energy consumption, better working environment and it needs less space in the factory.