Effect of processing on the composition and oxidative stability of coconut oil

The effect of various processing procedures on the composition and oxidative stability of coconut oil has been studied. The crude oil is relatively stable but major reductions in oxidative stability occur during the bleaching of oil degummed with phosphoric acid; during alkali refining; during the deodorization of oil degummed with citric acid and bleached; and during the deodorization of oil processed with a combined phosphoric acid degumming and bleaching operation. The reasons for the loss of oxidative stability during processing are discussed with reference to changes in the composition of the oil. Residual traces of citric acid or phosphoric acid play an important role in stabilizing processed oils. The tocopherol content is also important, although no additional stabilization of the oil occurs on adding levels of tocopherol above those present naturally in the crude oil. A combined phosphoric acid degumming and bleaching process leads to smaller losses of tocopherols than sequential treatments.     

Isolation of erucic acid from rapeseed oil by lipase-catalyzed hydrolysis

Three lipases were compared for their ability to hydrolyze high erucic acid rapeseed oil, with the objective of concentrating the erucic acid in a single glyceride fraction. Lipase fromPseudomonas cepacia released all fatty acids rapidly and did not result in selective distribution of erucic acid.Geotrichum candidum lipase released C20 and C22 fatty acids extremely slowly, resulting in their accumulation in the di- and triglyceride fractions. Less than 2% of the total erucic acid was found in the free fatty acid (FFA) fraction. Lipase fromCandida rugosa released erucic acid more slowly than C20 and C18 fatty acids at 35°C but only resulted in a limited accumulation of the erucic acid in the di- and triglyceride fractions. However, when hydrolysis catalyzed byC. rugosa lipase was carried out below 20°C, the reaction mixture solidified and was composed solely of FFAs and diglycerides. The diglyceride fraction contained approximately 95% erucic acid while about 20% of the total erucic acid was found in the FFA fraction. It is concluded that hydrolysis at low temperature withC. rugosa lipase results in a higher purity of erucic acid in the glyceride fraction than can be obtained withG. candidum lipase, but with considerable loss of erucic acid to the FFA fraction.     

国内外强化采油用表面活性剂研究进展

中国石油对外依存度持续上升,而采收率持续下降。中国剩余石油储量中大部分为高温高盐、低渗透、稠油油藏等难以开采的苛刻油藏。化学驱强化采油技术目前所使用的石油磺酸盐、烷基苯磺酸盐等常规表面活性剂由于活性低、耐盐性差而导致低效甚至无效。综述了新型表面活性剂,如阴-非离子表面活性剂、双子及寡聚表面活性剂、甜菜碱型两性表面活性剂、高分子表面活性剂、烷基糖苷表面活性剂、黏弹性表面活性剂、生物表面活性剂、阴阳离子混合表面活性剂等的研究进展。讨论了国内外强化采油用表面活性剂评价方法的差异。最后,对采油用表面活性剂的发展方向进行了展望。     

Increase in the γ-linolenic acid content by solvent winterization of fungal oil extracted fromMortierella genus

The fungal oil extracted fromMortierella ramanniana var.angulispora (IFO 8187) was solvent winterized in order to raise the content of γ-linolenic acid (GLA). Effects of winterization conditions (solvent, oil concentration in the solvent and temperature) and changes of glyceride compositions were discussed. The fungal oil was separated into four diglycerides and 17 triglycerides (TG) with high performance liquid chromatography. The predominant species were POO, POP and LOP, whose contents were 24.4, 22.9 and 9.4% of the total TG, respectively. Ethanol at 4°C gave the highest GLA content of 10.5% in spite of lower yield than with acetone at −20°C. The highest separation efficiency for GLA (η_GLA) was 0.27 with acetone at −20°C and 10% oil concentration, resulting in 8.3% of GLA from the fungal oil at 5.7% LGA. In case of lower oil concentration at 5–20%, η_GLA showed higher in the following order: acetone (−20°C)>n-hexane (−20°C)>acetone (4°C)>petroleum ether (−20°C). The winterization process also proved to be effective for the separation of TG type, Sa₂U (Sa; saturated fatty acid; U, unsaturated fatty acid) into the crystallized fraction and SaU₂ into the liquid fraction. Acetone at −20°C showed higher separation efficiency for triunsaturated TG than the other solvents.     

火力发电厂仪用压缩空气带水带油探究

采用系统分析、数学及物理计算的方法,对火电厂仪用压缩空气带水带油的原因进行论证,找出最主要原因,并有针对性地采取了预防和改造措施,对改造效果进行了分析与总结。     

油纸电容型套管缺油的危害及判断方法

通过解析油纸电容型套管的结构,介绍了套管四大组成部分的作用和原理,并重点阐述了套管内部绝缘介质的电气性能．同时指出了套管缺油的原因及危害,并说明了如何准确地判断缺油．通过实例阐述了套管缺油的查找方法,论证了综合利用电容量C、介质损失角tanδ、油中溶解气体色谱分析及红外线成像仪对发现套管缺油的合理性及准确性．     

低渗透油藏注CO2提高采收率技术探讨

低渗透油藏具有低孔、低渗、自然产能低、注水注不进采不出等特点,针对国内大部分低渗透油田开发难题,伴随着大批CO2气源的发现,低渗透油藏注CO2驱油成为提高采收率的一种方法。探讨了低渗透油藏注CO2提高原油采收率技术的驱油机理和适应性。     

鄂尔多斯盆地化子坪地区延长组长6沉积特征及其与油藏分布关系探讨

根据岩性、沉积结构与构造、测井相综合分析认为,本区长6油层组为三角洲前缘哑相沉积,可细分为三角洲前缘水下分流河道、分流间湾微相.水下分流河道砂体为其主要的储集层.这些砂体横向上复合连片往往呈带状展布,岩性以细粒长石砂岩为主,残余粒间孔和次生溶蚀也为主要的孔隙类犁.通过沉积相与油藏分布的关系研究,认为油气的聚集受沉积微相的控制,水下分流河道砂体为长6油层组良好的储集层,是有利的油气聚集场所.     

凝析气藏生产气油比混沌时间序列预测方法

混沌时间序列预测方法在油气田勘探开发过程中发挥着重要的作用。地下储层通常具有较强的非均质性,流体的流动也受到多种未知因素的影响,这也与各种混沌现象极为相似。根据相空间重构理论,应用遗传算法求取最小嵌入维数m及时间延迟τ,构建了混沌时间序列模型,并对牙哈凝析气藏两口井的生产气油比进行了模拟及预测,拟合误差小于6%。研究结果表明,该预测模型有较高的精度。     

BZ25-1油田产量递减因素的灰色关联分析

以BZ25-1油田为例分析平均渗透率、有效厚度、生产压差水平等因素对油田单井产量的影响.引入灰色关联分析方法,得到BZ25-1油田各个影响因素与单井产油量的灰关联度.获取平均渗透率、有效厚度、比采油指数、生产压差、平均含油饱和度这五个影响参数的最优组合,优化生产压差和比采油指数,可实现油田相对稳定高产的目的.