Making Syncrude

Making “syncrude” which is not actually a synthetic manmade chemical compound, rather it’s a kind of pre cleaned and semi refined crude oil, is a multistep process as done by Syncrude Canada. Because the oil used in making syncrude is not deeply buried, surface mining is the most viable method of recovery.  The oil is mined or more appropriately quarried out, much like the sand, stone or gravel quarry somewhere near you.  Currently huge electric shovels load trucks with 400-ton ratings to gather the oil sands for transport.  The oil sand is trucked to crushers, two rollers, where large chunks are broken down for transport via hydrotransport, a slurry system of water and the broken up oil sand or conveyors for short runs to the bitumen extraction facilities.

There the oil sand is fed into tumblers where steam, hot water and caustic soda are added to form a slurry and condition it for oil separation.  The slurry is discharged onto vibrating screens where large material is combed out.  Then the slurry is fed into four Primary Separation Vessels, deep cone vessels designed to recover most of the oil. Froth floats to the top, sand settles to the bottom and the middlings, the clay and small particles, are pumped to Tailings Oil Recovery. Two Auxiliary Settling Areas, smaller versions of the primary units stand by to assist. The oil primary froth floats to the top, the sand settles to the bottom, and middlings are pumped to Tailings Oil Recovery vessels where the oil froth from the tailing oil recovery vessels is recycled again to the primary separation vessels to improve its quality.  There is a whole lot of recycling going on to get all or very close to all the oil extracted.

Oil recovered from tailings oil recovery vessel middlings is processed by a secondary flotation plant, (the settling pond outside) then piped back for recombining with the primary separation vessels’ froth.  The oil is now about as clean from sand and dirt as its ever going to get so it’s de-aerated, reheated and fed into the Froth Treatment Plant.  Froth treatment removes water and solids by dilution with naphtha and then offloading into centrifuges or inclined plate settlers.

Syncrude converts bitumen oil into hydrocarbon streams – Naphtha, Light Gas Oil that ranges from 30 to 40 carbon atoms per molecule and Heavy Gas Oil which is on up from 40 carbons to about 70 atoms – that are blended to create the high quality, light, low sulfur crude oil known as Syncrude Crude Oil.  The conversion requires two steps.

Primary Upgrading begins with diluted bitumen fed into the Diluent Recovery Units a process of separating the already formed oil out from the remaining bitumen, which has been reduced to a solid.  Water is removed and the naphtha is recovered to be recycled through an extraction system.  The solid bitumen is fed to cokers where heat cracks it into fractions of naphtha, the light gas oil and heavy gas oil for further processing.  Syncrude also uses an LC-Finer, a continuous hydrocracking process, which breaks the bitumen down through adding hydrogen over an expanded ebullating catalyst bed to produce a lower boiling product. The Vacuum Distillation Unit is a Vacuum tower in which gas oils are flashed off and sent to hydrotreaters, bypassing cokers and LC Finer.  Just how the choices are made for what bitumen goes where seems to be proprietary.

Secondary Upgrading is where the cleaning of impurities such as sulfur and nitrogen are removed from the naphtha, light and heavy oil products. The treated gas oils and naphtha are then blended together forming Syncrude Crude Oil and shipped to downstream refineries.

It all seems very simple, but it is a large plant with the largest coker I’ve ever seen.  It was made in Chicago and assembled on site.  At something over 230 feet tall it dwarfs anything of this type I’ve seen so far.

That might also be because its a “fluid coker” that runs continuously rather than the usual coker that is loaded and runs accumulating the hard solid coke at the bottom for batch type removal.  It’s a front edge of technology thing that’s quite impressive.  There is also what looks like a bunch of frac towers or distillation unit as seen in refineries.  What’s different is there are few exits instead of many for the products.  Simpler, but refining isn’t the goal, upgrading is with a clean, high value crude to sell to already built refineries.

The product is great stuff, its pre-cleaned of sulfur and other impurities, falls into fractioning or distillers with superb product results. The Canadian Syncrude is premium crude selling at a price above West Texas Intermediate, the benchmark crude for pricing crude oil types.  Much of it goes to the U.S markets from Wyoming east to Michigan as far south as St Louis and Kansas City.  (That’s to help consumers ID who is benefiting from the production.)

Lots of energy is needed to run this process.  Steam from seven boilers, five standard ones produce 750,000 lbs/hr at a pressure of 915 psig. at a temperature of 499° C (930° F) and two secondary recovery boilers using exhaust from gas turbines are rated at 105,000 kg/hr of steam or 233,000 lbs./hr yielding nearly a million pounds of steam every hour.

Syncrude produces its own electricity.  At the facility we visited the rated capacity is 350 megawatts at 13.8 kv distributed at five voltage levels- 72 kv, 25 kv, 22.9 kv, 13.8 kv, 5 kv supplying all of the plant users.

Eight water demineralizer trains averaging about 6,000 gallons per minute produce water for the boilers and process heaters.  Cooling water is continuously cycled through three cooling towers, which keep plant cooling water at approximately 50º C.  Water is recycled through the extraction process for an average rate of 65,000 gallons per minute of recycled water. Water that comes from the tailings settling basin is heated through a series of heat exchangers located in the upgrading cooling water system and in the diluent recovery and coker units. The water is split into two streams, tumbler water at 95o C and flood water at 70oC.  These people take their water recycling very seriously because heated water is a major expense.  Water used is a big number, water consumed is very a very small number, losing that heat in the process water would be a financial disaster, the process would very likely become uneconomic.  Oil sands oil production economics depend on tight water recycling management and using heat as completely as possible.

Those of you looking at photos are going to wonder what those yellow squares are.  It’s sulfur.  Nearly pure, Syncrude casts them, stacks them up with the expectation of selling them into the sulfur market.  It seems that, geologists thoughts included but unsettled, that a lot of the oil and the capping clays must be volcanic in origin.  As you’ll see, there is lot of it stacked up.  Sulfur is a metal, casting them into shippable blocks makes sense, leaving them out in the weather is fine as fertilizer is major user of sulfur.

ShareThis

No tags for this post.