Hydrous Ethanol Can be Effectively Used in Most Ethanol/Gasoline Blending Applications
Ethanol fuel specifications traditionally dictate use of anhydrous ethanol (less than 1% water) for gasoline blending. This results in additional costs, energy usage and environmental impacts associated with the extra processing step required to dehydrate the hydrous ethanol (4-5% water) produced via distillation to meet the current anhydrous ethanol specifications. A recent study reveals for the first time what conventional wisdom has overlooked – namely that hydrous ethanol can be effectively used in most ethanol/gasoline blending applications, reducing or eliminating the need for anhydrous ethanol production and distribution.
The following article appeared in the May, 2008 issue of Ethanol Producer Magazine.
Testing the Water
Conventional wisdom says water in ethanol is bad, but a new technical understanding is emerging that could dramatically improve corn-based ethanol’s environmental footprint while revolutionizing how the alternative fuel is made, transported and used.
by Ron Kotrba
A lot of attention is being focused on midlevel ethanol blends. If that’s considered a hot topic then the issue of midlevel hydrous blends reaches the magnitude of a Super Nova. A convincing message is reaching influential ears in government and private industry, and it turns conventional wisdom on its head. The accepted truth is that water in ethanol is bad—period. As such, anhydrous “water-free” ethanol has been the norm in the United States since the blend component’s debut in gas supplies 25 years ago. Now enter a serendipitous, convincing find.
“This just happened last year—it’s very new,” says Frits Dautzenberg, a San Diego-based consultant. “How is it possible everyone missed this point?” Dautzenberg is retained as a consultant by the Netherlands-based Process Design Center Inc. What Dautzenberg is talking about is a new understanding of hydrous ethanol’s relationship to gas and ambient moisture.
This “new science” reveals midlevel hydrous ethanol (96 percent ethanol, 4 percent water, i.e., azeotropic) blends will not phase separate and can absorb five times more water than anhydrous ethanol blends. The implications of this are widespread, potentially affecting every aspect of ethanol’s role in fuel supplies. PDC works with many major oil and petrochemical companies, and owner Hans Keuken tells EPM how it all started.
One of his researchers was interested in challenging conventional ethanol drying methods using mol sieves and membranes. The goal was to find ways to reduce the cost and energy intensity of dehydration. A little bored by this proposal, Keuken said to his team, “If you really want to innovate—and the fuel-ethanol is going in the gasoline anyhow—maybe look for ways to separate ethanol and water with gasoline.” Keuken’s reasoning was that gasoline is full of aromatics also used in azeotropic distillation.
“In principle, one can use a liquid-liquid extraction column to extract ethanol from an ethanol-water mixture into a gasoline stream,” he says. This presumes that the two liquids then can be totally separated, but the researchers found this was not exactly the case. In the top of the extractor the densities of the two liquids were similar and took a long time to completely disengage, which led to prohibitively large extractor volumes that were operationally too expensive. An idea immediately followed, which was, “If we can’t get the water out, why not leave it in?” Keuken says. “So what appeared to be a show stopper for extraction promised to be an opportunity for hydrous ethanol blending—some call this serendipity.”
The oil industry looks at refinery streams as continuous mixtures of hydrocarbons with certain common behaviors which typically do not mix with water. “But ethanol is a substance that seriously disturbs this regular picture,” Keuken says. “Refiners were deceived by their intuitions.” PDC however approached gas-ethanol mixtures from more of a chemicals angle.
Many major oil companies are PDC clients. “Although they were reluctant to initially believe us, we are also in the lucky position to have enough technical credibility to be taken seriously,” Keuken says. After giving a presentation in Brussels, Belgium Walter Mirabella, an methyl tertiary butyl ether and ethyl tert-butyl ether lobbyist, was in the audience and asked Keuken, “Do you think the entire fuel industry is stupid?”
Shell Oil was approached with this information and according to Dautzenberg the oil major’s response was, ‘This cannot be true—we know everything about this.’ But everyone is using 20-year-old data,” he tells EPM. “They said they needed to repeat it and they did and conferred with us. They were surprised.”
Everyone working in ethanol thought they knew the whole concept of water separation and the necessity of extremely low water, says Tom MacDonald, who spent 30 years with the California Energy Commission as an ethanol fuels specialist. He retired last year and started his own consulting firm called MacDonald Associates. Dautzenberg and Keuken approached the CEC shortly before MacDonald’s retirement and asked if they could present their findings. “We were all skeptical in the beginning,” MacDonald says. After leaving the CEC, MacDonald went to Europe to meet with PDC officials who spun off a company called HE Blends BV, on the wet alcohol concept. He came back convinced. “I’ve had people looking hard at this to find any flaw, any problem, and it all looks very solid,” MacDonald says.
MacDonald still does some work for the CEC, but also finds interest in the Brazilian fuels industry where both hydrous and anhydrous blends exist. According to him, not much needs to be done in Brazil to transition to a hydrous ethanol economy. What’s harder though is convincing the U.S. federal and state governments, oil companies, pipeline operators and vehicle manufacturers that midlevel hydrous blends are a prudent evolution.
The team took its message to influential people in government and private industry in January, starting in Minnesota, the ethanol hotspot. The state passed the first E20 mandate in the United States a few years ago. “Minnesota is a place that could really do this the soonest,” MacDonald says. After visiting with the state agriculture department the team met with Kelly Davis the Renewable Fuels Association technical committee chair and ethanol specification guru.
ASTM revisited its water specification for ethanol (less than 1 percent) but the tests employed to verify PDC’s findings were bunk, McDonald says. “They had a procedure where you put anhydrous ethanol in the gasoline and then add water,” he says. “That’s a whole different animal than when it comes chemically bound in the ethanol itself.”
Implications and Research
An ethanol plant builder based in Minnesota is conducting a pro bono study to pinpoint the energy savings that result from skipping the dehydration step. The results are expected early this spring. Depending on the technology employed, Keuken suggests between 10 percent and 45 percent energy savings will be gained by eliminating dehydration. “The benefit of HE Blends’ discovery stem primarily from the avoided capital, operating and energy costs of eliminating the need for the hydrous-to-anhydrous ethanol step,” says Eric de Jager, marketing and sales manager with HE Blends. Jager also points out that a 4 percent product volume increase happens while reducing energy consumption and costs. “Overall a transition from anhydrous to hydrous ethanol for gasoline blending is expected to make a significant contribution to ethanol’s cost-competitiveness, fuel cycle net energy balance and greenhouse gas emissions profile,” he says.
Hydrous ethanol may be the key to ethanol’s acceptance in the mainstream fuel pipeline distribution network. “Conventional pipelining with [anhydrous] ethanol picks up water, and when it separates out corrosion is a concern,” Dautzenberg says. With higher concentrations of wet ethanol able to homogeneously retain up to five times more moisture than dry ethanol blends, the fear of phase separation is significantly reduced. Keuken backs up this point. “People associate water with corrosion but in this case the water is dissolved on a molecular level and completely sealed off by hydrocarbons, so these corrosion effects will not occur,” he tells EPM. Even international trade could benefit. “Stringent water specs on ethanol, which attracts water, oftentimes force people to dry twice,” Keuken says. This negatively impacts the alternative fuel’s overall energy balance.
Perhaps one of the most important aspects of hydrous ethanol blends is its effect on vehicle performance and emissions. Preliminary tests have already been done in Europe and the results on performance, fuel economy, emissions and engine wear for midlevel hydrous ethanol blends are all favorable, if not unexpectedly so. “Water injection in combustion engines increases the thermodynamic efficiency and this will increase mileage, which has never been properly investigated for normal cars,” Keuken says. “The water cools the mixture somewhat, which may allow for more mixture to enter the cylinder,” Jager explains. “But the greater effect comes later during combustion when the water takes in significant amounts of heat energy as it converts from liquid to gas, increasing piston pressure—torque—and reducing the peak temperature,” which reduces nitrogen oxide (NOx) formation.
Preliminary results of this kind were seen in a standard Volkswagen Golf 5 FSI tested on hydrous E15 by the SGS Drive Technology Center based in Austria and TNO Automotive in the Netherlands. A marginal increase in fuel efficiency coupled with hitting European Union 4 exhaust emissions targets and a cleaner engine internally were achieved. According to Jager, these results helped steer the Dutch and German governments to agree to fund an E0 to E85 performance curve research program for midlevel hydrous and anhydrous blends. Anhydrous and hydrous blends of E10, E25, E50 and E85, will be tested for blend optimization with respect to fuel consumption and engine emissions. MacDonald says he hopes to begin his own vehicle testing in the United States once he can convince an automaker to donate a car or two.
“In our view it’s a win-win for almost everybody,” Keuken says. “Producers can skip the drying step, sell 4 percent more volume, save on energy costs and operational headaches, maintenance and capital investments. International trade will benefit. Oil companies benefit from allowing higher water tolerances in their distribution systems. The car owners can benefit from a higher mileage per gallon and cleaner engine interior. The world can benefit from less overall greenhouse gas and NOx emissions.”
Ron Kotrba is an Ethanol Producer Magazine senior writer. Reach him at firstname.lastname@example.org or (701) 738-4962.
Renergie was formed by Ms. Meaghan M. Donovan on March 22, 2006 for the purpose of raising capital to develop, construct, own and operate a network of ten ethanol plants in the parishes of the State of Louisiana which were devastated by hurricanes Katrina and Rita. Each ethanol plant will have a production capacity of five million gallons per year (5 MGY) of fuel-grade ethanol. Renergie’s “field-to-pump” strategy is to produce non-corn ethanol locally and directly market non-corn ethanol locally. On February 26, 2008, Renergie was one of 8 recipients, selected from 139 grant applicants, to share $12.5 million from the Florida Department of Environmental Protection’s Renewable Energy Technologies Grants Program. Renergie received $1,500,483 (partial funding) in grant money to design and build Florida’s first ethanol plant capable of producing fuel-grade ethanol solely from sweet sorghum juice. On April 2, 2008, Enterprise Florida, Inc., the state’s economic development organization, selected Renergie as one of Florida’s most innovative technology companies in the alternative energy sector. On January 20, 2009, Florida Energy & Climate Commission amended RET Grant Agreement S0386 to increase Renergie’s funding from $1,500,483 to $2,500,000. By blending fuel-grade ethanol with gasoline at the gas station pump, Renergie will offer the consumer a fuel that is renewable, more economical, cleaner, and more efficient than unleaded gasoline. Moreover, the Renergie project will mark the first time that Louisiana farmers will share in the profits realized from the sale of value-added products made from their crops.