气液分离切流式回流型旋风管性能研究

发布时间：2018-04-30 19:38

本文选题：切流式 + 气液分离　；参考：《大连理工大学》2015年硕士论文

【摘要】：煤层气是一种非常规天然气,以吸附状态储存于煤系地层中,煤层气一般采用油管排水,套管采气的方式进行开采,在开采过程中不可避免混入一部分液体杂质,这部分液体杂质在输送过程中会对后续管路和设备造成腐蚀和堵塞,所以必须予以除去。本文在总结前人研究的基础上,针对煤层气地面开采生产实际需求开发高效气液旋流分离设备——切流式回流型旋风管。气液混合物进入该分离器经导向叶片产生高速旋转运动,由于气体和液体的密度不同,液滴受到的离心力大而向分离器壁面移动,最终到达壁面并进入排液结构,洁净气体从设置在分离器中心的排气管排出。本设备利用旋流器特有的流场特点,增设了回流管,将一部分进入排液部位的气体引回旋风中心低压区,进入主分离区继续参与分离过程,最终和主气流一起经排气管排出,完成气液分离过程。回流管一方面使排液腔内的气流流动起来,有利于排液过程的进行,另一方面回流消除了旋流中心低压造成的返流现象,能够提高分离器分离效率和抗流量波动能力。本文利用Fluent软件,结合雷诺应力模型(RSM)和DPM离散相模型对旋流器内部流场以及颗粒的运动情况进行了模拟。通过改变旋风管的结构参数和操作参数来研究这些参数对设备性能的影响,为分离器的设计和优化提供指导。本文加工了实验样机,设计了实验流程并且搭建了实验平台。实验通过调节结构参数和操作参数来测试旋风管在不同条件下的压降性能和分离性能,并与数值模拟结果进行对比,验证了本文开发的切流式回流型旋风管性能。为了对比验证新型旋风管的性能,本文在前人研究成果的基础上设计了传统三维导叶式旋风管,并对其进行了数值模拟和实验对比研究。经过数值模拟和实验得出,本文设计的新型旋风管在非常宽的流量范围内综合分离效率达到95%以上,能够有效去除5gm以上颗粒。回流管大大提高了设备的分离能力和抗流量波动能力,同时降低了设备压降；叶片高度越低,设备内部切向速度越高,分离效率越高,但抗流量波动能力会降低；本设备相对于传统三维导叶式旋风管,分离效率有较大提高；主分离段长度不宜过长,否则容易导致分离下来的液滴返混；环隙排液适用于流量长期低于设计流量的工况,而筒壁开侧缝排液适用于流量长期高于设计流量的工况,两种排液方式的旋风管均有较宽的流量范围。综合数值模拟和实验结果,本文设计的新型切流式旋流分离器具有高效低阻,抗流量波动能力强的特点,基本满足煤层气气液分离的需求。
[Abstract]:Coal bed methane is a kind of unconventional natural gas, which is stored in the coal measure strata in the state of adsorption. The coal bed methane is usually exploited by using tubing drainage and casing gas production, and a part of liquid impurity is inevitably mixed in in the process of exploitation. This liquid impurity can cause corrosion and blockage of subsequent pipelines and equipment during transportation, so it must be removed. In this paper, based on the previous studies, a high efficiency gas-liquid swirl separation equipment, tangent flow reflux cyclone tube, is developed to meet the actual demand of coal bed methane production. The gas-liquid mixture enters the separator and produces high-speed rotating motion through the guide blade. Because of the different density of gas and liquid, the liquid droplets are moved to the wall of the separator because of the large centrifugal force, and finally reach the wall and enter the drainage structure. The clean gas is discharged from the exhaust pipe located in the center of the separator. This equipment utilizes the characteristic flow field characteristic of the cyclone, has added the backflow tube, draws a part of the gas which enters the liquid discharge position back to the cyclone center low pressure area, enters the main separation area to continue to participate in the separation process, finally and the main airflow together through the exhaust pipe discharge, Complete the gas-liquid separation process. On the one hand, the reflux tube causes the flow of air in the cavity, which is propitious to the discharge process, on the other hand, the reflux eliminates the phenomenon of regurgitation caused by the low pressure in the swirl center, which can improve the separation efficiency of the separator and the ability of resisting the flow fluctuation. In this paper, the flow field and particle motion in hydrocyclone are simulated by using Fluent software, combined with Reynolds stress model (RSM) and DPM discrete phase model. The influence of these parameters on the performance of the equipment is studied by changing the structure parameters and operating parameters of the cyclone tube, which provides guidance for the design and optimization of the separator. In this paper, the experimental prototype is machined, the experimental flow is designed and the experimental platform is built. The pressure drop performance and separation performance of the cyclone tube under different conditions were measured by adjusting the structure parameters and operating parameters. The experimental results were compared with the numerical simulation results to verify the performance of the tangential reflux cyclone tube developed in this paper. In order to compare and verify the performance of the new cyclone tube, this paper designs the traditional three dimensional guide vane cyclone tube based on the previous research results, and carries on the numerical simulation and the experimental contrast research to it. Numerical simulation and experiments show that the new cyclone tube designed in this paper has a comprehensive separation efficiency of more than 95% in a very wide flow range, which can effectively remove the particles above 5gm. The reflux tube greatly improves the separation ability and anti-flow fluctuation ability of the equipment, and reduces the pressure drop of the equipment; the lower the blade height, the higher the tangential speed and the higher the separation efficiency, but the lower the anti-flow fluctuation ability is, the lower the blade height is, the higher the internal tangential speed is, and the higher the separation efficiency is. Compared with the traditional three dimensional guide vane cyclone tube, the separation efficiency of this equipment is greatly improved; the length of the main separation section should not be too long, otherwise, it is easy to cause the separation of droplets back mixing; the annular clearance discharge is suitable for the condition that the flow rate is lower than the designed flow rate for a long time. However, the open-side slit of cylinder wall is suitable for the condition that the flow rate is higher than the designed flow rate for a long time, and the cyclone tubes with two kinds of discharge modes have a wide flow range. Based on the numerical simulation and experimental results, a new tangential swirl separator designed in this paper has the characteristics of high efficiency and low resistance and strong resistance to flow fluctuation, which basically meets the needs of coal-bed gas-liquid separation.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE93

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