Mercury Adsorption Characteristics of Sulphur-Impregnated Activated Carbon Pellets for the Flue Gas Condition of a Cement-Manufacturing Process

Abstract

Powdered activated carbon is used for adsorption of mercury in flue gas. However, in the cement-manufacturing process, it is more suitable to use fixed-bed granular activated carbon than powdered activated carbon injection, so the cement can be reused. Because activated carbon is influenced by both adsorption temperature and composition of flue gas, its mercury adsorption capacity varies greatly. Therefore, it is necessary to evaluate the efficiency of activated carbon for mercury adsorption in advance under the operating conditions in which it is going to be used. We examined the mercury adsorption from exhaust gas in the cement-manufacturing process using sulphur-impregnated activated carbon pellets. The study results show that sulphur-impregnated activated carbon pellets had a high efficiency for mercury adsorption at a high exhaust gas temperature of 180 °C. Experimental results also indicated that the activated carbon pellets had a high efficiency for mercury adsorption (>93%) at 90, 135 and 180 °C from simulated gas without sulphur dioxide. These results indicate that activated carbon pellets have a high efficiency for mercury adsorption in the exhaust gas in the cement-manufacturing process, which is characterized by low levels of sulphur dioxide.