LCA of Small-scale Ethanol Production System from High-yield Rice

Abstract

This study carried out LCA of the project which cultivates high-yield rice in an abundant land and produces ethanol from the harvested rice. It is effective for high-yield rice cultivation to incorporate the nitrogen fixation crops in rotational system, and to adopt a dehumidifying drying system. GHG emission of cultivation system with these strategies is 20.7 g-CO₂eq/MJ. Ethanol production system generates steam with the dual fuel boiler using the gas by rice husk gasification and fuel oil A. when gasification is operated stably, fuel oil A consumption decrease and minimum GHG discharge is 62.7 g-CO₂eq/MJ. The amount of GHG emission of cultivation and ethanol production system and a gasoline are 83.4 g-CO₂eq/MJ and 81.7 g-CO₂eq/MJ, respectively. It is required for the GHG emission reduction to improve the thermal energy conversion efficiency of the steam production which has only been 53%. GHG emission of methane from paddy field is estimated to be 16.5-72.1 g-CO₂eq/MJ by the difference in soil species and existence organic fertilization. The GHG emission by methane from paddy fields has a high impact on research object system.