Properties and Performance of Levulinate Esters as Diesel Blend Components

Abstract

The properties of ethyl (EL) and n-butyl levulinate (BL), two potential cellulose-derived diesel blend components, were assessed as both neat oxygenates and blends with diesel fuel. The samples tested were produced commercially from cellulose and alcohols but were not reagent-grade samples. They were relatively free of impurities, although EL contained some acidic compounds and both contained parts-per-million levels of calcium. Both esters exhibited a very low cetane number. The melting points of both esters were less than −60 °C. The water solubility of EL was 15.2 wt %, while that of BL was only 1.3 wt %. Blends of diesel fuel with EL were found to have an elevated cloud point, despite the extremely low melting point of this compound, because EL separates from diesel fuel as a separate liquid phase at low temperatures. This can be mitigated to some extent by including biodiesel in the blend. BL remained in solution and raised the diesel cloud point only when blended into −45 °C cloud point/15% aromatic no. 1 diesel fuel. Both esters were found to significantly increase diesel lubricity and conductivity. The esters were treated with the cetane-enhancing compound 2-ethyl hexyl nitrate and were tested as blends with diesel fuel in a 2008 model year Cummins ISB engine with the measurement of regulated pollutant emissions over the federal heavy duty diesel transient cycle. Fuel chemistry had no effect on tailpipe total hydrocarbons, carbon monoxide, or particulate matter for this diesel oxidation catalyst and particle filter equipped engine. The engine-out smoke number was reduced by 41.3% with a 10% blend of EL (EL10) and reduced by 55% with a blend of 20% BL (BL20). EL10 had no effect on emissions of nitrogen oxides (NO x ), while BL20 increased NO x by 4.6%. Because of the poor solubility of EL in diesel fuel at low temperatures, its use as a diesel blend component will be technically challenging. The low cetane number of both esters can be addressed with cetane improver additives.

Computational and Experimental Investigations on Tailor-made Biofuel Blend Properties

“…Absolute error percentage was recorded at 6.78%. According to Christensen et al, presence of butyl levulinate in fuel blend reduce cetane number of the blend [21]. However, this claim is contradicting to the finding from this study as both predicted and tested fuel blend cetane number were higher than the EN590 minimum limit.…”

“…However, ethanol is easily attainable and contributes to emission reductions. Butyl levulinate is a promising oxygenated fuel candidate that has gained abundant of attention lately [19][20][21]. Its high oxygen content promotes reduced emissions.…”

“…Its high oxygen content promotes reduced emissions. Table 2 presents physiochemical properties for each blend component obtained through various literary sources [21][22][23][24][25]. …”

Direct Conversion of Carbohydrates into Ethyl Levulinate with Potassium Phosphotungstate as an Efficient Catalyst

“…Among these, ethyl levulinate, obtained by esterification of levulinic acid, is a versatile chemical compound and has been widely applied in food industry, as solvents and plasticizers. Besides, it can be used as an additive for transportation fuels, which shows excellent performance [11,12]. It is reported that furfuryl alcohol also can be converted into ethyl levulinate in the presence of an acid catalyst [13].…”

Efficient Production of N-Butyl Levulinate Fuel Additive from Levulinic Acid Using Amorphous Carbon Enriched with Oxygenated Groups

“…On the other hand, BL has an evidently lower solubility in water (1.3 wt %) than EL (15.6 wt %). In diesel blends containing 20% (v/v) alkyl levulinate, EL was found to form a separate liquid phase from diesel at 283 K, while BL remained constant miscibility in diesel even at the diesel cloud point (247 K) [20].…”