Volatilization of monoaromatic compounds (benzene, toluene, and xylenes; BTX) from gasoline: Effect of the ethanol (original) (raw)
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Volatilization of benzene from gasoline: the effect of ethanol blends
Water Pollution X, 2010
In this work experiments were performed with vapor collection in columns to assess the evaporation profile of benzene from gasoline-ethanol blend fuels. The vapors from two columns simulating gasoline-contaminated soils (with and without ethanol) were monitored for 77 d. The instrumental analysis was performed by Gas Chromatography (GC) with a Flame Ionization Detector (FID). Compound identification was based on the GC retention times of standard BTX (benzene, toluene and xylenes). The concentration of benzene in the vapor phase was decreased by 89.09%, considering the entire experimental period while the toluene and xylenes concentrations were increased by 239.34 and 251.78%, respectively. These results suggest that the benzene evaporation behavior was affected by the interactions among ethanol and other aromatic compounds. These results are especially important since ethanol is an alternative to gasoline blends. Furthermore, benzene (a well know carcinogen) was retained in the liquid phase and, in this way, can reach the underground water sources. These findings can point out necessary changes in traditional risk models for soil spills that are based on compounds concentration in the environment.
Journal of Environmental Sciences, 2014
The sorption and phase distribution of 20% ethanol and butanol blended gasoline (E20 and B20) vapours have been examined in soils with varying soil organic matter (SOM) and water contents via laboratory microcosm experiments. The presence of 20% alcohol reduced the sorption of gasoline compounds by soil as well as the mass distribution of the compounds to soil solids. This effect was greater for ethanol than butanol. Compared with the sorption coefficient (K d) of unblended gasoline compounds, the K d of E20 gasoline compounds decreased by 54% for pentane, 54% for methylcyclopentane (MCP) and 63% for benzene, while the K d of B20 gasoline compounds decreased by 39% for pentane, 38% for MCP and 49% for benzene. The retardation factor (R) of E20 gasoline compounds decreased by 53% for pentane, 53% for MCP and 48% for benzene, while the R of B20 gasoline compounds decreased by 39% for pentane, 37% for MCP and 38% for benzene. For all SOM and water contents tested, the K d and R of all gasoline compounds were in the order of unblended gasoline > B20 > E20, indicating that the use of high ethanol volume in gasoline to combat climate change could put the groundwater at greater risk of contamination.
The environmental aspects of the evaporation of BTEX from gasoline with and without ethanol
International Journal of …, 2013
In this work the vapours from two columns simulating gasoline-contaminated soils (with and without ethanol) were monitored. Standards mixtures of BTEX, containing different ethanol contents were also analysed. The instrumental analysis was performed by Gas Chromatography with a Flame Ionisation Detector. Among BTEX, except benzene, in both columns the evaporation rate increases with time. In the gasoline/ethanol column this effect is higher particularly for the xylenes. Although the benzene concentrations were reduced in both columns, this reduction was less marked in the gasoline/ethanol column. The toluene concentrations were higher in the pure gasoline column.
International Journal of Energy and Environmental Engineering, 2014
Lysimeter experiments were conducted to compare the vapour phase transport of 20 % ethanol-and butanol-blended gasoline (E20 and B20) compounds in soils using the unblended gasoline (UG) compounds as the standard. Sand containing approximately 0 and 5 % organic matter (0 %f om and 5 %f om) was used to simulate the vadose zone. The 5 %f om soil promoted higher vapour phase transport of compounds than the 0 %f om soil due to its higher porosity, hence, was used to compare the transport to the groundwater zone of the different gasoline blends. The addition of 20 % alcohol by volume to gasoline reduced the retentive capability of the soil for gasoline compound vapours and thus resulted in greater downward transport and higher accumulation of gasoline compounds in the groundwater zone. The transport of gasoline compounds from the vadose zone to the groundwater zone was found to be in the order of E20 [ B20 [ UG, indicating that the risk of groundwater contamination with gasoline compounds after a spill or leak is more likely to be greater for ethanolblended gasoline compared with butanol-blended gasoline.
2012
Laboratory batch microcosm experiments were conduct e to quantify the impact of soil organic matter (SOM) on the sorption and phase distribution of 20% ethanol-blended gasoline (E20) in the vadose zone. SOM was found to increase the sorption of all E20 gasoline compounds, thereby altering their mass distribution between the vadose zone phases. T his impact, quantified by the sorption coefficient (Kd) of E20 gasoline compounds, increased with decreas ing hydrophobicity, hence affected the aromatics to a greater extent of 7 times than the c ycloalkanes (4 times) and the alkanes (2 times). However, when compared with unblended gasoline, the e anol in E20 generally reduced the sorptive capability of SOM for gasoline compounds by a maxim um of 76% for the cycloalkanes, 73% for the aromatics and 60% for the alkanes.Therefore, the fu ll sorptive capability of SOM for gasoline compounds is unlikely to be realized for E20 gasoli ne compounds.
Influence of Ethanol on Vapor Pressure of Refinery Components and Commercial Type Gasoline Blends
2017
European member states have to comply with the Directive 2009/30/EC, which mandates the use of biofuels in motor fuels. Bioethanol is one of the possible renewable fuels that can be used. However, in Mediterranean member states with higher climate temperatures during summer, the production of gasoline with bioethanol as an oxygenate blending component will face increased volatility problems. This study examines the impact of ethanol addition (from 0.5 to 10% v/v) on vapor pressure of refinery streams used for gasoline blends and on commercial motor gasoline fuels. The addition of ethanol in small proportions increased the vapor pressure of the final gasolines tested. The change in vapor pressure was measured (expressed) using delta VP – ΔRVP. The ΔRVP was calculated in each blending component, in an attempt to identify the impact of the refinery stream composition on the change of vapor pressure due to the ethanol addition. The more volatile winter grade samples showed a lower incre...
Reducing gasoline loss from evaporation by the introduction of a surface-active fuel additive
Urban Transport XXI, 2015
Apart from the emission of hydrocarbons within the exhaust gases of vehicles, gasoline hydrocarbons are released into the environment from the tanks of cars during refueling and also during transportation and storage as a result of evaporation. Losses of gasoline when moving from producer to consumer are 1.5-2%. Up to 40% of the hydrocarbons emitted by road transport evaporate from the fuel systems of cars with gasoline engines. In the context of the global problem of depleting energy resources and the associated degradation of the environment the reduction of gasoline losses from evaporation remains an important environmental and economic issue. The aim of this work is to validate a method of reducing evaporation loss by modifying the quality of the fuel being used. An approach to assessing the toxicity of gasoline vapor has been proposed which may point to the effect that the individual components of gasoline have on this. A method has been developed to reduce evaporation loss and also improve the mixture in the engine by introducing a fuel additive which is a surface-active agent. The additive reduces the vapor pressure of gasoline while also reducing the surface tension of the fuel droplets at the interface with air. The results from studies on the additive's effect on the saturated vapor pressure, surface tension, and gasoline evaporation losses are given.
Static and Dynamic Studies of Gasoline in View of its Octane Number and its Toxic Effect
JOURNAL OF ADVANCES IN CHEMISTRY
Gasoline come primarily from petroleum cuts, it is the preferred liquid fuel in our lives. Two gasoline samples of octane numbers 91 and 95 from Saudi Arabia petrol stations were studied. This study was achieved at three different temperatures 20oC, 30oC and 50oC representing the change in temperatures of the different seasons of the year. Both the evaporated gases of light aromatic hydrocarbons (BTEX) of gasoline samples inside the tank were subjected to analyze qualitatively and quantitatively via capillary gas chromatography. The detailed hydrocarbon composition and the octane number of the studied gasoline samples were determined using detailed hydrocarbon analyzer. The idea of research is indicating the impact of light aromatic compounds in gasoline on the toxic effect of human and environment on the one hand, and on octane number of gasoline on the other hand. Although the value of octane number will be reduced but this will have a positive impact on the environment as a way t...
INVESTIGATION ON EVAPORATIVE EMISSION FROM A GASOLINE
It is estimated that about 15 to 20 percent of the vehicle hydrocarbon (HC) emission were due to evaporation of fuel. Hence a need was felt to understand the extent of evaporative emission from gasoline fuel system. A polycarbonate fuel tank that is predominantly used in two wheeled vehicles is considered for study. Emission can surface to atmosphere in three modes; diffusion through fuel tank wall, escaping through vent in tank and when fuel tank cap is opened for refueling. The average temperature condition which prevails in south India which is in the range of 27 o C to 34 o C was considered. From which temperatures which were at proximity to peak high and low day time were chosen. The complete set up was placed in open atmosphere to replicate the working environment. The emission constituents and its levels were measured by conducting the test particularly for averaged out day time high and low temperature condition. Further diffusion test was conducted within a range of 34 o C to 36 o C, this temperature is considered to be range of maximum temperature which prevails in south India. From which a temperature was chosen and the test was conducted. This comparative study gives an indication of emission and its quantity from the fuel tank at the ambient temperature.