Studying the rheological properties and the influence of drag reduction on a waxy crude oil in pipeline flow (original) (raw)
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Drag Reduction of Iraqi Crude Oil Flow in Pipelines by Polymeric Additives
IAEME, 2018
In this work, a Drag Reducing Agent (DRA) has been employed to reduce the drag of Iraqi crude oil using Poly Vinyl Pyridine (PVP) at different concentrations (0, 500, 750, 1000, 1250 and 1500 ppm). Results show that a significant decrease in flow index values has been achieved at a concentration range of (750-1500 ppm) in which the lowest value is obtained at a PVP concentration of 1000 ppm. This has been clarified by obtaining flow indexes of less than unity indicating the sample shear thinning. Thus, using a DRA concentration of 1500 ppm for a pipeline decreases the pressure drop by 35.7 % capacity, pipe diameter and length of 0.02 3/s, 0.0508 m and 10 m, respectively. In addition, a maximum drag reduction of 35.1 % has been achieved at the highest concentration (1500 ppm). Therefore, the DRA addition saves the pumping power and increases the produced flow by 35.1 % and 27.5 %, respectively.
Heavy crude oil viscosity reduction and rheology for pipeline transportation
Fuel, 2010
Different methods of reducing the viscosity of heavy crude oil to enhance the flow properties were investigated. Experimental measurements were conducted using RheoStress RS100 from Haake. Several factors such as shear rate, temperature and light oil concentration on the viscosity behavior have been studied. This study shows that the blending of the heavy crude oil with a limited amount of lighter crude oil provided better performance than the other alternatives. Experimental measurements in terms of shear stress s-shear rate _ c; and yield stress s 0 were conducted on the mixture of heavy crude oil-light crude oil (O-light). The results showed a significant viscosity reduction of 375 mPa s at a room temperature of 25°C. This study shows that the heavy crude oil required a yield stress of 0.7 Pa, whereas no yield stress was reported for the heavy crude oil-light crude oil mixture.
Journal of Rheology, 1980
The effects of solvent viscosity, bulk velocity, and pipe diameter on drag reduction have been investigated in order to ascertain the feasibility of utilizing polymer dragreducing additives 00 increase the flow rate in the T'rans-Alaska Pipeline. Laboratory screening studies were perforrned in 1-and 2-in. diam flow loops 00 determine the best eommereially available additive for the application. Field tests in a 14-in. erude pipeline and in the 48-in. Trans-Alaska Pipeline confirmed the material's effeetiveness in large-scale applications. This research program has resulted in the use of dragreducing additive in the Trans-Alaska Pipeline as a temporary replacement for unconstrueted pump stations. The effect of additive concentration was investigated over a range of 5 to 25 ppm. The erude-oil flow conditions that were studied included solvent kinernatic viseosities of 9 to 50 mm 2/see (9 to 50 es), Reynolds numbers of 4000 to 300000, wall shear rates of100 to 2000 sec-I, as weil as inside pipe diameters from 2.66 to U9.4 em (1.050047.0 in.). The drag-reduction results have been correlated based on an extension of a theoretieal model available in the literature. The funetional form of the model requires a knowledge of the wall shear rate, the friction factor, and the additive coneentration as independent variables.
Effect of drag reducing polymers on oil-water flow in a horizontal pipe
2009
Measurements of drag-reduction are presented for oil-water flowing in a horizontal 0.0254 m pipe. Different oil-water configurations were observed. The injection of water soluble polymer solution (PDRA) in some cases produced drag reduction of about 65% with concentration of only 10-15 ppm. The results showed a significant reduction in pressure gradient due to PDRA especially at high mixture velocity which was accompanied by a clear change in the flow pattern. Phase inversion point in dispersed flow regime occurred at a water fraction range of (0.33-0.35) indicated by its pressure drop peak which was disappeared by injecting only 5 ppm (weight basis) of PDRA. Effect of PDRA concentration and molecular weight on flow patterns and pressure drops are presented in this study. Influence of salt content in the water phase on the performance of PDRA is also examined in this paper.
Scientific Journal of Applied Sciences of Sabratha University, 2019
In this study the applicability of the Libyan crude oil flow induced by improved lab pumping system was examined in order to evaluate the effect of adding polymeric materials of Polystyrene and Polydimethylsiloxane as drag reducing agents (DRA) on the flow of Sharara crude oil in the pipeline. The polymers are injected through a pumping system at different concentrations rounded between (10-100) ppm. Several experiments were carried out to determine the best concentration of polymer, which satisfied lowest drag force on of crude oil flow rate. Furthermore, the effect of additive concentration on the Viscosity(μ), friction factor (ƒ), percentage drag reduction (%DR) and the amount of flow increases (%FI) were determined. The results show that the activities of Polydimethylsiloxane for Drag reduction is higher than drag reduction for Polystyrene. However, the %DR is generally increased with increasing of polymer concentration for all tested additives. It is progressively increased wit...
Fuel, 2012
The objective of this study was to investigate the rheological properties of the light crude oil and its emulsions in order to obtain more knowledge about the rheological behavior of oil flow in pipelines. The experiments were carried out at a temperature of 20°C by using the RS600 RheoStress (ThermoHaake, Germany). The results showed that the viscosity of the prepared emulsions varied with their water contents. In the case of 100% light crude oil, the study of the functional relationship demonstrated the quasi-Newtonian behavior with a moderate constant viscosity. However, for emulsions with different water concentrations, their rheological behaviors were described in better way by the Ostwald de Waele and the Herschel-Bulkley models. The stability of emulsions was identified by measuring the rheological properties including non-Newtonian viscosity, the elastic modulus, (G 0), the loss modulus, (G 00), the phase angle (d) and the complex viscosity (g ⁄). The results indicated that the rheological properties and the physical stability of emulsions were significantly influenced by the water contents and the nature of crude oils.
In this paper, experiments were conducted to understand the influence of a small change of pipe diam- eter in the effectiveness of drag reducing polymer (DRP) in horizontal oil–water flow. Two pipe diameters were used in this study; 19 and 25.4 mm pipes. The results showed a remarkable influence of pipe diam- eter on the polymer efficiency in modifying flow patterns and drag reduction. The results from both pipes showed that only 10 ppm polymer concentration is needed to achieve the maximum drag reduction for each investigated condition. The presence of DRP extended the region of stratified and dual continuous flows. However, the percentage increase in the stratified region is more significant in the 25.4-mm pipe while the extent of the dual continuous pattern in the 19-mm pipe is larger than that in the 25.4-mm pipe. Regardless of the pipe diameter, annular flow changed for all the investigated conditions to dual continuous flow. The dispersed region (water continuous or oil continuous) decreased after introducing DRP but the decrease is larger for the 19-mm pipe especially for dispersion of oil in water. The results for both pipes revealed that the maximum drag reduction is achieved when the flow is dispersed oil in water; however, higher drag reduction was obtained in the larger pipe diameter. Drag reductions up to 60% were observed in the 25.4-mm pipe in comparison with up to 45% achieved in the 19-mm pipe.
DRAG REDUCTION WITH POLYMER MIXTURES IN PIPES OF DIFFERENT DIAMETERS
Transporting crude oil and other fluid in pipelines of different sizes over long distances in process industries require high amount of energy which results to high cost of installing pumping stations and maintenance. Addition in part per million (ppm) of high molecular weight polymeric solution reduce such cost. The effect of pipe diameter, oil input volume fraction and flow rate (superficial velocity) on drag reduction (DR) in horizontal oil-waterflows was investigated in unplasticised polyvinylchloride (uPVC) horizontal pipe with two different pipe diameters (0.012 and 0.02 m IDs). The two liquids used were diesel oil (ρ = 832 kg/m 3 , µ = 1.66 cP) and water (ρ = 1,000 kg/m 3 , µ = 0.89 cP) as test fluids at ambient conditions (25°C, 1 atm). Partially hydrolyzed polyacrylamide (HPAM; magnafloc 1011), polyethylene oxide (PEO) and Aloe Vera Mucilage (AVM) separately, as well as mixture of HPAM-AVM and PEO-AVM at different oil input volume fraction (δo; 0,0.25, 0.5, 0.75 and 1) and flow rate (Q; 0.65, 1.28, 1.90 and 2.46 m 3 /hr) were used. The master solution of 2,000 ppm, 2,000 ppm and 20,000 ppm for HPAM, PEO and AVM respectively and their respective mixtures were used to achieve the required concentrations. Mercury U-tube manometer was used to measure the pressure drop. DR of 62%, 65%, 54% for HPAM, PEO and AVM; 69 and 71% for HPAM-AVM and PEO-AVM respectively at mixing ratio of 3:1 and 1:19 in 0.012 m ID. Also, DR of 58%, 62%, 43% for HPAM, PEO and AVM; 67% and 68% for HPAM-AVM and PEO-AVM respectively in 0.02 m ID were obtained at the same condition. The pressure drops observed in the smaller pipe (0.012 m ID) was higher than that of the larger pipe diameter (0.02 m ID). From the experimental results,
In this study, a HMW anionic co-polymer of 40:60 wt/wt NaAMPS/acrylamide was used as a drag reduc- ing polymer (DRP) for oil–water flow in a horizontal 25.4 mm ID acrylic pipe. The effect of polymer con- centration in the master solution and after injection in the main water stream, oil and water velocities, and pipe length on drag reduction (DR) was investigated. The injected polymer had a noticeable effect on flow patterns and their transitions. Stratified and dual continuous flows extended to higher superficial oil velocities while annular flow changed to dual continuous flow. The results showed that as low as 2 ppm polymer concentration was sufficient to create a significant drag reduction across the pipe. DR was found to increase with polymer concentration increased and reached maximum plateau value at around 10 ppm. The results showed that the drag reduction effect tends to increase as superficial water velocity increased and eventually reached a plateau at Usw of around 1.3 m/s. At Usw > 1.0 m/s, the drag reduction decreased as Uso increased while at lower water velocities, drag reduction is fluctuating with respect to Uso. A maximum DR of about 60% was achieved at Uso = 0.14 m/s while only 45% was obtained at Uso = 0.52 m/s. The effectiveness of the DRP was found to be independent of the polymer concentration in the master solution and to some extent pipe length. The friction factor correlation proposed by Al-Sarkhi et al. (2011) for horizontal flow of oil–water using DRPs was found to underpredict the present experimental pressure gradient data.
Effect of drag-reducing polymers on horizontal oil–water flows
Journal of Petroleum Science and Engineering, 2007
The effect of a drag-reducing polymer (DRP) in the water phase during horizontal oil-water flow was investigated in a 14 mm ID acrylic pipe. Oil (5.5 mPa s, 828 kg/m 3 ) and a co-polymer (Magnafloc 1011) of polyacrylamide and sodium acrylate were used. Two polymer concentrations were tested, 20 ppm and 50 ppm, made from a 1000 ppm master solution. The results showed a strong effect of DRP on flow patterns. The presence of DRP extended the region of stratified flow and delayed transition to slug flow. The addition of the polymer clearly damped interfacial waves. Annular flow changed in all cases investigated to stratified or dual continuous flow, while slug flow changed in most cases to stratified flow. In the cases where the slug and bubble flow patterns still appeared after the addition of the polymer, the oil slugs and bubbles were seen to flow closer together than in the flow without the polymer. The DRP caused a decrease in pressure gradient and a maximum drag reduction of about 50% was found when the polymer was introduced into annular flow. The height of the interface and the water hold up increased with DRP. There were no large differences on pressure gradient and hold up between the two DRP concentrations. Using a two-fluid model it was found that the addition of the polymer results in a decrease in both the interfacial and the water wall shear stresses.