Removal of elemental mercury by Ce and Co modified MCM‐41 catalyst from simulated flue gas

Abstract

Co and Ce based catalysts have been proven to possess a high Hg 0 removal efficiency. However, these catalysts have a low dispersion of active components and low mass transfer rate, which limits their catalytic activity. MCM-41 has a large surface area and a highly ordered mesoporous structure, which can improve the dispersion of Co and Ce, resulting in a high mass transfer rate. In this paper, different amounts of Co and Ce were loaded on MCM-41 to synthesize Co x -Ce x /MCM-41. The characteristic results of the catalyst showed that catalysts with a lower Co and Ce loading amount had a high dispersion and a low crystallinity, leading to more activity sites on the catalyst surface. Hence, the Hg 0 removal efficiency of the catalysts first increased with the increase of the Co and Ce loading amount. However, with the further increase of the Co and Ce loading amount, the crystallinity of the catalysts increased, which might cause the blockage of the pores and the decrease of BET surface areas, leading to a low Hg 0 removal efficiency. Along with the factors mentioned above, Co 0.15 -Ce 0.15 /MCM-41 had the best catalytic activity, which showed above 85 % Hg 0 removal efficiency in the temperature range of 200-300 8C at 180 000 h À1 . Flue gas components had different effects on catalytic activity. O 2 and NO could promote, but H 2 O and SO 2 inhibit the Hg 0 removal efficiency. The simulated flue gas of 300 ppm SO 2 , 400 ppm NO, 6 % H 2 O, and 5 % O 2 have serious effects on catalytic activity leading to a lower Hg 0 removal efficiency of 20 % for Co 0.15 -Ce 0.15 /MCM-4.

Preparation and stability of zinc‐based mesoporous sorbent modified with aluminium for high temperature coal gas desulphurization

“…Meanwhile, the synthesis of molecular sieves has the advantage of various preparation methods, high reproducibility, and structural controllability, making them become an applicable carrier for desulphurization sorbents. [10][11][12][13] Wang et al investigated the desulphurization performance and regeneration behaviour of Ni-doped ZnO-based sorbents supported on SBA-15 (ZnNi/SBA-15). [14] The results indicated that the sorbents demonstrated high performance for H 2 S removal.…”