The Elimination of Oxides of Nitrogen from the Exhaust of a Diesel Engine Using Cryogenic Air Separation

Abstract

The high temperatures associated with combustion in diesel Engines produce oxides of nitrogen as a pollutant. Under the Clean Air Act, it is desirable to eliminate both the oxides of nitrogen and particulate matter from diesel engine exhaust gasses. This paper presents a method for eliminating oxides of nitrogen from the exhaust stream by eliminating the nitrogen from the incoming air entering the engine. The proposed cycle for a cryogenic separation system that separates the oxygen and heavy inert gasses from nitrogen in the air is discussed. Much of the power needed to operate the cryogenic separation plant would come from the heated exhaust gas stream from the engine. Since there is almost no nitrogen in the incoming oxidizer stream, the engine can be run much leaner to reduce carbon monoxide, hydrocarbons, and particulate emissions from the engine exhaust stream.