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01446 Stable carbon and hydrogen isotopic fractionation of individual n-alkanes accompanying biodegradation: Evidence from a group of progressively biodegraded oils
02 Liquid fuels (economics, business, marketing, policy) efficiency was improved and the filtration temperature was also elevated. Oxalic acid can remove more than 98% of basic nitrogen compounds and more than 70% of nonbasic nitrogen compounds from the lubricating base stocks. The removal of basic nitrogen showed a linear relationship with the removal of nonbasic nitrogen.
05•01446 Stable carbon and hydrogen isotopic fractionation of individual n-alkanes accompanying biodegradation: evidence from a group of progressively biodegraded oBs Sun, Y. et al. Organic Geochemistry, 2005, 36, (2), 225-238. Seven crude oils of known source and maturity, representing a natural sequence of increasing degree of biodegradation, were collected from reservoirs in the Liaohe Basin, NE China, in an effort to determine the magnitude and direction of isotopic shift of carbon and hydrogen in individual n-alkaues during microbial degradation. The results show that biodegradation has little effect on the carbon isotopic composition of the whole oil. However, a sequential loss of n-alkanes leads to 13C depletion of the bulk residual saturate fraction. The stable carbon isotopic compositions of aromatics and macromolecular organic matter lresins and asphaltenes) follow a pattern, with an overall trend towards 3C enrichment of 0.8-1.7%0 in the residues. The stable carbon and hydrogen isotope values of individual n-alkanes demonstrate that they follow different trends during biodegradation. No significant carbon isotopic fractionation occurs for n-alkanes during slight to moderate biodegradation. However, there is a general increase of up to 4%0 in the 613C values of low molecular weight n-alkanes (C15-Ct8) during heavy biodegradation. In contrast no isotopic fractionation occurs for higher molecular weight n-alkanes (_>C19). The conservative character of 13C concentration for high molecular weight n-alkanes during biodegradation indicates that these compounds are effective tracers for source identification of heavily biodegraded oils. The hydrogen isotope compositions of n-alkanes show a significant fractionation as moderate biodegradafion proceeds, resulting in an enrichment in D of up to ~35%o upon heavy biodegradation. The dynamic fractionation in the stable carbon and hydrogen isotopes of n-alkanes accompanying biodegradation opens the possibility of quantitative estimation of the extent of biodegradation in subsurface petroleum reservoirs by introducing an isotopic kinetic modelling approach.
05•01447 Study on the relationship between the structure and activities of alkyl methacrylate-maleic anhydride polymers as cold flow improvers in diesel fuels Songa, Y. et al. Fuel Processing Technology, 2005, 86, (6), 641-650. In order to find efficient cold flow improvers for diesel fuels derived from crude oil, copolymers (R1MC-MA) were prepared making use of the copolymerization of methacrylate (R1MC) of various alkyls with maleic anhydride (MA), and terpolymers (R1MC-MA-R2MC) were prepared by the reaction of long-chain alkyl methacrylate (R1MC), maleic anhydride (MA), and short alkyl methacrylate (R2MC). The additives were purified and characterized by IR, 1H-NMR, and GPC. The activities of the synthetic products as the cold flow improvers in two diesel fuels were investigated. The results indicate that: (1) the alkyl chain length of R 1 in R I3M C - M A copolymers significantly affects the solid point depressing performance. When the long-chain alkyl R 1 is n-Ci4H29- and the reaction material molar ratio (R~MC/MA) is 1:2, the Ct~MC 2MA possesses the best DSP property; (2) the (C14MCMA R~MC) terpolymers all demonstrate excellent solid point depression properties when the short-chain alkyl R 2 varies from CH 3- to n-CsHts-; (3) however, all of the tested copolymers and terpolymers do not demonstrate necessary cold filter plugging point depression performance.
05•01448 Thermodynamic and kinetic modelling of an autothermal methanol reformer Chan, S. H. and Wang, S. H. Journal of Power Sources, 2004, 126, (1 2), 8-15. This paper consists of two parts. First, a complete thermodynamic analysis of autothermal methanol reforming over a wide range of airfuel and water-fuel ratios is described. Second, a detailed description is given to the development of a 1D, non-steady, oxidative methanol reformer model. Calculations of the chemical equilibrium composition show that the predicted H2 yield in the fuel-water-air reaction system is always lower than that obtained from experiment, while the predicted CO is always higher than that obtained from experiment. Corrections are made to the predicted results by incorporating a water-gas shift reaction, whereby the CO is oxidized by water to produce more H2. With this correction, the predicted H2 and CO yields are in good agreement with the experimental results. Some preliminary results from the kinetic model are also presented. The model considers the heat/mass transfer phenomena associated with the kinetics of the methanol reaction, and is able to express the temporal and spatial variations of the temperature of the catalyst, the concentration of the reactant gases, and the conversion efficiency of methanol in the reformer.
05/01449 Vapor-liquid equilibrium of systems containing alcohols, water, carbon dioxide and hydrocarbons using SAFT Li, X.-S. and Englezos, P. Fluid Phase Equilibria, 2004, 224, (1), 111118. The statistical associating fluid theory (SAFT) equation of state is employed for the correlation and prediction of vapour-liquid equilibrium (VLE) of eighteen binary mixtures. These include water with methane, ethane, propane, butane, propylene, carbon dioxide, methanol, ethanol and ethylene glycol (EG), ethanol with ethane, propane, butane and propylene, methanol with methane, ethane and carbon dioxide and finally EG with methane and ethane. Moreover, vapourliquid equilibrium for nine ternary systems was predicted. The systems are water/ethanol/alkane (ethane, propane, butane), water/ethanol/ propylene, water/methanol/carbon dioxide, water/methanol/methane, water/methanol/ethane, water/EG/methane and water/EG/ethane. The results were found to be in satisfactory agreement with the experimental data except for the water/methanol/methane system for which the root mean square deviations for pressure were 60-68% when the methanol concentration in the liquid phase was 60 wt%.
Economics, business, marketing, policy 05•01450 Long-run gasoline demand for passenger cars: the role of income distribution Storchmann, K. et al. Energy Eeonomics, 2005, 27, (1), 25-58. It is commonly agreed that the level of income and prices are crucial determinants of the consumption of motor gasoline. The respective long run price and income elasticities are regularly calculated using cross sectional models. Despite the acknowledgement of the role of income distribution, it plays no role in intercountry cross sectional models. This is due to a lack of appropriate data. This paper shows that the omission of distributional characteristics provides misleading elasticities. Using available distributional measures this paper is referring to an income threshold, which is crucial to the acquisition of an automobile. It is shown that on the one hand, in poor countries an unequal income distribution is needed to enable at least some people to buy automobiles. On the other hand, in wealthy countries an unequal income distribution would exclude some people from acquiring automobiIes. Hence, depending on the income level, inequality has a diverging impact on the ability to buy durable goods. The second part of this paper develops a pooled 90-country model to examine this approach empirically. It could be shown that distribution variables are highly significant to explain the demand for automobiles and motor gasoline. Moreover, the consideration of the distribution of income leads to a considerable decrease in income elasticity values. This is mainly due to the positive correlation between income level and income equality within the sample.
05/01451 Simulating the impacts of a strategic fuels reserve in California Ford, A. Energy Policy, 2005, 33, (4), 483 498. This paper describes a simulation analysis of the impacts of a strategic fuels reserve (SFR) designed to limit the increase in gasoline prices in the days following a refinery disruption. The analysis is based on a computer simulation model developed for the California Energy Commission. The model simulates the supply of gasoline as the sum of refinery production, cargoes arriving from outside California, withdrawals from private storage and the release of gasoline from the SFR. The demand for gasoline is the sum of the retail demand and the wholesale demand to rebuild inventory. The paper presents simulations to illustrate the impact on California consumers of refinery disruptions of different size and duration. The simulations are repeated with a strategic reserve operated with the time-swap mechanism proposed for California. The simulations demonstrate large intended benefits of a SFR in the event of a major refinery disruption. The simulations are then repeated with an unintended impact. The new simulations show that the SFR could lead to negative impacts on California consumers in the event of small disruptions. The paper concludes that the overall impact of the SFR is likely to be dominated by the frequency of large disruptions.
05/01452 The productivity-inflation nexus: the case of the Australian mining sector Mahadevan, R. and Asafu-Adjaye, J. Energy Economics, 2005, 27, (1), 209-224. This paper examines the causal links between productivity growth and two price series given by domestic inflation and the price of mineral products in Australia's mining sector for the period t968/1969 to 1997/ 1998. The study also uses a stochastic translog cost frontier to generate improved estimates of total factor productivity (TFP) growth. The
Fuel and Energy Abstracts
July 2005 219
05•01446 Stable carbon and hydrogen isotopic fractionation of individual n-alkanes accompanying biodegradation: evidence from a group of progressively biodegraded oBs Sun, Y. et al. Organic Geochemistry, 2005, 36, (2), 225-238. Seven crude oils of known source and maturity, representing a natural sequence of increasing degree of biodegradation, were collected from reservoirs in the Liaohe Basin, NE China, in an effort to determine the magnitude and direction of isotopic shift of carbon and hydrogen in individual n-alkaues during microbial degradation. The results show that biodegradation has little effect on the carbon isotopic composition of the whole oil. However, a sequential loss of n-alkanes leads to 13C depletion of the bulk residual saturate fraction. The stable carbon isotopic compositions of aromatics and macromolecular organic matter lresins and asphaltenes) follow a pattern, with an overall trend towards 3C enrichment of 0.8-1.7%0 in the residues. The stable carbon and hydrogen isotope values of individual n-alkanes demonstrate that they follow different trends during biodegradation. No significant carbon isotopic fractionation occurs for n-alkanes during slight to moderate biodegradation. However, there is a general increase of up to 4%0 in the 613C values of low molecular weight n-alkanes (C15-Ct8) during heavy biodegradation. In contrast no isotopic fractionation occurs for higher molecular weight n-alkanes (_>C19). The conservative character of 13C concentration for high molecular weight n-alkanes during biodegradation indicates that these compounds are effective tracers for source identification of heavily biodegraded oils. The hydrogen isotope compositions of n-alkanes show a significant fractionation as moderate biodegradafion proceeds, resulting in an enrichment in D of up to ~35%o upon heavy biodegradation. The dynamic fractionation in the stable carbon and hydrogen isotopes of n-alkanes accompanying biodegradation opens the possibility of quantitative estimation of the extent of biodegradation in subsurface petroleum reservoirs by introducing an isotopic kinetic modelling approach.
05•01447 Study on the relationship between the structure and activities of alkyl methacrylate-maleic anhydride polymers as cold flow improvers in diesel fuels Songa, Y. et al. Fuel Processing Technology, 2005, 86, (6), 641-650. In order to find efficient cold flow improvers for diesel fuels derived from crude oil, copolymers (R1MC-MA) were prepared making use of the copolymerization of methacrylate (R1MC) of various alkyls with maleic anhydride (MA), and terpolymers (R1MC-MA-R2MC) were prepared by the reaction of long-chain alkyl methacrylate (R1MC), maleic anhydride (MA), and short alkyl methacrylate (R2MC). The additives were purified and characterized by IR, 1H-NMR, and GPC. The activities of the synthetic products as the cold flow improvers in two diesel fuels were investigated. The results indicate that: (1) the alkyl chain length of R 1 in R I3M C - M A copolymers significantly affects the solid point depressing performance. When the long-chain alkyl R 1 is n-Ci4H29- and the reaction material molar ratio (R~MC/MA) is 1:2, the Ct~MC 2MA possesses the best DSP property; (2) the (C14MCMA R~MC) terpolymers all demonstrate excellent solid point depression properties when the short-chain alkyl R 2 varies from CH 3- to n-CsHts-; (3) however, all of the tested copolymers and terpolymers do not demonstrate necessary cold filter plugging point depression performance.
05•01448 Thermodynamic and kinetic modelling of an autothermal methanol reformer Chan, S. H. and Wang, S. H. Journal of Power Sources, 2004, 126, (1 2), 8-15. This paper consists of two parts. First, a complete thermodynamic analysis of autothermal methanol reforming over a wide range of airfuel and water-fuel ratios is described. Second, a detailed description is given to the development of a 1D, non-steady, oxidative methanol reformer model. Calculations of the chemical equilibrium composition show that the predicted H2 yield in the fuel-water-air reaction system is always lower than that obtained from experiment, while the predicted CO is always higher than that obtained from experiment. Corrections are made to the predicted results by incorporating a water-gas shift reaction, whereby the CO is oxidized by water to produce more H2. With this correction, the predicted H2 and CO yields are in good agreement with the experimental results. Some preliminary results from the kinetic model are also presented. The model considers the heat/mass transfer phenomena associated with the kinetics of the methanol reaction, and is able to express the temporal and spatial variations of the temperature of the catalyst, the concentration of the reactant gases, and the conversion efficiency of methanol in the reformer.
05/01449 Vapor-liquid equilibrium of systems containing alcohols, water, carbon dioxide and hydrocarbons using SAFT Li, X.-S. and Englezos, P. Fluid Phase Equilibria, 2004, 224, (1), 111118. The statistical associating fluid theory (SAFT) equation of state is employed for the correlation and prediction of vapour-liquid equilibrium (VLE) of eighteen binary mixtures. These include water with methane, ethane, propane, butane, propylene, carbon dioxide, methanol, ethanol and ethylene glycol (EG), ethanol with ethane, propane, butane and propylene, methanol with methane, ethane and carbon dioxide and finally EG with methane and ethane. Moreover, vapourliquid equilibrium for nine ternary systems was predicted. The systems are water/ethanol/alkane (ethane, propane, butane), water/ethanol/ propylene, water/methanol/carbon dioxide, water/methanol/methane, water/methanol/ethane, water/EG/methane and water/EG/ethane. The results were found to be in satisfactory agreement with the experimental data except for the water/methanol/methane system for which the root mean square deviations for pressure were 60-68% when the methanol concentration in the liquid phase was 60 wt%.
Economics, business, marketing, policy 05•01450 Long-run gasoline demand for passenger cars: the role of income distribution Storchmann, K. et al. Energy Eeonomics, 2005, 27, (1), 25-58. It is commonly agreed that the level of income and prices are crucial determinants of the consumption of motor gasoline. The respective long run price and income elasticities are regularly calculated using cross sectional models. Despite the acknowledgement of the role of income distribution, it plays no role in intercountry cross sectional models. This is due to a lack of appropriate data. This paper shows that the omission of distributional characteristics provides misleading elasticities. Using available distributional measures this paper is referring to an income threshold, which is crucial to the acquisition of an automobile. It is shown that on the one hand, in poor countries an unequal income distribution is needed to enable at least some people to buy automobiles. On the other hand, in wealthy countries an unequal income distribution would exclude some people from acquiring automobiIes. Hence, depending on the income level, inequality has a diverging impact on the ability to buy durable goods. The second part of this paper develops a pooled 90-country model to examine this approach empirically. It could be shown that distribution variables are highly significant to explain the demand for automobiles and motor gasoline. Moreover, the consideration of the distribution of income leads to a considerable decrease in income elasticity values. This is mainly due to the positive correlation between income level and income equality within the sample.
05/01451 Simulating the impacts of a strategic fuels reserve in California Ford, A. Energy Policy, 2005, 33, (4), 483 498. This paper describes a simulation analysis of the impacts of a strategic fuels reserve (SFR) designed to limit the increase in gasoline prices in the days following a refinery disruption. The analysis is based on a computer simulation model developed for the California Energy Commission. The model simulates the supply of gasoline as the sum of refinery production, cargoes arriving from outside California, withdrawals from private storage and the release of gasoline from the SFR. The demand for gasoline is the sum of the retail demand and the wholesale demand to rebuild inventory. The paper presents simulations to illustrate the impact on California consumers of refinery disruptions of different size and duration. The simulations are repeated with a strategic reserve operated with the time-swap mechanism proposed for California. The simulations demonstrate large intended benefits of a SFR in the event of a major refinery disruption. The simulations are then repeated with an unintended impact. The new simulations show that the SFR could lead to negative impacts on California consumers in the event of small disruptions. The paper concludes that the overall impact of the SFR is likely to be dominated by the frequency of large disruptions.
05/01452 The productivity-inflation nexus: the case of the Australian mining sector Mahadevan, R. and Asafu-Adjaye, J. Energy Economics, 2005, 27, (1), 209-224. This paper examines the causal links between productivity growth and two price series given by domestic inflation and the price of mineral products in Australia's mining sector for the period t968/1969 to 1997/ 1998. The study also uses a stochastic translog cost frontier to generate improved estimates of total factor productivity (TFP) growth. The
Fuel and Energy Abstracts
July 2005 219