Applications of dynamic simulations in the process industries : a safety case study using Texas City refinery explosion

Isimite, Joseph Ogochukwu

Abstract

Although process safety performance in petroleum refineries is much better today compared to several decades ago, major accidents still occur occasionally. The explosion and fires at Texas City refinery on 23 March 2005 is regarded as one of the worst industrial accidents in US history to date. Dynamic process simulation provides an effective means to collect, collate and analyze data from previous incidents and offer recommendations of good practice to further improve process safety outcomes.

A simulation of the sequence of events that led to the catastrophic explosions at Texas City refinery is presented in Aspen HYSYS. An initial steady state simulation of the operation of the raffinate splitter column at Texas City forms the basis for a subsequent dynamic simulation of the filling of the distillation column from 0213hrs until 1313hrs when the explosion occurred. A PID (proportional, integral, derivative) control scheme is implemented with appropriate tuning parameters.

The dynamic simulation of the overall tower filling dynamics from 1000hrs to 1320hrs when the explosion occurred revealed that the feed to the column vaporised at approximately 1310 hrs. This happened as a result of the additional heat input into the column through the feed-product heat exchanger. Subsequently, thermal expansion of the liquid in the column led to the filling of the overhead vapour line with hydrocarbon liquids and an increase in pressure as a result of the hydrostatic liquid head. Flammable hydrocarbon vapours subsequently flowed from the overhead line through the collection headers into the blowdown drum. An alternative accident pathway is presented as the basis for a quantitative hazard and operability study, HAZOP.

Citation

Isimite, J. O. (2014). Applications of dynamic simulations in the process industries : a safety case study using Texas City refinery explosion. (Thesis). University of Hull. Retrieved from https://hull-repository.worktribe.com/output/4216872

• Thesis Type: Thesis
• Deposit Date: Aug 6, 2015
• Publicly Available Date: Feb 23, 2023
• Keywords: Engineering
• Public URL: https://hull-repository.worktribe.com/output/4216872
• Additional Information: Department of Engineering, The University of Hull
• Award Date: Nov 1, 2014