2024 AIChE Annual Meeting
(173af) Study of Potential Environmental Impacts during Traffic Accidents Involving Vehicles Transporting Liquid Hydrocarbons
Authors
Based upon historical records of transported hazardous materials, it was found that 95% corresponded to hydrocarbons including crude oil, fuels, solvents and petrochemical feedstocks. Among these, around 30% corresponds to crude oil mainly transported from the east part of the country to the main refineries in north and central regions, whereas ~15% corresponded to gasoline. After application of a reported methodology for the preliminary evaluation of inherent hazard and potential risk, it was determined that gasoline and crude oil were also the substances that represent the greatest potential impact on the environment and the greatest risk in the social dimension. Thereby, crude oil and gasoline were used in the subsequent risk assessment.
Once the study case products were identified, the surrogate substances for the modelling in ALOHA® were selected. After minimization of the difference in the properties of interest (i.e. those used in spill, heavy-gas dispersion and pool fire models), it was found that local crude oil (i.e. Castilla crude oil) and gasoline could be adequately represented by using Cyclohexane, Ethylbenzene or n-Octane as surrogates. An alternative approach was also used by creating a new component in the data base with the properties of the studied hydrocarbons, but major issues occurred because ALOHA® do not allow to modify vapor pressure nor density of the materials. This generated a misprediction of spilled volume and of the evaporation rates during loss-of-containment events. This has been overlooked in previous studies and it is considered a major source of uncertainty when using ALOHA® for risk assessment. Finally, geographical information and data from a real truck accident was used to assess the goodness of the model. It was found that the software enabled to accurately predict some of impacts that occurred in the studied event. This indicate that the developed methodology and the use of ALOHA were suitable for conducting preliminary risk assessments and to develop contingency plans in the management of accidents involving transportation of liquid hydrocarbons.
References
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Jones, R., W. Lehr, D. Simecek-Beatty, R. Michael Reynolds. 2013. ALOHA® (Areal Locations of Hazardous Atmospheres) 5.4.4: Technical Documentation. U. S. Dept. of Commerce, NOAA. Technical Memorandum NOS OR&R 43. Seattle, WA: Emergency Response Division, NOAA. 96.
Bare, J. C. 2012. Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI), Version 2.1 - User’s Manual; EPA/600/R-12/554
Figure 1. Distribution of total number of transportations of liquid fuels in Colombia for 2018 and 2019