Mercury adsorption on activated carbon in Waste-to-Energy: Model development and validation on real plant data

A model capable to estimate the mercury (Hg) removal efficiency in the fabric filter of a real Waste-to-Energy plant with dynamic operating conditions has been developed. The mathematical model is based on Langmuir equation and Hg mass balance on mercury, in both gaseous and adsorbed phases, along the growing filter cake and inside the activated carbon particles. The activated carbon properties and the Langmuir isotherm parameters have been obtained by fitting the model to real plant data, characterized by variable mercury inlet concentrations. The model is then validated on another dataset coming from the same plant. The obtained Hg removal efficiency falls within ± 3 % error band and with a mean absolute percentage error equal to 0.87 %. The model is suitable for the development of a data-driven activated carbon feed control strategy to increase the economic and environmental sustainability of the WtE plants as well as in the development of virtual sensors to use as a replacement when the continuous stack mercury monitors fail.