REMOVAL OF NOX AND SO2 FROM FLUE-GAS USING AQUEOUS EMULSIONS OF YELLOW PHOSPHORUS AND ALKALI

Aqueous emulsions of yellow phosphorus (P4) have been shown to be effective in removing NO from flue gas in a simple wet scrubber. Factors infuencing NO removal efficiencies include the concentration of P4 used, the temperature and pH of the aqueous emulsion, and the concentration of O2 in flue gas. When limestone was added to the phosphorus emulsions, up to 100% removal efficiencies of both NO and SO2 could be achieved. The NO absorbed can be converted to ammonium, nitrite, and nitrate ions, whereas the P4 consumed can be recovered as a mixture of hypophosphite, phosphite, and phosphate. The stoichiometric ratios for NO removal by P4 (i.e., moles of P consumed per mole of NO removed) were measured to be 0.5 when bisulfite was absent and 0.8 when bisulfite was also present in the scrubbing liquor.