Báo cáo nghiên cứu khoa học: INFLUENCE OF PARAFIN CONCENTRATION ON THE SEDIMENTATION OF DISPERSED PARTICLES IN THE PETROLEUM MEDIA

Bồi lắng pha rắn trong các phương tiện truyền thông liên tục phụ thuộc vào độ nhớt của phương tiện truyền thông, tính chất vật lý, hình thức, bề mặt gồ ghề, nồng độ của các hạt [1]. Bên cạnh đó, sức căng bề mặt cũng có tác dụng để lắng.
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Báo cáo nghiên cứu khoa học: "INFLUENCE OF PARAFIN CONCENTRATION ON THE SEDIMENTATION OF DISPERSED PARTICLES IN THE PETROLEUM MEDIA"Science & Technology Development, Vol 11, No.02- 2008INFLUENCE OF PARAFIN CONCENTRATION ON THE SEDIMENTATION OF DISPERSED PARTICLES IN THE PETROLEUM MEDIA Phan Dinh Tuan, Ta Dang Khoa University of Technology, VNU-HCM Received on January26th, 2006, Manuscript Revised August 29th, 2007) (Manuscript ABSTRACT: The sedimentation of solid phase in continuous media depends on themedia’s viscosity, physical properties, forms, surface roughness, concentration of particles[1]. Besides, surface tension also has effect to the sedimentation. To include all these factorsin the Stockes’ equation, experiments on the sedimentation of sand particles in paraffin-dissolved petroleum have been done. Viscosity has been adjusted to required values bychanging temperature. Paraffin amount, which changes the surface tension of the media, wasincluded as an adjustment in Richardson & Zaki’s correlation [2]. Calculated results havebeen shown to be quite appropriate with the experiments. Keywords: Sedimentation, paraphin, surface tention.1. INTRODUCTIONAccording to the investigation results before [1], adjusting the Stokes’s equation bycoefficients in Richardson and Zaki‘s correlation leads to a rather good adequateness with theexperiments. However, experiments on the sediment of sand-particles in petroleum containingparafin with different amount at constant viscosity pointed out a disagreement insedimentation speed. Besides the base factors, surface tention also has effect to thesedimentation because of the interaction between continuous media and particles. Thisinvestigation complements the referred factors into the Richardson and Zaki‘s correlation.2. INVESTIGATION RESULTS 2.1. Methods Methods, the equipments and standard tests are the same to the study in [1]. The study is carried out with the experimental sedimentation column. Sedimentation speedis determined also by measuring sand concentration along the column after periods of time.The continuous phase is the crude oil of the White Tiger Well, adjusted by different amountsof parafin and applied with different temparatures, so as to keep set-constant viscosities. Tostabilize temperature, outter hot water jacket has been used. Sediment concentration isdetermined by ASTM D-473-69 standard, other parameters of the continuous phase andparafin – by UOP-46 and viscosity – by ASTM D445 [1] Experimental results will be then compared with theoretical values which are found byapplying Stockes’ equation for particles of the same diameters and the same continuous phase.The deviations will be adjusted by a function describing influence of the surface tension whichaffects the existance and amounts of parafin. Coefficients in the function will be found withthe help of the least square method. 2.2. Study on the sedimentation of particles in petroleum containing parafin The experiment results of the sedimentation of particles in petroleum containing parafinare described in the tables 1 to 6. Table 1 is for the sedimentation in petroleum media ofviscosity μ=0,0043 Pa.s, Table 2 - the sedimentation in petroleum media of viscosities in theTrang 60 TẠP CHÍ PHÁT TRIỂN KH&CN, TẬP 11, SỐ 02 - 2008range of μ = 0,0017 - 0,0069 Pa.s. Tables 3 and 4 are for the ratio coefficient K between themeasurred and theoretical speed calculated to Stokes’s equation. Tables 5 and 6 are for thesame ratio coefficient K in tables 3 and 4, but the Stokes equation is replaced by theRichardson & Zaki’s correlation. 2.3. Influence of parafin concentration on the sedimentation of dispersed particles inthe petroleum media Methods of calculating the influence of parafin concentration to the sedimentation ofparticles are same to the one were shown in [1]. The coefficient of the parafin amount in theRichardson & Zaki equation is determined by planned experiments with the calculations asfollows: The definition of the ratio coefficient K: U′Pa = C′(1 − ω) d β P γ α K= U LT (C′: haèng soá tyû leä) Logarithmization the above equation leads to the following correlation: lnK = lnC′ + αln(1 – ω) + βlnd + γlnP The real variables are coded by the correlations: 2[ln(1 − ω) − ln(1 − ω)max ] 2(ln d − ln d max ) X1 = + 1 X2 = +1 ln(1 − ω)max − ln (1 − ω)min ln d max − ln d min 2(ln P − ln Pmax ) X3 = +1 ln Pmax − ln Pmin The regresion equation will be found in the form Y ...