November 2019
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What's new in production

What to do with CO₂
Don Francis / Contributing Editor

What if the chief driver of petroleum’s opprobrium—carbon dioxide—became just another useful by-product of its consumption? How, then, would the value of oil and gas production be appraised?

It’s too early to tell for sure, but some interesting possible reasons why attitudes eventually could be moderated are offered in a recent paper provocatively titled, What Should We Make with CO and How Can We Make It?

“Similar to how a plant takes carbon dioxide, sunlight and water to make sugars for itself, we are interested in using technology to take energy from the sun or other renewable sources to convert CO₂ into small building block molecules, which can then be upgraded using traditional means of chemistry for commercial use. We’re taking inspiration from nature and doing it faster and more efficiently.” So says Phil De Luna, a co-author.

Perhaps the problem is not quite as intractable as it appears to the public mind. The authors propose a timeline of CO₂utilization methods and some relevant considerations of each:

Five to ten years

Electrocatalysis: Flexible electricity source. Closest to scale and commercial application.

Photocatalysis: Direct solar to fuel conversion.

Ten to 50 years

Biohybrid: Coupling of enzymes to inorganic water splitting. Microbial synthesis. Complicated-molecule synthesis.

Nanoporous confinement: Catalysis of hydrocarbons achieved in zeolites and MOFs.

70 years and beyond

Chain insertion: Metal catalysts for polymerization through chain insertion. Currently highly adopted by industry.

Molecular Machines: Artificial enzymes with dynamic components. Potential for tandem catalysis with high selectivity.

The authors insert a caveat here: “The specific time ranges are based on extrapolation of timeline development of other disruptive technologies, such as the advent of 3D printing, solar energy adoption, and electric vehicle development.” The paper elaborates (and those of us who weren’t chemistry majors may have to take some of this on faith):

“While low-cost electricity from renewable sources is desirable, the issues of intermittency and grid balancing remain. Energy storage is essential, to enable even deeper penetration of renewables; to this end, it is important to take renewable electrons directly to fuels. Electrolyzing water to hydrogen is one possible solution that can integrate deeply in the energy and chemical production economy. The production of liquid fuels that can integrate with the existing transportation system, as well as more complex chemical feedstocks for chemical production, would be tremendously beneficial.

“The electrochemical conversion of CO₂ to fuels and feedstocks—the CO₂ reduction reaction (CO₂RR)—is an elegant solution to closing the carbon cycle, when it is powered by renewable energy. In this process, CO₂ is converted to hydrocarbons, using water and renewable electricity. From a capital equipment perspective, the systems hold analogy with commercialized hydrogen electrolyzers. As in the case of the net-carbon-neutral H2/H2O couple, the hydrocarbon/CO₂ couple is also net carbon neutral when powered by renewables.”

Long-term, large-scale, seasonal energy storage. “Electrochemical transformation of renewable energy into high-energy-density liquid fuels, using captured CO₂, offers the prospect of long-term, large-scale, seasonal energy storage; and it allows for integration of renewable electricity into the transportation system and in chemical production. A carbon-based strategy has advantages in implementation and logistics; it takes advantage of an expansive already-built infrastructure created for gaseous and liquid fossil fuels. CO₂ can be captured from emission-point sources, using carbon capture technologies. The long-term seasonal storage of renewables holds the potential to increase the adoption of renewable energy sources.”

“We wanted clear insight into whether this could be economically viable, and whether it’s worth the time to invest in it,” De Luna said. “This is still technology for the future,” said co-author Oleksandr Bushuyev, “but it’s theoretically possible and feasible, and we’re excited about its scale-up and implementation.”

Space prevents discussion in detail, but the authors’ analysis “…finds that short-chain simple building-block molecules currently present the most economically compelling targets. Making an optimistic prediction of technology advancement in the future, we propose the gradual rise of photocatalytic, CO₂ polymerization, biohybrid, and molecular machine technologies to augment and enhance already practical electrocatalytic CO₂ conversion methods.  

Whether or not any or all of the milestones on their technology timeline are eventually realized is anyone’s guess. But in the meantime, the possibilities bring other tantalizing, what-if questions to mind: What if CO₂ ceases to be the industry’s Achilles Heel and devolves into something more akin to a sore knee? What if oil and natural gas return to their role, in the public mind, as a welcomed and valuable part of the world’s energy mix?

While our topic today may not immediately solve any of the specific problems that oil and gas production staff will face when they go to work, it’s still worth a look. If any of this becomes real, in a commercial sense, it may have a large effect on the odds that such work for them—or their children—will be there in the future.

About the Authors
Don Francis
Contributing Editor
Don Francis DON@TECHNICOMM.COM / For more than 30 years, Don Francis has observed the global oil and gas industry as a writer, editor and consultant to companies marketing upstream technologies.
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