Adsorption isotherms of sesame oil in a concentrated miscella system

The adsorption of peroxides, unsaturated carbonyls, free fatty acids and carotenoids from unrefined sesame oil on vegetable carbon (5%, w/w) in a miscella system was studied. Three different solvent conditions (hexane/ethanol, 100:0, 95:5 and 75:25, vol/vol), combined in a factorial design with five levels of solvent (0, 10, 20, 30 and 40%, w/w), were used to develop the miscella. Equilibrium adsorption was not achieved during the 100 min of adsorption, mainly because the oil components were involved in oxidation reactions during the adsorption process. However, for a given solvent concentration, adsorption of the oil components showed a significant linear regression on their respective initial concentration in the miscella (C_i). Peroxides and carbonyls showed, at all solvent levels investigated, an affinity for the carbon more independent of their C_i than free fatty acids and carotenoids. In general, at the same C_i, a higher adsorption was achieved as solvent concentration increased. The results indicated that free fatty acid adsorption may depend on competitive adsorption based on molecule hydrophobicity. However, in spite of the higher hydrophobicity of carotenoids, compared with free fatty acids, they might not be competing for the same adsorbing sites. Ethanol showed a prooxidant effect that increased peroxide production during adsorption but did not affect the reaction involved in carbonyl production.     

Kinetics of the decomposition of total aliphatic waxes in olive oil during deodorization

Changes in the content of aliphatic waxes during industrial deodorization and/or physical refining of bleached olive oil were studied in an experimental discontinuous pilot plant of 250 kg deodorizer using nitrogen as stripping gas in place of steam. The kinetic constants for the decomposition of waxes during the deodorization process were determined. The reaction orders studied are zero (or can be considered zero) within the working interval. The values of rate constants, activation energy, frequency factor, increment of activation Gibbs free energy, activation enthalpy, and activation entropy are established.     

Phase transitions of canola oil sediment

Canola sediment was obtained from an industrial filter cake by solvent extraction. When heated in the differential scanning calorimeter (DSC) (5–100°C), the sediment exhibited a single narrow melting peak at around 74.8°C. No solid-state polymorphic transformation of the material could be detected over this temperature range. The X-ray powder diffraction pattern of canola sediment resembled waxes from other sources with an orthorhombic unit cell. The phase transition behavior of canola sediment in oil was studied by both DSC and polarizing microscopy. With increasing ratio of oil/sediment, a reduction in both melting temperature and transition enthalpy was observed. The shape of the supercooling curve resembled that of the melting curve. The induction time was determined by spectrophotometry and was used to calculate the interfacial free energyσ between sediment and oil; σ=4.71 erg/cm². The effect of temperature and sediment concentration on the clouding time of canola oil was studied; the clouding time was the shortest at 5°C.     

催化裂解废旧不饱和聚酯树脂新技术

对不饱和聚酯树脂 (UPR)废料裂解制原料油技术进行了研究 ,系统地考察了催化裂解反应工艺条件。试验结果表明 ,催化裂解所需反应温度为 40 0～ 45 0℃ ,反应时间为 70～ 80min ;剂油比 1∶5 ;试验对 4种催化剂的催化性能进行了评价 ,研究表明单独使用YB -2催化剂 ,液相产品收率为 5 8.2 2%～ 5 9.1 4% ;YB -1和YB -2混合使用 ,最高液相产品收率为 68.76%。     

焦化柴油不安定因素考察

对焦化柴油的不安定因素进行了研究.通过研究发现,焦化柴油中的酸性物质、碱性物质、微量金属及可见光均是影响焦化柴油安定性的因素,空气对焦化柴油的安定性影响较小.     

Relationship between oxidative stability of vitamin E and production of fatty acids in oils during microwave heating

Effects of microwave heating on the oxidative stability ofd-tocopherols were studied in relation to the production of fatty acids in oils. During microwave heating, the stability of tocopherols decreased in the orderδ>β>γ>α. This order did not depend on the types of ethyl esters of fatty acids or oils present. But, the shorter the chainlength and the lower the degree of unsaturation of the fatty acid ethyl esters, the greater was the reduction in amount of individual tocopherols. A similar tendency was observed when tocopherol-stripped vegetable oils, with equimolar mixtures of tocopherols added, were treated under the same conditions. The reduction in tocopherols became greater with increasing levels of free fatty acids.     

棉籽油间歇式酯交换反应动力学的研究

生物柴油(棉籽油甲酯)可以由棉籽油与甲醇在催化剂KOH存在下通过酯交换反应制得。故对棉籽油间歇式酯交换反应动力学进行了研究,并考察了反应温度和催化剂浓度对产物棉籽油甲酯浓度的影响。用液相色谱法分析棉籽油的组成;用气相色谱法分析产物中棉籽油甲酯的含量。由实验数据绘制的动力学曲线得到酯交换反应在开始阶段为准二级反应,以后紧接转为一级反应和零级反应,与文献报导的棕榈油酯交换反应动力学结果一致。由实验数据求出酯交换反应在开始阶段的动力学参数,35℃、45℃时的反应速率常数分别为0.9179Lmol-1min-1和1.049Lmol-1min-1,酯交换反应的活化能为10.88kJmol-1。根据实验结果得到棉籽油酯交换反应的最佳反应温度为45℃,最佳催化剂为1.1%KOH。     

De-oiling contaminated bleaching clay by high-pressure extraction

The disposal and re-use of spent bleaching clay from the vegetable oil processing industry is a problem of growing importance. Although today the only practical way of removal of the spent material is disposal, extraction with organic solvents is a well-known method of de-oiling contaminated bleaching clay. In our investigations we compare the extractibility of two different types of bleaching clays with CO₂ as a solvent. All experiments were carried out with a high-pressure extraction plant. The extraction and separation conditions, temperature and pressure, as well as the CO₂ mass flow, were varied during experiments. The aim of our investigations was a complete separation of the oil from the adsorbent. The latter should then be re-used as bleaching clay. The oil and the bleaching clay were analyzed and tested, respectively. The results show that oil of good quality can be recovered and the bleaching clay still has an activity approximately 50% of fresh clay.     

The Viscosity of cottonseed oil,fractionation solvents and their solutions

Cold fractionation of cottonseed oil is made difficult by the high viscosity of the oil. This study was aimed at demonstrating the effect of solvents on the viscosity of mixtures between 0°C and 25°C with a view to facilitating the fractionation of refined cottonseed oil. The solvents used were acetone, methylethylketone, methylisobutylketone, hexane and heptane. Measurements of viscosity were carried out by means of a capillary viscometer. The ratio of the viscosity of cottonseed oil to that of pure solvents is of the order of 300. The viscosities of solutions of various ratios of solvent to oil (1/3, 1/1, 3/1) are between those of cottonseed oil and the pure solvents. The effect of the solvent/oil ratio overrides that of solvent nature. The effect of solvent in reducing the viscosity of cottonseed oil is by descending order: acetone, hexane, methylethylketone, heptane, methylisobutylketone.     

压缩机废油回收工艺小结

介绍了压缩机废油回收的原理、工艺及操作要点,达到了节油降耗的目的。