1 / 22

Implications of AERMOD on a Chemical Plant

Implications of AERMOD on a Chemical Plant. William B. Jones Roger P. Brower Zephyr Environmental Corporation Columbia, Maryland Presented at 100 th Annual AWMA Conference and Exhibition Pittsburgh, PA June 26, 2007. Outline of Presentation. Background on project Comparative Modeling

terrence
Download Presentation

Implications of AERMOD on a Chemical Plant

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Implications of AERMOD on a Chemical Plant William B. JonesRoger P. BrowerZephyr Environmental CorporationColumbia, Maryland Presented at 100th Annual AWMA Conference and Exhibition Pittsburgh, PA June 26, 2007

  2. Outline of Presentation • Background on project • Comparative Modeling • ISC3 • AERMOD • Conclusions

  3. Background on Project • Chemical plant in southwestern Louisiana • Several permitting efforts required modeling over the past few years (modeling done with ISC3) • November 9, 2006: AERMOD replaced ISC3 as preferred dispersion model • Chemical plant was curious as to what effect going from ISC3 to AERMOD would have

  4. Three projects examined • Vinyl Acetate • Modeling performed in 2005 • In support of Title V application for Plant’s polyethylene manufacturing complex • Butadiene • Modeling performed in 2003 • In support of revised Title V application for Plant’s ethylene/styrene manufacturing complex • PM10 • Modeling performed in 2003 • In support of “retroactive” PM10 NAAQS and PSD Increment modeling

  5. Comparative ModelingVinyl Acetate • Original ISC3 modeling • Initially only Plant sources, then offsite sources • Flat terrain (no receptor elevations) • Meteorological data from 2004 (Lake Charles surface and upper air) • AERMOD modeling • Plant sources only • Flat terrain (no receptor elevations) • Meteorological data from 2004 (Lake Charles surface and upper air) processed using AERMET • Bowen Ratio, Albedo, and Surface Roughness Lengths assumed constant for entire area

  6. LDEQDefault Meteorological Values Taken from “Developing State-Wide Modeling Guidance for the Use of AERMOD, A Workgroup’s Experience” (Presented at 2005 Louisiana AWMA Fall Conference)

  7. Comparative ModelingVinyl Acetate: ISC3 Results

  8. Comparative ModelingVinyl Acetate: AERMOD Results

  9. Comparative ModelingVinyl Acetate: Q-Q Plot, AERMOD and ISC3

  10. Comparative ModelingVinyl Acetate Observations • Highest contributing source is same with ISC3 and AERMOD • Highest source-specific impacts for each model roughly the same • AERMOD consistently over predicts relative to ISC3 (for highest 8-hr concentrations)

  11. Comparative ModelingButadiene • Original ISC3 modeling • Initially only Plant sources, then offsite sources • Flat terrain (no receptor elevations) • Meteorological data from 2000 (Lake Charles surface and upper air) • AERMOD modeling • Plant sources only • Flat terrain (no receptor elevations) • Meteorological data from 2000 (Lake Charles surface and upper air) processed using AERMET • Bowen Ratio, Albedo, and Surface Roughness Lengths assumed constant for entire area

  12. Comparative ModelingButadiene: ISC3 Results

  13. Comparative ModelingButadiene: AERMOD Results

  14. Comparative ModelingButadiene: Q-Q Plot, AERMOD and ISC3

  15. Comparative ModelingButadiene Observations • Major contributing sources in ISC3 are not consistent with those in AERMOD • Highest source-specific impacts for AERMOD are higher (roughly an order of magnitude) than ISC3 • AERMOD consistently over predicts relative to ISC3 (for highest annual concentrations)

  16. Comparative ModelingPM10 • Original ISC3 modeling • Initially only Plant sources, then offsite sources • 24-hr and Annual NAAQS and PSD Increment • Flat terrain (no receptor elevations) • Meteorological data from 1996-2000 (Lake Charles surface and upper air) • AERMOD modeling • Plant and offsite sources • 24-hr NAAQS only • Flat terrain (no receptor elevations) • Meteorological data from 1996-2000 (Lake Charles surface and upper air) processed using AERMET • Bowen Ratio, Albedo, and Surface Roughness Lengths assumed constant for entire area

  17. Comparative ModelingPM10: ISC3 Results (1996)

  18. Comparative ModelingPM10: AERMOD Results (1996)

  19. Comparative ModelingPM10: Q-Q Plot, AERMOD and ISC3 (1996)

  20. Comparative ModelingPM10 Observations • Major contributing sources in ISC3 are consistent with those in AERMOD • The two Plant sources in the Top 5 for ISC3 and AERMOD only had increases in their predicted 24-hr concentrations of 20% and 12% going from ISC3 to AERMOD (larger increases from offsite sources) • Highest source-specific impacts for AERMOD are higher than ISC3 • AERMOD and ISC3 are consistent in lower concentrations (AERMOD sometimes slightly lower), but at higher concentrations AERMOD over predicts relative to ISC3 (for highest second-high concentrations)

  21. Conclusions • Examined vinyl acetate, butadiene, and PM10 modeling • AERMOD nearly always predicted higher concentrations than ISC3 • For some lower PM10 concentrations AERMOD slightly under predicted relative to ISC3 • Plant should exercise caution in future permitting efforts that involve updated previous dispersion modeling analyses

  22. Contact Information Zephyr Environmental Corporation 10420 Little Patuxent Parkway, Suite 320 Columbia, Maryland 21044 Bill Jones 410-312-7910; bjones@zephyrenv.com visit us at www.ZephyrEnv.com and www.HazMatAcademy.com

More Related