Emergy analysis using US economic input-output models with applications to life cycles of gasoline and corn ethanol

A commonly encountered challenge in emergy analysis is the lack of transformity data for many economic products and services. To overcome this challenge, emergy analysts approximate the emergy input from the economy via a single emergy/money ratio for the country and the monetary price of economic inputs. This amounts to assuming homogeneity in the entire economy, and can introduce serious uncertainties in the results. This paper proposes and demonstrates the use of a thermodynamically augmented economic input-output model of the US economy for obtaining sector-specific emergy to money ratios that can be used instead of a single ratio. These ratios at the economy scale are more accurate than a single economy-wide emergy/money ratio, and can be obtained quickly for hundreds of economic products and services. Comparing sector-specific emergy/money ratios with those from conventional emergy studies indicates that the input-output model can provide reasonable estimates of transformities at least as a stop-gap measure until more detailed analysis is completed. A hybrid approach to emergy analysis is introduced and compared with conventional emergy analysis using life cycles of corn ethanol and gasoline as examples. Emergy and transformity data from the hybrid approach are similar to those from conventional emergy analysis, indicating the usefulness of the proposed approach. In addition, this work proposes the metric of return on emergy investment for assessing product alternatives with the same utility such as transportation fuels. The proposed approach and data may be used easily via web-based software.     

Giving green to get green? Incentives and consumer adoption of hybrid vehicle technology

Federal, state, and local governments use a variety of incentives to induce consumer adoption of hybrid-electric vehicles. We study the relative efficacy of state sales tax waivers, income tax credits, and non-tax incentives and find that the type of tax incentive offered is as important as the generosity of the incentive. Conditional on value, sales tax waivers are associated with more than a ten-fold increase in hybrid sales relative to income tax credits. In addition, we examine how adoption varies with fuel prices. Rising gasoline prices are associated with greater hybrid vehicle sales, but this effect operates almost entirely through high fuel-economy vehicles. By comparing consumer response to sales tax waivers and estimated future fuel savings, we estimate an implicit discount rate of 14.6% on future fuel savings.     

汽油加生物添加剂对发动机废气排放的影响研究

通过发动机的台架试验,系统研究了将一种热带植物提取物作为添加剂加入到不同成分的汽油中对汽油机废气排放特性的影响．结果表明：对于93^#高清洁汽油和93^#成分汽油,除了未燃碳氢(HC)略有上升外,其他排放物如氮氧化物NOx、一氧化碳等有所减少,CO2排放有明显的改善．对于乙醇汽油,则HC和CO2略有上升．     

聚乙烯塑料类固体废弃物热裂化研究

在反应温度455-495℃,氢气压力0.1～4.0MPa和反应时间2～12h的范围内,就聚乙烯塑料类固体废弃物热裂化时温度、压力和反应时间的影响以及不同反应条件下产物的碳数分布、馏程变化进行了探讨,得出适合于生产柴油馏分的反应条件是温度475℃,常压或低压,反应时间4h等。     

清洁汽油生产过程中的蒸馏技术

汽油中的硫会增加汽车尾气中有害物质的排放，世界各国相继制定了越来越严格的规定，限制汽油中的硫含量。加氢技术虽然能够显著降低汽油中的硫含量，但却存在着烯烃饱和而导致辛烷值损失和氢耗高的问题。将汽油切割成不同的馏分段，根据其各自的组成特点选择不同的脱硫工艺，为这一问题提供了经济可行的解决方案。并针对汽油中硫和烯烃的分布特点，对不同汽油切割方案及蒸馏技术进行了分析。     

气相色谱-质谱法测定土壤中的汽油及其组分含量

对土壤中的汽油,采用外标法,经吹扫捕吸仪浓缩后,用气相色谱-质谱法分析定量。同时,用峰面积归一化法,可以测定土壤中汽油的组分含量。     

Subsoil TPH and other petroleum fractions-contamination levels in an oil storage and distribution station in north-central Mexico

Many oil industry related sites have become contaminated due to the activities characteristic of this industry, such as oil exploration and production, refining, and petro-chemistry. In Mexico, reported hydrocarbon spills for the year 2000 amounted to 185 203, equivalent to 6252 tons (PEMEX, 2000). The first step for the remediation of these polluted sites is to assess the size and intensity of the oil contamination affecting the subsoil and groundwater, followed by a health risk assessment to establish clean up levels. The aim of this work was to characterize the soil and water in a north-central Mexico Oil Storage and Distribution Station (ODSS), in terms of TPHs, gasoline and diesel fractions, BTEX, PAHs, MTBE, and some metals. Besides, measurements of the explosivity index along the ODSS were made and we describe and discuss the risk health assessment analysis performed at the ODSS, as well as the recommendations arising from it. Considering soils with TPH concentrations higher than 2000 mg kg⁻¹, the contaminated areas corresponding to the railway zone is about 12 776.5 m², to the south of the storage tanks is about 6558 m², and to the south of the filling tanks is about 783 m². Total area to be treated is about 20 107 m² (volume of 20 107 m³), considering 1 m depth.     

Clearing the air: The costs and consequences of higher CAFE standards and increased gasoline taxes

Concerns about energy security and climate change have sparked legislators’ interest in reducing gasoline consumption by increasing corporate average fuel-economy (CAFE) standards. Using an empirically rich simulation model and cost estimates for anticipated fuel-economy technologies, we estimate annual costs of reducing long-run gasoline consumption by 10% via a 3.8 miles per gallon increase in the standards, and the potential cost savings from allowing manufacturers to buy and sell fuel-economy credits. Maximum gasoline savings would be realized only after all existing vehicles were replaced, or 14 years in our model. A gasoline tax would produce greater immediate savings by encouraging people to drive less, and eventually to choose more-fuel-efficient vehicles. We demonstrate the advantage of a tax by comparing the cost of the higher CAFE standards over the first 14 years against the cost of a gasoline tax that would save the same amount of gasoline over that time.     

机动车燃料清洁化趋势

阐述了机动车燃料清洁化的主要方法和趋势。分析了几种汽油添加剂和替代品的使用对发动机，机动车排放及人体和环境的影响，以及我国燃料油质量标准和清净剂，燃油添加剂，清洁燃料替代品等技术。     

Biodegradation modelling of a dissolved gasoline plume applying independent laboratory and field parameters

Biodegradation of organic contaminants in groundwater is a microscale process which is often observed on scales of 100s of metres or larger. Unfortunately, there are no known equivalent parameters for characterizing the biodegradation process at the macroscale as there are, for example, in the case of hydrodynamic dispersion. Zero- and first-order degradation rates estimated at the laboratory scale by model fitting generally overpredict the rate of biodegradation when applied to the field scale because limited electron acceptor availability and microbial growth are not considered. On the other hand, field-estimated zero- and first-order rates are often not suitable for predicting plume development because they may oversimplify or neglect several key field scale processes, phenomena and characteristics. This study uses the numerical model BIO3D to link the laboratory and field scales by applying laboratory-derived Monod kinetic degradation parameters to simulate a dissolved gasoline field experiment at the Canadian Forces Base (CFB) Borden. All input parameters were derived from independent laboratory and field measurements or taken from the literature a priori to the simulations. The simulated results match the experimental results reasonably well without model calibration. A sensitivity analysis on the most uncertain input parameters showed only a minor influence on the simulation results. Furthermore, it is shown that the flow field, the amount of electron acceptor (oxygen) available, and the Monod kinetic parameters have a significant influence on the simulated results. It is concluded that laboratory-derived Monod kinetic parameters can adequately describe field scale degradation, provided all controlling factors are incorporated in the field scale model. These factors include advective–dispersive transport of multiple contaminants and electron acceptors and large-scale spatial heterogeneities.