Using a Novel Chemistry for Hydrogen Sulfide Abatement in Asphalt

摘要

Hydrogen sulfide (H_2S) is a safety and environmental concern to the petroleum industry. Vacuum tower bottoms (VTB) often contain high levels of H_2S that pose significant danger to individuals involved in its production and handling. While H_2S is removed from refined fuels by refinery processes, bottom of the barrel products such as VTB used for asphalt production do not receive additional processing to remove H_2S. Moreover, petroleum products exposed to temperatures above 300°F may generate additional H_2S from cracking of sulfur compounds inherent in the oil. H_2S concentrations can easily exceed 2% in the vapor space of asphalt storage tanks and pose a significant health and safety risk to exposed personnel. Local regulations may also limit asphalt production by capping H_2S emissions. The reduction of hydrogen sulfide in asphalt is therefore an important consideration that presents unique challenges. Its viscous nature, high storage temperatures and the propensity to continue to produce hydrogen sulfide are obstacles to the efficient scavenging of H_2S from asphalt blend components. Difficulties measuring H_2S content in asphalt safely and reproducibly compound the issue. This presentation discusses a novel chemical solution for the removal of hydrogen sulfide from asphalt in vapor and liquid phases as well as a reproducible method for measuring H_2S content. Data from independent laboratory evaluations, field trials, and commercial applications will be presented.