Renergie to Test Hydrous Ethanol Blends

Posted on July 28, 2008. Filed under: Field-to-Pump, Hydrous Ethanol | Tags: , , , , , |

As provided for in Act No. 382, the use of hydrous ethanol blends of E10, E20, E30 and E85 in motor vehicles specifically selected for test purposes will be permitted on a trial basis in the State of Louisiana until January 1, 2012.  During this period the Louisiana Department of Agriculture and Forestry Division of Weights & Measures will monitor the performance of the motor vehicles. The hydrous blends will be tested for blend optimization with respect to fuel consumption and engine emissions.  Preliminary tests conducted in Europe have proven that the use of hydrous ethanol, which eliminates the need for the hydrous-to-anhydrous dehydration processing step, results in an energy savings of between ten percent and forty-five percent during processing, a four percent product volume increase, higher mileage per gallon, a cleaner engine interior, and a reduction in greenhouse gas emissions.

 

The following is an excerpt from an article by Troels Johansen that appeared in the July, 2007 issue of the Technical University of Denmark’s IC Engine Group newsletter.

 

The water tolerance of bioethanol fuel blends is being studied as part of a Bachelor thesis concerning specifications of fuel blends with a high ethanol content.

 

This spring, the first flexible fuel vehicle (FFV) will be available for car buyers in Denmark – the Ford Focus Flexifuel. Together with the governments’ newfound enthusiasm for biofuels, this seems to mark the beginning of a more environmentally friendly transport sector in Denmark. For biofuels to be commercially viable outside a small “green” segment of the population they have to be competitive both with regard to price, availability and performance.

 

In the case of USA and Sweden, these three factors have been incorporated through a common concept for introducing biofuels in general and bioethanol in particular. This entails:

• a certain lowering of taxes on biofuels, thereby reducing prices.

• adding a lesser amount of gasoline (15-25%) to the bioethanol to alleviate cold start difficulties which can be a problem in northern climates. This is known as the ‘E85’ blend.

• the ‘Flex Fuel’ option. This means that cars that can run on E85 can also run on gasoline and any mixture of the two. This effectively solves the availability issue, since a ‘northern hemisphere’-FFV will be able to refuel almost anywhere in the world, also where biofuels are not available.

 

In Brazil (where the market for FFVs is huge) a FFV is something quite different.  A Brazilian FFV is not designed to run on straight gasoline, but on either E100 (‘hydrous’ ethanol consisting of 93% ethanol and 7% water), E22 (22% Ethanol, 78% gasoline, 0% water) or any mixture of these two.  In theory this restricts the ‘southern hemisphere’-FFVs to areas where fuels with less than 78% gasoline are available (still primarily South America). The up side is that the production cost of the E100-fuel is much lower than for northern hemisphere E85.  The reason for this (and many of the other commercial choices concerning bioethanol) is the water content.

 

The production of bioethanol is in the main a question of removing water from the 11% ethanol/89% water-blend that fermentation produces. This is achieved through distillation up to the point where the blend is about 95% ethanol, and a so-called dehydration from that point up. The energy cost of removing one unit of water from the blend is at a constant low value up until about 80% ethanol in the blend, where it starts to increase quite sharply. If an ethanol purity of more than 95.6% (the azeotrope concentration) is required, the producer not only has to field these larger energy expenses but also needs to invest in separate dehydration equipment.  Clearly there is an economic incentive for using less than pure ethanol as a fuel and in fuel blends, as has been done in Brazil since the seventies.  The Brazilian experience shows that the presence of small (<10%) amounts of water in the fuel does not in itself cause a greater tendency to misfire in SI-engines than a proportionate leaning of the fuel/air mixture would do, provided that the vapor pressure of the hydrated ethanol at the ambient temperature is high enough. Experiments have even shown that the evaporation of the water in the intake manifold acts as a charge air cooling, which improves the volumetric efficiency and thereby the overall efficiency of the engine.  One of the most obvious downsides is, of course, that the heating value of water is zero and as such water is simply dead weight in the fuel tank. This clearly means that a car running on water-free (anhydrous) ethanol will still (even with the better volumetric efficiency) have a higher mileage per liter than one running on hydrous ethanol.  If the cost of the hydrous ethanol is sufficiently lower, it may, however, still provide a lower cost per mile travelled, that is if the percentile monetary saving of one liter hydrous ethanol vs. anhydrous is greater than the percentile reduction in heating value of one liter.

 

As mentioned above, the current ‘northern hemisphere’-FFVs are not designed to use either hydrous or anhydrous ethanol by itself, but rely on a measure of gasoline to alleviate cold start problems.  The higher vapor pressure of the gasoline (60-90 kPa vs. about 17 for ethanol) ensures that enough fuel (primarily the gasoline) will be vaporized in the injection process for the engine to start on, even when cold. However, the presence of gasoline in the fuel blend puts severe limits on how much water can be in the blend without phase separation occurring, that is the blend separating into two distinct liquid phases: an upper gasoline/ethanol phase and a lower water/ethanol phase. Because of the molecular dissimilarity of water and gasoline, these two are immiscible above a very few ppm. When adding ethanol as a third component, however, significantly more gasoline and water can coexist in the same blend, the ethanol effectively acting as a mediator between the two.  When using ethanol in blends with more than 90% gasoline, such as the ‘Bio 95’ offered by Statoil in Denmark, the ethanol volume is too small to significantly improve the water tolerance, and the ethanol produced for this purpose is therefore almost anhydrous. In fuel blends with a high ethanol content, however, this requirement should in theory be less strict, though few experimental data are available to substantiate exactly what the tolerances are of E85-type blends.

 

From a Danish perspective, the best experimental results that are available (produced in Brazil in 1993) have two different shortcomings.  Firstly, it does not supply data for temperatures below -10 degrees Celsius.  Since the miscibility of liquids depends heavily on the ambient temperature, though not in a strictly linear way, it is unknown what the water tolerances would be at the lowest Danish winter temperatures (-20 degrees Celsius during the night not being rare). Secondly, the exact composition of the gasoline used in these experiments is sure to have been different from the gasoline available in Denmark today, gasoline specifications not being uniform across time and borders.  As an example the upper limit of content of aromatics in gasoline was in 2005 lowered from 42 vol% to 35 vol%, something which in itself could have a relevance for the subject at hand, since studies have concluded that the content of aromatics are proportional with the water tolerance of gasoline.

 

As a part of the Bachelor thesis project, experiments have been performed to evaluate the water tolerances of ethanol/gasoline/water blends with a high content of ethanol (60-90%) at 0 and – 23 degrees Celsius, these being estimates of the lowest temperatures during the summer and winter half-year, respectively.  

 

Even though the long term stability of the fuel blends have not been fully tested yet, the test data strongly indicates that the ethanol used in E85-type fuel blends could be significantly less pure, and therefore cheaper, than the ethanol used now for these purposes (the overall vol% of water currently not being above 0.5% in E85).

 

 

About Renergie

Renergie was formed by Ms. Meaghan M. Donovan and Mr. Michael J. 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.

 

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    Renergie created “field-to-pump," a unique strategy to locally produce and market advanced biofuel (“non-corn fuel ethanol”) via a network of small advanced biofuel manufacturing facilities. The purpose of “field-to-pump” is to maximize rural development and job creation while minimizing feedstock supply risk and the burden on local water supplies.

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