Bioethanol

The ethanol produced can be used as a fuel additive and as an industrial chemical product. Most of the fuel ethanol in the USA and Canada is used as a gasoline additive and an enhancer of the number of octanes to replace the MTBE (Methyl-Tertiary-Butyl-Ether) by the direct mixing with the gasoline. A 10% volume ethanol blend (e10), known as gasohol, can increase the number of octanes by two to three points, providing an added value to the mid-to-low octane gasoline. Fuel ethanol can also be used as e85, a mixture of 85% ethanol and 15% gasoline. E85 is used in "flexible fuel vehicles" (FFV) designed specifically for the consumption of this type of fuel.

However, in Europe the maximum limit of ethanol is restricted by the specification of the oxygen content of 2.7%, which means limiting the use of ethanol to 7.8%. No waiver for ethanol mixtures higher than 7.8% is provided. In some European countries a mixture of 5% ethanol is normally used. European refineries and car manufacturers prefer the ETBE (Ethyl-Tertiary-Butyl-Ether) instead of ethanol as a renewable oxygenate additive. In order to increase the ethanol market and the demonstration programs on the end uses of ethanol, ABNT is conducting research and development in different areas to support the business in Europe, among which stands out, FFV, fuel cells, e-Diesel, etc.

The Flexible Fuel Vehicles (FFV) are specially designed automobiles or light trucks with the ability to operate on multiple fuel mixtures. The flexibility to the mixtures is achieved through special sensors that determine the fuel mixture and automatically adjust the synchronization of the engine's ignition and air/fuel coefficients. The FFV can use fuels with any gasoline and alcohol ratio, or use normal gasoline directly. As a global producer of ethanol, Abengoa Bioenergía is promoting the use of ethanol as fuel and is constantly improving its corporate image. ABNT is involved in experimental tests of FFV to supply consumers with information on vehicle performance, driving and emissions. The data collected enables the generation of fact sheets to introduce this fuel and assist consumers in making decisions to purchase vehicles prepared for the use of alternative fuels.

The cells are one of new markets for ethanol. Electrochemical fuel cells convert the chemical energy from ethanol directly into electrical energy to provide a clean and highly efficient energy source. Fuel cells work similarly to conventional batteries, but can run continuously as long as fuel is supplied, and they can achieve 40 to 50% efficiency in the conversion of fuel energy into useful power, compared with the approximate 18% efficiency for the average internal combustion engine. Besides high efficiency, other benefits of using the fuel cell in the transport sector include a huge reduction in emissions, less vehicle maintenance and the ability to reach up to 80 mpg (33 km/l). Fuel cells could eventually be used to supply power to homes, vehicles, and small electronic devices.

Ethanol is one of the most suitable fuels for a fuel cell. Besides resulting from renewable resources, purified ethanol can solve the major problem of membrane contamination and catalyst deactivation within the fuel cell, which limits its life expectancy. In order to develop a common vision of the role that ethanol can play in the fuel cell industry, ABNT has been involved in the research and development of ethanol fuel cell technologies. These research activities will ensure that ethanol remains among the most suitable fuels for fuel cells, providing all the benefits that the ethanol fuel cell technology promises.

The ethanol-diesel blend, better known as e-diesel, is obtained by mixing bioethanol with traditional diesel oil, in a percentage that varies between 5 and 15%, and an additive that ensures the stability of the mixture. It can be used in traditional diesel oil motors with slight modifications or without them. Compared with regular diesel fuel, e-diesel can significantly reduce the emissions of particles and other contaminants, and improve cold start-up properties. It is currently in the development stage, and not yet commercially available. ABNT is working to reduce the main technical and regulatory barriers for its commercialization. These barriers include:

• Low flashpoint and tank volatility.
• Instability of the micro-emulsion (separation of ethanol phases and diesel at low temperatures).
• Guarantee from the Original Equipment Manufacturer (OEM), by generating data in real tests.
• Lack of process standardization that allows its registration according to the standards on emissions and health.

The use of e-diesel will further expand the market for ethanol applications.

E-diesel has been mainly tested in the USA and Brazil and currently in Spain and Europe. Fleet demonstrations indicate that the e-diesel can be easily handled and used with proper staff training. No significant operational or material problems have been reported. The main differences in the handling of e-diesel compared with conventional diesel oil are based on ensuring that water is not added to the fuel. In order to ensure a correct performance of the fuel, a quality control system of the ethanol, the diesel oil, and the final blend are necessary, as well as the establishment of a fuel specification.

One of the main difficulties for the commercial introduction of e-diesel is that its flashpoint is intermediate between diesel oil and gasoline, which means that for its handling, storing and use, it must be treated as though it were gasoline. Thus, diesel oil facilities must be slightly modified to these purposes. The results from the tests conducted by NREL show that the e-diesel implies safety implications the same as gasoline.

In terms of emissions, the resulting blend of 8% ethanol, less than 1% of a suitable additive and 91% of diesel oil, generates reductions of the typical emissions reported:

• Reduction of visible smoke by up to 70%.
• Reduction of particulate matter (PM) emissions by up to 40%.
• Reduction of carbon monoxide (CO) emissions by up to 30%.
• Reduction of nitrogen monoxide (NOx) emissions by up to 6%.

Thanks to a project financed by the Spanish Ministry of Education and Science (Fit-120000-2004-108), Abengoa Bioenergy has evaluated the optimal blend formulation, the compatibility of the materials and the performance of engines in a Spanish automotive research and development center (Cidaut), testing both off-road and LDV engines.

The latest studies developed by Abengoa Bioenergía in cooperation with several research centers determine that not only is the conventional ethanol-diesel blend satisfactory but that the ethanol-diesel-biodiesel blend is showing good results. Specifically, for the ethanol-diesel-biodiesel blend, also known as ebdiesel, the analysis of the results obtained shows an increase in the miscibility of ethanol-diesel blends with the addition of biodiesel, the reduction in the emission of particles and gaseous emissions such as NOx both in stationary tests and transitory tests, as well as the reduction of the opacity of gases among other advantages.

In January 2005, Abengoa Bioenergy joined the US E-diesel Consortium, which includes the involvement of a broad and active industry and the US government.