Enbridge drawing up plans for a liquid carbon dioxide pipeline
Imagine a super fire extinguisher, built as a carbon-dioxide-filled tube stretching hundreds of kilometers from Fort McMurray to central Alberta.
Natural chemistry still works on this big scale.
As inside an extinguisher, the gas compresses at room temperatures into a liquid propellant or carrier for active ingredients. The pipeline’s contents are a “slurry” or mud-like soup of solids ground into particles.
On the large as on the small scale, liquefied carbon dioxide works better than water as a delivery medium. The cargo can be 80 per cent of the slurry’s weight. Water’s upper limit is 50 per cent.
Solids shipped in liquid carbon dioxide also blow bone dry as soon as they come out of the pressurized container. Freight shipped in water needs machinery and time to dry out.
Instead of foam for dousing flames, the cargo delivered by Enbridge’s vision are leftovers from oil sands production that would otherwise be piling up with no place to go such as charcoal-like petroleum coke and sulphur. Other useful items such as crushed limestone can be added.
This idea is no science fiction fantasy. It is a serious theory proposed by a senior pipeline executive after long experience with carbon dioxide and discussion with his peers.
“It’s a creative concept,” says engineer Chuck Szmurlo, Enbridge vice-president of alternative and emerging technologies. “It’s trying to find a solution to emitting carbon dioxide into the air that defrays some of the costs.”
He was arranging an information session for September with the Petroleum Technology Alliance Canada, an industry-supported innovation incubator that also includes government and scholarly agencies.
The thinking about a carbon dioxide slurry pipeline started with Enbridge research into building a northbound delivery service to the bitumen belt for coal from central and southern Alberta. The idea was to supply a replacement for expensive natural gas burned as boiler fuel in steam-powered bitumen extraction. Industry showed little interest, Szmurlo says.
A southbound version is liable to inspire more enthusiasm because it has potential to relieve multiple, growing industry headaches with a single bold stroke, the Enbridge executive suggests.
For starters, the scheme would create a method for oil sands plants to send out clouds of carbon dioxide that they would otherwise have no prospect of clearing away. Unlike central and southern Alberta, the northern bitumen belt lacks spongy deep rock formations for absorbing the exhaust in permanent geological disposal sites, Szmurlo says.
Greenhouse gas emissions are also far from the only cleanup problem on industry and government minds. Sooner or later realists expect critical attention to focus on other waste that has piled up since the birth of oil sands production in the 1960s and that can only grow as output expands.
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