Utah refinery owner taking steps to prevent repeat of 2009 blast

11 April 2014 03:01 Source:ICIS News

HOUSTON (ICIS)--Silver Eagle Refining has taken numerous steps to better ensure safety at its Woods Cross refinery in the years following the 2009 explosion and fire at the facility, a company executive said late on Thursday.

The 2009 explosion and fire at the Silver Eagle Refining facility in Utah was caused by a corroded pipe and could have been prevented with better safety controls, the US Chemical Safety Board (CSB) said on Thursday.

Sulphidation in a 10in pipe at the bottom of a reactor in the mobile distillate dewaxing unit led to a massive release of hydrogen that caught fire and exploded, the CSB said in a metallurgical report put together for the agency by Texas-based engineering and scientific consulting company Exponent.

No one was killed in the blast and fire in the Utah town of Woods Cross, but more than 100 homes were damaged.

Four workers near the process unit at the time of the explosion were blown to the ground but were not seriously injured. Another worker had been taking readings next to the pipe that failed just one to two minutes before the release, the CSB said.

“The findings in the Exponent report are all too familiar: Mechanical integrity programs at refineries repeatedly primarily emphasise inspection strategies rather than the use of inherently safer design to control the damage mechanisms that ultimately cause major process safety incidents," said CSB chairman Rafael Moure-Eraso.

“This is the same syndrome we found in the Bay Area Chevron refinery fire of 2012 and the Tesoro refinery explosion and fire that killed seven in Anacortes, Washington in 2010,” he added.

Since the explosion, safety measures have been put in place in hopes of preventing such an accident, said Jerry Lockie, general manager, refining for Silver Eagle Refining.

Lockie said that, to the best of the company’s knowledge, Silver Eagle Refining has “addressed everything put forth by the CSB”.

The line that exploded “has been replaced and has been put on a regular inspection programme”, Lockie said.

The CSB said that an examination of the ruptured pipe segment and adjacent piping showed wall thinning had occurred due to sulphidation.

The elbow adjacent to the pipe segment that failed was noted to have had an original thickness of 0.719in, but a 2007 measurement of the elbow indicated a wall thickness of 0.483in, the agency said. The adjacent straight-run segment that failed was found to have a wall thickness as low as 0.039in, but there were no records of previous inspection, the CSB said.

The Woods Cross refinery currently processes yellow wax crude from Utah’s Uinta basin into ultra-low sulphur diesel (ULSD), Lockie said. The crude’s low sulphur content aids the effort to prevent sulphidation of lines, he said.

The November 2009 explosion was the second accident at the Utah refinery that year. On 12 January 2009, two refinery operators and two contractors were burned from a flash fire that occurred when a large vapour cloud was released from a storage tank that contained an estimated 440,000 gal of light naphtha, the CSB said.

Silver Eagle Refining is a part of Toronto-based private firm International Group, a leading wax producer. International Group purchased Silver Eagle Refining in June 2011, Lockie said.

By Jeremy Pafford