An evaluation of alternate fuels for cement kilns

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Diverting non-recyclable waste plastic (WP) destined for landfill presents a dual solution to both waste diversion and alternate fuel use in Canadian cement kilns. Preliminary laboratory trials estimate that there would be a significant reduction in particulate and gaseous air pollution emissions when using WP as an alternative fuel in cement kilns. However, there are major concerns by stakeholders that WP alternative fuel may produce undesirable emissions when used in cement kilns across Canada. This five year research program will include four interrelated themes: (1) the most appropriate WP alternative fuel handling methods; (2) the optimum method for delivering WP derived fuel into cement kilns (3) the impact of WP derived fuel on cement kiln stack emissions and (4) estimating the impact of these emissions on ambient air quality, communities and the environment. A combination of laboratory and field trials will be conducted to determine the optimum WP alternative fuel handling and kiln delivery method. Laboratory analysis will include the complete chemical characterization of the WP. Cement kiln stack emission characteristics will be tested at the Lafarge Canada Inc. cement plant in Brookfield, Nova Scotia, before and after WP supplemental fuel usage. Further stack testing would be completed at other cement kilns in Canada, e.g. St. Constant, Quebec. Two ambient air quality monitoring sites would be established at the Brookfield plant to determine the impact of the kiln emissions on surface air quality before and after the use of WP alternative fuel. One site would be located upwind and one downwind of the cement kiln. These two air quality sites would be relocated to other cement kilns after the emissions from the Brookfield cement plant have been characterized. The USEPA AERMOD Gaussian air dispersion, USEPA CMAQ and Land Use Regression models will be used to model community exposure to air pollution emissions from the Lafarge cement plants in Canada. The USEPA Positive Matrix Factorization receptor model will be used for the source apportionment of particulate and gaseous air emissions from the cement plants in downwind communities. In addition, remote sensing measurements from the geostationary, high spatiotemporal resolution, new NASA TEMPO satellite will also be used to track the dispersion of air pollutants from the cement kilns. Together, these state-of-the-art measurements, modelling and remote sensing methodologies will be used to estimate community exposure and impacts on the environment from emissions related to the use of non-recyclable WP as an alternative fuel source in rotary cement kilns in Canada. This research has the potential to divert WP from landfill, provide alternative energy at a reduced cost, improve air quality in downwind communities and reduce the impact of the cement industry on downwind ecosystems and ultimately helping to mitigate climate change.