基于离心脱水的含油污泥油—水分离特性及分离机理研究

发布时间：2018-03-01 03:29

本文关键词： 含油污泥离心脱水油-水分离特性油-水分离技术　出处：《浙江大学》2016年博士论文　论文类型：学位论文

【摘要】：含油污泥是石油勘探、开采、炼制、加工、储存、运输等过程中产生的主要固体废弃物之一。油泥中含有30%～80%的碳氢化合物(PHCs),回收油泥中的原油将会产生一定的经济效益和环境效益。油泥离心相分离技术具有能耗低,污染小,操作简单等优点,适合油泥资源化处理的工业化应用。含油污泥中含有水、油及固体颗粒,油泥在形成过程中受到剪切力作用发生乳化,使水呈颗粒状分散到主体油相中形成十分稳定的油包水(W/O)型原油乳化液,给油泥的离心脱水带来了很大困难。本文研究的主要目的是提高含油污泥中油-水分离效率,围绕油泥中水分分布特性,水滴在离心场中的分离规律,以及高效离心预处理技术展开研究,进行了以下工作：首先,开展了含油污泥理化特性分析研究。结果表明,油泥中含有多种重金属和多环芳烃；不同来源的油泥水、油、固体颗粒三组分差异较大,这主要与油泥的生成条件有关；通过显微观测,可以确定油泥中各组分的相对含量、形态结构、存在条件以及各成分的粒径大小；油泥热值与其碳含量呈正比,且H/C约为2；根据油泥油相色谱模拟蒸馏结果可知,油泥中含有高比例的重质组分。采用差示扫描量热技术(DSC)建立了含油污泥水分综合表征方法,首次实现了对油-水分离“指纹特征”——水滴粒径分布的测量。应用DSC表征方法对三种不同来源的油泥进行了测量分析,结果显示,-60℃到室温程序升温过程中,结晶水的融化吸热峰可用于计算油泥的含水量。并且由-23.5℃度附近的盐-水共晶熔融峰,可以判断油泥中的含盐量。此外,提出了油泥乳化水滴粒径分布计算经验公式,可以根据0℃到-60℃之间的水滴结晶温度计算水滴粒径。这是首次将DSC测量技术应用到表征油泥水滴粒径分布上。这一表征方法为油泥油-水分离模型的建立和分离技术的研究提供了基础。对影响油泥中油-水离心分离的参数进行了分析,并通过正交实验探明了提高油-水分离效果的关键因素。对于高粘度、粒径分布广的油泥,制约脱水率提高的关键因素是温度和离心转速。升温可以有效降低油泥的粘度而转速的提高可以降低油泥中水滴的临界分离粒径。对于水滴粒径小于5μm的油泥乳化液,制约脱水率提高的关键因素是离心转速,为了提高油泥机械脱水的效率,油泥需经破乳预处理提高水滴粒径。保证油泥在离心机内有足够的停留时间可以显著提高水滴粒径大于10μm的油泥的脱水率。应用纳维-斯托克斯沉降方程,建立了基于蒙特卡洛随机统计的油泥乳化水分离模型。实现了对不同离心工况下水滴分离效果的预测。模型计算与实验结果均显示,随着离心转速的提高,油泥脱水率显著提高。当转速由2000rpm提高至10000rpm时,脱水率由28%提高至99%,同时,水滴临界分离粒径也由2000 rpm时的14 μm提高至10000 rpm时的3μm。此外,基于蒙特卡洛随机统计的油泥乳化水分离模型还可以对不同粘度油泥在不同离心工况下的脱水率及临界分离粒径进行预测,计算结果与实验值吻合良好。分离模型可以为不同油泥脱水工况选择提供定量指导。采用了超声波、掺混轻质油、添加微乳液等预处理技术优化油泥油-水离心分离特性,并提出多途径耦合的降粘破乳预处理工艺。研究发现,25 kHz和30 kHz超声波可以直接脱除26.3 wt%和28.1 wt%的水分,但会导致残留水滴的粒径减小。虽然35 kHz和40kHz超声对油泥直接脱水影响不大,但可以大幅度增加油泥乳化水的水滴粒径。超声改变油-水分离特性的作用机理可以由超声共振效应和超声空化效应解释。掺混轻质油可以有效降低油泥的粘度并显著提高脱水率。微乳液具有超低的界面张力,可以对油包水结构实现有效破乳。为了促进含油污泥资源化利用的工程化应用,提高回收油品质并减少二次污染,开发了含油污泥两级分离系统集成工艺,并选用典型的油泥样品在实验室条件下进行了工艺优化实验。结果表明,在高含固预处理一级分离中添加20%的煤油,可脱除粒径在15.1μm以上的固体颗粒。一级分离产物经7%微乳液化学调质后进行二级离心分离,得到的回收油中含水和固体颗粒重量比小于3%。该分离系统将应用于日处理100t的油泥资源化处理集成技术示范工程。
[Abstract]:The oily sludge is oil exploration, mining, refining, processing, storage, transportation of solid waste generated in the process of hydrocarbon containing from 30% to 80%. The sludge (PHCs), the recovery of crude oil sludge will produce certain economic benefits and environmental benefits. The sludge centrifugal separation technology with low energy consumption, small pollution and the advantages of simple operation, suitable for industrial application of sludge treatment resources. Oily sludge containing water, oil and solid particles, sludge by shear stress occurs in the emulsion forming process, so that the water was dispersed into the main oil granular phase to form very stable water in oil (W/O) crude oil emulsion, great difficult to centrifugal dewatering sludge. The main purpose of this study is to improve the separation efficiency of oily sludge in oil water, around the water distribution characteristics of oil, separation of water droplets in the centrifugal field, and high Study on effect of centrifugal pretreatment technology, the following work: firstly, the oily sludge physicochemical characteristics analysis. The results showed that the sludge contains many kinds of heavy metals and polycyclic aromatic hydrocarbons; different sources of oil slurry, oil, solid particles of three components is different, this is mainly related with the formation conditions of sludge by; the microscopic observation, can determine the relative content of each component in the sludge, the morphological structure, existence condition and each component of the particle size is proportional to the calorific value of sludge; and carbon content, and the H/C is about 2; according to the sludge oil chromatographic simulated distillation results, heavy group sludge contains a high percentage of points. By using differential scanning calorimetry (DSC) method was established for water comprehensive characterization of oily sludge, for the first time to measure the oil - water separation "fingerprint" of water droplet size distribution. The application of DSC method on three different characterization The source of the sludge were measured and analyzed. The results show that the temperature of -60 DEG C to room temperature programmed during the melting endothermic peak of crystal water can be used to calculate the water content of sludge. And by the near -23.5 degrees C salt water eutectic melting peak, can determine the quantity of salt sludge. In addition, the oil emulsion droplet size distribution calculation formula, can according to 0 DEG C to drop the crystallization temperature between -60 DEG C calculation of droplet size. This is the first time DSC measurement technology is used to characterize the oil droplet size distribution. The research provides the basis for the establishment of oil sludge water separation model and the separation technology of this characterization method. The parameters affecting the sludge oil water separation was analyzed, and through the orthogonal experiment proved the key factors to improve the oil-water separation effect for high viscosity, particle size distribution of sludge, restricting the dehydration rate is the key factor to improve Temperature and centrifugal speed. Temperature can effectively reduce the viscosity and improve the speed of sludge can reduce the sludge water separation critical particle size. For oil emulsion droplet size less than 5 m, the key factors restricting the dehydration rate of increase is the centrifugal speed, in order to improve the efficiency of mechanical dewatering of sludge, sludge by pre emulsion increased water droplet size. To ensure sufficient residence time of sludge in centrifuge can significantly improve the water droplet size larger than 10 m sludge dewatering rate. Using Navier Stokes equation of settlement, established the model of separation of Monte Carlo statistical clay emulsified water. Based on the prediction effect of different centrifugal separation conditions of water the calculated and experimental results show that with the increase of rotational speed, sludge dewatering rate increased significantly. When the speed is increased from 2000rpm to 10000rpm, the dehydration rate by 28%. Up to 99%, at the same time, 3 m. drop critical separation particle diameter from 2000 rpm to 14 m increased to 10000 RPM in addition, clay emulsified water separation model of Monte Carlo stochastic statistics can also be on the dehydration rate of different sludge viscosity at different centrifugal conditions and the critical separation particle diameter was predicted based on the calculation. Results are in good agreement with the experimental values. The separation model can provide quantitative guidance for the selection of different sludge dewatering conditions. Using ultrasonic, mixing light oil, adding micro emulsion pretreatment technology optimization of oil - water sludge characteristics of centrifugal separation, and put forward the viscosity demulsification pretreatment process of multi way coupling. The study found that 25 kHz and 30 kHz ultrasonic can direct removal of 26.3 wt% and 28.1 wt% of water, but will lead to residual droplet diameter decreases. Although the 35 kHz and 40kHz ultrasound has little effect on sludge dewatering, but can greatly increase oil emulsion Water droplet size change mechanism. Ultrasonic oil - water separation properties can be explained by ultrasonic resonance effect and cavitation effect. The mixing light oil can effectively reduce sludge viscosity and improve the dehydration rate. The microemulsion with ultra-low interfacial tension of oil and water, can realize the effective structure. In order to demulsification to promote the application of oily sludge utilization project, improve the recovery of oil quality and reduce pollution two, development of oily sludge integrated process of two stage separation system, and selects the typical sludge samples process optimization experiments were carried out under laboratory conditions. The results show that in high solids pretreatment stage separation adding 20% the kerosene can be removed with particle size of solid particles of more than 15.1 m. The product level separation by 7% micro emulsion chemical conditioning after two stage centrifugal separation, water and solid particles weight recovery oil obtained in small ratio The 3%. separation system will be applied to the integrated technology demonstration project for the daily processing of 100t.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：X741

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