A decision support tool formulti-pollutants reduction incement industry using analytic hierarchy process (AHP)

Several energy intensive industries are contributing to air pollution problems. Cement industry, as an example, is one of these significant sources of several air pollutants and these must be monitored and controlled. This paper deals with five air pollutants from cement plants and these are SO₂, NO_x, CO₂, dust, and volatile organic compounds (VOC). The purpose of this study is to evaluate several available technologies to control each pollutant. Analytic hierarchy process (AHP) technique is used as a decision support tool to find the best technology for each pollutant under multi-criteria. These criteria are: cost, efficiency, lifetime or duration, and industry acceptability. The technique is illustrated in a case study from St. Marys Plant, located in St. Marys, Ontario, Canada. The results show that adsorption on activated coke technology will be recommended for SO₂ reduction. For NO_x reduction, the AHP suggests to apply selective non-catalytic reduction (SNCR) technology based on the four criteria defined. Carbon capture and sequestration (CCS) using MEA technology is chosen for CO₂ reduction. For dust reduction, bag filters should be used and increase oxygen concentration at the kiln inlet is the selected technology for VOC reduction. The current paper covers the set of criteria weights considered typical for cement plants. The results presented here are illustrative and user defined weighting is required to make this study valuable for a specific group of users.