• Experienced H2S regeneration after adding PPA to asphalt
  • Increased hazardous exposure to H2S and safety code violations
  • Continued desire to use PPA modifiers
  • Mitigated H2S to 0 ppm after initial application to asphalt
  • Reduced H2S regeneration beyond target rates after PPA was added to asphalt
  • Avoided additional HSE risks and safety violations

Case study details

An asphalt terminal in the United States was experiencing issues with hydrogen sulfide (H2S) regeneration when a polyphosphoric acid (PPA) modifier was added to their asphalt product. Though the terminal had a scavenger program in place for H2S abatement, it was not controlling the H2S regeneration problem. This triggered an increase in H2S alarms at the loading area, and violated the terminal’s internal safety regulations. It also put employees at risk of exposure to H2S. The terminal was faced with the choice of either discontinuing their use of the PPA asphalt modifier or finding an alternate chemical H2S scavenging program that could effectively mitigate PPA-based H2S regeneration and help keep their plant personnel safe. They chose to find an alternate chemical scavenger treatment and reached out to Baker Hughes for help.

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