Oxygenates for Advanced Petroleum-Based Diesel Fuels: Part 1. Screening and Selection Methodology for the Oxygenates

The overall program objectives were three fold:

• assess the benefits and limitations of oxygenated diesel fuels on engine performance and emissions
• identify oxygenates most suitable for potential use in future diesel formulations based on physico-chemical properties (e.g. flash point), toxicity, biodegradability and estimated cost of production
• perform limited emissions and performance testing of the oxygenated diesel blends
• select at least two oxygenated compounds for advanced engine testing

In Part 1 of this program which is described in this paper, an extensive literature review was conducted to identify potential oxygenates for blending into diesel fuels. As many as 71 oxygenates were identified for the initial screening process. Based on a set of physical and chemical properties, a screening methodology was developed to select the 8 oxygenates that will be eligible for engine testing. The following properties were used:

• oxygen content, flash point, solubility in low aromatic diesel fuel and stability
• fuel properties such as viscosity, cetane number and lubricity
• corrosivity
• elastomer compatibility
• toxicity
• biodegradability

Initial screening resulted in 43 candidate oxygenates. Properties not found in the literature such as solubility and corrosivity were evaluated using bench tests. These tests resulted in the selection of eight oxygenates for engine testing in Part 2 of this program. These oxygenates were blended with alternative low sulfur diesel (ALS) to achieve an oxygen content of 7 wt%. Tables showing oxygenate properties are included.