Method and composition for treating flue or exhaust gases utilizing modified calcium hydroxide
AssigneeS.A. Lhoist Recherche et Developpement
InventorsPhilippe A. Dumont, Robert Goffin
Life of this patent
Estimating the term…
Abstract
A process is shown for treating flue or exhaust gases in order to remove sulfur oxides and hydrochloric acids in which calcium hydroxide having a surface area of at least 25 m.sup.2 /g and a moisture content lower than 50% is injected in the gases to be treated either alone, or in a mixture with magnesium hydroxide The calcium hydroxide used in the process is prepared by reacting quicklime or dolomitic quicklime with water in the presence of a glycol or an amine companion additive
Claims6
A calcium hydroxide modified by an additive selected from the group consisting of ethyleneglycol, diethyleneglycol, triethyleneglycol, monoethanolamine, diethanolamine, triethanolamine and mixtures thereof, said calcium hydroxide being suitable for treating gases for removing therefrom undesirable compounds including sulfur oxides and hydrochloric acid, the calcium hydroxide being prepared by the process of slaking quicklime or dolomitic quicklime in presence of the said additive , the weight ratio of water to quicklime or dolomitic quicklime which is used in the preparation of the modified calcium hydroxide being in the range from about 0.6 to 2, while the weight ratio of the said additive to quicklime or dolomitic quicklime is comprised between 0.005:1 and 0.02:1, the calcium hydroxide so prepared being characterized as having a surface area of at least 35 m.sup.2 /g and a moisture content lower than 50%.
A calcium hydroxide modified by an additive selected from the group consisting of ethyleneglycol, diethyleneglycol, triethyleneglycol, monoethanolamine, diethanolamine, triethanolamine and mixtures thereof, said calcium hydroxide being suitable for treating gases for removing therefrom undesirable compounds including sulfur oxides and hydrochloric acid, the calcium hydroxide being prepared by the process of slaking quicklime or dolomitic quicklime in presence of the said additive , the weight ratio of the said additive to quicklime or dolomitic quicklime being in the range of 0.005:1 to 0.02:1, while the weight ratio of water to quicklime or dolomitic quicklime being in the range from about 0.8:1 to 1.1:1, the calcium hydroxide having a surface area of at least 40 m.sup.2 /g and a moisture content lower than 50%.
Dependencies are inferred from the claim text.