Experimental and Kinetic Analysis of H2O on Hg0 Removal by Sorbent Traps in Oxy-combustion Atmosphere

Oxy-combustion technology is under development for CO2 capture. H2O could influence the H-0 removal by sorbent traps in an oxy-combustion atmosphere. A study of the effects of H2O on H-0 removal by biomass char under oxy-combustion conditions is presented in this paper. The kinetic model analysis was conducted to study the adsorption process of H-0, which included a pseudofirst-order kinetic model, a pseudo-second-order kinetic model, and intraparticle diffusion kinetic model. Experimental results showed that a low-level of H2O had a promoting effect on the adsorption of H-0, and high-level of H2O had an inhibiting effect. A high concentration of H2O would form a water film on the surface of sorbent traps to hinder the removal of external mass transfer on H-0. Although the adsorption rate of H-0 depended both on external mass transfer and intraparticle diffusion, external mass transfer was a more important controlling factor. It was found that physical adsorption was one of the main forms of H-0 removal on the surface of sorbent traps, owing to the large specific surface area and good pore structure of the modified corn straw char. The removal of H-0 was mainly attributed to capture by physical adsorption and the formation of HgO by chemisorption.

Automated summary

Experimental results showed that a low-level of H2O had a promoting effect on the adsorption of H-0, and high-level of H2O had an inhibiting effect. A high concentration of H2O would form a water film on the surface of sorbent traps to hinder the removal of external mass transfer on H-0.