Entrained-flow gasifier fuel blending studies at pilot scale

For the foreseeable future, coal and petroleum-based materials, such as petroleum Coke, residuals, and high-sulphur fuel oil, are being adopted as the feedstocks of choice for gasification projects. Of particular interest from a Canadian perspective is Coke generated from the thermal cracking of the oil sands in Western Canada. Oil sand Coke contains high sulphur (5 - 6%), and also typically has a low volatile content, and lower reactivity than most coals. Experimental runs have recently been conducted on the pilot-scale entrained-flow gasifier at CETC-Ottawa, blending oil sand Coke with sub-bituminous and lignite coals, to try and enhance the gasification potential of these materials. Blending Genesee sub-bituminous coal with the delayed oil sands Coke was found to alleviate problems encountered with slag plugging the reactor when running with Genesee coal alone. Blends of Genesee sub-bituminous and Boundary Dam lignite coals with Coke achieved higher carbon conversions and cold gas efficiencies than runs completed with the Coke by itself. While using CO2 as the conveying gas into the gasifier was not found to significantly affect the conversion obtained, steam addition was found to have a marked effect on CO and H-2 concentrations in the syngas.