"Staged" combustion for low-NO/sub x/ calciners

This paper presents NO/sub x/ reduction theory for cement plants. From NO/sub x/ reduction theory, it is hypothesized that an in-line calciner that combines high temperature combustion and firing under the strongest possible reducing conditions (without staging air or staging fuel) results both in the simplest calciner configuration and in the lowest possible NO/sub x/ and CO emissions. This hypothesis is supported by actual NO/sub x/ and CO emissions results from several US cement plants.