Mercury emissions and distribution in a waste incineration plant based on the 30B and Ontario Hydro methods

Abstract

Flue gas mercury emissions from waste rotary kiln incineration plants in Northern China was sampled using the US Environmental Protection Agency's 30B method and Ontario Hydro (OH) method. The average mercury emissions concentration was 13.38 ± 4.08 μg/Nm3 (based on the 30B method) and 18.66 ± 8.19 μg/Nm3 (based on the OH method). Coincidentally, it was also found that the uncertainty in Hg measurements of the raw feedstock was responsible for the fluctuation in the flue gas Hg data. The Hg emission consisted of Hg0, followed by Hg2+ and Hgp species, accounting for 59–82%, 3–26% and 14.84–16.03% of total Hg, respectively. Mercury was released from the ash to the flue gas after the fabric filter due to the high temperature. Based on the 30B and OH methods, the re-release rates of total Hg were 45.09% and 40.38%, respectively. The scrubbing tower in this type of system can remove most of the Hg2+ from the flue gas, and the total Hg removal efficiencies across the desulfurization units were 59.70% and 92.19%, respectively.