Liquid Tin Irrigated Packed Bed for Hot Fuel Gas Desulfurization

Abstract

Hot fuel gas cleaning for gasification of coal can increase the energy efficiency by minimizing the loss of thermal energy. The current hot gas desulfurization studies focus on the development of various metal oxide sorbents. This paper presents a novel approach using liquid tin as a nonwetting scrubbing medium in a countercurrent packed bed. The H2S removal efficiency of liquid tin was investigated in a 200 mm high reactor for various tin and gas flow rates, bed heights, and H2S concentration at operating temperatures of 300−400 °C. For tested conditions, gas transfer unit heights of 0.084−0.181 m were obtained at H2S concentration of 1000 ppm, which corresponded to an H2S removal efficiency of up to 91% in the small test reactor. These results are promising since higher efficiencies can be achieved at larger scales. The effects of thermal equilibrium and interaction with other gases are also discussed. Further studies are required on various aspects including higher operating temperatures, larger flow rates, and the regeneration of tin using zinc.