Climate Research | Columbia News
The enclosed release, from Columbia University, affirms in general other reports we've cited, wherein Carbon Dioxide can be directly utilized, in addition to being indirectly recycled via natural botanical processes, in the conversion of some biomass into liquid fuels.
We perceive there to be a few errors in their over-generalizations, and we believe their scope is too broad.
But, we think their contention, at it's base, is valid; as we attempt to explain following excerpts from:
"Researchers Use Carbon Dioxide in Conversion of Biomass Into Biofuel
Researchers at Columbia University have successfully discovered a beneficial use for carbon dioxide in the conversion of organic materials, such as grass and bark, into fuel. Their findings show that if utilized on a broad scale, their technique could help significantly reduce overall carbon emissions, both from the use of carbon dioxide in biofuel production and the creation of a more energy-efficient production process.
Increasing global energy use coupled with the need to reduce greenhouse gas emissions such as carbon dioxide has resulted in the exploration of viable alternative fuel sources that are carbon neutral. Biomass fuels—consisting of organic, biological materials—hold promise as renewable sources for energy, but present a double-edged sword: Current approaches for turning biomass into fuel involve a considerable amount of energy and water to form the steam needed to convert the raw, organic materials. In addition, the conventional conversion of such fuels typically leads to the emission of additional atmospheric carbon dioxide.
To solve this challenge, Marco Castaldi, assistant professor, and Heidi Butterman, postdoctoral researcher, in the department of earth and environmental engineering at Columbia’s Fu Foundation School of Engineering and Applied Science, have found that by using carbon dioxide in the actual conversion of biomass, the process becomes more energy efficient and reduces carbon dioxide emissions.
“Hopefully these findings will stimulate people to think about utilizing carbon dioxide and other waste streams to make chemicals and products that society wants,” said Castaldi, a chemical engineer. “This is what engineering does best, developing processes that can extract value from unwanted materials—to help make the world a better place.”
Gasification is a process that converts materials with high carbon content, such as coal, petroleum, or biomass, into volatile products—mostly hydrogen and carbon monoxide—by reacting the raw material at high temperatures with a controlled amount of oxygen and/or steam. The resulting mixture is a fuel called synthesis gas or syngas.
In their study, Castaldi, and Butterman, along with another postdoctoral researcher, Eilhann Kwon, processed 50 different kinds of biomass, including beach grass, pine needles, poplar wood, municipal solid waste and coal, from 25°C to 1000°C at rates of 1-100 C per minute in pure carbon dioxide and in a mixture of steam, nitrogen gas and carbon dioxide. They found that a carbon dioxide–steam mixture significantly increased the conversion of biomass to volatile products at lower temperatures.
When carbon dioxide and steam are present in gasification, the carbon dioxide reacts first to convert the solid fuel to syngas, leaving the steam to react with some of the syngas in a reaction called water-gas shift, which liberates some energy. The researchers found that by replacing 30 percent of the steam with carbon dioxide, the overall process is more efficient because the CO2 is more reactive than steam and can more readily access the carbon char (unprocessed biomass) for conversion into syngas.
The researchers believe that the use of carbon dioxide in biomass conversion, if applied on a mass scale, hold the potential to globally process tens to hundreds of megatons of carbon dioxide per year. According to their calculations, using CO2 during gasification of biomass fuels results in an additional emissions reduction than just the use of biofuels alone. For low-temperature gasification of beach grass, for example, the incorporation of carbon dioxide could create a beneficial use for 437 million metric tons of CO2 (based on estimated transportation fuel needs for 2008). For a typical automobile producing 6 metric tons of CO2/year this would be equivalent to removing 308 million vehicles from the road.
Carbon dioxide used in a mass-scale gasification process can be diverted from a variety of industrial sources, including power plant exhaust, future power plants that use syngas and compressed carbon dioxide, or from food and beverage manufactures that emit carbon dioxide as a by-product. Using industrial carbon dioxide would lead to a further reduction of emissions."
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First of all, in what seems to be a bit of journalistic sloppiness, the author writes that experiments were performed with "50 different kinds of biomass, including ... coal".
But, when you really think about it, that is precisely what Coal is: Biomass.
Really, really old biomass; but, biomass nonetheless. Just because the plants from which it formed didn't grow in our lifetimes doesn't negate it's botanical origins.
Philosophical excursions aside, we note that Columbia displays a candor surprising in dissertations about the virtues of biomass fuels, when they clearly state: "Current approaches for turning biomass into fuel involve a considerable amount of energy ... (which) ... leads to the emission of additional atmospheric carbon dioxide."
That's because of the energy needed to process typical alcohol fuels from biomass, via distillation; and, from the biomass itself, during fermentation into the alcohols.
And, those issues are aside from the CO2 arising from the various liquid fuels used in the cultivation and harvesting of biofuel crops.
Nobody much likes to talk about that muddy side of things, though.
However, in line with earlier reports we've made, Columbia discusses a different process for converting biomass: thermal gasification, which would be similar to Coal gasification, and wherein adding CO2 to a bio-gasification process stream, along with Steam, made the "overall process ... more efficient".
That seems in line with the earlier research we've recorded for you, wherein Steam and Carbon Dioxide, when combined under proper conditions, can be made to react synergistically to form hydrocarbons.
In fact, in a broad speculation, the process described herein by Columbia might be related to the process of "tri-reforming", described best so far by Penn State University. Therein, as we have documented in multiple reports, from both Penn State and Korea, Carbon Dioxide and Steam can be reacted with Methane to synthesize higher hydrocarbons.
At Columbia, they seem to be using gasified biomass in place of the Methane.
Any way you cut it: Carbon Dioxide is a valuable raw material resource. One way, or the other, we can recycle it back into liquid hydrocarbon fuels, among other useful things. Unless, of course, you would rather hold a gun to our vital Coal industries' collective head and force them to subsidize Big Oil's petroleum reservoir scavenging through enforced geologic sequestration.
As Columbia's Marco Castaldi puts it, let's start "utilizing carbon dioxide ... to make chemicals and products that society wants".