PRECESSING JET BURNERS FOR STABLE AND LOW NOX PULVERIZED FUEL FLAMES - PRELIMINARY-RESULTS FROM SMALL-SCALE TRIALS

A new technique for stabilising pulverised coal flames for rotary kiln s was demonstrated at 150 kW scale in a model kiln using a burner cons isting of a central precessing air jet nozzle and an outer annular coa l transport channel. Effective flame stabilisation was achieved by the influence of the precessing air jet on particle trajectories resultin g in a reduction in ignition distance by a factor of three compared to a mono-channel burner. A corresponding reduction in CO emissions from 810 to 190 ppm (0% O-2 basis) and an increase in carbon burnout from 84 to 92% were achieved without any increase in NO, emissions, which w ere in the region of 85-100 ppm (0% O-2). (C) 1998 Elsevier Science Lt d. All rights reserved.