Trans Mountain and its Westridge Marine Terminal contractor recently planned and executed the relocation of the Vapour Combustion Unit (VCU) and corresponding systems at Westridge.

The relocation of the VCU earned the contractor, Kiewit Ledcor Trans Mountain Partnership (KLTP), its first mechanical completion certificate and is a major milestone for early works at Westridge.

What’s a VCU?

When oil is pumped into tanker ships during loading, vapours are produced. As the oil rises in the cargo hold, vapours are expelled from the tanks. These vapours are captured and destroyed in the VCU.

Where did the VCU move?

The VCU was moved 130 metres east of its original location to create room for the foreshore expansion of Westridge Marine Terminal.

Who did the work?

The execution of the relocation was a complex 13-day operation that required six months of planning. The move was carried out by a team of 45 people — major disciplines involved in this scope of work included civil, concrete, electrical and piping. Trans Mountain’s operations team supported the contractor with the startup of the unit once the work was mechanically complete.

What did the work entail?

  • 130 cubic metres (13 commercial dump trucks) of concrete slabs and pedestals were demolished  
  • Concrete foundations were poured at the new location
  • The VCU system was decommissioned
  • Five major pieces of mechanical equipment were relocated Emergency fire-water supply, including 120 metres of underground pipe (almost the length of two hockey rinks), was relocated
  • A new vapour recovery pipeline and new propane lines were fabricated and relocated
  • Two kilometres of cable was pulled and terminated at the new location

Of the five pieces of mechanical equipment that were moved, two were notably heavy; the 21-metre tall vapour stack weighing 31,000 kilograms (about the weight of three cruise ship anchors) and a propane tank weighing as much as a railroad boxcar. The job of lifting these items was carried out by the D.B. General, the largest floating and revolving derrick barge on the West Coast of North America.

All units were lifted, loaded onto the barge, moved 130 metres east and then set in place. Moving this equipment took approximately two days.

Is this the final step for managing emissions related to ship loading at Westridge?

Despite more active terminal operations at Westridge, our emissions management system complies with Metro Vancouver air quality objectives. Additional investments at Westridge will be substantial. Trans Mountain’s expansion at Westridge includes construction of two Vapour Recovery Units. These units will capture nearly all the vapours associated with ship loading and reinject them into the tankers rather than burning them. A new Vapour Combustion Unit will replace the existing VCU once construction is complete. It will only be used occasionally — about five per cent of the time — when three ships are simultaneously loading at Westridge or as a backup if one of the vapour recovery units is undergoing maintenance.

This means that even with more vessels being loaded, there will be no increase in emissions at Westridge.