In Alberta, Oil & Gas operators are developping Extra Heavy Oils (EHO) production fields requiring much more processes and energy than conventional oil. Consequently, the associated GHG emissions could be potentially huge and operators are seeking options to reduce them. Among the possible options, Carbon Capture and geological Storage (CCS) appears to be the most promising option in addition to power efficiency increase and use of renewable or alternatives energies.
For EHO thermal production, a huge quantity of steam is required; therefore a large quantity of CO2 per produced barrel could be emitted. The existing and future boilers will have to capture these emissions efficiently, either with post-combustion like amine unit, or oxycombustion. New boilers have to be designed to integrate the most appropriate "capture ready" solutions.
TOTAL launched at the end of 2006 an integrated CCS project at Lacq, in the South-West of France. It entails the conversion of a steam boiler into an oxy-fuel combustion unit. The pilot plant, which will produce some 40 t/h of steam, will emit up to 120,000 tons of CO2 over a 2-year period. The CO2 rich flue gas will be cleaned up and compressed. The resulting CO2 will be conveyed via pipeline to a depleted gas field, 30 kilometers away, where it will be injected into a deep carbonate reservoir. CO2 injection start-up is scheduled beginning 2009.
This paper demonstrates that oxycombustion could have some adavantages compared to post-combustion for CO2 capture in term of energy efficiency for steam generation. Secondly, it presents the characteristics of the 30MWth oxy-gas boiler, one of the first world industrial oxy-combustion units. Then, it focuses on the new equipment to retrofit the drum boiler to oxycombustion: the Air Separation Unit, the Oxy-combustion System developed by Air Liquide, the Flue Gas Recycle set up, the CO2 cooling, compression and drying before transportation.
Introduction
The necessary oil sands production and processing schemes in Alberta require massive quantities of energy, in the form ofSteam: for the SAGD (Steam Assisted Gravity Drainage) or for the separation of sand / bitumen extracted from miningElectricity: for the water treatment units, pumping units, separation and treatment units…Heat: for the treatment and ugrading of the produced bitumen (in particular SMR for hydrogen production)
To produce these utilities, natural gas is burned and thermal equipments (boilers, gas turbines and furnaces) will generate important quantities of CO2 at the exhaust. To compare this bitumen production vs. other oil extraction, we use the ratio: quantity of generated CO2 per produced barrel (extraction and upgrading).
