High-temperature flue-gas desulfurization by injection of carbonatation lime

Studies have been performed by the Institut Français du Pétrole and Babcock Entreprise to demonstrate the feasibility of using carbonatation lime as a sulfur dioxide sorbent in the AUDE boiler, a new clean combustion equipment which allows for combustion of high sulfur fuel-oil. The tests were carried out on laboratory scale, under well-controlled conditions, and on a 10 MW (thermal) semi-industrial pilot plant. As a result, carbonatation lime gave desulfurization yields higher than those obtained with finely crushed limestones. Moreover, the nitrogen content was found to reduce the NOx emissions according to the Selective Non-Catalytic Reduction mechanism. The users of high sulfur fuel-oil, who will be faced with increasingly strict regulations, could reduce, in this way, their annual sorbent expenses whilst sugar producers have an opportunity to set and control a new valorization route for their carbonatation lime. Owing to its high water content, the carbonatation lime may not be transported over large distances and calculations were made to define the distance at which this product is no longer cost-effective compared with natural limestone.