Use of Hydrochar Produced by Hydrothermal Carbonization of Lignocellulosic Biomass for Thermal Power Plants in Chile: A Techno-Economic and Environmental Study

Abstract

Hydrothermal carbonization makes it possible to transform lignocellulosic biomass into hydrochar, a carbon-rich material that can be used as fuel. Hydrochar has less calorific value than standard coal but generates less ashes during combustion. This study is a pre-feasibility analysis carried out to evaluate technically-economically and environmentally the use of hydrochar as fuel or co-fuel in thermal power plants in Chile. Until now there are no reports about it. The proposal of this work was to study the replacement of coal with a fuel that uses the same equipment and processes in power generation but with less air emission and with an economically profitable change. The results suggest that a plant with a supply of 104 t/h of bituminous coal could be replaced between 18 and 37 t/h of hydrochar, with a reduction of 8 and 27% in NOx and SO2 emissions, a reduction in 7 to 24% in ashes and a marginal increase in CO2 emission. The proposed use of hydrochar was economically profitable, with internal rates of return of up to 40% and with cash flows that reached USD 22 million.