Canada refinery explosion and fire caused by corroded pipe

17 August 2012

Scott Banda, CEO of Federated Co-operatives Limited, told reporters on August 16 that his company accepted the results of the investigation into the explosion at the Co-op Refinery Complex in Regina, Sakatchewan, last October, which injured 52 people and caused $100 million in property damage and production loss.

The October 2011 refinery explosion caused 52 injuries

One pipe ruptured in an overhead pipe rack in a diesel processing area called the Middle Distillate Unifier (MDU). The failure resulted in a 7.5 inch long rupture in the six-inch diameter reactor effluent line, triggering an explosion, fire and subsequent explosions. The fire-damaged area was 90 feet by 130 feet or less than half an acre within a complex covering almost 640 acres.
Banda said the company regretted the incident and apologised to the citizens of Regina. With respect to the corroded pipe, he said thinning of the wall was detected when the 20-foot pipe was inspected in 2010.
"Corrective actions were taken in terms of replacing some pipe, decisions were made and the protocols were followed as to how far those went. In short, something was missed," he said.
Since the fire and explosion, Banda noted the company's "outstanding safety record," but added that "clearly we can do better." Since the incident, he said the company has improved its inspection procedures because "this is not something we ever want to have happen again."
The explosion happened in the early afternoon with about 400 refinery employees and 1,000 contractors working in the area. The contractors were working on a $1.9-billion renovation and expansion of the refinery, located in north Regina. Injuries included burns, smoke inhalation, minor bruises, sprains and abrasions.
Gerard Kay, deputy fire chief for the City of Regina, explained that a six-inch-diameter reactor effluent line carrying hydrogen gas, hydrogen sulphide and diesel fuel suffered a "catastrophic failure" when a 7.5-inch breach occurred due to wall thinning from internal corrosion. The leaked contents caused the explosion when encountered with multiple ignition sources and "hyper static electricity," said Kay. The fire caused four other hydrogen lines to breach, resulting in more explosions.
Besides the effect of chemicals passing through the pipe, corrosion was enhanced when a heat exchanger was cleaned in 2008, which caused the temperature of the substance to increase by about 10 C. Normally, the substance is about 177 C, said Mark Simpson, superintendent of equipment integrity and engineering for the refinery. He estimated the pipe was installed in 1961.
The fire damaged an 11,700-square-foot area of the refinery, including the compressor building and the processing area where the explosion occurred. Piping has been replaced in the area or deemed to be in good condition.
Prior to the explosion, 42,000 litres of diesel was being produced a day. As a result of the incident, the company lost 20% of its diesel production. Banda said he doesn't expect the two processing units that were affected by the explosion to be operational until November.
On May 15, another fire broke out at the refinery when an oil pump overheated and ignited crude oil, setting a building on fire. The incident caused $5 million in damage.