Fuel Processing Technology, Vol.115, 130-138, 2013
Pressurized oxygen blown entrained flow gasification of a biorefinery lignin residue
Renewable fuels could in the future be produced in a biorefinery which involves highly integrated technologies. It has been reported that thermochemical conversion (gasification) of lignocellulosic biomass has a high potential for end production of renewable biofuels. In this work, lignin residue from biochemical conversion of wheat straw was gasified in an oxygen blown pressurized entrained flow gasifier (PEBG) at 025-030 MWth, 0.45 < lambda < 0.5 and 1 bar (g). A video camera mounted inside the PEBG was used to observe the flame during start up and during operation. Hydrogen (H-2), carbon monoxide (CO) and carbon dioxide (CO2) were the main gas components with H-2/CO ratios varying during the gasification test (0.54-0.63). The methane (CH4) concentration also varied slightly and was generally below 1.7% (dry and N-2 free). C-2-hydrocarbons (<1810 ppm) and benzene (<680 ppm) were also observed together with low concentrations of hydrogen sulfide (H2S, <352 ppm) and carbonyl sulfide (COS, <131 ppm). The process temperature in the reactor was around 1200 degrees C. The slag seemed to consist of Cristobalite (SiO2) and Berlinite (AlPO4) and Na, Ca, Mg, K and Fe in lower concentrations. Cooling of the burner will be necessary for longer tests to avoid safety shut downs due to high burner temperature. The cold gas efficiency and carbon conversion was estimated but more accurate measurements, especially the syngas flow, needs to be determined during a longer test in order to obtain data on the efficiency at optimized operating conditions. The syngas has potential for further upgrading into biofuels, but will need traditional gas cleaning such as add gas removal and water gas shifting. Also, higher pressures and reducing the amount of N-2 is important in further work. (C) 2013 Elsevier B.V. All rights reserved.