digging in the dirt dirty oil stigma vs oilsands

Digging in the dirt: Dirty oil stigma vs oilsands

Gobind Khiani - 28 July 2016

This is the third part of the series of articles on the topic of oil sands.

About the author

Mr Gobind Khiani
Gobind Khiani P.Eng. (AB, BC, SK) is a Valve World columnist and Lead Discipline Engineer at Fluor Corporation, Canada.
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Although there are many factors influencing the future of Canadian oilsands, including technology advances and oil price, production will not grow without the consent of local public. Various options have been discussed on regulatory requirements; these include the carbon tax, renewable fuel standard, low carbon fuel standard and regulations by US Environmental Protection Agency.

Oilsands companies are investing effort and money in optimizing plant operations including development and implementing new processes and technologies to reduce GHG emissions. As the majority of oilsands emissions come from the consumption of energy, it is important to understand the key parameters that drive energy consumption during oilsands production.

The production methods on oilsands are:

  1. Open pit mining (20%) – only a small percentage of total production as major deposits are deep beneath the reach of mining methods.
  2. In-situ (80% ) – the majority of production is done by this method and is considered the most common method of producing oilsands namely:
    (a) SAGD (Steam Assisted Gravity Drainage)
    (b) CSS (Cyclic Steam Simulation)
    (c) CCS (Carbon Capture and Storage, one of the methods used to enhance oil recovery)

The Alberta government has committed $2Billion+ to support CCS research, development and demonstration projects and this is helping Alberta reduce 4milliontonnes annual GHG emissions (i.e. 700,000 vehicles on the road). While there are risks, there are also solutions to minimize risks and we do not have to make the wrong choice between bitumen and biodiversity.

In this article we are discussing aspects of using knife gate valves in open pit mining application (20% of Canadian oilsands production only). Mining requires tough valves – ones that withstand intense abrasion, extreme pressures and temperatures of the tundra in Alberta winters. Some applications such as hydrotransport slurry, carrying bitumen ore from the mining pits to extraction plants, include large, jagged stones as well as coarse sand and clay. Bitumen itself has a density similar to cold molasses, so it requires heat and high pressures to transport long distances to extraction plants.

The valves most commonly used for such an application are heavy-duty knife gate valves, installed with sharp blades to cut through sticky bitumen. They often include scrapers engineered to remove bitumen from gates as part of opening and closing. The valve gates are made of hardened materials such as 17-4ph stainless material in addition to abrasion-resistant coatings such as tungsten carbide to extend the life of the valve.

Heavy duty knife gate valves can withstand abrasive, high pressure oilsands slurries. They are used in the froth flotation area, where break down is considered a loss of production, and for applications where highly concentrated slurries require nondischarging valves so precious product is not discharged to the ground or localized drains. Improved production methods have been developed enough to justify the extra barrel production costs of oilsands mining. These trends see leading mining companies who extract from the oilsands eager to find ways to increase production rates and reduce downtime.

valve from ITT Engineered Valves LLC, USA.

Industry continuously works with users of these applications and major industry players to jointly develop custom solutions to meet growing demands for such valves.

As production has increased and the cost expenditure ratio continues to improve with the rising global costs of oil, more stringent specifications continue to drive innovation. Valves involved in every stage of transport are subject to wear and tear from the nature of bitumen slurries. If there are not fist sized stones in the mix, there are highly abrasive sands. Slurry flow speeds have been increased to help reduce the slurry’s stickiness. However, this causes high abrasion rates. In any case, bitumen transport takes place under incredibly high pressures at up to 700 psi or more.

All of this has combined to create a demand for knife gate valves that can withstand the extreme abrasive qualities of oilsands mixtures and the high pressures required to transporting slurries over long distances. Engineers are looking for more robust valves that can endure longer intervals between required maintenance. Around 2000 leading companies in the Canadian oilsands underwent a major growth step at various plant sites, adding new processing units including the largest fluid coker and hydrogen plants ever built, in addition to upsizing another 100 processing units. That process involved the purchase of about 100,000+ manual isolation valves and brought the oilsands daily production capacity up to 750,000bpd. A variety of valves were in use including modified versions of standard knife gate valves.

oilsands upgrading process

Oilsands producers utilize over 1Billion+manual isolation valves in various processes, including some 70000 pressure safety valves, 150,000 control valves, dampers and large actuated isolation valves. Few knife gate valves are in this mix today, though those that are have been specially fabricated and deployed to meet unique needs in situations where standard valves could not stand up. The processes were becoming more and more rigorous and the need for a super duty valve became apparent. As time passed, more robust valve designs were required by multiple leading Canadian oilsands. At this time, there were so many different applications for valves emerging in oilsands mining and refinement that there truly was no such thing as a standard valve. This need spurred a drive to innovate and evolve the knife gate valves used in the oilsands, reducing maintenance and meeting ever increasing specifications.

Energy demand continues to drive future innovation in valve technologies

With increasing demands surely on the horizon for valves in the Athabasca oilsands of Alberta, sturdier system components will need to evolve and improve for the foreseeable future. These demands will result in increased unconventional oil mining, production processes and advanced challenges. Heightened complexity will be unavoidable and demand for more customized and durable components will follow suit. The endless global demand for energy should drive the growth of new processes such as in situ. One primary area for growth is deep extraction in the oilsands using in situ methods. Certain methods using in situ such as steam and water treatment, require valves requiring high alloy steels to be compatible with the aggressive temperatures and chemical characteristics in the process. Heavy scaling will continue to be a growing challenge and new product evolutions with improved designs will be better equipped to tackle heavy scaling. The future will demand that engineers build longevity into their products and continually push to improve engineering technologies with interchangeable internal parts, more robust materials and improve coatings to reduce wear. The oilsands of Alberta will continue to drive innovation and progress with its endless energy opportunities.

Photos courtesy of ITT Engineered Valves LLC, USA.

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