Storage Tank Emissions Calculation Tool

⚠ Errors have been identified that impact versions 21294 and earlier of the Storage Tank Emissions Calculation Tool.  A release date for a new version correcting the errors has not been set. The tool is not recommended for calculating emissions from Horizontal Storage Tanks. In emission calculations for vertical storage tanks, it is recommended to input throughput instead of the number of turnovers to avoid an error. See the linked errata for a more complete discussion.
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DEQ has developed a tool for estimating emissions from working and breathing losses from volatile organic liquid storage tanks. The tool is based off EPA’s updated AP-42 calculation method, which also replaces the outdated TANKS emissions estimation software. The new AP-42 method corrects errors for more accurate estimates.

You may use the tool below or download it as a standalone .zip file (Updated October 22, 2021). The tool opens in a compatible browser but does not require an internet connection. This release of the tool only includes calculations for fixed roof tanks. Floating roof tanks, landing, and cleaning calculations will be addressed in a future release. For any questions or comments, please contact Richard Kienlen / Phillip Fielder.

 

Release Notes
Version 21294 – Released October 22, 2021

  • Clarifying how to address flashing.  This includes considerations for tank which are manifolded together with a shared vapor headspace.
  • Added a tooltip regarding our current produced water policy.
  • Added additional flexibility for users manually entering liquid properties and using Antoine’s Equation coefficients.  The user may now enter coefficients based on various temperatures and pressures.
  • Included guidance for how to calculate speciated emissions after running the tool.
  • The output report clearly indicates when the user manually entered liquid properties.
  • Added the ability for a user to give a manually entered liquid a name.
  • Corrected several typos and added various minor clarifications.
Errata 2/21/2023

Oklahoma DEQ Storage Tank Emissions Calculation Tool

versions 21294 and earlier

Errata 2/21/2023

The following problems have been identified when using versions 21294 and earlier of the Oklahoma DEQ Storage Tank Emissions Calculation Tool:

  1. The calculation of the average daily vapor temperature range (ΔTV) is not executed correctly for Horizontal Storage Tanks.  This error affects the calculation of KE (vapor space expansion factor).
  2. The calculation of the average daily liquid surface temperature (TLA) is not executed correctly for Horizontal Storage Tanks.  This error affects the calculation of KE (vapor space expansion factor), PVA (true vapor pressure), TLN (average daily minimum liquid surface temperature), TLX (average daily maximum liquid surface temperature), PVN (vapor pressure at the average daily minimum liquid surface temperature), PVX (vapor pressure at the average daily maximum liquid surface temperature), and ΔPV (average daily vapor pressure range).
  3. The calculation of the average vapor temperature (TV) is not executed correctly for Horizontal Storage Tanks.  This error affects the calculation of WV (vapor density).
  4. The number of turnovers displayed during user input are not calculated correctly on the user input screen when the user enters tank throughput.  The number of turnovers is calculated correctly when calculating emission and does not affect the results.
  5. The throughput is not calculated correctly during user input when the user enters the number of turnovers.  This affects the throughput used for calculating emissions from a storage tank.  It is recommended to input throughput instead of the number of turnovers to avoid this error.

The Storage Tank Emissions Calculation Tool is not recommended for calculating emissions from Horizontal Storage Tanks.  At this time it is uncertain when a new version of the Storage Tank Emissions Calculation Tool will be released to correct these problems.