Impact of Bio-Ethanol, Bio-ETBE Addition on the Volatility of Gasoline with Oxygen Content at the Level of E10

This study examines the impact of the addition of bio-ethanol/bio-ETBE on the main volatility properties of gasoline. Although several studies have been published on the addition of ethanol or ETBE to gasoline, the simultaneous addition of these oxygenates has not been studied by taking the maximum oxygen content of 3.7% m/m into account. The EN 228:2012-A1:2017 standard specifies the requirements for marketed unleaded gasoline. This standard is able to determine, among other things, a gasoline type with a maximum oxygen content of 3.7% m/m and sets the maximum limits for ethanol content at 10% v/v and 22% v/v for ethers with a minimum five carbon atoms, such as ΕΤΒΕ. Five refinery fractions were mixed in various proportions and were used as base fuels. A total of 30 samples were prepared by blending the base fuels with bio-ethanol/bio-ETBE. In each of these base fuels, bio-ethanol was added in concentrations up to 10% v/v. Subsequently, bio-ETBE was added to each of these fuels in concentrations up to 20.8% v/v for use as a stabilizer. All of the samples were examined using the EN ISO 13016-1 and EN ISO 3405 test methods while considering the volatility requirements set by EN 228. The results showed that the addition of bio-ETBE has a beneficial effect on the volatility characteristics of the samples, as it reduces the vapor pressure of the final blend and sets all fuels in compliance with the required specification limits set by the EN 228 standard.

A Proposal to Fix the Number of Factors on Modeling the Dynamics of Futures Contracts on Commodity Prices

In the literature on modeling commodity futures prices, we find that the stochastic behavior of the spot price is a response to between one and four factors, including both short- and long-term components. The more factors considered in modeling a spot price process, the better the fit to observed futures prices—but the more complex the procedure can be. With a view to contributing to the knowledge of how many factors should be considered, this study presents a new way of computing the best number of factors to be accounted for when modeling risk-management of energy derivatives. The new method identifies the number of factors one should consider in the model and the type of stochastic process to be followed. This study aims to add value to previous studies which consider principal components by assuming that the spot price can be modeled as a sum of several factors. When applied to four different commodities (weekly observations corresponding to futures prices traded at the NYMEX for WTI light sweet crude oil, heating oil, unleaded gasoline and Henry Hub natural gas) we find that, while crude oil and heating oil are satisfactorily well-modeled with two factors, unleaded gasoline and natural gas need a third factor to capture seasonality.

Fuel prices at petrol stations in touristic cities

While it may seem obvious from common sense that retail fuel prices should be higher in touristic rather than in nontouristic cities, the related empirical literature has failed either to clearly support this assumption or to qualify and quantify the effect of tourism on retail fuel prices. Using a self-created data set that includes prices across a large sample of petrol stations located in mainland Spain and the Balearic Islands, we seek to evaluate the effects of tourism on local destination retail petrol prices. The estimations prove three main effects: Petrol prices are higher in cities with high levels of tourism, nearby beaches, and/or with the socioeconomic influence of a national park. In fact, petrol stations add a margin of around 6.6% and 6.4% for unleaded gasoline 95 and diesel, respectively, in touristic cities. Second, the more touristic the city, the higher these prices. Third, in the case of touristic municipalities, the percentage of travelers from abroad and being within the area of influence of a national park are two of the main drivers that explain this overpricing.

Effects of triglyceride gasoline blends on combustion and emissions in a common rail direct injection diesel engine

This study presents the combustion and emission results using a blend of unrefined triglycerides (straight vegetable oils) and regular unleaded gasoline in a compression ignition engine typically used in farming machinery. Most farm equipment is powered by diesel engines. A sizable cost of producing a crop on a farm can be attributed to fuel—diesel in such cases. Farmers and researchers have been interested in the use of alternative fuels, especially triglycerides, which could potentially bring down the fuel cost portion of the farm input costs. One of the major drawbacks of using unrefined triglycerides is poor cold flow properties due to high density and viscosity. To overcome this, the triglycerides can be blended with gasoline to lower the density and viscosity. This blend has been used in existing diesel engines without the need for any modification to the engine or its control system. The experiments were conducted on a 4.5-L Tier 3 engine. The fuel used was a blend of unrefined canola triglyceride and regular unleaded gasoline (10% by volume). Measurements include mass fraction burned combustion pressure, fuel consumption and pollutant emissions. The fuel consumption of TGB10 was lower than most straight vegetable oils found in the literature, but higher than diesel. The peak pressure of TGB10 was slightly higher than diesel and occurred earlier than diesel. The brake-specific NOx was lower than diesel at lower and no load points. Particulate matter emissions of TGB10 were higher than diesel at rated speed. Total hydrocarbon emissions were generally higher than diesel. CO emissions were lower than diesel except at low or no load points where they were significantly higher.

Gene Expression during BTEX Biodegradation by a Microbial Consortium Acclimatized to Unleaded Gasoline and a Pseudomonas putida Strain (HM346961) Isolated from It

Pseudomonas putida strain (HM346961) was isolated from a consortium of bacteria acclimatized to unleaded gasoline-contaminated water. The consortium can efficiently remove benzene, toluene, ethylbenzene and xylene (BTEX) isomers, and a similar capability was observed with the P. putida strain. Proteome of this strain showed certain similarities with that of other strains exposed to the hydrocarbon compounds. Furthermore, the toluene di-oxygenase (tod) gene was up-regulated in P. putida strain when exposed to toluene, ethylbenzene, xylene, and BTEX. In contrast, the tod gene of P. putida F1 (ATCC 700007) was up-regulated only in the presence of toluene and BTEX. Several differences in the nucleotide and protein sequences of these two tod genes were observed. This suggests that tod up-regulation in P. putida strain may partially explain their great capacity to remove aromatic compounds, relative to P. putida F1. Therefore, new tod and P. putida strain are promising for various environmental applications.