PHA guidance for correlating H2S concentrations in process streams to severity of adverse health outcomes in the event of a leak

Abstract

Process hazard analysis (PHA) teams are responsible for determining and categorizing the potential impact of a loss of containment. For streams containing hydrogen sulfide (H₂S), the health and safety consequences of a worker being exposed to H₂S are a function of airborne concentration in the breathing zone and duration of exposure. PHA teams often do not have the technical knowledge to link the known concentration of H₂S in the process stream to an adverse health outcome. This paper describes the methodology and the assumptions made in developing such guidance. H2S concentration in the stream was correlated to concentration of H2S in the breathing zone. Vapor releases used dispersion modeling, while liquid releases required additional modeling to determine the amount of H2S liberated from the released liquid. Modeling was done on different process streams under a variety of conditions. Concentration in the breathing zone was linked to the most probable health and safety outcome by surveying relevant literature published by private and government sources. This correlated the stream concentration of H2S directly to the consequence categorization used in the PHA. Results were summarized, providing simplified guidance that is valid over a wide range of process conditions and release scenarios.

Risk Analysis H2S And NH3 Exposure to Local Community Around Benowo Landfill Surabaya

“…Health effects are contingent upon the duration of exposure to the gas concentration. [13] A concentration of 0.06 ppm of H2S has led to respiratory disturbances among the community near the Tanjung Pinang Landfill [14].…”

Safety distances for the sour biogas in digestion plants

“…The causes of biogas releases are generally attributed to equipment failure, component failure, and operational error, whereas fire and explosion scenarios are mainly related to maintenance or design errors [12]. Once released, the presence of a toxic compound in gaseous mixtures requires proper comparisons between H2S concentration and toxicological endpoints, especially in the areas where personnel may be present [13]. Besides, the flammability of the H2S/air mixture requires proper investigations on accidental scenarios generated by the presence of an ignition source.…”

Evaluación de la remoción de sulfuro de hidrógeno de biogás empleando arcilla ecuatoriana modificada con sodio, zinc y cobre y adaptada morfológicamente

“…Para aprovechar la ventaja competitiva de utilizar el biogás, es necesario reducir su contenido de H2S hasta niveles que aseguren la salud, la infraestructura y el medio ambiente [9], [10]. Actualmente, existen tecnologías eficientes para la purificación de biogás de tipo fisicoquímico, pero presentan altos costos de adquisición y de operación [11], [12].…”