ENV-15-5 Air Permitting Impacts of New Emissions Estimation Techniques for Heater and Hot Product Storage Tanks

Description:

With more widespread use of remote sensing techniques, such as thermal infrared cameras, by EPA and other state regulatory agencies to quantify fugitive VOC and HAP emissions from various refinery source types, evaporative losses from fixed roof storage tanks that are externally heated or store a hot petroleum product have been receiving increasing levels of attention and scrutiny. In a recent Federal Register notice, EPA even solicited comment on adding VOC and HAP emissions from organic liquid storage tanks to its list of fiscal year 2017-2019 National Enforcement Initiatives under the category of “Protecting Communities from Exposure to Toxic Air Emissions.”1 For many years, the TANKS software program distributed and supported by EPA has been the default approach for implementing the emissions estimation techniques in AP-42 Chapter 7.1 for Organic Liquid Storage Tanks. However, EPA has recently abandoned its efforts in maintaining the TANKS v4.09D software and now recommends the direct use of equations/algorithms specified in AP-42 Chapter 7.1. Switching from TANKS embedded routines for handling heated and hot product tanks to other approaches derived from applicable AP-42 algorithms (such as custom spreadsheet-based tools or TankESP software developed by Rob Ferry of TGB Partnership) can have significant impacts on emissions. Coupled with the poor characterization of vapor pressure and other properties of heavy petroleum liquids commonly stored in heated/hot product tanks, implementing EPA preferred emission calculation methods can cause unforeseen air permitting issues for this subcategory of refinery storage tanks. Using actual examples of representative heated and hot product tanks at a refinery, this paper will demonstrate how new petroleum stock property characterization techniques implemented with new emissions estimation techniques can introduce retrospective and future air permitting challenges.