Blue Fire - Old School Celluosic Ethanol

Corn based ethanol may be fairly cold, but cellulosic ethanol is still hot, the hope of the future according to the political candidates and many of the lay commentators in the mass media.Blue Fire Ethanol, discussed below, is one of several firms active in this area and hoping that political support results in the emergence of a thriving industry.

The public perception of cellulosic ethanol is that it represents one unified approach to producing cheap motor fuel, but we, the cognoscenti, know better. We know that numbers of schemes have been cooked up for transforming wood waste and crop residues into ethanol, and we also know that this isn't a new idea. German chemists were making ethanol out of cellulose in the late nineteenth century, and transportation experts were seriously advocating cellulosic ethanol in the nineteen twenties here in America on the theory that petroleum reserves were running low. Henry Ford was a big proponent of the idea, and threw all of his considerable influence behind it.

In addition, we know that cellulose which consists of chains of fermentable sugars, is one tough sonofabitch, and is highly resistant to heat, enzymes, and caustic chemicals, which is why wood is such an excellent, durable structural material.

The New Orthodoxy

In the distant past, extending from the eighteen eighties all the way up to the nineteen sixties, the usual approach to rendering cellulose into six and five carbon sugars suitable for fermentation into ethanol was to douse it with a concentrated strong acid, generally sulfuric acid.

No question that this approach worked, but it never proved very cost effective, and when the modern biofuels industry began to emerge around a decade ago, those favoring ethanol as a successor to gasoline tended to look at a variant approach—a maverick approach really since it had never been attempted outside of university laboratories. And that approach, known as enzymatic hydrolysis involved the utilization of various enzymes to perform the work of breaking down cellulose into sugar, and largely or entirely dispensed with caustic chemicals. Iogen in Canada began to garner a lot of attention in the business press for its efforts to commercialize enzymatic hydrolysis early in the present decade, and they were followed by others including Mascoma, SunOpta, and Abengoa. Later, the Department of Energy pronounced enzymatic hydrolysis as the technique most likely to be successfully commercialized, lending further luster to the approach.

But was the DOE right?

The Retro Approach

"We don't think so," avers Arnold Klann founder of the California based Blue Fire Ethanol and probably unique among ethanol executives in actually having had a career as an executive in the oil industry. "Twenty years ago we were in a different business," explains Klann, "but based on our own tracking of oil field discoveries we assumed that supply problems would begin to appear early in the twenty-first century, and that a real demand for alternative fuels would materialize then. Ethanol looked to us to be the most likely to succeed, and we wanted to be part of the ethanol fuel industry. So we hired scientists to study all known production techniques including enzymatic hydrolysis. We were agnostic at first, we didn't favor one technique over the other. But our eventual conclusion was that the economics of enzymatic hydrolysis were inherently unfavorable as were the prospects for improving them. The persistent problems of high costs, high enzyme loading, and low yields have not been solved in the time since then."

Blue Fire bet instead on the oldest and best established production technique—that involving concentrated acid. Concentrated acids had been shown to work well in the course of countless studies and pilot operations over the course of decades, but the use of them had always been deemed too expensive because of poor recovery rates and reuse factors for the acids. "We've solved that problem," Klann maintains, alluding to his firm's patented Arkenol process.

Blue Fire's literature doesn't show exactly how the recovery is accomplished, but it must be at least somewhat efficacious because a plant licensing the technology has been operating in Japan for years. Now Blue Fire has announced a 3.1 million gallon per year pilot operation in Lancaster, California.

Recently two newer companies have formed a partnership to commercialize another concentrated acid technique, this one employing CleanTech Biofuels and HFTA, the latter a U.C. Berkeley spinoff. At this point the agreement only involves intellectual property and no pilot has yet been launched.

Cellulosic Ethanol - Bluefire

John N. Davenport

The Arkenol process is interesting. Looks to me like they may be using ion-exchange resins to separate acid and sugars. Inevitably, some acid is lost with the sugar and precipitated with lime. It takes a fair bit of energy to produce lime and I would think it also takes a fair bit of energy to reconcentrate the reclaimed acid. It appears they use steam for this purpose. Also the use of lime means the loss of acid. Then there are disposal issues with the precipitates and filtration stages. I don't know if the there is any serious heating value in the lignin residue. If so, can it be used to fire a boiler and produce steam as in the case of Kraft pulp mills? I'm surprised Bluefire hasn't made more of an appearance on the alternative energy scene. There's a lot of waste material from various sources just waiting to converted to a portable form of energy, forestry comes to mind.