A Closed Model of Production System for Energy Self-Sufficiency Rice Mill

Abstract

Rice mills consume considerable amount of energy, which is mainly supplied by fossil fuel. It has been approved that such energy is declining, and its negative impacts on the environment has also been significant. A more sustainable energy resource, such as biomass, should be considered to replace fossil energy. This research was aimed to assess energy potential of generated waste and to develop a model of energy self-sufficiency rice mill through by-products utilisation as energy source. The model was based on mass balance principles by assuming that there is a linear relationship of material flows in and out of each process compartment. The simplest model assumed the rice mill as a single compartment, while the complex model used a more detailed step of processes as compartment. The complex model was suitable to represent real process of rice mill. According to this model, head rice yield, rice husk ratio, and bran ratio is 0.572; 0.231, and 0.074 of dried paddy respectively. Energy potential of by-product is about 18,830 MJ/day from processing 20 tons harvested paddy. This energy potential exceeds the need of the rice mill at 28.25% surplus. This research revealed that rice mills can be energy self-sufficient. Therefore, it is possible to propose regulation to limit the use of fossil fuel in rice mill.

Keywords: rice mill, closed production system, energy self-sufficiency