(77b) Improving Mass Balance Data Quality for Process Unit Optimization

In response to high profile train incidents earlier in the decade (such as the Lac Megantic incident, which was presented at the 2016 GCPS), PHMSA issued Final Rule HM-251 which established new rules concerning the transportation of certain “high hazard flammable trains” or HHFTs to reduce the risk of transporting these materials. The Final Rule was issued in May 2015 and created, in part, new requirements for the design of tank cars intended to replace the ubiquitous DOT-111 and operational rule changes. DOT-111 tank cars were historically used to transport crude oil and ethanol, among other flammable liquids. HM-251 defined new rail tank cars types, the DOT-117, DOT-117R, and DOT-117P – coupled with the phase out of the approximately 100,000 DOT-111 rail tank cars that had been in service for decades. Nearly 5 years after the rule, all crude oil transport has been phased out of DOT-111 rail tank cars as per HM-251 (ethanol phase-out is schedule for 2023). In this paper, we look at the history of transport of flammable materials in the DOT-111 which includes notable historical incidents, historical transport capacities, and key design features. We then contrast the design of the DOT-111 with the new DOT-117x rail tank cars, and then focus on a deep dive into the historical accident statistics of the DOT-111s and compare them against the recent data generated from the DOT-117x rail tank car accident data. Through this discussion, we will benchmark and evaluate the risk reduction accomplished through implementation of HM-251.