Assessment of Carbonization of Coal as a Potential Strategy to Reduce Emissions for Domestic Applications

Abstract Coal mining areas in India have a large number of households that use raw coal for cooking. Emissions from such cookstoves lead to issues of both ambient as well as indoor air pollution. Several studies report that PM≤2.5μm emissions from coal cookstoves are influenced by the volatile content of the coal. The present study investigates the effect of temperature of carbonization on the extent of reduction in PM≤2.5μm emissions for two types of bituminous coals. Raw coals and coals carbonized at 200, 400 and 600°C, are burnt in two different types of domestic cookstoves. PM≤2.5 μm, EC-OC, and CO measurements are made in a 90-minute combustion cycle. Emissions are found to decrease from 20-70% for the two coals carbonized at 400 and 600 °C. The corresponding ignition temperatures are also estimated for the fuels to address the issue of ignitability with traditional methods. Emission factors for PM≤2.5μm, CO and EC-OC are developed, and suggest that carbonization at 600°C is adequate for minimizing PM emissions while assuring ignitability in the cookstoves tested.