Evaluation of Bioethanol Production System from Rice Straw

Abstract

bioethanol plant on the ethanol production cost. Results and Discussion. The energy consumption was estimated to be 728MJ, and CO 2 emissions were estimated to be 39kg-CO 2 per production of 1 GJ of ethanol. Energy input and CO 2 emissions of the ethanol conversion process were the most aspects of the life cycle of ethanol. Bioethanol uses about 39% less energy and produces 51% less CO 2 emissions than gasoline. Lignin residue combustion has a high potential for reducing energy consumption and CO 2 emissions. The bioethanol cost was estimated to be 181 JPY/L. The rice straw cost and its conversion cost account for 68% and 30% of the total cost, respectively. In terms of cost, ethanol is not competitive with gasoline. However, if ethanol becomes tax-exempt from the gasoline tax, the ethanol price can become competitive for the end user. Conclusions. From the viewpoint of energy consumption and CO 2 emissions, bioethanol is likely superior to gasoline. The system which utilizes lignin in a boiler and recovers heat effective increases the energy balance and reduces CO 2 emissions. Since the rice straw collection/transportation cost accounts for a large part of the total cost in the ethanol production system, it is significant to make the price competitive. The development of low cost technologies to collect rice straw and ethanol conversion as well as a financial support system are needed.