Abstract: The invention is a method for removing sulfur oxides, nitrogen oxides and particulate from the products of combusted carbonaceous fuels. Sulfur oxides, nitrogen oxides and particulate are currently discharged to the atmosphere as flue gas in quantities highly detrimental to the environment. Potassium compounds, as are found in agricultural grade potash, are dispersed throughout the combustion products at the exit of the combustion zone of boilers. The potassium compounds decompose as a result of combustion temperatures in excess of their melting points. The potassium, as an ionic vapor, reacts with the sulfur and nitrogen oxide gases present, to form potassium sulfates, potassium nitrites and potassium nitrates. When the combined products stream, tranversing the boiler equipment train, cool sufficiently, the potassium, present in excess, condenses as potassium oxide on the surfaces of the particles present.

Abstract: A method of desulfurizing carbonaceous fuel, such as coal and oil containing sulfur. The fuel is ignited in a boiler combustion zone and a saturated solution of potassium carbonate and potassium hydroxide is sprayed into the flue gas stream immediately downstream of the boiler combustion zone at a sufficiently high temperature to volatilize said sprayed solution to an ionic form. In the presence of excess oxygen at a temperature in excess of 1315.degree. C., the sprayed flue gas combines to form potassium sulfate particulates which are collected and removed dry, along with flyash particles, by mechanical or electrostatic precipitator equipment from the flue gas stream. The insoluble ash is separated from the soluble potassium sulfate by water elution. The solubilized potassium sulfate is separated by ion exchange mechanisms with the potassium, as potassium hydroxide, being recycled to the head of the system and the sulfate being reacted to form ammonium sulfate.