压力溶气法溶气罐内压及释放器倾角对气泡影响的研究

发布时间：2018-05-28 04:24

  本文选题：气浮 + 溶气法　； 参考：《西安石油大学》2017年硕士论文

【摘要】：气浮净水技术是一种能够实现固液分离或液液分离的净水方法,它被广泛的应用于石油工业、毛纺工业、食品工业以及造纸废水处理等领域。压力溶气法是气浮净水技术中生成微气泡的方法之一,该方法生成的微气泡具有尺寸细微、大小均匀、数量大等特点。压力溶气气浮法净水的原理是:在高压下通过使空气分子进入水分子间隙或与水分子发生反应生成水合物的方法将空气溶解在水中,之后令压力溶气水经过释放器减压、消能,气体分子就会迅速聚集形成大量细微、均匀的微小气泡,微小气泡与水中的杂质结合,最终携带杂质上浮至水面从而达到净化水体的过程。压力溶气气浮法影响净水效果的最主要因素是微气泡的尺寸以及数量。研究压力溶气气浮法气体在水中的溶解过程、气泡生成的过程以及影响气泡尺寸的因素对提高气浮净水效果具有非常重要的意义。文章以改变溶气压力、释放器倾角以及气泡浮升高度为依托,研究了不同溶气压力、不同释放器放置倾角以及气泡上升的高度与生成气泡尺寸之间的关系。首先对空气在水中的溶解形式进行了研究,并对空气中氧气和氮气溶解时所占比重进行了计算和对比,为提高溶气效率提供了理论依据;随后使用热力学和动力学的方法研究了高压溶气水释压情况下微气泡的成核过程以及其上升时的受力情况,得到了微气泡成核过程中的能量变化以及气泡上升过程中浮升速度与气泡直径的关系;在此基础上,使用数值模拟的方法对两种不同形式的TS-Ⅲ型溶气释放器在不同入口压力的情况下其内部流场进行了对比分析,得出出口端添加孔板的溶气释放器内部流场更均匀,更有利于微气泡的生成,又分别对不同放置倾角的释放器进行了模拟分析,得出由于释放器倾角的变化会导致气相分布的不均匀从而影响气泡的直径;最后通过微气泡拍摄的试验方法得到不同情况下的微气泡图像,并对气泡尺寸进行了测量。通过以上理论及试验研究,可以得到在TS型释放器出口端添加孔板会使得微气泡的尺寸更均匀;当释放器倾角相同时,随着溶气压力的增大,气泡尺寸会逐渐减小,且在0.25~0.3MPa后趋于缓和;相同溶气压力下,随着释放器倾角由垂直变为倾斜,气泡直径逐渐增大;当溶气压力和释放器倾角都一定时,气泡随着高度的上升,直径逐渐变大,当高度大于25厘米时,释放器倾角的改变不会对气泡直径造成太大影响。
[Abstract]:Air flotation water purification technology is a kind of water purification method which can realize solid-liquid separation or liquid-liquid separation. It is widely used in petroleum industry, wool spinning industry, food industry and papermaking wastewater treatment and so on. The pressure-dissolved gas method is one of the methods to generate microbubbles in the air flotation water purification technology. The microbubbles generated by this method have the characteristics of fine size, uniform size and large quantity. The principle of water purification by pressure-dissolved gas floatation is that air is dissolved in water by making air molecules enter water intermolecular gaps or react with water molecules to form hydrates under high pressure. Gas molecules will rapidly gather to form a large number of tiny, uniform tiny bubbles, which combine with impurities in the water, and eventually carry impurities to the surface of the water to achieve the process of purifying the water. The size and quantity of microbubbles are the most important factors that affect the water purification effect by pressure dissolved gas flotation method. It is very important to study the process of dissolved gas in water, the process of bubble formation and the factors affecting bubble size. Based on changing the pressure of dissolved gas, the inclination of the releasing device and the height of bubble floating, the relationship between the bubble size and the different pressure of dissolved gas, the inclination angle of different emitter and the height of bubble rising are studied in this paper. Firstly, the dissolved form of air in water is studied, and the proportion of oxygen and nitrogen dissolved in air is calculated and compared, which provides a theoretical basis for improving the efficiency of dissolved gas. Then, the nucleation process of microbubbles and the forces acting on them when they rise are studied by thermodynamics and kinetics under the condition of high pressure dissolved gas, water release, and pressure release. The energy changes in the nucleation process of microbubbles and the relationship between the floating velocity and bubble diameter during bubble rising are obtained. The internal flow field of two different TS- 鈪，

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