Co-Gasification of Coal/Biomass Blends in a Pressurized Fluidized-Bed Gasifier: The Advantageous Synergies in the Process

Abstract

An experimental study on co-gasification of coal and biomass blends in an oxygen-containing atmosphere has been carried out in a pressurized fluidized-bed gasifier. Several different biomass materials including wood and energy crops were used in the study, whereas two coals ranked of bituminite from Poland and UK were used in the investigation. The gasifier used was a Laboratory Development Unit (LDU) with an inner diameter of 144 mm. The operation temperature was 900 °C, and the pressure was 0.4 MPa. The research was part of the European Commission’s APAS and JOULE III clean coal technology programs. The study was focused on possible synergistic effects in the thermochemical treatment of the fuel blends. The char formed was examined. The tar produced in the process was analyzed. The environmentally concerned nitrogen compounds emitted from the process were detected. An unexpected result was that the blends of the fuels and their char formed in situ exhibited higher gasification reaction rate under the studied conditions. The yield of char diminished and consequently the gas production increased. Furthermore, both the formation of tar and nitrogen compounds seemed also affected synergistically in co-gasification process of the fuel blends. The yields of tar and ammonia were lower than expected.