Preparation of lignite-based activated carbon and its flue gas desulfurization performance

Abstract

Activated carbon (AC) is a porous carbon material with a developed pore structure and large specific surface area, which has been widely used in adsorption, catalysis, energy storage, etc. In this paper, the AC samples were prepared from Huolinhe lignite by the KOH activation method. The effects of the alkali-to-carbon ratio and activation temperature on the yield and surface properties were investigated. The textural and chemical properties of the AC samples were investigated using N2 adsorption-desorption and scanning electron microscopy (SEM). Their desulfurization performances were also studied. With the increase of the alkali to carbon ratio, the yield of AC gradually decreased, the specific surface area first increased and then decreased, and the pore volume gradually increased. With the increase of the activation temperature, the yield of AC decreased, while the specific surface area and pore volume increased. Since the desulfurization of AC was mainly related to the specific surface area and micropores, an alkali-to-carbon ratio of 3 and activation temperature of 800 °C were selected as the optimum conditions of AC preparation. The AC with a specific surface area of 3231 m2 g−1 and micropore volume of 0.948 cm3 g−1 was used for desulfurization. In the flue gas flow rate range of 400–1000 ml min−1, the desulfurization efficiency and desulfurization time of AC decreased with the increase of the flue gas flow rate. With the increase of the SO2 concentration from 1000 to 3000 ppm, the desulfurization time and desulfurization efficiency decreased. When the oxygen content was in the range of 0 to 5%, the increase of the oxygen content was not conducive to the desulfurization process.