John Storey

FUNGIBLE AND COMPATIBLE BIOFUELS: LITERATURE SEARCH, SUMMARY, AND RECOMMENDATIONS

The purpose of the study described in this report is to summarize the various barriers to more widespread distribution of bio-fuels through our common carrier fuel distribution system, which includes pipelines, barges and rail, fuel tankage, and distribution terminals. Addressing these barriers is necessary to allow the more widespread utilization and distribution of bio-fuels, in support of a renewable fuels standard and possible future low-carbon fuel standards. These barriers can be classified into several categories, including operating practice, regulatory, technical, and acceptability barriers. Possible solutions to these issues are discussed; including compatibility evaluation, changes to bio-fuels, regulatory changes, and changes in the distribution system or distribution practices. No actual experimental research has been conducted in the writing of this report, but results are used to develop recommendations for future research and additional study as appropriate. This project addresses recognized barriers to the wider use of bio-fuels in the areas of development of codes and standards, industrial and consumer awareness, and materials compatibility issues.

Novel Approaches to Catalytic Upgrading of Bio-Oil

To date the upgrading of bio-oils has primarily been achieved by means of acid catalyzed ncracking or hydrotreating. Given that hydrotreating requires large volumes of hydrogen, which has a nsignificant impact on process economics, cracking represents a more economically attractive option. nHowever, there are difficulties encountered in the use of acid cracking catalysts such as H-ZSM-5. nThese include high yields of gaseous hydrocarbons of low value, and the occurrence of coke nformation. Coke formation results in rapid catalyst deactivation (as a consequence of the high npolymerization activity of pyrolysis oils). An alternative concept aimed at catalytic deoxygenation of nbio-oil to a stabilized product is mild cracking over base catalysts. To maximize liquid product yields, nmild cracking has been studied for the decomposition of polysaccharides and polysaccharide-derived nproducts in the crude bio-oil, without cracking the lignin-derived oil. Commercial ZnO and freshly ncalcined Zn/Al and Mg/Al layered double hydroxides were used to upgrade a synthetic bio-oil ncomposed of methanol (5%), acetaldehyde (12%), acetic acid (14%), glyoxal (4%), acetol (8%), nfurfural (4%), glucose (8%), guaiacol (17%), vanillin (8%), and water (20%). These compounds ncorrespond to some of the main components found in pyrolysis oils, and represent the most reactive nfunctional groups present (aldehyde, carboxylic acid, ketone, and phenol). The composition of the nupgraded bio-oil was assessed based on GC, GC/MS, and elemental analysis (for C, H, and O).

Lowering NOx and PM Emissions in a Light-Duty Diesel Engine with Biodiesel-Water Emulsions

A key barrier limiting extended utilization of biodiesel is higher NOx emissions compared nto petrodiesel fuels. The reason for this effect is unclear, but various researchers have attributed this nphenonmena to the higher liquid bulk modulus associated with biodiesel and the additional heat nreleased during the breaking of C-C double bonds in the methyl ester groups. In this study water nwas incorporated into neat biodiesel (B100) as an emulsion in an attempt to lower NOx and nparticulate matter (PM) emissions. When added to petroleum diesel, water has been shown to nimprove fuel/air mixing, reduce peak combustion temperatures, and increase mass during ncombustion, resulting in lower NOx and PM emissions with no fuel penalty. A biodiesel emulsion ncontaining 10wt% water was formulated and evaluated against an ultra-low sulfur petroleum diesel n(ULSD) and neat biodiesel (B100) in a light-duty diesel engine operated at 1500RPM and 50ft-lbs. nThe influence of exhaust gas recirculation (EGR) was also examined. The incorporation of water nwas found to significantly lower the NOx emissions while maintaining or improving fuel efficiency nwhen operating at 0 and 27% EGR, while the total PM mass was lowered dramatically for the 27% nEGR condition only. Analysis of the emissions and heat release data indicate that water enhances nair-fuel premixing to maintain fuel economy and lower PM.