Global Bioenergies (GBE), a leading developer of one-step fermentation processes for the direct and cost-efficient transformation of renewable resources into light olefins (earlier post), has signed a collaboration agreement with Audi on the development of bio-isooctane—a high-performance drop-in biofuel for gasoline engines—derived from bio-isobutene. In 2011, GBE had announced an agreement “with a major German car manufacturer” regarding an undisclosed application of GEB’s technology. (Earlier post.)
Under the agreement, GBE will supply Audi with isooctane derived from isobutene produced at its new pre-commercial pilot system at the Fraunhofer CBP in Leuna. (Earlier post.) During the two-year collaboration, this agreement also foresees the possibility for Audi to acquire shares of Global Bioenergies corresponding to less than 2% of its capital.
Global Bioenergies has engineered an initial series of bacterial strains that can produce light olefins via the fermentation of sugars. The process is designed to be used downstream from multiple sugar production pathways: sugar, starch and cellulose. The process can thus be used with cellulosic biomass, following pretreatment and hydrolysis.
|SAE High Octane Fuels Symposium|
|Coincident with the announcement of the GBE-Audi collaboration, SAE is holding its second High Octane Fuels Symposium (HOFS) in Washington, DC. (earlier post).|
|The inaugural HOFS last year explored the pros and the cons of high octane fuels, with a particular focus on using ethanol as the source of the octane improvement.|
|This year’s HOFS will focus on two key aspects of high-octane fuels that were identified during the 2013 symposium.|
|The first is whether high-octane fuels can be produced with the goal of enabling improvements in vehicle efficiency while retaining a full life-cycle benefit in terms of energy use and CO2 production. In other words, can high-octane fuels enable overall energy use and greenhouse gas reductions in the future, or is a better overall outcome achieved through making the best of today’s fuels?|
|The second is the retail and infrastructure requirements to support a future high-octane fuel.|
Light olefins are key chemical building blocks that can be converted into transportation fuels, polymers and various commodity chemicals. GBE’s first, and most advanced program, is the production of bio-isobutene. Currently, more than 10 million metric tons of petrochemical-derived isobutene are produced on a yearly basis.
Isobutene—a four-carbon branched alkene and one of four isomers of butylene (C4H8)—is a molecule with multiple applications, one of which allows its transformation into isooctane. Pure isooctane (2,2,4 trimethylpentane) has both a high research octane number (RON) and a high motor octane number (MON): 100 RON and 100 MON. A low Reid vapor pressure of 1.8 psi make it also attractive for bending into reformulated gasoline.
As a 100% drop-in fuel, isooctane can be used in any blending ratio with all standard fuels for gasoline motors. It does not present the drawbacks associated with alcohol-based biofuels such as ethanol or isobutanol which lead to limited blending ratios and lower mileage per liter. Isooctane also is a hydrocarbon with a high energetic density (approx. 44 MJ/kg), compared to the 27MJ/kg of ethanol.
Using bio-isooctane instead of ethanol would be a way to get through the blend wall (limits on the percentage by volume of ethanol permitted in the standard fuel pool) facing fuels providers in the US, suggests GBE CEO Marc Delcourt.
(Further, Germany experienced a rocky introduction of E10 in 2011; consumers balked at the blend fuel, and despite some gains in adoption, E10 has yet to capture a significant portion of the market. A renewable bio-isooctane would address renewable fuel content issues without perturbing the consumer.)
The conversion of standard isobutene (isobutylene) to isooctane is a well-known refinery process. For example, KBR offers the NExOCTANE process for the selective conversion of isobutylene to isooctane. The NExOCTANE process, developed by Fortum’s Neste Engineering Oy and licensed in the Americas through KBR, selectively converts isobutylene to mainly di-isobutylene (isooctene) that is optionally hydrogenated to paraffinic isooctane.
GBE will produce the bio-isooctane itself at the Leuna pilot facility, said Delcourt. “We will be working at setting up small scale production, not industrial—enough for doing engine testing,” he said.
Audi is a frontrunner at implementing sustainable solutions for all aspects directly linked to its products. Three parameters are key to Audi in pushing forward the development of new biofuels: the quality of the fuel to ensure optimal compatibility with its engines; the environmental footprint in particular regarding CO2 emissions; and the requirement to use feedstock not in competition with food.
Audi’s “e-gasoline” initiative with Global Bioenergies is part of the overall Audi e-fuels strategy, the company said. Audi is already operating a research facility for the production of e-ethanol and e-diesel with its partner Joule in Hobbs, New Mexico. (Earlier post.) The Audi e-gas plant in Werlte began feeding into the grid a few months ago. (Earlier post.) Synthetically produced gas is used here to store electric surplus energy.
Bianca N. M. van Leeuwen, Albertus M. van der Wulp, Isabelle Duijnstee, Antonius J. A. van Maris, and Adrie J. J. Straathof (2012) “Fermentative production of isobutene,” Appl Microbiol Biotechnol. 93(4): 1377–1387 doi: 10.1007/s00253-011-3853-7