| OCR Text |
Show CONCLUSIONS In this study, HAP and OP emissions, specifically VOCs, were measured in a scaled, generic, natural gas-fired, low-NOx burner, operating under lean burn conditions. The results suggest evidence of unburned fuel, pyrolytic dehydrogenation of alkanes into alkenes and alkynes, synthesis of aromatics, and oxidation of aliphatics into aldehydes. The emission concentrations the individual VOCs were generally low (< 100 ppbv), except under certain conditions which generated much higher total VOC levels (2-118 ppmC). In order to address concerns regarding the release of HAPs and OPs from stationary combustion systems, a previously defined performance function was modified to include cost functions for HAPs, based on annual mass emissions of HAPs, and for OPs, based on their ozone forming potentiaL Using this modified performance function, an optimal set of conditions was found (at low S' and high V for this burner) for which NOx, CO, and VOCs are rninimized and performance is maximized. These results suggest that by identifying and mamtaining a natural gas-fired system within a region of optimum performance, crucial regulatory concerns with respect to HAP and OP emissions can be avoided. Indicator species for HAPs and OPs may play an important role in optimizing performance. The data show a positive correlation between VOCs, CO, and THCs, suggesting that CO and THCs could potentially serve as surrogates for VOC emissions under lean burn conditions. J 21 |
