In-situ generation of special sorbents in combustion gases for the removal of mercury and other pollutants present in them

摘要

The present invention provides compositions including a mixture containing sulfides and/or polysulfides of ammonium, sodium, potassium, lithium, etc., gold and/or compounds of gold, copper and/or compunds of copper, silver and/or compounds of silver, sulfur or potassium tri-iodide, and ammonium nitrate, ammonium sulfate, ammonium acetate, ammonium formate, ammonium thiosulfate, ammonium peroxy sulfate, sulfuric acid, zinc chlride, phosphoric acid, or its ammonium and alkali salts and mixtures thereof, and polyhydroxy organic compounds such as glycerol, mono and di saccharides such as glucose, fructose, sucrose, molasses, lactose, polysaccharides and derivatives thereof and mixtures threreof in which the polyhydroxy compound is utilized as a sorbent precursor and the first group of inorganic salt or mixture thereof is utilized to impart the specificity for mercury removal into the said generated sorbent and the second group of inorganic salt or the mixture thereof is utilized as a catalyst to generate the sorbent at low temperatures, say above 200° F. into combustion gases produced from the combustion of fossil and derived fuels, for the removal of mercury and/or other pollutants present in such gases. The polyhydroxy compound alone or in conjunction with the first group of inorganic salt and mixtures thereof mentioned above is also shown effective to generate the special sorbent having the unique properties to remove mercury and/or other pollutants from the said gas stream. The aforementioned composition can be mixed with fly ash, clays of various types, silica, alumina, titania, zirconia or mixtures thereof for the removal of mercury and/or other pollutants present in combustion gas streams. Methods are provided for applying and generating the above mentioned sorbent in the flue gases of fossil and derived fuel fired systems and waste and municipal incinerators for controlling the emissions of mercury and/or dioxin contained in such gas streams.