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Show Paper No. 13 Fossil Fuel Combustion in an 0 2/C02 Medium: Preliminary Data from Highvale Coal K.V. Thambimuthu*, C.R. Conrad, R. Nadarajah, A.D. Palmer, T.J. Sellers, J.K.L W o n g and W . Yan+ C A N M E T Energy Technology Centre, Natural Resources Canada, 1 Haanel Drive, Nepean, Ontario K 1 A 1M1, Canada. Abstract With growing interest in the capture and utilisation of greenhouse gases, experiments have been undertaken to evaluate a novel combustion process that produces an enriched concentration of C 0 2 in flue gases. The process evaluated relies on fossil fuel combustion in 0 2 and C 0 2 mixtures, thereby eliminating nitrogen dilution of flue gases. Preliminary data obtained from studies with a western Canadian sub-bituminous coal in 21/79, 28/72 and 35/65% 02/C02 mixtures show that the fuel ignition and combustion characteristics can be comparable to that for coal burning in air. As expected from theory, dry flue gas C 0 2 compositions of around 94.8 vol % were measured in the tests, with the balance of the gases made up of N O x and SOx and a 5 vol% excess 0 2 concentration maintained for fuel burnout in the combustor. Other measured values of the inflame gas compositions, temperatures, radiant and convective heat fluxes noted in the 02/C02 combustion tests are compared with the results obtained for coal combustion in air. 1. Introduction Rising concerns about global warming and climatic change have focused attention on the need to reduce the atmospheric emissions of greenhouse gases. The greenhouse gases of principal interest in fossil fuel utilization are C 0 2 , N 2 0 and CH4. Among these gases, C 0 2 and N 2 0 are produced from fossil fuel combustion, while C H 4 is released mainly from fossil fuel production and distribution systems. C 0 2 released from fossil fuel combustion retains a major focus of attention in the search to reduce greenhouse gases due to the much larger quantities emitted. Canada is pursuing a voluntary program to limit greenhouse gas emissions at 1990 levels by the year 2000 as part of its commitments under the United Nations Framework Convention on Climate Change. Canada's total greenhouse gas emissions in 1990, expressed on a C 0 2 equivalent basis, is estimated at 577 million tonnes (Mt). Current projections based on some underlying assumptions about energy prices and growth in the Canadian economy, estimate that greenhouse gas emissions in the year 2000 will rise by approximately 9 % over 1990 levels. To achieve the national commitments under the Framework Convention on Climate Change, the Government of Canada (through the Minister of Natural Resources Canada) has embarked on a voluntary * corresponding author, + presently at North China Electric Power University, Hebei, PRC. 1 |