Oil Sands
May 5, 2009 by admin
Source: African Oil Journal
If you hear the term “froth treatment”, you would be forgiven for thinking it was a device for making the perfect cappuccino. What you might not expect to hear is that it is one of several technologies that help Shell extract oil from sand in Canada.
Oil from sand
Canada’s oil sands are one of the unconventional sources that we are now developing thanks to advances in technology. Shell’s Athabasca Oil Sands Project already provides more than 10% of Canada’s oil needs and there are plans to increase production to more than 500,000 barrels a day.
Oil sands are a blend of clay, sand, water and bitumen – a very thick oil. Unlike conventional oil recovery techniques that require drilling underground, in oil sands mining, the ore is excavated using shovels and trucks. The material is then mixed with warm water to separate the oil from the sand. The bitumen rises to the surface and the resulting mixture, called froth, is treated to remove the remaining sand and fine clay, producing clean, dry bitumen that is diluted and transported for further processing.
Shell recently developed a new froth treatment technology called Shell Enhance, the first commercial application of an innovative technology that will reduce costs and improve energy efficiency in oil sands production. By using higher temperatures, Shell Enhance froth treatment technology can more efficiently remove impurities from the oil sands froth because it uses less energy, less water, and fewer vessels for cooling and reheating. By saving energy, about 40,000 tonnes per year of greenhouse gas emissions are prevented.
Upgrading the oil
The diluted bitumen still requires further upgrading before going to a refinery and is transported via pipeline from Shell’s oil sands mine to Shell’s Scotford upgrader. Unlike other oil sands operators in Alberta who utilize coking technology to extract the carbon from the very heavy oil material, Shell at Scotford uses “hydrogen addition” technology to break the large carbon molecules into smaller ones by increasing the hydrogen to carbon ratio. Through this chemical reaction, Scotford actually produces more than 100 barrels of synthetic crude from every 100 barrels of bitumen processed and enables refiners to produce clean, high-quality refined products, such as gasoline and diesel fuel, with low levels of aromatics, particulates and sulphur.
