A team from Argonne National Laboratory and the University of Illinois reports that the heavy alcohol phytol (C20H40O)—which can be produced by photosynthetic bacteria—may be a suitable blending agent with diesel fuel for compression ignition (i.e., diesel) applications. The team’s latest report on this work appears in the journal Fuel.
Researchers at Argonne earlier filed a patent application on engineered bacteria that produce phytol (tetramethyl-2-hexadecen-1-ol), the physical and chemical properties of which (cetane number, heat of combustion, heat of vaporization, density, surface tension, etc.) correspond in magnitude to those of diesel fuel.
The Fuel study investigated the feasibility of using phytol as a blending agent with diesel, and evaluated three blend levels: P5, P10, and P20 (5%, 10%, and 20% phytol by volume). The fuel blends were extensively analyzed to determine their chemical and physical properties, with mostly comparable values, excepting viscosity and vapor pressure.
In order to understand the effects of higher viscosity phytol in the fuel injector, three-dimensional simulations of transient, turbulent nozzle flow compared the injection and cavitation characteristics of the various blends. Specifically, area and discharge coefficients and mass flow rates of diesel and phytol blends were compared under corresponding engine operating conditions.
The team used a single-cylinder engine under conventional operating conditions to gather comparative performance and emissions characteristics of the various blends of phytol and diesel. The influence of the fuel’s chemical composition on performance and emission characteristics was captured by executing an injection timing sweep.
Combustion characteristics such as the in-cylinder pressure trace were comparable for the diesel and all the blends with phytol at each of the injection timings. The diesel/phytol blends show similar emissions characteristics as the diesel. The combustion event was depicted by performing high-speed, natural luminosity endoscopic imaging. The conclusion is that phytol may be a suitable blending agent with diesel fuel for CI applications.—Ramírez et al.
A.I. Ramírez, S.K. Aggarwal, S. Som, T.P. Rutter, D.E. Longman (2014) “Effects of blending a heavy alcohol (C20H40O) with diesel in a heavy-duty compression-ignition engine,” Fuel, Volume 136, Pages 89-102, ISSN 0016-2361, doi: 10.1016/j.fuel.2014.06.039
US Patent application Nº 20110302830 Engineered photosynthetic bacteria, method of manufacture of biofuels
A.I. Ramírez, S. Som, L.A. LaRocco, T.P. Rutter, D.E. Longman (2012) “Investigating the use of heavy alcohols as a fuel blending agent for compression ignition engine applications,” ICES2012-81169, ASME Internal Combustion Engine Division Spring Technical Conference, Torino, Italy doi: 10.1115/ICES2012-81169