Alternative hydrocarbon solvents for cottonseed extraction

Hexane has been used for decades to extract edible oil from cottonseed. However, due to increased regulations affecting hexane because of the 1990 Clean Air Act and potential health risks, the oil-extraction industry urgently needs alternative hydrocarbon solvents to replace hexane. Five solvents,n-heptane, isohexane, neohexane, cyclohexane, and cylopentane, were compared with commercial hexane using a benchscale extractor. The extractions were done with a solvent to cottonseed flake ratio of 5.5 to 1 (w/w) and a miscella recycle flow rate of 36 mL/min/sq cm (9 gal/min/sq ft) at a temperature of 10 to 45°C below the boiling point of the solvent. After a 10-min single-stage extraction, commercial hexane removed 100% of the oil from the flakes at 55°C; heptane extracted 100% at 75°C and 95.9% at 55°C; isohexane extracted 93.1% at 45°C; while cyclopentane, cyclohexane, and neohexane removed 93.3, 89.4, and 89.6% at 35, 55, and 35°C, respectively. Each solvent removed gossypol from cottonseed flakes at a different rate, with cyclopentane being most and neohexane least effective. Based on the bench-scale extraction results and the availability of these candidate solvents, heptane and isohexane are the alternative hydrocarbon solvents most likely to replace hexane. Presented in part at the AOCS Annual Meeting & Expo, Atlanta, Georgia, May 1994.     

THE ISOTHERMAL COMPRESSIBILITY OF GAS-SATURATED HYDROCARBON LIQUIDS

Volumetric measurements were made on compressed solutions of carbon dioxide in n-decane and trans-decalin at 37.78°C at pressures up to 60 bar. The data were numerically analyzed to yield the isothermal compressibility function of the solutions at their saturation pressures.     

Ignition and Combustion of Dust-Gas Suspensions

The ignition and combustion of dust-gas suspensions are considered. It is shown that the ability of these systems to accumulate heat is determined not only by their kinetic and thermal properties but also by the relation between their reaction surface and the heat-removal surface (f). Experimental information on flame temperatures, ignition delays, and flame propagation over gas suspensions is processed using the parameter f, and the postulate on the stimulating role of the developed reaction surface in activating these processes is validated. It is shown that during overall burning, diffusion combustion of particles occurs only for rather small values of f. The ambiguous effect of the parameter f on the ignition and combustion processes leads to the necessity of optimizing the fuel size distribution and concentration for the effective operation of the power devices. The role of the macroparameters of two-phase flames of refractory metals in the synthesis of combustion nanoproducts is analyzed. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 6, pp. 3–14, November–December, 2005.     

Sub-ambient cold-start emissions reduction using SwRI® PO x catalyst technology

This paper describes the application of SwRI’s cold-start PO _x catalyst technology to reduce cold-start hydrocarbon emissions from a US Tier 2 vehicle at −7 °C. A reduction in −7 °C (20 °F) cold-start hydrocarbons will help US Tier 2 vehicles meet the proposed EPA NMOG standards. Improvements in cold temperature hydrocarbon emissions would also be beneficial in many parts of Europe during the winter months. In this work, a total hydrocarbon reduction of 19% was realized at 24 °C, in line with previous results, but only up to 3% at −7 °C. Insufficient oxygen in the engine-out exhaust gas at −7 °C was determined to be the reason why the PO _x catalyst failed to significantly reduce HC emissions. Addition of supplemental oxygen to the exhaust during the cold-start, to simulate an adjustment in the engine calibration to less rich operation, resulted in a total hydrocarbon reduction of 18% with the PO _x catalysts in place, but no benefit when the PO _x catalysts were removed. Hence, the PO _x catalyst approach can be used to good effect, even under sub-ambient cold-start conditions.     

鄂尔多斯盆地下古生界构造-沉积演化、古地理重建及有利成藏区带划分

鄂尔多斯盆地下古生界是重要的天然气勘探层位,相继发现了奥陶系顶部风化壳、古隆起周缘中组合和马家沟组盐下等多套含气层系,证明了盆地下古生界具有良好的勘探开发潜力,也揭示出深化古地理重建工作的急迫性。在分析鄂尔多斯盆地构造-沉积演化过程的基础上,对早古生代重点时期的古地理进行了重建,进而提出了成藏区带划分的新思路。研究表明,鄂尔多斯盆地经历了太古宙—元古宙裂陷沉积、寒武纪—奥陶纪沉积-剥蚀、石炭纪—三叠纪拗陷稳定沉积、侏罗纪—白垩纪挤压成藏和晚白垩纪—现今调整定型等5大阶段。盆地下古生界古地理格局经历了早-中寒武世的古陆消减、沉积增长、边缘裂陷阶段和早奥陶世的隆-坳相间阶段,并控制了优质成藏区带的分布。结合近期勘探研究进展,依据源-储组合和空间分布,划分出了基于主控因素的4类成藏区带：潮缘滩白云岩成藏区、奥陶系盐下台内丘滩成藏区、西部双滩带白云岩和页岩成藏区以及岩溶-滩相白云岩成藏区。不同区带显示出了不同的成藏条件和主控因素,需要选择针对性的勘探策略。     

塔里木盆地顺北地区克拉通内走滑断裂带中-下奥陶统储集体方解石脉形成及其与油气充注耦合关系

塔里木盆地顺北油气田为克拉通内走滑断裂多期活动控制下形成的碳酸盐岩超深层油气田,不同断裂带及同一走滑断裂带不同分段的油气性质和油气丰度等均存在显著差异。基于岩心和岩石薄片观察以及阴极发光、微区原位微量元素-稀土元素、流体包裹体的系统分析,对塔里木盆地顺北1号和顺北5号走滑断裂带中-下奥陶统储集体中的裂缝脉体序次、成脉流体来源及其与油气充注耦合关系进行研究,并结合走滑断裂演化过程和油气分布特征,探讨了顺北地区油气差异聚集的控制因素。结果表明：顺北1号和顺北5号走滑断裂带中-下奥陶统至少发育4期方解石脉体（Cal-1,Cal-2,Cal-3,Cal-4）。Cal-1成脉流体主要为海源性流体,Cal-2,Cal-3和Cal-4成脉流体来源于同地层成岩流体。Cal-2,Cal-3和Cal-4脉体的形成分别与加里东晚期—海西早期、海西晚期—印支期、燕山期—喜马拉雅期构造活动和油气充注相伴生。不同断裂带油气充注过程存在差异,顺北5号断裂带主充注期为海西晚期—印支期,顺北1号断裂带主充注期为海西晚期—印支期及燕山期—喜马拉雅期。走滑断裂构造样式及演化历史控制下的油气差异充注过程是顺北地区油气差异聚集...     

A study of replacement rules for a parallel fleet replacement problem based on user preference utilization pattern and alternative fuel considerations

Parallel fleet replacement problems deal with determining an optimal replacement schedule that results in a minimal total cost of owning and operating a fleet within a finite planning horizon. In this paper, the fleet consists of service vehicles, varying in age and cumulative mileage, commonly owned by government agencies or private business organizations. The paper focuses on three main aspects of the problem, including the effects of some widely used replacement rules, consideration of alternative fuel vehicles for replacement, and a new “user preference” utilization pattern. The vehicle replacement rules under study include purchase-new-vehicles-only, no-splitting-in-selling, one-purchase-choice, older-vehicles-selling, and all-or-none rules. The initial fleet consists of gasoline vehicles, while alternative-fuel vehicles using either compressed natural gas (CNG) or liquefied petroleum gas (LPG) are included as challengers in every replacement decision period. The user preference utilization pattern denotes a pattern in which yearly usage of vehicles declines as the vehicles grow older or have higher cumulative mileage. Integer programming formulation of the defined problem that incorporates these new factors is provided. Small numerical examples under various scenarios and a large problem instance with model parameters estimated from actual data are solved to optimality to gain some insights about the replacement rules and other considered factors.     

EM>N/EM>，EM>N-/EM>二乙基

研究了N,N-二乙基羟胺(DEHA)水溶液辐解产生的气态烃。当DEHA浓度为0.1~0.5 mol/L,剂量为10~1 000 kGy时,甲烷、乙烷、丙烷和正丁烷的体积分数随剂量的增加而增加,但随DEHA浓度的增加而减少。乙烯和丙烯的体积分数随DEHA浓度的增加而增大,它们与剂量的关系与DEHA浓度有关。     

Emission Control of NO and SO2 for the High-Temperature and Low O2 Concentration Combustion of Coke by Urea and NH4HCO3

Urea and NH4HCO3 were used to control the emission of NO and SO2 from the combustion of coke at high-temperature and low oxygen concentration. Urea and NH4HCO3 could control NO emission only under 1100°C. Their effects disappeared above 1100°C even though the increase of urea and NH4HCO3 content from 10?to?50?wt?%. However, they showed good desulfurization effect on the emission of SO2 at all combustion temperatures and their effects showed remarkable results even at 1500°C. Only 10?wt?% of urea or NH4HCO3 could control the emission of SO2 effectively at 1400 and 1500°C. This effect was caused by ?NH and ?NH2 from the thermal decomposition of reducing agents at high temperature. Low O2 concentration showed little effect on the removal of SO2. Ammonia slip from the thermal decomposition of reducing chemical was not a considerable level.     

A New Synthetic Hydrocarbon Liquid Lubricant for Space Applications

Synthetic hydrocarbon liquid lubricants (based on polyalphaolefins) have been developed for use in space applications. These materials have been fully characterized and their physical properties reported which include: kinematic and absolute viscosity, viscosity index, vapor pressure, evaporation, specific gravity, pour point, coefficient of thermal expansion, refractive index, and flow activation energy. In addition, tribological properties under ultrahigh vacuum conditions have been determined. These include: lubricated lifetimes using a spiral orbit tribometer (SOT) and vacuum four-ball wear rates. These values are compared to existing state-of-the-art space lubricants.