嵌段聚醚强化高稳含油污水破乳过程的机理研究

发布时间：2018-05-31 14:40

本文选题：嵌段聚醚 + 高稳含油污水　；参考：《西南石油大学》2015年硕士论文

【摘要】：随着渤海油田聚合物驱油技术的实施,相应产生了大量的含聚采出水。采出水由于残余聚合物的存在,异常稳定。目前,处理这种污水较为有效的方法是加入阳离子型聚合物絮凝剂,虽然效果明显,但分离过程中的絮凝体粘附性很强,易堵塞污水处理设备及管道。通过前期研究发现,用非离子型嵌段聚醚处理这类污水,既能使处理后污水水质达标,同时还不会产生大量粘性絮凝体。但其作用机理不够明确,无法确定影响聚醚处理含聚污水性能的主要因素以及相应的调控方法,因此药剂的优化及现场应用受到限制。本文针对这一问题,对嵌段聚醚强化高稳含油污水破乳过程的机理进行了研究。本文以SZ36-1CEPK油田生产污水为处理对象,首先测定了污水的基本性质,其PH=6.8,含油量为4724mg/L,固含量为80mg/L,聚合物浓度为282mg/L,粒径中值为5.1μm,污水中原油的等效烷烃碳数为9.2,油水乳化程度高,属于高稳含油污水。针对这类污水具有净水性能的嵌段聚醚亚组分EO、PO摩尔比接近0.75。分离的几种聚醚中,产物中有效组分不超过50%,如果在实际生产中能很好控制产物的EO/PO比值,提高其有效含量,将大大降低产物的使用浓度。具有良好处理效果的嵌段聚醚,起效温度均大于浊点小于PIT；无处理效果的嵌段聚醚,其浊点或小于30℃(过小)、或大于40℃(过高),在嵌段聚醚分子设计中,可按照使用温度设计合成起效温度介于浊点和PIT之间的产物。嵌段聚醚从水相扩散至界面是自发过程,该过程是熵驱动过程,熵变可反映嵌段聚醚分子顶替原界面活性物质及改变界面膜紧密度的能力。几种典型嵌段聚醚中,DMEA1231(以醇胺为起始剂的四嵌段聚醚,分子结构中EO、PO、EO、PO的质量比为1：2：3：1)扩散过程的熵变最大,为614J/K·mol,即具有处理效果的嵌段聚醚,扩散过程中熵变相对较大。宏观絮凝动力学实验表明,阳离子型絮凝剂的絮凝速率是嵌段聚醚的3-5倍,对于DMEA1231,其最佳处理条件：温度在55℃附近,搅拌强度为200rpm。微观絮凝动力学实验结果表明,嵌段聚醚作用下,油滴的聚并速率常数七明显大于阳离子絮凝剂,但嵌段聚醚受温度影响较阳离子絮凝剂大。即与阳离子絮凝剂不同,嵌段聚醚主要是通过油滴聚并实现乳液破乳,对油珠的聚集行为无明显影响。 Zeta电位测定结果表明,阳离子絮凝剂能有效破坏乳液双电层结构,通过静电中和实现除油；而加入嵌段聚醚后,其电性未发生改变。这证实了阳离子絮凝剂与嵌段聚醚强化污水破乳过程的机理的差异性。嵌段聚醚能有效顶替界面活性物质,降低油水界面膜强度,从而破坏其稳定性。随着温度的升高,扩张模量随温度的升高呈降低趋势。55℃时界面扩张模量最低,与相转变温度和絮凝动力学测定结果相符。油滴聚并-再聚集过程是嵌段聚醚强化高稳含油污水破乳的过程,其中油滴聚并是关键,这一步骤是通过相转变驱动乳液失稳实现。用量升高扩张模量降低；随着聚合物浓度和分子量的增大,界面扩张模量会随之增大。通过DMEA1231相转变温度测定结果以及组分分析结果,引入HLD值(亲水亲油差异值)理论,对破乳机理进行了宏观理论描述。计算得到在DMEA1231作用下,温度为55℃时,乳状液体系的HLD值为0.886,DMEA1231在其相转变温度(55℃)附近,会诱导乳液体系发生相转变,此时乳液稳定性较差。
[Abstract]:With the implementation of polymer flooding technology in Bohai oilfield, a large amount of water containing polymining produced water has been produced. The produced water is abnormally stable because of the existence of residual polymer. At present, the more effective method to treat this kind of sewage is to add cationic polymer flocculant, although the effect is obvious, the flocculation of the flocculant is strong and easy to plug in the process of separation. The sewage treatment equipment and pipeline have been found. Through the previous study, it is found that the treatment of this kind of sewage with non-ionic block polyether can not only make the sewage water quality reach the standard after treatment, but also do not produce a large number of viscous flocculates, but its mechanism is not clear enough to determine the main factors affecting the performance of polyether treatment and the corresponding regulation and control. In this paper, the mechanism of the demulsification process of the embedded polyether reinforced high stability oily wastewater was studied in this paper.
In this paper, the basic properties of sewage in SZ36-1CEPK oilfield are measured, and the basic properties of the sewage are measured first, which is PH=6.8, the oil content is 4724mg/L, the solid content is 80mg/L, the concentration of the polymer is 282mg/L, the median diameter is 5.1 u m, the equivalent alkane carbon number of the raw oil in the sewage is 9.2, the oil and water emulsification is high, which belongs to the high stability oily sewage.
For this kind of sewage with water purification capacity of the block polyether subcomponent EO, PO mole ratio close to 0.75. separation of several polyether, the product is not more than 50% of the effective component, if the actual production can well control the product's EO/PO ratio, improve its effective content, will greatly reduce the use of low product concentration. With good treatment effect of block polymerization. The starting temperature of the ether is greater than the cloud point less than PIT, and the untreated block polyether, whose cloud point is less than 30 C (too small), or more than 40 degrees C (too high), can be designed in the block polyether molecular design, and can be designed to synthesize the products with the starting temperature between the cloud point and the PIT according to the use temperature.
The diffusion of block polyether from the water phase to the interface is a spontaneous process. This process is an entropy driven process. The entropy change can reflect the ability of the block polyether molecules to replace the original interface active material and change the tightness of the boundary mask. Several typical block polyether, DMEA1231 (four block polyether with alcohol amine as starting agent, EO, PO, EO, PO in molecular structure) have a mass ratio of 1: 2:3:1) the entropy change of diffusion process is the largest, which is 614J/K? Mol, that is, block polyether with processing effect, and the entropy change is relatively large during diffusion.
The macro flocculation kinetics experiment shows that the flocculating rate of the cationic flocculant is 3-5 times as high as that of the block polyether. For DMEA1231, the optimum treatment condition is that the temperature is near 55, and the stirring intensity is 200rpm. micro flocculation kinetics experimental results show that the coalescence rate constant seven of the oil droplets is obviously greater than the cationic flocculant under the action of the block polyether. However, the block polyether is more affected by the temperature than the cationic flocculant. That is, different from the cationic flocculant, the block polyether is mainly through oil droplets and emulsion demulsification, and has no obvious effect on the aggregation behavior of the oil beads.
The results of Zeta potential determination show that the cationic flocculant can effectively destroy the structure of the double layer of emulsion and realize the deoiling by electrostatic neutralization, but the electrical property of the cationic flocculant is not changed after adding the block polyether. This proves that the mechanism of the cationic flocculant and the block polyether to strengthen the demulsification process is different. The block polyether can effectively replace the interfacial activity. As the temperature rises, the dilatation modulus of the interfacial dilatation modulus is the lowest at.55 C with the increase of temperature, which is consistent with the phase transition temperature and flocculation kinetics. The process of oil droplet aggregation and re aggregation is the process of demulsification of the embedded polyether and high stable oily wastewater. The key is the accumulation of oil droplets. This step is realized by the phase transition driven emulsion instability. As the amount increases, the dilatation modulus decreases. With the increase of polymer concentration and molecular weight, the interfacial dilatation modulus will increase.
Through the results of DMEA1231 phase transition temperature determination and component analysis, the theory of HLD value (hydrophilic difference value) is introduced to describe the mechanism of demulsification. The HLD value of the emulsion system is 0.886 at the temperature of 55, and DMEA1231 will induce the emulsion system near the phase transition temperature (55 degrees C). The phase change occurs, and the stability of the emulsion is poor at this time.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X741;O631

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