Lowering NOx and SO2
There are several options for reducing NOx and SO2 in the cement pyroprocess. However, the solution selected must be both cost-effective and flexible in terms of raw materials, fuels and operating conditions. Making the correct choice requires the necessary process know-how and advanced technical solutions to handle NOx and SO2 emissions at all levels. FLSmidth is one of the few companies to offer both. Lars Schultz explains.
Reducing NOx and SO2 can be attained through primary or secondary measures – the former entailing process optimisation and the latter injection of a reducing agent. A further option is to combine the two measures. For example, one can adjust the calciner feed split or the kiln operating parameters and thereby save on the expensive ammonia for NOx reduction. Or one can increase the kiln inlet oxygen level to remove SO2 in the kiln bypass and minimise the consumption of hydrated lime.