WEECO INTERNATIONAL CORPORATION

WEECO INTERNATIONAL CORPORATION (WI)

The World Leader in Vapor Recovery and Degassing

Typical Degassing Operation:

Unocal Beaumont Terminal,

April 1, 2003

Crude Oil Tank - 150’ Diameter x 48’ Height, on 8.2’ Legs

Weeco International (WI) arrived at the job site with 2 units (containing a total of 4 engines) at

2:30 pm to degas a Unocal crude oil tank. Texas’ TCEQ regulations call for a four-volume sweep of the tank vapor space below the floating roof or the reduction of hydrocarbon concentration in the vapor space to 34,000 ppmv (measured as methane). After a safety meeting and the installation of a 33-inch degassing manway adaptor, WI linked the tank vapor space to the degassing units parked outside of the firewall with degassing hoses and began degassing the tank at 3:15 pm. Initial tank vapor readings were at 100% LEL (equivalent to 53,000 ppmv methane). Degassing was stopped at 10:15 pm when the tank vapor space had been swept 4.47 times. Because the tank had been well stripped prior to degassing, final tank hydrocarbon concentrations were able to be lowered to 5,300 ppmv (measured as methane) in 7 hours.

Degassing Operation During Product and Sludge Removal:

Equistar Chemical LP, March 13–

March 28, 2003

Gas Oil Tank – 160’ Diameter x 48’ Height, on 6’ legs

Weeco International (WI) was called to assist Equistar during a product and sludge removal operation. The purpose of the project was to minimize VOC emissions into the atmosphere, to keep the tank vapor space under a nitrogen atmosphere, and to degas the tank by burning vapors. With help from Equistar personnel, WI attached 350 ft. of degassing hoses from Weeco’s degassing engine unit to the top of the floating roof of the tank. Initial hydrocarbon concentrations below the floating roof were well over 1,000% LEL. The WI crew continued to degas the tank as it was initially stripped, then water washed, and finally washed with surfactant. The degassing rate was controlled between 100 cfm to 400 cfm as needed while the nitrogen injection was kept at slightly lower rates to keep the tank under negative pressure. Final hydrocarbon concentration readings were approximately 15% LEL when WI was instructed to shut down by the Equistar representative.

Combustion of VOC Vapors During Plant Turnaround:

Nova Chemical Company, August 31 – September 5, 2003

During the initial stages of this styrene plant turnaround, residual products in the columns, vessels, other process units and piping were drained or purged into the chemical sewer (process drain system). Weeco connected three dual engine units to five strategically selected locations in the chemical sewer system, pulled vapors and combusted them. The objectives of the degassing operation were to minimize VOC emissions to the atmosphere and to minimize potential vapor locks in the chemical sewer, thereby enhancing flow of fluids to the API separators. The operation started with all three units but after two days one unit was taken off because of reduced vapor loads. The plant did not experience a single atmospheric hydrocarbon alarm while the Weeco units were in service. In the previous years when carbon canisters were used there were frequent alarms that required operators wearing full-face masks. As a result the purge phase of the turnaround was shortened to 5 days vs. 7 days planned.