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2003年上半年委内瑞拉供应量剧减,以及美伊战争等因素影响,上半年布伦特油价为28.17美元/桶,同比上涨19.7%,其中一季度为30.62美元/桶,二季度为25.80美元/桶。三、四季度世界石油需求增长有所回升,但欧佩克履约情况、伊拉克产量恢复情况及美国石油库存等是影响未来石油市场的不确定因素。预计三季度油价仍将起伏不定,布伦特油平均价格可能维持在28美元/桶左右,四季度为25.5美元/桶。 相似文献
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The apolar and hydrophobic jojoba molecule was made more hydrophilic by the incorporation of primary amino groupsvia the introduction and subsequent reduction of azido groups. The azides were obtained by the substitution of bromine or a mesylate
group introduced into the jojoba oil molecule; by opening of the epoxide ring in epoxy jojoba; or by the addition of bromoazide
to the double bonds of jojoba. 相似文献
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研究了不同条件(静置时间、速度梯度、温度、添加电解质)下模拟含油废水中浮油凝并聚结的过程,探讨了影响浮油稳定性的因素。实验结果及分析表明,适当的静置(20min左右)、一定的速度梯度(1.5~6.9 s~(-1))、较低的温度(5~20℃)以及加入电解质(如NaCl)均可降低浮油废水的稳定性。 相似文献
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Five vegetable oils were each randomized by chemical means (with the use of a sodium potassium alloy) and by enzymatic means
(using a nonspecific lipase). The success of the randomization procedure was confirmed via positional analysis. The oxidative
stabilities of the native and chemically randomized oils were determined at storage temperatures of 28°C and 55°C using absorbance
at 234 nm as indicative of conjugated diene content. No difference between curves occurred in oils stored at 55°C, however,
at the lower temperature all chemically randomized oils had significantly steeper slopes (P<0.05), suggesting a lower stability.
When both enzymatically and chemically randomized oils were compared to native oils at 28°C, no significant difference occurred
between slopes of native and enzymatically randomized oils, however, the end content of conjugated dienes was significantly
higher for chemically randomized canola, corn and soybean oils (P<0.05). No difference was seen between the slopes of the
three different oils from either linseed or sunflower. Since both of these oils exhibited higher oxidation rates, it is possible
that observation of differences between the stability of native and chemically randomized oild is dependent upon the rate
of the reaction. 相似文献
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Temperature effect on the viscosities of palm oil and coconut oil blended with diesel oil 总被引:1,自引:0,他引:1
One of the major difficulties in using crude vegetable oils as substitute fuels in diesel engines is their relatively high
viscosities. Increasing the temperature of the crude vegetable oil, blending it with diesel oil, or the combination of both
offers a simple and effective means of controlling and lowering the viscosities of vegetable oils. This work reports viscosity
data, determined with a rotational bob-and-cup viscometer, for crude palm oil and cononut oil blended with diesel oil over
the temperature range of 20–80°C and for different mixture compositions. All the test oil samples showed a time-independent
newtonian type of flow behavior. The reduction of viscosity with increasing liquid temperature followed an exponential relationship,
with the two constants of the equation being a function of the volume percentage of the vegetable oil in the mixture. A single
empirical equation was developed for predicting the viscosity of these fuel mixtures under varying temperatures and blend
compositions. 相似文献
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研究了用南阳脱沥青油生产凡士林的可能性,提出南阳脱沥青油含有较多的微晶蜡,滴点较高,不是生产凡士林的合适原材料;但若与蜡下油和中等粘度的润滑油、基础油调配后,可生产出同时满足医药和化妆用品标准要求的凡士林产品。 相似文献
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以黄岛油库为例,分析了油库混油现象的原因和解决的办法,在保证生产有序进行的同时,又确保同类不同牌号的油品质量不受影响,对成品油的贮运和管理提供了很好的借鉴。 相似文献