Characterisation and evaluation of the emissions from the combustion of orimulsion-400, coal and heavy fuel oil in a thermoelectric power plant

An experimental campaign was carried out in a thermoelectric power plant in Southern Italy in order to evaluate the emissions released during the utilisation of three different fuels, Orimulsion-400, coal and heavy fuel oil (HFO) with high content of sulphur. Macropollutant concentrations in the exhaust gases were recorded by the continuos monitoring system and the Institute on atmospheric pollution of the Italian National Research Council (CNR) carried out samplings and analysis of Polycyclic aromatic hydrocarbons (PAHs), Polychlorodibenzo-p-dioxins (PCDD) and Polychlorodibenzofurans (PCDF), halogenidric acids and metals. The pollutant concentrations, mass flows and emission factors were compared. Each fuel met the air emission limits for all the pollutants. Coal showed the highest emission levels, whilst HFO and Orimulsion were fairly similar. NOx, SO2 and particulate matter showed constant concentration for all the fuels, while Orimulsion and HFO SO2 concentrations were critical at the highest operating power. Orimulsion showed the lowest PAHs values and PCDDs and PCDFs were much lower than the limits for all the fuels. A particular attention must be paid with vanadium and nickel during Orimulsion utilisation. For these metals mass balances were carried out.