粗萘精制加工工艺技术

介绍了化学精制法、物理精制法和联合精制法工业粗萘精制提纯技术的发展现状,并对各种方法的技术特点进行分析,通过比较各种精制提纯方法的优缺点,对工业粗萘精制提纯技术的发展方向提出建议。     

盐水精制过程及影响因素

综述了盐水精制过程,浅析影响因素,结合澄清桶内盐水净化过程,探讨提高出力和净化效果的一些措施。     

Oilseed pretreatment in connection with physical refining

Tests have shown that the nonhydratable phosphatides (NHP) arising by the action of phospholipases are not present in significant quantities in commercial soybeans, but that they are formed predominantly only during extraction. By a moisture-heat treatment of the soy flakes prior to the extraction, this enzyme activity can be almost completely eliminated so that, during the subsequent extraction, an enzymatic change of the oil no longer occurs. In comparison with the extraction of untreated soy flakes, the yield of soy lecithin is doubled; the lecithin has a higher content of phosphatidylchol ine; the crude, degummed soy oil has extraordinarily low NHP contents; and the soy meal tastes less bitter.     

Pretreatment of edible oils for physical refining

Physical refining of edible oils is briefly reviewed. Recent developments regarding the pretreatment of oils and fats are described in detail and methods are critically evaluated with special emphasis on their effectiveness in removing undesired minor components, their cost of operation and their effect on the environment.     

Pretreatment of corn oil for physical refining

Crude corn oil that contained 380 ppm of phosphorus and 5% of free fatty acids was degummed, bleached, and winterized for physical refining. The pretreatment and the steam-refining conditions were studied in pilot plant scale (2 kg/batch). The efficiency of wet degumming and of the total degumming processes, at different temperatures, was evaluated. TriSyl silica was tested as an auxiliary agent in the reduction of the phosphorus content before bleaching. The experimental conditions of the physical refining were: temperature at 240 or 250°C; 8 to 18 mbar vacuum, and distillation time varying from 1 to 3 h. Degumming at 10 or 30°C resulted in the removal of more phosphorus than at 70°C. Water degumming was more efficient than the processes of total degumming or acid degumming. Corn oil, degummed at 10 or 30°C, after bleaching passed the cold test, irrespective of the degumming agent used. Degumming and winterization took place simultaneously at these temperatures. The pretreatment was able to reduce the phosphorus content to less than 5 ppm. The amount of bleaching earth was reduced by carrying out dry degumming or by using silica before bleaching. Corn oil acidity, after physical refining, varied from 0.49 to 1.87%, depending on the residence time. Contrary to alkali refining, physical refining did not promote color removal due to the fixation of pigments present in the crude corn oil.     

一次盐水精制工艺改造

分析了石河子化工厂一次盐水精制旧工艺中存在的原盐质量差、库存面积小、加精制剂操作不当、存在Si2+造成的二次污染及含有SO2-4等问题。将戈尔过滤技术的新工艺应用在盐水精制工艺后,原盐储量由394m2增大到2000m2,保证了粗盐水的浓度和精盐水的质量,避免了Si2+造成的危害;同原工艺相比,新工艺可节约电费134083.95元/a;用戈尔膜过滤器而去掉碳素管过滤器,又可节省2.07元/(t·NaOH)的设备费。     

一次盐水精制工艺改进

介绍了唐山三友氯碱有限责任公司在一次盐水工序增设和安装化盐水换热器蒸汽换热管线、增设换热器酸洗甩头、连通粗盐水泵进口管线及改造气水混合器等多项工艺改进的过程,总结了现有工艺流程的优化效果。     

炼油工艺优化分析

为解决当前汽油、柴油仍存在严重污染环境且对汽车零部件造成不同程度损伤的问题,在对炼油工艺简单概述和对所炼制成品油提出指标要求的基础上,重点对炼油工艺中第一道蒸馏工序进行研究,分析该道工序中注剂参数由于考虑不周全导致注剂量把握不准确的问题,根据神经网络模型和遗传算法得出不同条件下对应的注氨量和缓蚀剂量,为提升成品油质量奠定基础。     

Non-catalytic biodiesel process with adsorption-based refining

Different feedstocks of varying acidity ranks and water contents were subjected to a series of discontinuous steps that simulated a biodiesel production process. The three steps comprised: (i) the non-catalytic transesterification with supercritical methanol at 280 °C; (ii) the distillation of the unreacted methanol, water and volatile products; and (iii) the adsorption of the impurities with adequate adsorbents. Refined soy oil, chicken oil and waste cooking oil were subjected to the same simple procedure. The process produced biodiesel complying with the water, acid, glycerides and methyl esters content specifications of the EN 14214 standard.Biodiesel production by the reaction of oils in supercritical methanol at 280 °C and methanol-to-oil molar ratios of 15 and 20 produced amounts of glycerol as small as 0.02%. This simplified the subsequent refining of the biodiesel and is considered an advantage over the classic alkali-catalyzed process (that produces 10% of glycerol by-product) because washing steps can be spared.The contents of methyl esters, water and free fatty acids showed a volcano pattern when plotted as a function of the reaction time. In the case of the free fatty acids this was attributed to the initial reaction of water and triglycerides to form acids and glycerol that increased the acidity of the product mixture. At longer reaction times these acids were likely transformed into methyl esters or were decarboxylated to hydrocarbons and CO₂. Water formation was attributed to glycerol decomposition and esterification of free fatty acids.The design of a simple process for biodiesel production using a single reaction step with negligible glycerol production and an adsorption-based refining step was thus studied. A possible scheme integrating reaction, methanol recycling, biodiesel purification and heat recovery was discussed. Advantages and disadvantages of process units were analyzed on terms of operating cost and simplicity.     

EG精制间歇和连续流程对比选择

介绍了PET生产中粗EG精制常用的连续化和间歇精制的流程,针对年产1.5万t改性PET的粗EG处理项目,从工艺复杂性、设备配置、可操作性、产品品质及投资等方面进行比较,间歇精制为适合该项目的流程。     

Pretreatment efficiency for physical refining of sunflowerseed oil

The appropriate pretreatment of crude oil is of crucial significance for the application of physical refining. This paper presents a simplified process for the preparation of sunflowerseed oil by applying multistep acid degumming as the only pretreatment step. Amorphous silica hydrogel was used instead of treatment with bleaching earth. The results obtained showed that samples of crude-pressed and extracted sunflowerseed oil differ significantly with respect to the content and composition of phosphatides, which is important for the pretreatment. The proper choice of oil and the application of multistep acid degumming results in an effective pretreatment of sunflowerseed oil for physical refining.     

Simulation of batch physical refining and deodorization processes

This work presents an application of a differential distillation model for the simulation of batch physical refining and/or deodorization processes in the vegetable oil industry. The vapor-liquid equilibria of these fat systems are described by group contribution equations for vapor pressures and activity coefficients published elsewhere, (Ceriani, R., and A.J.A. Meirelles, Predicting Vapor-Liquid Equilibria of Fatty Systems, Fluid Phase Equilib. 215:227–236, 2004; Fredenslund, A., J. Gmehling, and P. Rasmussen, Vapor-Liquid Equilibria Using UNIFAC, Elsevier Scientific, Amsterdam, 1977). The full complexity of the oil, expressed as its total composition of TAG, DAG, MAG, and FFA, is considered within the simulation. This approach permitted us to quantify and quality distillative neutral oil losses during physical refining. Three different models of differential distillation were tested to develop a good representation of the batch process to be applied to the physical refining and/or deodorization of complex mixtures such as vegetable oils. To evaluate the recommended approach, a case study was performed, namely, a batch deodorizer was simulated for coconut oil refining, and the results were compared with those reported in the literature.     

盐水二次精制工艺控制

介绍了二次盐水精制中使用的螯合树脂的类型和工作机理、盐水二次精制的工艺流程、工艺控制对树脂塔的操作影响及树脂塔再生过程中应注意的问题。     

一次盐水精制工艺的优化改造

对一次盐水系统存在的控制瓶颈进行分析,膜法除硝改造后闲置设备的利用和自动控制的综合运用,优化盐水控制系统,减少盐质变化和过碱量变化的因素对盐水质量的影响。     

一次盐水精制工艺改造总结

介绍了在一次盐水精制装置上实施的几项工艺改造措施:用高纯水代替工业水配制碳酸钠,实时监控精盐水饱和度,避免粗盐水管线结晶,构筑去除游离氯的防线。总结了改造产生的效果。     

一次盐水精制工艺的发展

介绍了传统的一次盐水精制工艺及凯膜过滤技术的工艺流程、盐水质量及运行情况。通过对2种生产工艺的比较,指出了凯膜技术的优越性。