Transient puffs of trace organic emissions from a batch-fed waste propellant incinerator

Emissions data have been obtained from a waste propellant incinerator. The incinerator is a dual fixed hearth, controlled air incinerator equipped wit h acid gas and particulate scrubbing. "Puffing" has been evident in this wa ste propellant incinerator by spikes in the CO concentration. Transient puf fs of organics may travel down the combustion chambers and lead to stack em issions. The major conclusions from this study are that (1) transient puffs are formed due to the semi-batch feed nature of the combustion process (ca using a local oxygen deficiency) and high water content of the desensitized propellant; (2) in batch-fed combustors, puffs can contribute to most of t he organic emissions (which are relatively low) measured with US EPA sampli ng and analytical methods; (3) it is estimated that batch-fed combustion co ntributes up to 7-18 times more emissions than steady-state combustion will generate; (4) by applying dispersion analyses to determine the amount of o xygen deficiency in the flame zone, the combustion zone concentration of CO during batch-fed operation could be as high as 160,000 ppm, compared to a measured peak stack concentration of 1200 ppm CO; and (5) an organic sample is collected and averaged over at least a 2-h period that smooths out the transient peaks of organics emissions during batch-fed operation. For emiss ions that are associated with long-term potential health impacts, this is a n appropriate sampling method. However, if a compound has a short-term pote ntial health impact, it may be important to measure the time-resolved emiss ions of the compound. (C) 2001 Elsevier Science Ltd. All rights reserved.