DEVELOPMENT OF AN IMPROVED NOZZLE FOR FLUE GAS HUMIDIFICATION

FLUE GAS HUMIDIFICATION DOWNSTREAM OF THE AIR PREHEATER PLAYS AN IMPORTANT ROLE IN ALL CALCIUM-BASED DRY SORBENT PROCESSES. FOR IN-DUCT SORBENT INJECTION PROCESSES, HUMIDIFICATION IS REQUIRED TO ACHIEVE THE DESIRED REACTION RATES BETWEEN THE SORBENT PARTICLES AND THE FLUE GAS SO2; FOR FURNACE SORBENT INJECTION, SUPPLEMENTAL SO2 CAPTURE IS POSSIBLE. HUMIDIFICATION ALSO IS THE MOST ECONOMICAL MEANS TO RESTORE ELECTROSTATIC PRECIPITATOR PERFORMANCE TO PRE-SORBENT INJECTION LEVELS. THE OBJECTIVE OF PHASE I IS TO DETERMINE THE TECHNICAL FEASIBILITY OF IMPROVING THE FLUEGAS HUMIDIFICATION PROCESS WITH THE LINEAR VARIABLE GAS ATOMIZATION (VGA) NOZZLE. THIS NOZZLE CAN PRODUCE MUCH FINER DROPLET SIZES THAN OTHER COMMERCIALLY AVAILABLE AIR ATOMIZING NOZZLES BECAUSE IT FORMS A MUCH THINNER LIQUID SHEET WHILE MAINTAINING RELATIVELY HIGH WATER FLOW RATES. IN ADDITION, UNLIKE ALL AXISYMMETRIC NOZZLES, THE LINEAR GEOMETRY OF THIS NOZZLE ALLOWS SCALE-UP WITH NO CHANGE IN ANY PARAMETER AFFECTING DROPLET SIZE. PHASE I IS DIRECTED TOWARD THE DESIGN, FABRICATION, AND TEST OF A PROOF-OF-CONCEPT LINEAR VGA NOZZLE. THE TESTS WILL CHARACTERIZE THE NOZZLE UNDER A VARIETY OF OPERATING CONDITIONS. A RANGE OF BOTH AIR AND WATER FLOW RATES WILL BE TESTED. THE NOZZLE SPRAY PATTERN WILL BE DOCUMENTED BOTHVISUALLY, WITH VIDEO CAMERA COVERAGE, AND ANALYTICALLY, WITHAN INSTRUMENT THAT MEASURES DROPLET SIZE AND VELOCITY DISTRIBUTION.