Research On The Migration And Separation Behavior Of Drill Cuttings In The Spin Dryer

Drilling cuttings dryer is the core equipment of drilling fluid waste "no landing"treatment system.In the actual use of drilling platform,there are many problems,such as variable properties of separation media,low separation efficiency and high moisture content of discharged materials.Faced with the above problems,this paper combines theoretical research with numerical simulation.Firstly,the similarities and differences of the migration of different separation media in the flow field of the drilling cuttings dryer are analyzed.Through the analysis of the movement and distribution of particles on the surface of the screen basket,the dehydration effect is evaluated;Secondly,the separating behavior of the dryer under different structure parameters,operation parameters and physical parameters was analyzed,and the range of working parameters with relatively high separating efficiency and relatively low moisture content of export materials was summarized;Finally,the optimum combination of parameters of the dryer is obtained by optimum software analysis,and the separation performance of the dryer is improved.The main research contents are as follows:(1)This paper investigates the research status of drilling fluid waste treatment at home and abroad as well as the research status of drilling cuttings dryer,and understands the process flow of drilling fluid waste "no landing" treatment system;This paper investigates the field application of WSM-0136 drilling cuttings dryer products,understands the problems it is facing in the field application process,and determines the necessity and importance of the research.(2)Starting from the structure characteristics,working principle and basic characteristics of drilling cuttings dryer,the movement and stress of particles in the centrifugal separation field of drilling cuttings dryer are analyzed.Combining with the principle of centrifugal filtration and separation,the basic equation of constant pressure filtration is obtained,which lays a theoretical foundation for the optimization design and numerical simulation of the cuttings dryer.(3)Solidworks software is used to build the three-dimensional model of the cuttings dryer and Fluent software is used to analyze the similarities and differences of the movement of different separation media in the flow field of the cuttings dryer.It is found that the rheological characteristics of non-Newtonian fluid will make the distribution of its parameters in the flow field of the dryer similar to that of Newtonian fluid,but there are some differences in numerical values;By analyzing the influence of rheological parameters on drilling cuttings migration,it can be found that:With the increase of consistency coefficient and liquidity index,the axial and radial velocity of liquid phase decreases,the effect of slag transport and filtration becomes worse,the time of particle transport decreases,the separation effect becomes worse,and the volume fraction of particles on the wall of screen basket and scraper rotor decreases,the viscosity of medium increases,and the dehydration effect becomes worse.(4)Based on the theoretical study,the related factors affecting the separation effect of the cuttings dryer are analyzed,and the calculation formula of the separation efficiency of the cuttings dryer when the separation medium is power law fluid is proposed.Fluent software is used to simulate and calculate the different structure parameters,operation parameters and physical parameters of the cuttings dryer,and the influence rules of each parameter on the separating effect and separating efficiency of the cuttings dryer are obtained.lt was found that when the gap between scraper and screen basket is 4 mm,the half cone angle of screen basket and scraper is 27.5°,the rotation speed is between 900 rpm and 1000 rpm,the rotation speed difference is between 20 rpm and 25 rpm,the processing capacity is between 40t/h and 50 t/h,the solid phase concentration is between 60%and 80%,and the average particle size is above 0.07mm,the moisture content at the bottom outlet of drilling cuttings dryer is relatively low and the separation efficiency is relatively high.(5)The main and minor factors affecting the separation performance of the cuttings dryer are analyzed by the orthogonal experimental design method;Design-Expert software is used to analyze and optimize the main factors,and the optimal combination of parameters of the dryer is obtained and verified by simulation.It was found that the moisture content of the bottom outlet material of the cuttings dryer decreased from 13.5%to 6.1%before optimization,while the separation efficiency increased from 74.1%to 88.5%.