13 "Materials Selection Considerations for Recycle Water Systems for the Horizon Oilsands Project", A.I. (Sandy) Williamson, Brent Harle, Rafael Gay-de-Montella, John Baron, Mike Rogers, NACE Northern Area Conference, February 2005, Saskatoon, Saskatchewan.
ABSTRACT
Canadian Natural Resources Limited (CNRL) will commission Phase I of its Horizon Oil Sands Project by the fourth quarter of 2008. Synthetic crude oil (SCO) will be produced from the oil sands at the plant site located approximately 70 km North of Fort McMurray. In this process large amounts of water (12 500 m3/hr) are needed to liberate the bitumen from the oil sands. Initially, fresh water from the Athabasca River will be used to fill the various ponds; however, ongoing plant demands for water will be met through recycling of the tailings pond water. Over time the water used in the extraction process will gain characteristics that will present challenges to the materials used for its transport. The water will have high salinity (primarily chlorides, sulfates, sodium and bicarbonate), high microbiological activity, dissolved oxygen, and varying amounts of suspended material. This means that the water will be corrosive and have high scaling and fouling tendencies. As a result careful material selection as well as some mitigating water treatment efforts will be required. Operational experience of other current oil sands projects also supports this increase in water corrosivity. Since the recycle water (RCW) is used ascooling medium for other processes in the plant and for separating the bitumen from the oil sand, the continuous operation of the RCW system is critical to preventing an unexpected plant outage which could result in millions of dollars of lost production. CNRL has taken a proactive approach to RCW systems integrity management through the use of appropriate materials and monitoring systems. This paper will discuss both of these mitigating efforts.