The price of crude oil is making the Canadian oil sands more important for crude oil production, and thus for the overall oil supply. Oil sands extraction is a very complicated process – the oils often have to be extracted from great depths or under difficult climate conditions, and complicated techniques requiring high water usage are needed to accomplish this. Steam-assisted gravity drainage (SAGD) has become one of the primary ways of getting the bitumen (oil trapped in sand or other natural materials) out of the ground.

Canada’s Long Lake Project uses the SAGD process for oil extraction, but it is also using a new type of processing to upgrade the bitumen into a premium, synthetic crude. At the same time, they will use the waste products to make Syngas, which provides a very big portion of the fuel required by their SAGD process, making the Long Lake site nearly energy self-sufficient.

A key role in ensuring the plant’s better environmental compatibility will also be played by a waste minimization technique developed by Siemens, led by Chad Felch, 35. Waste product from the crude upgrader is gasified to make Syngas. A by-product of the gasification is a soot containing heavy metals. The process developed by Felch uses a Zimpro® wet air oxidation (WAO) process to destroy 90 percent of the soot, minimizing the amount of waste soot requiring disposal. In addition, the heavy metals in the soot may be able to be recovered and sold as a product.

The Zimpro WAO process has been used for many years to treat heavily polluted industrial waste water and sewage sludge. Felch, a chemist at Siemens for the past eight years, optimized the process to be used for this application.

The wet air oxidation process for waste water treatment was developed by Zimpro, now a part of Siemens. The process involves oxidizing waste water or polluted sludge in a reactor at high pressures and temperatures. Conventional facilities use normal air or pure oxygen as oxidizers. The waste water is first subjected to high pressures and mixed with compressed air or pure oxygen. This mixture is then heated in a heat exchanger until the wet air oxidation process commences. It is then sent to a reactor, where the oxidation process continues until it has reached a predefined level. In the next step, the oxidized mixture is separated into gas and waste water, with the latter undergoing further treatment in a biological water treatment plant, for example.

In a series of tests, Felch discovered that wet air oxidation is also suited for treating the soot slurry of the Long Lake project. One of the main benefits of the process is that it eliminates around 98 percent of the carbon in the sludge, making it possible to reduce the amount of soot that must be disposed of in landfills by up to 90 percent. Felch also determined that the soot slurry contains certain metals whose catalytic effect helps to improve the oxidation process. In addition, Felch will boost the Long Lake treatment process by adding various acids and bases that make it possible to oxidize the slurry at a lower temperature.

The wet air oxidation method will substantially improve the Long Lake project’s environmental performance by filtering out recyclable metals and drastically reducing the amount of waste requiring disposal. Felch already has 28 inventions to his credit, including two that are patented.

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