Friday, October 25, 2019

LNG by Rail Suggestions

Earlier this week the DOT’s Pipeline and Hazardous Materials Safety Administration (PHMSA) published their notice of proposed rulemaking (NPRM) for authorizing the shipment of liquified natural gas (LNG) by rail. In that NPRM PHMSA specifically solicited comments on additional controls that could be added to the regulatory requirements proposed to increase the safety of the shipment of LNG by rail. In this blog post I will propose a number of those controls.

Application of HHFT Rules

A number of opponents to this NPRM and the PHMSA LNG by rail special permit have painted horrific pictures of the explosive results of accidents involving unit trains of LNG railcars. While the preamble to this NPRM provides a rebuke of the potential for explosive accidents, the experience with unforeseen safety consequences with crude oil unit trains should be fresh in the mind of regulators and emergency response planners. With that in mind it would seem prudent to include LNG rail shipments in the High Hazard Flammable Train (HHFT) requirements.

The administratively simplest way of doing this would be to revised the definition of High Hazard Flammable Train found in 49 CFR 171.8 by adding the phrase “, including Methane, Cryogenic Liquid, UN1972,” after the words “Class 3 flammable liquid” where ever that appears in the HHFT definition or the definition of ‘high hazard flammable unit trains’ in the same section.

Unfortunately, that would be a complicated solution due to the fact that the §174.310 operational requirements for HHFT pertain to the switch over from DOT 111 to DOT 117 railcars. Most of those railcar provisions clearly apply only to flammable liquids and would thus not affect LNG by rail operations. There is one exception §174.310(a)(4) that would need to be revised to read:

“(4) New tank cars. After October 1, 2015, tank cars manufactured for Class 3 flammable liquid use in a HHFT must meet:”

PRV Flaring

One of the concerns related to the shipment of LNG is that methane is a very powerful greenhouse gas and any emissions from the shipment of LNG could have a disproportionate effect on climate change. Opponents to this rulemaking will inevitably claim that this was not adequately addressed in the environmental impact portion of the preamble.

One way to address this issue would be require that the pressure relief devices required to be employed on these railcars be equipped with a flaring device. This would ignite the LNG being released and convert the methane emission to a CO2 emission. There is already such a requirement for DOT 107 specification railcars (49 CFR 179.500-12).

Pressure and Temperature Reporting

Since PHMSA recognizes that the implementation of rail shipments of LNG will require the construction of a new fleet of DOT 113 railcars, they should take the opportunity to bring safety measurement into the 21st Century. There are two key factors that should be monitored to ensure the safe shipment of LNG by rail; temperature and pressure. This is already recognized in the modification of the requirements in §179.319(d)(2).

Technology currently exists that allows for the real-time measurement, recording and reporting of these two parameters by electronic devices installed on the railcar. PHMSA should require DOT 113 railcars used to transport LNG to be equipped with such electronic pressure and temperature devices and communication between those devices and alarm systems installed in the controlling locomotive for the trains containing such railcars. This would allow train crews and emergency response personnel to have operational awareness of impending releases and would provide for appropriate pre-emergency response to those impending conditions.

PHMSA should envision requiring all hazmat railcars to have similar critical measurement capabilities, but that would require extensive and expensive refit requirements. Here, a new DOT requirement could be included in the early production of new railcars.

Moving Forward

The measures that I have proposed above would be relatively cost-effective measures that would increase the safety of the transportation of liquified natural gas by railcars.

No comments:

/* Use this with templates/template-twocol.html */