Incident Report

Subject:                   USA - Fire at Lemont refinery caused by Loss of Containment

Date of Email report:   Fri 01/11/2013 05:50

Report Detail:

A leak of combustible fluid from hot machinery is viewed as the likely cause of last week's fire at Citgo Petroleum Corp.'s refinery in Lemont, according to sources familiar with the investigation.  Workers found the leak while replacing a pump last Wednesday in the bottom section of a distillation unit at the refinery, which has total capacity of 174,500 barrels per day.  As the leak increased, workers sprayed water on the unit, which typically runs at about 650 degrees, hot enough to melt lead.  Despite the water spray, the fluid found an ignition source. The conflagration burned for three hours at the base of the VDU, causing heat distress to the supports. Up to six months of repairs are needed and refinery rates will be cut during the work by at least 40 percent, the sources said.  "It about burned that VDU up," one of the sources said. The blaze caused no injuries, but it damaged piping interconnecting the VDU with the refinery's crude distillation unit.   The CDU, the workhorse of the refinery, begins the refining process by breaking oil down into feed for all the other units in the plant.  The 75,000 bpd VDU is the first unit taking feed from CDU and is often seen as an extension of the crude unit.  The process of operating the CDU while bypassing the VDU, as Citgo plans to do at the Lemont refinery, is often compared to major surgery, and called "cutting out" the unit.

Unlike the CDU, which operates at or near atmospheric pressure, the VDU refines residual crude in a vacuum, boosting the yield of motor fuels from a barrel of oil.  Along with the CDU and the VDU, most of the refinery's other units, including the 69,000 bpd gasoline-producing fluidic catalytic cracker and 40,000 bpd coker were shut after the fire.  By last Friday, Citgo officials had their first good look at the damage from the fire.

The damage appeared to be heavy to the VDU and its supports. The piping connecting it with the CDU also appeared to be damaged.  It looked as if the refinery wouldn't be able to refine crude for up to six months while repairs were under way.  Over the weekend, however, further inspection showed the CDU could likely resume production at a reduced rate, with the VDU cut out for up to six months of repairs.  How much of a reduction depends on the refinery's configuration.  The cut in production, will be more than the 75,000 bpd capacity of the VDU, the sources said.  The refinery's 40,000 bpd delayed coking unit won't be able to take the residual crude from CDU as it is already processing near its capacity. Residual crude coming from the CDU will have to be sold to other refiners.  Citgo may also have to shift to a different crude oil for the refinery, which currently processes heavy crude from Canada's tar sand fields, to reduce producing more residual crude. 

Additional Documentation:

Citgo Fire Aug 2001 Showing Vac tower Collapse…