Abstract
In this paper, we designed biomass gasification cogeneration plant in a sawmill. The sawmill in K town in Ehime prefecture was selected as the model plant. The biomass material used as the fuel is cedar (scrap wood). The plant consists of a fluidized-bed gasifier and a gas engine. These components produce steam, hot water and electricity. The net electricity and steam power from the plant are 2, 000kW and 7, 492 MJ/h respectively. The fuel of gas engine is mixture of low calorific biogas and LPG. The condition of steam by recovering from a heat recovery boiler and a exhaust boiler is 0.9MPa and 175°C. The net efficiency of this system was 41.6%-LHV. In addition, the basic data on the performance of the gasifier were obtained from the two experiments concerning the pyrolysis of wood and the gasification of Char. Using the basic data of both experiments, the efficiency of the gasification was calculated.
From the results of energy demand, especially electricity and heat, the biomass of 10, 512 t/year and LPG of 593t/year are consumed. Furthermore, the CO2 emission of 3, 468 t-CO2/year and the weight of final disposal of 8, 857 t/year are reduced compared with conventional case (non-biomass energy system).
