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Licensed To Flex Feedstock Muscle

Mon, 01/04/2010 - 8:16am
Carrie Ellis & Luke Simpson, Editors, Chem.Info

Nobody would believe it until they saw it—especially leery investors. But FlexEthanol technology is here today and readily available.

October 15 was the big day for Coskata Inc. After more than three years spent refining the technology that has excited investors like General Motors, the ambitious cellulosic ethanol company declared itself open for business. A semi-commercial facility built in Madison, PA is proof that the conversion of woodchips, municipal waste and plant matter to ethanol is realistic on an industrial scale. The company is now ready to demonstrate and license its technology to both ethanol producers and facilities looking to convert on-site feedstocks to fuel.

Flexible Feedstocks & Bug Technology

Coskata’s new facility—dubbed Project Lighthouse—is annexed onto a plasma gasification unit run by the Westinghouse Plasma Corp., a wholly owned subsidiary of Alter NRG. Originally developed by NASA in the 1950s to create the heat necessary to test the shields that protect spacecraft on re-entry, plasma gasification uses temperatures around 2,500ºF to break the chemical bonds of any organic feedstock, creating a mixture of carbon monoxide and hydrogen gas, known as synthesis gas or syngas. After the syngas passes through a scrubber to remove particulates, it is ready for use.

Coskata decided to use woodchips as the first feedstock because of favorable market conditions and the commercial plant opportunities that exist for this feedstock. Introduced in 500-pound bags, the woodchips can be fed straight into the gasifier without any pretreatment. If feedstocks such as tires or municipal waste are used, however, some resizing may be required. While most feedstocks don’t need pretreatment prior to processing, in rare cases, it may also be necessary to remove moisture. The system currently generates 100 gallons of ethanol per ton of dry, ash-free biomass material; Coskata calls this feedstock-flexible fuel FlexEthanol.

Although plasma gasification plays a large role in the process, Coskata’s most significant technology lies within specifically engineered microorganisms that are used to convert the syngas into ethanol. The anaerobic bacteria originate in freshwater ponds, but are quite different from the original species. Laboratories at the company’s Warrenville, IL headquarters were used to manage and develop the most effective strains, while researchers investigated the ways to most efficiently deliver gas to the microorganisms.
Bill Roe, Coskata president and CEO, proclaims, “We were able to suppress certain characteristics so that the bacteria focused on producing ethanol.”

Before being placed into a specially designed bioreactor, vessels are used to grow the microorganisms—also referred to as “bugs”—into the volumes necessary for production. When the syngas is sent to the bioreactor, a fermentation process occurs as the microorganisms consume the carbon monoxide and hydrogen, and produce ethanol.

A specifically designed microfiltration system then separates the bacteria from the wet ethanol, and any live bacteria are returned to the system. Due to the fact that they are constantly reproducing, bacteria are also purged from time to time in order to manage the population. Because water is produced in the process, distillation or membrane permeation can be used to separate the ethanol, although distillation is currently the preferred method. The separated water is then returned to the bioreactor to be recycled and the final product—fuel-grade ethanol—is collected.

Lighthouse Highlights

Although the semi-commercial facility does not have a specified capacity, it was built using “minimum-scale engineering,” which means the plant mimics the exact behavior that occurs in 50- to 100-million gallon facilities. In all actuality, the plant is a culmination of three or four semi-scale operations because it incorporates not only a few reactors, but also several separation technologies in order to model distinct processes. In practice, a facility would only use one of each.

“This demonstration plant has just as many valves as a full-scale plant. We’re just using smaller equipment,” explains Wes Bolsen, Coskata’s chief marketing officer and vice president of government affairs.

With miles and miles of pipes connecting the microorganism vessels, bioreactor and separation units, the process is surprisingly fast. From the time the feedstock enters the gasification process, it is literally minutes before ethanol is flowing from the system.
But very little of the fuel produced at the plant is being used. While some of the ethanol is being sent to GM for testing in flex-fuel vehicles, the primary purpose of the facility is to prove that the FlexEthanol technology works at scale—a capacity of as much as 400 million gallons can be achieved from just this demonstration. After this phase is complete, the modular $25 million plant can be disassembled and relocated.

Measurable Biobenefits

What’s the other main objective when it comes to biofuels? First and foremost, to compete with gas. Coskata admits, “It must be cost-competitive. When determining the value of alternatives to gasoline, any developer has to answer two fundamental questions: First, can this new technology compete head-to-head with gasoline without long-term government subsidies?

“And second, would it have a positive and measurable environmental impact when looking at the entire lifecycle of the process?” For Coskata, the answer to both of these questions is a resounding yes.

Net energy balance refers to the amount of fossil fuel input required to produce a given amount of liquid fuel energy output. It becomes critical as it correlates with the greenhouse gas emissions associated with a process. To determine net energy balance, fossil energy inputs for the entire supply chain are taken into account—from growing, harvesting and transporting the feedstock to producing and distributing the fuel into gas tanks.

Coskata’s net energy balance was determined by the Argonne National Laboratory to be 7.7. The company also asserts that its technology can reduce greenhouse gases by as much as 96 percent (well-to-wheel efficiency) over conventional gasoline, while using less than half the water it takes to process gas.

Roe goes into detail, “We even recover water from drying processes and reuse it. By tightening up our whole water circuit, and recycling water when we can, we end up with losses in the 1- to 1-1/2-gallon range. And most water loss is evaporative via cooling systems.”

Environmental benefits also stem from the flexible-feedstock aspect of the process. The company eventually expects to process municipal waste, agricultural residues, recycled tires, used bitumen and river sludge at the Lighthouse facility. But according to Bolsen, “If you’re going to build it in Georgia, it’s not going to be corn stover. If you’re going to build it in New York City, it’s most likely going to be waste. If you’re in pulp and paper, you’re going to be looking at integrating wood waste into your core business. You start with what feedstock is available. Biomass must be local, otherwise the economics don’t work.”

With this versatility of flexible feedstocks, the process also allows operators to choose to abstain from use of food crops, in addition to sourcing locally abundant raw materials to further shrink their carbon footprint.

Collocation With Your Processing Plant

Coskata is targeting industries, especially in the processing marketplace, in addition to feedstock-oriented companies, such as those that involve timber and/or construction, for collocation opportunities. Collocation has the potential to supply power to a facility, as well as put 20 to 50 megawatts back on the grid, according to the company.

Roe says, “In a steel mill, you have an oxygen furnace, and it’s basically the heart of the mill, where you do initial conversions of the ore into molten metals. In the process, a massive quantity of carbon monoxide is generated, and carbon monoxide is bug food in our vernacular. Harnessing that carbon monoxide stream and using it as fuel makes a lot of sense.

“In this or any other industrial process, you have mass and energy inputs and outputs. Pulp and paper mills, for instance, operate massive boilers to recover pulp and chemicals. A collocated facility could potentially eliminate the need for those boilers from an energy standpoint. And we have so much energy available in the form of steam. The heat of gasification is tremendous, and we recover it in order to supply it to neighbors.

“Think of Coskata as a British thermal unit (BTU) machine.” Roe continues, “Fuel and energy come out of this thing. How do you want to use the heat? Turn a turbine that makes electricity? Deliver steam? That’s the true power of collocation—doubling the utility of one resource, in addition to achieving a better carbon footprint. It’s about energy conservation.”

For existing ethanol plants, the process is best optimized within facilities that have a capacity of more than 50 million gallons per year, requiring roughly 1,500 plus dry tons of material per day.

Production costs are and always will be dependent on the feedstock supply chain. According to Bolsen, “Although technically feasible, smaller facilities are more costly to develop. Our process can scale to much larger sizes as well, with size being limited only by the amount of available feedstock in a local area. Paying $50 a dry ton, Coskata can be directly competitive with gasoline—long-term and unsubsidized—today.”

Biofueling The Tide

Bolsen warns, “You start demanding too much of one feedstock, and it becomes unaffordable. To have the diversity that FlexEthanol affords, we can get up to 90 billion gallons of ethanol without significant land-use changes; yet we only have a mandate for 36 [billion gallons]. Let’s just get to the point in which a consumer can drive up to a pump and have a choice to put it in his car. It’s good for his pocketbook, and it’s good for the environment. Today, people shouldn’t have to sacrifice one for another.” 

Bolsen refers to the Energy Independence and Security Act of 2007 (H.R. 6). This comprehensive energy legislation amends the Renewable Fuels Standard signed into law in 2005, increasing the reach of the renewable fuel mandate to 36 billion gallons in 2022, alongside a requirement for 21 billion of those gallons to come from non-food sources.
“Coskata has not taken any government funding to date. Great ideas get commercial backing.” Bolsen continues, “Then again, I love a mandated market. The government can do what no single consumer can.”

Although Coskata hasn’t had to take any government handouts, the company isn’t opposed to the idea. Bolsen alludes, “There has been some interest from the Department of Energy (DOE) to further [FlexEthanol] technology. They don’t have the bugs, and they don’t have the bioreactors [of which Coskata can boast]. The National Renewable Energy Laboratory (NREL) has worked with gasifiers, but we’re new. We don’t have enzymes. We don’t do pretreatment. We don’t use chemical catalysts. And that’s what they spent hundreds of millions of dollars on … I think they want to understand why FlexEthanol is the best of both worlds—the best of gasification and the best of syngas fermentation.”

What Now?

Coskata leverages proprietary microorganisms and efficient bioreactor designs, along with biological fermentation technology that is ethanol-specific and enzyme-independent, to contribute high-energy conversion rates and ethanol yields to the commercial market. To top it off, the process does not require additional chemicals or acid pretreatments, further streamlining prospective operational costs.

Moreover, Roe acknowledges, “We have already developed engineering designs for our first commercial-scale facility located in the southeastern United States, and depending on the timing of financing, it could come to fruition in late 2012. The facility will be run on wood biomass and produce 50 to 60 million gallons per year.”

The FlexEthanol fuel is already compliant with American Society for Testing and Materials (ASTM) and International Organization for Standardization (ISO) specifications, so what are you waiting for? According to Roe, “The next step is construction of full-scale facilities.”

As far as ethanol refueling infrastructure is concerned, Bob Babik, GM vehicle emissions policy director, adds, “I think people have been reticent to really roll out the E85 infrastructure. We’ve made progress, albeit slow. How do you tell a consumer why a certain fuel is good? If we get competitive ethanol in the marketplace, however, I think that we’ll have a chance to spur a real sea change.”

The team believes that FlexEthanol’s cost-competitiveness, combined with its newfound commercial availability, will be the inspiration of that biofuel tide.

For more information, visit www.coskata.com.

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