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Show AFRC 2013 INDUSTRIAL COMBUSTION SYMPOSIUM Safe and Responsible Development in the 21st Century Sheraton Kauai, Hawaii, September 22-25, 2013 Special Colloquium* All Talk and No Do! Why No Reported Successes in Optimizing Industrial Flare CEs and DREs by Automatic Control to the Incipient Smoke Point? Led by Jim Seebold - Chevron (Ret); AFRC 2013 General Chairman ¡¡Talking Points Only !! OPTIMIZING FLARE DESTRUCTION EFFICIENCY Recent Successes in Implementing Automatic Control to the Incipient Smoke Point Evaluate the viability and reliability of utilizing an infrared smoke detector to maintain flare operation at the "incipient smoke point", a point that has been demonstrated through third-party pilot-scale test programs to be the highest point of combustion efficiency. If an infrared smoke monitor could provide this range of operation with a high level of accuracy, it was hoped that it could be tuned to assist in keeping the steam at the incipient smoke point, as this point is believed to produce the highest combustion efficiency for flare operation.1 The most consistently high combustion efficiencies appeared to be near the incipient smoke point. For the conditions tested, the highest DRE and CE were achieved at or near the incipient smoke point.2 For the conditions tested, the highest DRE was achieved at or near the point when smoke first appeared (incipient smoke point).3 For the conditions tested, the highest DRE and CE were achieved at or near the incipient smoke point. The most efficient operation, as measured by the DRE and CE, was achieved at or near the incipient smoke point.4 The correlation between a flare operating at the incipient smoke point and good combustion efficiency has been enumerated throughout the literature.5 Surprising to most flare operators though, the best DRE was achieved at or near the incipient smoke point (i.e., at the operating point at which the minimal amount of air or steam assist is needed to prevent visible emissions).6 The highest DRE occurs when the flame is at or near the incipient smoke point, which occurs when the quantity of added steam or air is slightly greater than the amount where the flare smokes. At this point, steam emissions from the flare are not visible but the flame is visible, often yellowish or orange. With this new understanding, as flare operators now try to operate closer to the incipient smoke point to minimize VOC emissions, flares may have a bright orange or yellow flame and occasional wisps of smoke.7 A flare with a good visible flame and smoke at the point that it first becomes visible (at its "incipient smoke point") destroyed 99.4% of the test gases vented to it.8 For the conditions tested, the highest DRE and CE were achieved at or near the incipient smoke point.9 AFRC 2013 INDUSTRIAL COMBUSTION SYMPOSIUM Safe and Responsible Development in the 21st Century Sheraton Kauai, Hawaii, September 22-25, 2013 A flare operating slightly above the incipient smoke point appears to be in an ideal range for higher levels of combustion efficiencies, but current regulations do not allow smoking flares. In fact, these regulations provide, at least in part, a driver for the use of more steam than optimal from an efficiency standpoint.10 The efficacy of the concept of introducing a control system that would keep flare operation just above the incipient smoke point to ensure high near-optimal combustion efficiency is amply supported by the landmark studies of both past and present. That a smoking flare is often the most efficient flare remains a perhaps inconvenient truth. Smoking flares are not inefficient, only illegal.11 _____________________________ *Colloquium, n (Ancient Greece) A drinking party at which ideas were freely exchanged. Following the scheduled conclusion, those interested will continue the colloquium in more convivial surroundings... 1 http://www.tceq.texas.gov/assets/public/implementation/air/rules/Flare/2010flarestudy/mpc-txc.pdf 2 http://www.awma-gcc.org/docs/2011_10_Flare_Issues.pdf 3 http://www.deerparkcac.org/uploads/DPCAC_flaring_presentation_11-28-11_EHCAP.pdf 4 http://www.cleanairinfo.com/regionalstatelocalmodelingworkshop/archive/2012/presentations/Friday/9-4_TCEQ_Modeling_Update_20120504.pdf 5 http://www.epa.gov/airtoxics/flare/2012flarepeerreviewmemo.pdf 6 http://www.zephyrenv.com/currents_archive/4Q11_currents.pdf 7 http://www.ehcma.org/files/DDF/Volume_5_Fall_2011.pdf 8 http://www.deerparkcac.org/uploads/DPCAC_web_mtg_summary_11-28-11.pdf 9 http://www.tceq.texas.gov/assets/public/implementation/air/rules/Flare/Presentation_2010FlareStudy_PreliminaryResults_Accessible.pdf 10 http://www.tceq.texas.gov/assets/public/implementation/air/rules/Flare/06012011/TxOGA.pdf 11 http://www.tceq.texas.gov/assets/public/implementation/air/rules/Flare/06012011/James_Seebold.pdf |
