An experimental study of NO{sub x} recycle in the NOXSO flue gas cleanup process. Quarterly technical progress report, April 1--June 31, 1992

NO{sub x} recycle is one part of the NOXSO process. In this process, 90% of the acid pollutants (NO{sub x} and SO{sub 2}) can be removed simultaneously by adsorption on the surface of a sorbent material. The sorbent is subsequently regenerated by heating and contacting the hot sorbent with a reducing gas followed by steam. The NO{sub x} is removed in the heating process, and the SO{sub 2} is removed by the chemical reaction of the reducing gas and steam. The NO{sub x} stream produced is returned to the combustion process with combustion air, which is called the NO{sub x} recycle. The NO{sub x} is reduced in the flame to N{sub 2}, H{sub 2}O, and CO{sub 2}. The tests of NO injection with combustion have demonstrated very promising results. The test data showed quite consistent NO{sub x} reduction efficiencies, which is similar to the previous test results on the pulverized coal combustor at DOE-PETC. An average of about 70 % NO. destruction efficiency was achieved for the NO injection into the primary air duct independent of injected NO flow rates and exit 02 concentrations. About 58%, 50%, and 46% average destruction efficiencies were obtained for the NO injection into the secondary air duct corresponding to the exit O{sub 2}concentrations of 2%, 3%, and 4% respectively