McLeish

SANTA BARBARA, Calif. – Plastic here, newspapers there, glass bottles in that pile, aluminum cans over there. These days, it seems as if much of the waste that humans produce – especially from those individuals living in rich nations – can be recycled. That’s a far cry from just a few decades ago, when most of what we threw away ended up in landfills.

Despite this progress, scientists have been stymied in their efforts to develop an effective and cost-efficient method of recycling carbon dioxide and other greenhouse gases, which are emitted into the Earth’s atmosphere during the combustion of coal, oil and other hydrocarbon-based fuels. But this problem could soon be a thing of the past, thanks to a breakthrough technological development by researchers at Carbon Sciences Inc.

The Santa Barbara-based firm claims to have developed a new “biocatalyst” technology that can convert carbon dioxide into the three basic hydrocarbons – methane, ethane and propane – needed to produce gasoline, diesel fuel, jet fuel and other liquid energy sources. The company plans to test the process next spring; if it proves effective and Carbon Sciences succeeds in deploying it on a larger scale, then the technology could help to reduce carbon-dioxide emissions from power plants, oil refineries, factories and other industrial sites – all while producing a clean and renewable supply of energy.

Carbon Sciences Chief Executive Officer Derek McLeish announced the breakthrough – which was invented and perfected by the firm’s chief technology officer, Naveed Aslam – at the International Summit on Policy, Technology and Investment, which took place late last September on the campus of Cambridge University in England.

"We are very excited about this breakthrough," McLeish said. "By innovating at the intersection of chemical engineering and bio-engineering disciplines, we are developing a highly scalable biocatalytic process to meet the fuel needs of the world. With over 28 billion tons of CO2 emitted each year, there is an abundant supply of raw material available to produce renewable and sustainable fuels for global consumption."

Fossil fuels consist of chains of hydrogen and carbon atoms and are also known as hydrocarbons. They range from volatile materials with low carbon-hydrogen ratios like methane, to liquid petroleum to nonvolatile materials comprised almost entirely of pure carbon, like anthracite coal. It is generally accepted that fossil fuels are formed from the fossilized remains of dead plants and animals by exposure to heat and pressure in the Earth's crust over hundreds of millions of years.

The more carbon atoms in a particular fossil fuel, the greater its energy content. For instance, gasoline typically has seven to 10 carbon atoms, while jet fuel, which burns hotter and is more explosive, has between 10 and 16 carbon atoms. When hydrocarbons burn, they emit carbon dioxide.

The U.S. Department of Energy estimates that the burning of fossil fuels produces around 21.3 billion tons of carbon dioxide every year, double the amount that the Earth’s natural processes are capable of absorbing. Thus, there is a net annual increase of 10.65 billion tons of atmospheric carbon dioxide. Carbon dioxide is a greenhouse gas that is known to disrupt the normal warming and cooling of the Earth – a major contributor to human-caused global warming, according to the United Nations’ Intergovernmental Panel on Climate Change.

In theory, carbon dioxide could be divorced and its carbon atoms used to produce more hydrocarbons. The problem is, carbon dioxide is an extremely stable compound that requires a tremendous amount of heat and pressure to split – so much so that it has remained economically unviable to do so. Carbon Sciences aims to change that. The company’s “CO2-to-Fuel” technology emulates certain metabolic strategies employed by living organisms where fuel molecules (hydrocarbons) are produced from carbon dioxide and water via low-energy, biocatalytic processes. These natural processes occur under mild conditions due to low temperature and low pressure. Biocatalysis is a more energy-efficient and cost-effective way to break down carbon dioxide, making the possibility of a large-scale ramp up economically feasible.

Carbon Sciences’ biocatalytic process works by splitting water molecules into hydrogen atoms and hydroxide ions. The hydrogen is used to create hydrocarbons, while the free electrons in the hydroxide are used to fuel the biocatalytic process. “Our technology is not based on photosynthetic plants where sunlight is used to drive biofuel production reactions, such as in algae,” Aslam said. “Instead, it is based on natural organic chemistry processes that occur in all living organisms where carbon atoms, extracted from CO2, and hydrogen atoms extracted from [water], are combined to create hydrocarbon molecules using biocatalysts and small amounts of energy. Our innovative technology allows this process to occur on a very large industrial scale through advance nano-engineering of the biocatalysts and highly efficient process design.”

The challenge for Carbon Sciences, according to Aslam, is to lower the manufacturing cost of the fuel “by enabling the biocatalyst to go through many cycles before replacement.”

“To address that challenge, we are developing a proprietary nanoparticle structure around the biocatalysts, which we expect to be available in the second version of the prototype,” he added.

Carbon Sciences is just one of several entities that has developed or is developing technologies to convert greenhouse gases into burnable fuels. In Austin, Texas, the for-profit enterprise Skyonic Corp. has discovered a method for capturing up to 90 percent of the carbon dioxide emitted from smokestacks by combining it with sodium hydroxide to make sodium bicarbonate, or baking soda.

And Novomer Inc., an Ithaca, N.Y.-based startup manufacturer of eco-plastics, announced in November that it intended to convert carbon dioxide into different forms of biodegradable plastic using an undisclosed chemical catalyst.

Even scientists at Sandia National Laboratories in New Mexico are exploring the idea of using concentrated solar energy to turn carbon dioxide into fuel. The Sunshine-to-Petrol project is testing a prototype device called the Counter Rotating Ring Receiver Reactor Recuperator, or CR5 for short, which converts carbon dioxide into carbon monoxide. This reduces the amount of energy required to convert the gas into a liquid fuel.

“Unlike other CO2-to-fuel approaches, Carbon Sciences' technology does not use molecular hydrogen because the creation and reaction of H2 is very energy-intensive,” Aslam said. “Rather, the company's approach is based on a low energy biocatalytic hydrolysis process where water molecules are split into hydrogen atoms and hydroxide ions using a biocatalyst. The hydrogen atoms are immediately used in the production of hydrocarbons and the free electrons in OH are used to power the various biocatalytic processes."

Converting a greenhouse gas such as carbon dioxide into a burnable fuel might sound exciting, but it won’t be easy. Because carbon dioxide is so stable, the amount of energy required to convert it to other substances could make Carbon Sciences’ CO2-to-Fuel technology prohibitively expensive. McLeish acknowledges this challenge, but he also believes that the technology’s potential outweighs that of existing alternatives for removing carbon from the atmosphere, like underground sequestration.

"That is akin to putting your garbage in a landfill – you can’t be sure what it will do to the environment, and there is always the threat of a natural disaster like an earthquake,” he said. “What we are trying to do is recycle carbon dioxide.”

Carbon Sciences expects to complete a prototype that it will use to demonstrate its biocatalytic by the end of March. "The prototype under development is a flexible laboratory-scale setup comprising three primary sections: gas-treatment section, biocatalytic reaction chamber and fuel-separation and collection chamber,” Aslam said. “It is also equipped with in-line sampling and analysis equipment to provide real-time information of process streams. We expect that the stream of CO2 can be transformed into a flammable liquid fuel."

Carbon Sciences hopes to eventually license the technology to oil and gas companies and large carbon-dioxide emitters, such as power plants.