innovation

US Technology breakthrough

DARIUS SNIECKUSBRISTOL

Santa Barbara, California-based Carbon Sciences last month put the fi nish-

ing touches to the prototype of a potentially revolutionary sys-tem that promises to transform a stream of carbon dioxide (CO2) gas into a range of fuels.

The company, set up in 2006, is developing a biocatalytic proc-ess that breaks down a mixture of CO2 and water, then combines the freed carbon and hydrogen to form methanol, which can be used for products including anti-freeze, or be processed into ‘higher-level’ fuels such as gaso-line, butanol and jet fuel.

Turning CO2 into fuel has been possible for some time through direct photolysis, where intense light energy is used to break off the oxygen atoms in CO2, and

by chemically reacting CO2 gas with hydrogen gas (H2) to create methane or methanol.

Being high-pressure and high-temperature chemical processes, both require immense energy — and have a prohibitively high price tag of around $150 per litre. By contrast, Carbon Scienc-es’ multi-stage biocatalytic proc-ess, invented at the University of Houston by chief technology

offi cer Naveed Aslam, does not need high-cost inorganic cata-lysts such as zinc, gold or zeolite to create fuel.

Instead, it uses low-cost, nano-engineered, organic renewable molecules in a low-temperature, low-pressure environment.

Carbon Sciences’ patent-pend-ing system is reckoned to be able

to produce a fuel competitive with ethanol, which sells for un-der $0.75 a litre.

“The process uses naturally occurring biocatalysts that have one mission: to put together carbon and hydrogen, as hydro-carbons — the building blocks of fuels,” states Carbon Sciences president Byron Elton.

“This is how nature does it with micro-organisms, where carbon

atoms extracted from CO2 and hy-drogen atoms ex-tracted from H2O are combined to create hydrocar-bon molecules.

“Nature does it on its own timetable — however, this is over millions of years.

“Our process is virtually the same, but we do it in a matter of hours,” he adds.

Where the Carbon Sciences’ system steals a march on nature is through nano-engineering the biocatalysts so that they can perform their CO2-to-fuel cycle

Scientists on verge of fuel revolution

A MARCH ON NATURE: Carbon Science president Byron Elton

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Nano-engineered biocatalytic technologies are currently being advanced that could radically short-circuit the carbon dioxide capture-and-storage loop by providing a way of changing emissions directly into fuel

There is no other single approach that can match this impact in addressing our

energy and climate challenges”BYRON ELTON

How Carbon Sciences’ biocatalytic process turns CO2 from an industrial-scale emitter into fuel

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innovation

Scientists on verge of fuel revolutionnot once — as in nature — but millions of times, without de-composing. It is this that helps cut the production cost of the hydrocarbons.

The company’s process — what Elton calls its “secret sauce” — centres on creating an enclosed environment of polymer beads where the biocatalysts can continue to perform their mis-sion repeatedly. Scale is a matter of numbers. “The more biocata-lysts and the more CO2, the more fuel,” he says.

The prototype system, accord-ing to Elton, is proof positive not only that the CO2-to-fuel concept works, but that the company’s “technology team [is] headed in the right direction” in its quest to scale up the process for indus-trial use.

Carbon Sciences’ process be-gins with a fl ue-gas processor to purify the CO2 stream of heavy particulates. From here, the gas enters the ‘biocatalytic reactor matrix’ where mass quantities of biocatalysts work in liquid reac-tion chambers carrying out the breakdown of CO2 into basic gas and liquid hydrocarbons.

The liquid solutions are then fi ltered through membrane units to extract liquid fuels, while gase-ous fuels are extracted using con-densers. The low hydrocarbon

fuels that fl ow from the fi ltration stage can then be further pro-cessed into higher fuels such as gasoline, diesel fuel and jet fuel.

Biocatalysts are meanwhile regenerated to carry on the CO2-to-fuel conversion process.

Carbon Sciences hopes to move from the laboratory set-ting, where it is producing “vials’ worth of fuel in beakers”, up to a mini-pilot that could gener-ate “gallons on a regular basis” within a year. Currently, for the process to create one gallon of gasoline, it needs 1.84 cubic metres of CO2 feedstock.

Should it ramp up to a gallon-after-gallon level of production, the company aims to partner with a large-scale emitter — a coal-fi red power plant or similar — to license its CO2 to fuel tech-nology for industrial trials.

“With our CO2-to-fuel technol-ogy, mitigating emissions doesn’t have to be an expense. Instead, it can be a revenue stream for large CO2-emitting companies and countries,” notes Elton.

“This is a much more attractive option [than carbon capture and storage] for emitters, we think: the opportunity to turn waste — CO2 emissions — into very valu-able revenue.”

The company calculates that 30% of total global liquid-fuel

demand could be met by 2030 by processing 25% of the CO2 emissions from coal-fi red power plants around the world.

“There is no other single ap-proach — not biodiesel, and not cellulosic ethanol — that can match this impact in address-ing our energy and climate chal-lenges,” says Elton, pointing to the multi-stage, energy-intensive chain — harvest, transport, bio-refi nery production, distribution — involved in the biomass-to-fuel process. “Because our process is

biocatalytic — it’s not hydrolysis, it’s not nuclear, it’s not electric-ity we are using to make this happen — it happens at room temperature and atmospheric pressure, and so it is a very low-energy output,” he underlines.

Beyond being an energy-effi cient system, the other central advantage the Carbon Sciences process has is that its product — fuel — fi ts the existing infrastruc-ture, supply chain and transpor-tation vehicles.

Given current worldwide CO2

emissions levels, Carbon Sci-ences believes its technology can generate “extraordinary volumes of fuel [and] provide a signifi cant amount of the needs of the US and the globe” as an off set to fur-ther exploration and production or import of oil and gas.

More than this, stresses Elton, a higher motivation remains: “We have a responsibility, in terms of the stewardship of the planet, to our grandchildren, for political stability, and because it is the right thing to do.”

The CO2-to-fuel biocatalytic reactor matrix

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