Pure oxygen fixed-bed gasification of wood under high temperature (>1000 °C) freeboard conditions

In this paper, the performance (syngas composition, syngas production and gasification efficiency) of an 18 kW atmospheric fixed bed oxygen blown gasifier (FOXBG) with a high temperature (>1000 degrees C) freeboard section was compared to that of a pressurized (2-7 bar) oxygen blown entrained flow biomass gasifier (PEBG). Stem wood in the form of pellets (FOXBG) or powder (PEBG) was used as fuel. The experimentally obtained syngas compositions, syngas production rates and gasification efficiencies for both gasification technologies were similar. Efficient generation of high quality syngas (in terms of high concentration and yield of CO and H-2 and low concentration and yield of CH4, heavier hydrocarbons and soot) is therefore not specific to the PEBG. Instead, efficient gasification seems to be linked to high reactor process temperatures that can also be obtained in a FOXBG. The high quality of the syngas produced in the FOXBG from fuel pellets is promising, as it suggests that in the future, much of the cost associated with milling the fuel to a fine powder will be avoidable. Furthermore, it is also implied that feedstocks that are nearly impossible to pulverize can be used as un-pretreated fuels in the FOXBG. (C) 2017 Elsevier Ltd. All rights reserved.