Grafted natural polymer as new drag reducing agent: An experimental approach

The present investigation introduces a new natural drag reducing agent which has the ability to improve the flow in pipelines carrying aqueous or hydrocarbon liquids in turbulent flow. Okra (Abelmoschus esculentus) mucilage drag reduction performance was tested in water and hydrocarbon (gas-oil) media after grafting. The drag reduction test was conducted in a buildup closed loop liquid circulation system consists of two pipes 0.0127 and 0.0381 m Inside Diameter (ID), four testing sections in each pipe (0.5 to 2.0 m), tank, pump and pressure transmitters. Reynolds number (Re), additive concentration and the transported media type (water and gas-oil), were the major drag reduction variables investigated. The experimental results show that, new additive drag reduction ability is high with maximum percentage of drag reduction (%Dr) up to 60% was achieved. The experimental results showed that the drag reduction ability increased by increasing the additive concentration. The %Dr was found to increase by increasing the Re by using the water-soluble additive while it was found to decrease by increasing the Re when using the oil-soluble additive. The %Dr was higher in the 0.0381 m ID pipe. Finally, the grafted and natural mucilage showed high resistance to shear forces when circulated continuously for 200 seconds in the closed-loop system

Introducing Slag Powder as Drag Reduction Agent in Pipeline: An Experimental Approach

Main by product in ore smelting from tin production in Malaysia has become a trigger for this investigation. Slag waste can be categorized as suspended solid. Utilization of this waste in fluid transportation can reduce the pressure drop in pipelines. Experimental works had conducted in order to test slag waste in a closed loop of turbulence water flowing system with water and fuel as the transport liquid. The procedures start by pumping liquid suspended solid combination from reservoir tank with varies flow rates into two different pipe diameters (0.0127 m ID and 0.038 m D.I). The types of pipe used are PVC pipe. The testing length of this flow system is 2.0 m. The pressure drop and drag reduction were measured in varied addition concentration. The results have show percentage drag reduction (Dr%) is over 60% in certain range and condition. It is proved that slag is a potential DRA

Elucidation of Longitudinally Grooved-Riblets Drag Reduction Performance using Pressure Drop Measurements

The need to determine affordable and environmentally friendly methods of reducing skin friction can be identified as one of the reasons contributing towards the study of the effectiveness of riblet shapes. Water tank experiments were carried out to optimize the shape and dimensions of microstructure grooves over a flat plate. The use of organized microstructures on channel walls is proposed to obtain lower values of pressure losses on smooth walls. Three shapes of microstructure grooves were investigated, with same groove height (600 μm) and five spacing dimensions (600, 750, 1000, 1500 μm), in water flows with velocities of up to 0.4 m/s. This was done for all selected types of riblet, which are fixed with the direction aligned with the flow. The experimental results showed that the size and shape of the riblets can massively incubate some of the turbulent structures formed on the surface and that will lead to a more controllable flow environment, which can result in drag reduction

Experimental investigations on biopolymer in enhancing the liquid flow in microchannel

Drag reduction has been incorporated in various industrial fields. Most of the works proved that drag reduction is efficient in turbulent flow. It is also observed that polymers can enhance the laminar flow which could be a milestone in medical field. In this work, five straight microchannels with fixed depth of 100, 50, and 60 μm in width and 200, 300, 400, and 500 μm in length were designed and fabricated using direct writing method. Xanthan gum as bio‐based drag reducing additive was chosen and diluted with deionized water to investigate its feasibility in enhancing the laminar flow in the microchannel. Eight different concentrations of xanthan gum ranging from 20 to 500 ppm were used to evaluate the effect of concentration on drag reduction performance using pressure measurement. The maximum flow increment of 34.90% was achieved by utilizing 500 ppm of xanthan gum at an operating pressure of 100 mbar in the microchannel with a width of 500 μm

Active drag reduction in hydrocarbon media using rotating disk apparatus

A high precision rotating disk apparatus (RDA) is designed and employed to investigate the turbulent drag reduction characterization induced by polymeric additives. For the past few decades, polymers have been used widely as drag reducer agents in a pipeline and RDA successfully due to its viscoelastic properties that can suppress the turbulent at high ranges of Reynolds number. In this study, drag reduction efficacy of diesel fuel in a rotating disk apparatus is investigated using high molecular weight polyisobutylene polymer as drag reducing agent. Dependence of drag reduction on different parameters such as: polymer concentration and rotational disk speed (RPM) are also investigated. In addition, the mechanical stability of this polymer with time was studied by measuring torque values for 300 sec at a fixed rotational speed (2000 rpm). It was observed that the drag reduction of diesel fuel increases withthe rotational disk speed and polymer concentration till a critical concentration at which the maximum drag reduction achieved. The maximum DR obtained was about 19.197% at Re = 902062 and PIB concentration of 150 ppm

Rotating Disk Apparatus: Types, Developments and Future Applications

Power consumption reduction investigations attracted the attention of enormous numbers of researchers in the past few decades due to its high academic and economic impacts. The pumping power losses during the transportation of crude oils are considered as one of the main power consuming applications due to the turbulent mode of transportation. Investigating the possible solutions for this problem is expensive and time consuming due to the large apparatuses needed to simulate the flow in real pipelines. Rotating disk apparatus (RDA) is an instrument mainly comprising a rotating disk and an electrical motor to rotate the disk, which was implemented as an efficient and economical path to simulate what can be done in pipelines through generating a controlled degree of turbulence. This technique was also used in many other scientific applications due to its dynamic mode of operation. For example, a rotating disk electrode was used in electrodeposition processes and to characterize deposition film thickness and uniformity. The rotating disk reactor was employed to investigate the reaction rate between fluids and solid surfaces. The present work evaluates the RDA from different prospective and applications in order to introduce it as an efficient research tools for future dynamic investigations

Surfactant–solid complex for enhancing the low in pipelines : An experimental approach

Background: Viscoelastic soluble polymeric additives have been used successfully for a long time as drag reducers in pipelines carrying commercial liquids like crude oil. Most of these polymers suffer from irreversible degradation when exposed to high shearing zones as in valves, elbows, and pumps which reduces, or eliminates, its flow enhancement effect. Insoluble additives were proven to be an effective drag reducer that overcomes the degradation drawback of soluble additives. On the other hand, insoluble additives suffer from the lack of viscoelasticity which limits their use as flow enhancers. The creation of complexes from soluble and insoluble additives is a field of research that is rarely explored despite its importance in introducing new flow enhancement methods for a higher drag reduction performance. The present work introduces a new surfactant–solid complex as a drag-reducing agent for turbulent flow in pipelines. Results: The surfactant, solid, and their complexes’ drag reduction performance was tested in a closed-loop turbulent flow liquid circulation system, while rheological characteristics of the soluble additives were tested using a standard rheometer. All the surfactant solutions showed non-Newtonian shear thinning behavior in all the investigated concentrations that ranged between 500 and 1300 wppm. The initial experimental result indicated that the surfactant solution's drag reduction performance was higher than that of the solid suspensions. On the other hand, the drag reduction performance was enhanced by 52% when creating a 1300 wppm surfactant–2000 wppm solid complex. This improvement in the drag reduction performance is due to the formation of surfactant–solid-enforced aggregates with high resistance to shear forces and high turbulence suppression efficiency. Conclusions: The present work introduces a new drag reduction solid–surfactant complex by creating aggregates combining the viscoelastic properties of surfactants with the resistance to high shear forces exerted by the solid particles. The polar nature of the surfactant micelles that form in single-phase flow systems contributed significantly to trapping the solid's micro-particles as enforcement to resist the shearing forces applied by the turbulent flow system

Demulsification of petroleum emulsions using microwave separation method

The formation of emulsions during oil production and processing is a costly problem, both in terms of chemicals used and production losses. For economic and operational reasons, it is necessary to separate the water completely from crude oils before transporting or refining them. Experimental data are presented to show the influences of Triton X-100, low-sulfur wax residue (LSWR), sorbitan monooleate (Span 83) and sodium dodecyl sulfate (SDS) on the stability and microwave demulsification of petroleum emulsions. It was found that emulsion stability was related to several parameters including the surfactant concentration, water-to-oil phase ratio (10 to 90%), temperature and agitation speed. Based on this study, a possible emulsion-minimization approach utilizing microwave irradiation is suggested, which could be implemented in refineries. Compared with conventional heating, the use of microwave heating can significantly enhance the demulsification rate, reaching over 90 v/v% for the emulsions studied in this work

Assessment of capacitive deionization microfluidic desalination via electrode microstructure analysis

Microfluidics desalination technology is an immerging path of technology to utilize the domination of many apparent fluids physical properties (viscosity and surface tension) in the micro-flow systems. The traditional and commercially applied desalination methods suffer from several drawbacks such as high power consumption and low separation performance. It is believed that the flow of liquids in the micro-scaled structures will optimize the mixing efficiency and that will definitely lead to higher desalination performance. The present work introduces a microfluidics chip for water desalination. The chip was fabricated using polydimethylsiloxane soft lithography method. The aluminium electrodes were coated with carbon powder in order to avoid dissolution. The desalination efficiency was analyzed and evaluated with different feed flow rate (70, 90, 110, 130 and 150 mL/h) using capacitive deionization method. The dissolution of electrodes were observed for 35 min with the feed flow rate ranging 70 to 150 mL/h. The desalination efficiency with aluminium electrodes and carbon-coated electrodes was 65% and 58% respectively. The microstructure of electrode was analyzed by using scanning electron microscopy coupled with energy dispersive X-ray (SEM/EDX). The result revealed that the aluminium electrode experienced dissolution at 70 mL/h while the carbon-coated electrodes start to dissolve at t = 30 min. The findings in this work shows that the dissolution time for electrodes were relies on its surface properties

The Potential of Ultrasonic Membrane Anaerobic Systems in Treating Slaughterhouse Wastewater

Direct discharge of slaughterhouse wastewater causes serious environmental pollution due to its high chemical oxygen demand (COD), total suspended solids and biochemical oxygen demand. In this study, an ultrasonic-assisted membrane anaerobic system was used as a novel method for treating slaughterhouse wastewater. Six steady states were achieved, using concentrations of 7,800–13,620 mg/l for mixed liquor suspended solids and 5,359–11,424 mg/l for mixed liquor volatile suspended solids. Kinetic equations were used to describe the kinetics of treatment at organic loading rates of 3–11 kg COD/m3/d. The removal efficiency of COD was 94.8–96.5% with hydraulic retention times of 308.6–8.7 days. The growth yield coefficient was found to be 0.52 g VSS/g. COD was 0.21 d−1 and methane gas production rate was 0.24–0.56 l/g COD/d. Steady-state influent COD concentrations increased from 8,000 mg/l in the first steady state to 25,400 mg/l in the sixth steady state. The minimum solids retention time, θcmin obtained from the three kinetic models was 6–14.4 days. The k values were 0.35–0.519 g COD/g VSS.d and μmax values were between 0.26 and 0.379 d−1. The solids retention time decreased from 600 to 14.3 days. The complete treatment reduced the COD content and its removal efficiency reached to 94.8%