Study On Characteristics And Mechanisms Of Dynamic Pressure Degaser

The problem of degassing in oil often occurs in petrochemical,engine lubrication systems,and degassing capacity directly affects the normal operation of the related equipment and machinery.According to the amount of gas content in liquid,this problem can be divided into super critical ratio of liquid to gas separation,separation of conventional liquid gas ratio and ultra small ratio of liquid to gas degassing.On the basis of different purpose,the specific requirements of two-phase separation are different: degassing problem requires underflow separation with high quality;mist romval problem needs high purity gas overflow;some special problems require high quality of the in both overflow and underflow.This paper mainly studies on degassing from liquid,focusing on the quality of liquid in underflow,the effects of flow rate,gas-liquid ratio and dielectric properties on separation performance and pressure drop characteristics is also cared besides.The main work of this dissertation about the above problems is as follows:1.The concept of fractionation is applied to the design of degasers.A structure of two-stage degassing is proposed,which can take into account both the volumetric efficiency and separation efficiency of the equipment.Under the standard operating conditions,internal flow analyses of the degaser in used are carried out,It was found that no delamination occurred in the helical flow passage except for agglutination,so the separation process is separated into separate independent double stage degassing processes using a barrier,the primary degassing process is crude separation,to reduce separator operating load.The secondary degassing is accomplished by high speed swirling flow and fine separation improving separation efficiency.Continuous structural optimization is carried out following the "simulation analysis structure improvement" cycle mode,and key parameters are parameterized,a optimized flow field and a dual stage dynamic pressure degassing apparatus are obtained in the end.2.According to the optimization of the structure,the experimental prototype and the experimental platform are set up,and the pressure drop characteristics and separation characteristics of the deaerator are studied.Liquid gas ratio-pressure drop and liquid gas ratio-separation efficiency experiments showe that the pressure drop decreased with the increase of gas content,and the separation efficiency increased first and then decreased with the increase of gas volume fraction.Flow pressure drop and flow separation efficiency experiments show that the optimal flow range is near 80% of the maximum flow,and the results are poor in both too high or too low conditions.The experiments of temperature-pressure drop and temperature-separation efficiency show that the pressure drop decreased with the increase of temperature,the trend is first and then delayed,and the separation efficiency reached the optimum near 60% of the highest temperature.Every data point was conducted by numerical simulation when the experiments were carried out.Experiment results are in good agreement with simulation results without consideration of the influence of random measurement error and systemic resistance.3.Study on separation characteristics and adaptability of two-stage deaerator in multi degree of freedom motion environment.By using momentum control equation,the dynamic source terms with multiple degrees of freedom are added to establishe a numerical simulation model of gas-liquid separation under the condition of simulating,translational,accelerating and sloshing.This can realize the numerical study on dynamic degassing process.The effects of translational acceleration,sloshing angular velocity and radius of sloshing on the degassing process are investigated in this paper.The results show that the influence of sloshing state on the degassing process is more serious than that of the translational acceleration process.In the translational state,the acceleration will change the flow field characteristics,the gas-liquid interface will rise,the pressure will increase,and the performance and efficiency of the deaerator will decrease slightly,but the degassing process can still proceed normally.In the slosh condition,effect of sloshing radius on the degassing process is far greater than the angular velocity,a large sloshing radius is will lead to a large area of the gas-liquid mixed liquid reflux,velocity field disorder,pressure surge phenomenon.Therefore,it is recommended that the installation position should be considered first when installing the degaser,the position of the degaser shall be located near the center of the sloshing.Secondly,the influence of the limit sloshing angular velocity in the working condition can be taken into account.Finally,considering the influence of translational acceleration,in this way,the effect of dynamic conditions on the performance of the deaerator can be reduced to the greatest extent.