Modeling of mercury desorption from activated carbon at elevated temperatures under fluidized/fixed bed operations

An effective method for controlling elemental mercury emission is to employ activated carbon (AC) to adsorb mercury from the combustion flue gas. An environmental concern regarding the process is the low sorption capacity of AC. The mercury control practice, therefore, will need a large quantity of fresh AC and generate an equally large quantity of spent AC contaminated with various forms of mercury. A practical solution to this problem is to regenerate the AC for reuse. In this study, an activated carbon mercury sorption/desorption model was developed for simulating the mercury sorption/desorption process at various temperatures under both the fixed and fluidized bed conditions. Mercury sorption experiments were carried out to determine the best-fit model parameter and the parameter-fitted model was then used to simulate the mercury desorption processes under various conditions. The simulation results have indicated that both the desorption temperature and the fluidization condition affect significantly the mercury desorption rates.