Innovative oxygen injection for emission reduction in cement kilns

The reduction of CO and NO
_x
from the cement process is a continued requirement for many cement manufacturers and often involves very expensive end-of-pipe pollution abatement solutions. The injection of highly reactive hot oxygen is a new approach that can be used to address lower emission requirements or complement under-performing existing solutions. The innovative oxygen lancing technology discussed in this paper is installed in the outlet of the kiln or calciner to address primarily CO from the system. Through careful excess oxygen reduction, the NO
_x
generated in the main burner can be lowered as well because resulting CO can be oxidized with the oxygen injection. The technology consists of a lance that preheats oxygen to very high temperatures and effectively mixes this relatively small oxygen flow at high speed into much larger flue gas streams. The paper introduces the injection of oxygen into a cement kiln to reduce CO slip from the combustion process and includes data from a cement plant where the technology was implemented for the first time to simultaneously reduce CO and NO
_x
.