Heat Transfer Analysis for Gas-to-Liquids Transportation Through Trans Alaska Pipeline

Gas-to-liquids (GTL) technology involves the conversion of natural gas to liquid hydrocarbons. In this article, theoretical studies have been presented to determine the feasibility of transporting GTL products through the Trans-Alaska Pipeline System (TAPS). To successfully transport GTL through TAPS, heat loss along the route must be carefully determined. This study presents heat transfer and fluid dynamic calculations to evaluate this feasibility. Because of heat loss, the fluid temperature decreases in the direction of flow and this affects the fluid properties, which in turn influence convection coefficient and pumping power requirements. The temperature and heat loss distribution along the pipeline at different locations have been calculated. Fairly good agreement with measured oil temperatures is observed. The powers required to pump crude oil and GTL individually, against various losses have been calculated. Two GTL transportation modes have been considered; one as a pure stream of GTL and the second as a commingled mixture with crude oil. These results show that the pumping power and heat loss for GTL are less than that of the crude oil for the same volumetric flow rate. Therefore, GTL can be transported through TAPS using existing equipment at pump stations.     

THE NIGER DELTA COMPLEX BASIN: STRATIGRAPHY, STRUCTURE AND HYDROCARBON POTENTIAL

The Agbada Formation is the major oil-producing formation in the Niger Delta Complex Basin, and overlies the Eocene Akata Formation, which is the principal hydrocarbon source rock. The Basin is deformed by large synsedimentaty faults, roll-over anticlines and diapirs; hydrocarbon accumulations are largely controlled by growth faults. A review of the influence of the stratigraphic and structural features on the migration and accumulation of hydrocarbons is given in this paper.     

A simplified couette flow solution of non-newtonian power-law fluids in eccentric annuli

Flow of non-Newtonian fluids in both the concentric and eccentric annuli is of great importance in extruders for molten plastics and wellbore fluid circulation for the removal of drilling cuttings. The steady laminar couette flow of non-Newtonian power-law fluids in eccentric annulus is employed in this study to analyze the problems of surge or swab pressures encountered when running or pulling tubular goods (pipes) in a liquid filled borehole. This is similar to the annular space created by two long co-axial cylinders with the inner cylinder in motion at a steady velocity, and a stationary outer cylinder. The solutions of the equations of motion are presented in both dimensionless form and as a family of curves for different pipe/borehole eccentricity ratios and power-law fluid index values for a more general application. The expected error in surge computation for concentric annulus as a result of eccentricity is evaluated.     

Tabletting Properties of Musol; A New Direct Compression Vehicle

A new autocompressible vehicle, Musol, obtained by chemical modification of an edible seed polysaccharide was evaluated for direct compression properties, A Hausner ratio of 1,2 and percent compressibility of 16.7 obtained for Musol indicate that it has very good flow properties. Musol showed superiority over Avicel PH 101, USP Fast-Flo lactose, and Encompress when evaluated in terns of flow rake of powders and moisture sorption by both powders and their slugs, Compacts prepared with Musol were found to disintegrate by erosion and therefore did not perform as well as either alginic acid or Ac-disol in 250 mg Sulphadimidine tablets. However, good drug release was obtained from aspirin tablets containing 5% w/w Musol as a dry binder. The t₅₀, t₉₀ and Dissolution efficiency were as good as the values obtained with 5% w/w Avicel PH 101, A 50/50 blend of Musol and Avicel PH 101 surpassed other blends in performance.     

Compaction Behaviour of Musol, A New Direct Compression Vehicle

The compaction characteristics of Musol, a new autocompressible vehicle derived through chemical modification of mucuna gum was investigated. Avicel PH 101, Zeparox and Encompress were used as reference tablet vehicles. Values of the mean yield stress derived from the analysis of Heckel plots indicate that Musol consolidates principally by plastic deformation, The effect of lubrication and recompression on friability, tensile strength and re-working potential of the tablets prepared with the vehicles were determined. While Avicel PH 101 yielded the strongest tablets, Musol showed the highest re-working potential for lubricated and un-lubricated slugs. On the basis of friability, tensile Values of strength and re-working potential, Musol than the grades of Zeparpx or Encompress performed better used in the study.     

Temperature dependent rheological property of copper oxide nanoparticles suspension (nanofluid)

A nanofluid is the dispersion of metallic solid particles of nanometer size in a base fluid such as water or ethylene glycol. The presence of these nanoparticles affects the physical properties of a nanofluid via various factors including shear stress, particle loading, and temperature. In this paper the rheological behavior of copper oxide (CuO) nanoparticles of 29 nm average diameter dispersed in deionized (DI) water is investigated over a range of volumetric solids concentrations of 5 to 15% and various temperatures varying from 278-323 degrees K. These experiments showed that these nanofluids exhibited time-independent pseudoplastic and shear-thinning behavior. The suspension viscosities of nanofluids decrease exponentially with respect to the shear rate. Suspension viscosity follows the correlation in the form ln(mus) = A(1/T)-B, where constants A and B are the functions of volumetric concentrations. The calculated viscosities from the developed correlations and experimental values were found to be within +/- 10% of their values.     

Prediction of fluid-flow parameters in a gas-cut mud, 1. A basic computer program for determining the fluid-flow parameters in a gas-cut mud

Reduction of mud density at the surface is a serious problem but it has not received the attention given to effects of density reduction in the annulus due to gas-cut. Gas enters the well bore annulus from drilled gaseous sands, shales, or durings swabbing operations.Mathematical equations and computer programs were developed to predict changes of annular fluid-flow parameters caused by volumetric changes of entrained gas as it is transported to the surface. A computer program for a microcomputer (Appendix A) was used to predict changes in the drilling-fluid density, flow rate, velocity and gas expansion. Data from a Gulf Coast well were used in the analysis and results shown in Appendix B.The computed mud density was 0.36 pounds per gallon less than the measured mud density at the flow line. The difference may be attributed to errors of gas volume measured at the surface.     

Application of unsteady couette flow of non-Newtonian power-law fluids in concentric annular wellbore

Fluid flow phenomena that occur when the fluid is confined between two co-axial cylinders, one of which is stationary and the other is moving at a specified velocity, is known as couette flow. Such flow is representative of that which occurs in the borehole annulus where the wall of the wellbore is represented by the stationary cylinder, and the drill string or casing is represented by the moving cylinder. The fluid local velocity is dependent on the velocity of the moving cylinder or pipe.Different mathematical relations have been developed for surge and swab pressure calculations for flow of power-law fluids in the wellbore annulus. The application of couette flow equations and relationships to evaluate the surge or swab pressure has been limited. These equations are either too complex for field use or require much computation for field application.In this study, the motion equations are analytically solved for non-Newtonian power-law fluids. The solutions of the equations are presented in both dimensionless and graphical forms, which are applied to predict the surge or swab pressure encountered when running tubular goods in liquid-filled boreholes. The technique presented here is easy to use and requires minimal computational efforts for determining the surge or swab pressure for an unsteady motion of a moving inner pipe in a concentric annulus. The results of this study show that the magnitude of surge or swab pressure increases with increase in the pipe acceleration.     

product literature

In this study the pH levels of aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), and zinc oxide (ZnO) nanoparticles dispersed in propylene glycol and water mixture were measured in the temperature range of 0°C to 90°C. The volumetric concentration of nanoparticles in these fluids ranged from 0 to 10% for different nanofluids. The average particle sizes (APS) considered were from 10 nm to 70 nm. The pH measuring apparatus and the measurement procedure were validated by measuring the pH of a calibration fluid, whose properties are known accurately. The measured pH values agreed within less than ±0.5% with the published data reported by the manufacturer. Following the validation, the pH values of different nanofluids were measured. The measurements showed that pH of nanofluids decreased with an increase in temperature and increased with an increase in particle volumetric concentration. For the same nanofluid at a fixed volumetric concentration, the pH was found to be higher for larger particle sizes. From the experimental data, empirical models were developed for three nanofluids to express the pH as functions of temperature, volumetric concentration, and the size of the nanoparticles.     

The use of liquid self-microemulsifying drug delivery systems based on peanut oil/tween 80 in the delivery of griseofulvin

Peanut oil and Tween 80 blends devoid of any cosurfactant were employed in the formulation of different batches of liquid self-microemulsifying drug delivery systems (LSMEDDS) and their suitability as vehicles for the delivery of a typical lipophilic drug-griseofulvin-was investigated. The LSMEDDS were evaluated using the following parameters: phase separation, globule size, viscosity, solubility of griseofulvin, and partition coefficient. The release profile of griseofulvin from the optimized LSMEDDS was evaluated in citrate/phosphate buffer solutions of pH 2.0, pH 6.5, and pH 7.4. The results obtained indicated that there was significantly higher (alpha 相似文献