Abstract
The release of xylene isomers from storage tanks poses a significant threat to petrochemical industries, and their safe transportation and storage is a widely researched topic. This paper focused on modeling the environmental, health, and safety effects of P-xylene and O-xylene leakage from storage tanks via Areal Locations of Hazardous Atmospheres (ALOHA) and Wireless Information System for Emergency Responders (WISER). The meteorological data of the area, characteristics of the tanks, and the roughness of the land surrounding the tanks were used to run the ALOHA model. The dispersion distances of P-xylene and O-xylene toxic and flammable vapor clouds were estimated according to the Immediately Dangerous to Life or Health (IDLH) and lower explosive limit (LEL) criteria. Also, the levels of thermal radiation due to the burning of P-xylene and O-xylene were estimated. The results showed that in the cold seasons, the IDLH was a maximum distance of 62 m and 45 m for P-xylene and O-xylene, respectively. The LEL criteria were 10% with a magnitude of 1100 ppm for a maximum distance of 54 m and 35 m for P-xylene and O-xylene, respectively. The maximum distance of 20 m for O-xylene based on the results of the LEL criteria of 60% (6600 ppm) was attained in the warm seasons. They are potentially lethal within 60 s at 21 m (10.0 kW/m2) when burned. The WISER software predicted the protective distance for xylene isomers to be about 300 m. The results show that creating a protective zone around the P-xylene and O-xylene tanks with a radius of 54 m is necessary to reduce hazards.
Introduction
The introduction highlights the hazards of xylene isomers (ortho-, and para-xylene), commonly used in petrochemical industries. It emphasizes their toxic, flammable, and volatile nature and the importance of assessing emissions from storage tanks. The study aims to model the environmental, health, and safety impacts of xylene emissions using risk assessment and simulation tools.
Materials and Methods
This section explains how emission modeling was performed using software tools like ALOHA. It describes the storage tank conditions, meteorological data, chemical properties of xylene isomers, and how exposure risk zones (thermal radiation, dispersion, and toxicity) were calculated. Health risk assessments were conducted based on inhalation exposure and regulatory thresholds.
Results and Discussion
Simulation results show the differences in behavior and impact zones among the two xylene isomers under warm and cold conditions. Health risk assessments identified areas with unacceptable risk levels. The discussion highlights seasonal variations, dispersion patterns, and the differences in outputs between modeling tools.
Conclusions
The study concludes that xylene emissions pose significant safety and health risks, especially in warmer seasons. Regular monitoring and improved tank management are recommended for safety enhancement.