Influence of biochar pyrolysis temperature and post-treatment on the uptake of mercury from flue gas

Authors: Klasson, K Thomas; Boihem, Larry; Uchimiya, Sophie; Lima, Isabel

Submitted to: Fuel Processing Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2014
Publication Date: 7/1/2014
Citation: Klasson, K.T., Boihem, Jr., L.L., Uchimiya, M., Lima, I.M. 2014. Influence of biochar pyrolysis temperature and post-treatment on the uptake of mercury from flue gas. Fuel Processing Technology. 123:27-33.

Interpretive Summary: Thermal processing, or pyrolysis, of plant and animal waste under oxygen limiting conditions results in a carbonized material called biochar. Most often, the proposed application for the biochar is soil applications as a conditioner or for the purpose of carbon sequestration. In this paper we demonstrate that this material can also be used as a mercury sorbent in flue gas applications. Four different raw materials (almond shells, cottonseed hulls, lignin, and chicken manure) were pyrolyzed at four different temperatures (350, 500, 650, and 800°C) and washed or left unwashed. These materials were systematically evaluated for their potential to sorb mercury from a simulated flue gas. The material that performed the best were washed biochars made from poultry manure at 650 and 800°C, and these materials sorbed over 95% of the mercury from the flue gas. It was also shown that mercury sorbed to the biochar at 150°C was stable and was not easily thermally desorbed at 450°C.

Technical Abstract: Thermal processing, or pyrolysis, of plant and animal waste under oxygen limiting conditions results in a carbonized material called biochar. Most often, the proposed application for the biochar is soil applications as a conditioner or for the purpose of carbon sequestration. In this paper we demonstrate that this material can also be used as a mercury sorbent in flue gas applications. Four different raw materials (almond shells, cottonseed hulls, lignin, and chicken manure) were pyrolyzed at four different temperatures (350, 500, 650, and 800°C) and washed or left unwashed. These materials were systematically evaluated for their potential to sorb mercury from a simulated flue gas. The material that performed the best were washed biochars made from poultry manure at 650 and 800°C, and these materials sorbed over 95% of the mercury from the flue gas. It was also shown that mercury sorbed to the biochar at 150°C was stable and was not easily thermally desorbed at 450°C.