The Use of Stable Isotopes to Differentiate Specific Source Markers for MTBE

The recent controversy over the use of MTBE within gasoline to boost oxygen content and decrease carbon monoxide emissions to the atmosphere has led to a proposed phase-out of this compound by 2002. This paper is a preliminary investigation into the use of gas chromatography isotope-ratio mass spectrometry (GCIRMS) to determine both carbon and hydrogen isotopic compositions of MTBE as a means of differentiating sources of MTBE. Three pure MTBE samples were purchased from chemical distributors. Little variation of the i 13 C values were observed although the samples had isotopically distinct i -D values. Four different methods of obtaining carbon isotope ratios of neat MTBE, MTBE in gasoline, and MTBE in water are described, and the precision and accuracy of each is discussed. The carbon isotopic compositions of MTBE within 10 gasoline samples from three different areas of the United States show a wide range of carbon isotope compositions. This novel method of MTBE analysis could be valuable in forensic investigations.     

What do consumers believe about future gasoline prices?

A full understanding of how gasoline prices affect consumer behavior frequently requires information on how consumers forecast future gasoline prices. We provide the first evidence on the nature of these forecasts by analyzing two decades of data on gasoline price expectations from the Michigan Survey of Consumers. We find that average consumer beliefs are typically indistinguishable from a no-change forecast, justifying an assumption commonly made in the literature on consumer valuation of energy efficiency. We also provide evidence on circumstances in which consumer forecasts are likely to deviate from no-change and on significant cross-consumer forecast heterogeneity.     

A ban on one is a boon for the other: Strict gasoline content rules and implicit ethanol blending mandates

Ethanol and methyl-tertiary butyl ether (MTBE) were close substitutes in the gasoline additives market until MTBE was banned due to the concerns about groundwater contamination, leading to a sudden and dramatic substitution toward ethanol as an alternative oxygenate and octane-booster. We use variation in the timing of MTBE bans across states to identify their effects on gasoline prices. We find that state bans increased reformulated gasoline prices by 3–6 cents in non-Midwestern states for which the bans were binding, with larger impacts during times of high ethanol prices relative to MTBE and crude oil. We find qualitatively similar, yet smaller effects for conventional gasoline. We argue on the basis of a simple conceptual model and supporting empirical evidence that these bans functioned as implicit ethanol blending mandates in areas that were previously using MTBE to comply with strict environmental constraints. Overall, our results are consistent with the theoretical prediction that mandating a minimum market share for a more costly alternative fuel—either directly, or implicitly through a ban on the preferred conventional fuel—will inevitably increase fuel prices in a competitive market.     

Fuel consumption and gasoline prices: The role of assortative matching between households and automobiles

Analyses of policies to reduce gasoline consumption have focused on two effects, a compositional effect on the fuel economy of the automotive fleet and a utilization effect on how much people drive. However, the literature has missed a third effect: a matching effect, in which policies change how high-utilization households are matched to fuel-efficient vehicles in equilibrium. We show that higher gas prices should lead to stronger assortative matching. Empirical estimates using US micro-level data are consistent with this hypothesis. We find a $0.50 increase in the gas tax would reduce US gas consumption by 0.8% through the matching effect alone, bringing annual environmental benefits of about $1.7 billion.     

HK－Ⅰ型汽油节油净化添加剂的研制

HK－I型汽油节油净化添加剂的研制,是为厂提高汽油本身的燃烧性能和对油路和化油器的清洗性能,从而达到降低排气污染,提高发动机动力性和节油的目的。经台架实验和汽车实跑证明,HK－I型添加剂可使油耗下降10％以上,同时也减少了CH、CO的排放．      

Study on accidental fire at a large-scale floating-roof gasoline storage tank

For an accident involving a large-scale internal floating-roof tank with 28.4 m diameter and filled with 4600 m³ gasoline, the actual behavior of the gasoline fire and the fire-fighting strategies that were applied to it were analyzed in terms of the heat release rate, burning rate, and regression rate. During the accident, the initial fire suppression strategy failed and the gasoline was moved to an external tank. A total of 2800 m³ gasoline was burned for 17 h with a resulting heat release rate of 1475 MW. The long duration of the fire burning was attributed to the burning surface of the gasoline, which was not covered with foam at the beginning of the fire using the active foam fire-extinguishing system due to damage to one of the foam chambers. The average regression rate of the gasoline was 0.16 m/h after 8 h of burning and 0.35 m/h when the fire was completely suppressed.     

Improvement in the prediction of gasoline pool fire behaviour: CFD modelling and validation

The development and implementation of mathematical models through Computational Fluid Dynamics (CFD) techniques has been acknowledged as a promising tool for the prediction of hydrocarbon pool fires behaviours. In this sense, different approaches, with different assumptions and simplifications, and accounting for different phenomena, have been developed in the literature. However, the deviations in the predictions of the experimentally determined parameters, such as temperatures profiles, flame heights and radiative heat flux, by the implemented models are still high. Therefore, the implementation of these models to predict combustion phenomena and flame behaviours for various scenarios is limited. In this work, the software C3D is used to model gasoline pool fires of different diameters, and under different wind conditions, in order to improve the quality of the predictions of the flame behaviour. The modelled cases correspond to the experimental studies reported in literature. The results from the implemented model show an improved predictive quality when compared with other modelling works reported on literature for the same experimental cases. The deviations in the time averaged temperature, flame height, surface emissive power and radiative heat flux, has been calculated to be 5.0%, 0.05%, 6.32% and 3.82%, respectively.     

Explosions of gasoline–air mixture in the tunnels containing branch configuration

In order to investigate the effects of branch tunnels on explosion propagation, experiments were performed in five different configuration tunnels (straight configuration and configurations with 1 branch, 2 branches, 3 branches and 4 branches). Pressure and flame transducers were used to record the history of the pressure development and track the velocity of the flame front. It was shown that the branch tunnels had ability to enhance the maximum overpressure, rate of overpressure rise, and deflagration index (K_G) of the gasoline–air mixture explosion due to the turbulence induced by the branch tunnels. The overpressure rise rate and K_G of the explosion increased as a function of the number of branch tunnels. Experiments also showed that the maximum flame speed increased as the branch number increasing from 0 to 3 due to the enlargement of turbulence induced by the branch tunnels. However, an increase of branch number did not always lead to an enhancement of flame speed because the heat loss was intensified resulting from the increase of flame surface caused by the branch tunnels. When the number of branch tunnels exceeded 3, the maximum flame speed dropped.     

Lose some, save some: Obesity, automobile demand, and gasoline consumption

This paper examines the unexplored link between the prevalence of overweight and obesity and vehicle demand in the United States. Exploring annual sales data of new passenger vehicles at the model level in 48 U.S. counties from 1999 to 2005, we find that new vehicles demanded by consumers are less fuel-efficient on average as a larger share of people become overweight or obese. The OLS results show that a 10 percentage point increase in obesity and overweight reduces the average MPG of new vehicles demanded by 1.4 percent, an effect requiring a 12 cent increase in gasoline prices to counteract. The 2SLS results after controlling for possible endogeneity in overweight and obesity prevalence put those two numbers at 5 percent and 54 cent, respectively. These findings, robust to a variety of specifications, suggest that policies to reduce overweight and obesity can have additional benefits for energy security and the environment.