scholarly journals A New Device for Field Recovery of Barite: II. Scale-Up and Design

1965 ◽  
Vol 5 (02) ◽  
pp. 100-108 ◽  
Author(s):  
R.F. Burdyn ◽  
D.E. Hawk ◽  
F.D. Patchen
Keyword(s):  
Particle Size ◽  
Scale Up ◽  
Large Field ◽  
Drilling Mud ◽  
Frictional Drag ◽  
Fixed Rate ◽  
New Device ◽  
Field Unit ◽  
Operating Equation ◽  
Design And Construction

Abstract Earlier work on a mud separator for barite recovery is extended to the design and construction of a rugged field unit. Problems associated with scale-up for field use include the use of dilution water and its effect on capacity, power requirements and pressures developed. Equations for these quantities are derived and applied in maximizing the beneficial effects of dilution and minimizing the power required. Tests on the full-size rotor show that its performance can be predicted by theory. The completed unit is compact and lighter than current decanting types. Its capacity is from 10 to 22 gal/min with corresponding barite recovery efficiencies of 92 to 86 per cent. Introduction In an earlier publication a new type of centrifugal device was described for solid-liquid separations. In that paper an operating equation was derived, and its validity demonstrated in laboratory scale experimentation. Some of the features apparent in this new device seem particularly well suited to the conservation of barite in field drilling-mud systems, hence the development was extended to the design and construction of a field unit. In the present paper the design problems associated with scale-up are considered. A full-scale, rugged, self-contained field unit is described, and test results discussed which verify that the performance of the large field unit can be described by a simple operating equation. PRINCIPLE OF OPERATION OF SEPARATOR In principle, the new device is simply a perforated cylinder rotating within a body of fluid which is contained within a stationary case, as in Fig. 1. The frictional drag generated by the rotating cylinder causes part of the fluid to rotate. At the surface of the cylinder, assuming no slip occurs, the angular velocity of fluid and of the cylinder are identical. if there are suspended particles present of greater density than the fluid, the centrifugal force acting on these particles causes them to move radially away from the cylinder at some velocity, vp. Where the Stokes settling equation holds, this velocity may be expressed as: ....................(1) If the case is provided with openings at both ends, a suspension can be pumped in at one end at a fixed rate. Part of the suspension can then be removed at a fixed rate at the other end of the case as underflow, and the remainder forced through the perforations and hollow shaft of the rotor to appear as effluent, also at a fixed rate. the radial component of the flow velocity of this stream as it reaches the rotor surface, is simply effluent flow rate divided by cylindrical surface area: ....................(2) Because vp is a function of particle size, for some particular particle size, the velocities vp and vr will be equal in magnitude. This is defined as the critical particle size and represents the size above which all particles appear in the underflow and below which all particles appear in the effluent. SPEJ P. 100ˆ

Azithromycin nanosuspension preparation using evaporative precipitation into aqueous solution (EPAS) method and its comparative dissolution study

2020 ◽  
Vol 17 ◽  
Author(s):  
Mohammad Hossain Shariare ◽  
Tonmoy Kumar Mondal ◽  
Hani Alothaid ◽  
Md. Didaruzzaman Sohel ◽  
MD Wadud ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Dissolution Rate ◽  
Average Particle Size ◽  
Scale Up ◽  
Average Particle ◽  
Total Drug ◽  
Residual Solvent ◽  
Dissolution Study ◽  
Drug Content

Aim: EPAS (evaporative precipitation into aqueous solution) was used in the current studies to prepare azithromycin nanosuspensions and investigate the physicochemical characteristics for the nanosuspension batches with the aim of enhancing the dissolution rate of the nanopreparation to improve bioavailability. Methods: EPAS method used in this study for preparing azithromycin nanosuspension was achieved through developing an in-house instrumentation method. Particle size distribution was measured using Zetasizer Nano S without sample dilution. Dissolved azithromycin nanosuspensions were also compared with raw azithromycin powder and commercially available products. Total drug content of nanosuspension batches were measured using an Ultra-Performance Liquid Chromatography (UPLC) system with Photodiode Array (PDA) detector while residual solvent was measured using gas chromatography (GC). Results: The average particle size of azithromycin nanosuspension was 447.2 nm and total drug content was measured to be 97.81% upon recovery. Dissolution study data showed significant increase in dissolution rate for nanosuspension batch when compared to raw azithromycin and commercial version (microsuspension). The residual solvent found for azithromycin nanosuspension is 0.000098023 mg/ mL or 98.023 ppb. Conclusion: EPAS was successfully used to prepare azithromycin nanoparticles that exhibited significantly enhanced dissolution rate. Further studies are required to scale up the process and determine long term stability of the nanoparticles.

Wellbore Strengthening Design Criteria and Enhanced Fracture Gradient for Widening Stable Mud Weight Window and Enabling Safe and Efficient Drilling in Depleted Reservoirs

2021 ◽  
Author(s):  
Chee Phuat Tan ◽  
Wan Nur Safawati Wan Mohd Zainudin ◽  
M Solehuddin Razak ◽  
Siti Shahara Zakaria ◽  
Thanavathy Patma Nesan ◽  
...  
Keyword(s):  
Particle Size ◽  
Ct Scan ◽  
Design Criteria ◽  
Drilling Mud ◽  
Fracture Width ◽  
Wellbore Strengthening ◽  
Fracture Gradient ◽  
Mud Loss ◽  
Gradient Enhancement ◽  
Compound Particle

Abstract Drilling in permeable formations, especially depleted reservoirs, can particularly benefit from simultaneous wellbore shielding and strengthening functionalities of drilling mud compounds. The ability to generate simultaneous wellbore shielding and strengthening in reservoirs has potential to widen stable mud weight windows to drill such reservoirs without the need to switch from wellbore strengthening compound to wellbore shielding compound, and vice-versa. Wellbore shielding and strengthening experiments were conducted on three outcrop sandstones with three mud compounds. The wellbore shielding stage was conducted by increasing the confining and borehole pressures in 4-5 steps until both reached target pressures. CT scan images demonstrate consistency of the filtration rates with observed CT scanned mud cakes which are dependent on the sandstone pore size and mud compound particle size distributions. In wellbore strengthening stage, the borehole pressure was increased until fracture was initiated, which was detected via borehole pressure trend and CT scan imaging. The fractures generated were observed to be plugged by mud filter solids which are visible in the CT scan images. The extent of observed fracture solid plugging varies with rock elastic properties, fracture width and mud compound particle size distribution. Based on the laboratory test data, fracture gradient enhancement concept was developed for the mud compounds. In addition, the data obtained and observations from the tests were used to develop optimal empirical design criteria and guidelines to achieve dual wellbore strengthening and shielding performance of the mud compounds. The design criteria were validated on a well which was treated with one of the mud compounds based on its mud loss events during drilling and running casing.

Design and construction of the IMACS-IFU: a 2000-element integral field unit

2004 ◽  
Author(s):  
Juergen Schmoll ◽  
George N. Dodsworth ◽  
Robert Content ◽  
Jeremy R. Allington-Smith
Keyword(s):  
Field Unit ◽  
Integral Field ◽  
Design And Construction

scholarly journals An EAGLE’s view of ex situ galaxy growth

2020 ◽  
Vol 497 (1) ◽  
pp. 81-93 ◽  
Author(s):  
Thomas A Davison ◽  
Mark A Norris ◽  
Joel L Pfeffer ◽  
Jonathan J Davies ◽  
Robert A Crain
Keyword(s):  
Analytical Techniques ◽  
Mass Range ◽  
Morphological Type ◽  
Stellar Mass ◽  
Ex Situ ◽  
Large Field ◽  
Mass Fractions ◽  
Satellite Galaxies ◽  
Galaxy Assembly ◽  
Field Unit

ABSTRACT Modern observational and analytical techniques now enable the direct measurement of star formation histories and the inference of galaxy assembly histories. However, current theoretical predictions of assembly are not ideally suited for direct comparison with such observational data. We therefore extend the work of prior examinations of the contribution of ex situ stars to the stellar mass budget of simulated galaxies. Our predictions are specifically tailored for direct testing with a new generation of observational techniques by calculating ex situ fractions as functions of galaxy mass and morphological type, for a range of surface brightnesses. These enable comparison with results from large field of view (FoV) Integral Field Unit (IFU) spectrographs, and increasingly accurate spectral fitting, providing a look-up method for the estimated accreted fraction. We furthermore provide predictions of ex situ mass fractions as functions of galaxy mass, galactocentric radius, and environment. Using z = 0 snapshots from the 100 and 25 cMpc3 EAGLE (Evolution and Assembly of GaLaxies and their Environments) simulations, we corroborate the findings of prior studies, finding that ex situ fraction increases with stellar mass for central and satellite galaxies in a stellar mass range of 2 × 107 to 1.9 × 1012 M⊙. For those galaxies of mass M* > 5 × 108 M⊙, we find that the total ex situ mass fraction is greater for more extended galaxies at fixed mass. When categorizing satellite galaxies by their parent group/cluster halo mass, we find that the ex situ fraction decreases with increasing parent halo mass at fixed galaxy mass. This apparently counterintuitive result may be due to high passing velocities within large cluster haloes inhibiting efficient accretion on to individual galaxies.

Nanocrystal Approaches for Poorly Soluble Drugs and their Role in Development of Marketed Formulation

2021 ◽  
Vol 11 ◽  
Author(s):  
Vijay Agarwal ◽  
Nitin Kaushik ◽  
Pankaj Kumar Sharma
Keyword(s):  
Particle Size ◽  
Ostwald Ripening ◽  
Review Paper ◽  
Scale Up ◽  
Wet Milling ◽  
Particle Size Range ◽  
Preparation Methods ◽  
Characterization Methods ◽  
Poorly Soluble ◽  
Pharmaceutical Industries

Objectives: This review paper gives focus on the nanocrystal approaches and their uses in pharmaceutical applications. Also, various preparation methods of the nanocrystal are briefly described in this presented review paper. The paper also describes several factors that are involved in the production of stable drug nanocrystals and provides suggestions for overcoming instability-related issues like aggregation and Ostwald ripening. Finally, the specific opportunities and challenges that are applicable to nanocrystal technology are summarized in this paper. Methods: In this paper, we summarize and discuss the special features of drug nanocrystals that include the enhancement of dissolution velocity, adhesiveness to the surface, and saturation solubility. Nowadays, pharmaceutical industries are using different approaches to prepare the nanocrystal, like bottom-up approach (precipitation), the top-down approach (wet milling, high-pressure homogenization), and some other combinational approaches. Results: Drug nanocrystals can be administered through different routes. Besides this, the various fabrication methods and characterization methods may be used for the development and scale-up production of drug nanocrystals. Conclusion: In this review article, the relevance of drug nanocrystals are presented and illustrated according to their research done by different researchers and finally concluded that marketed formulation related to nanocrystal are gradually in progression. However, some related and developed formulations are under clinical trial. Background: Poor solubility of the drug compounds is a major problem in the pharmaceutical field; therefore, the reduction of particle size may be one of the simplest and efficient processes for enhancing the solubility of such compounds. Drug nanocrystals are the crystals available with some drugs and having a particle size range of 100 to 1000 nm, covered by stabilization.

Experimental Study of Drilled Cuttings Transport Using Common Drilling Muds

1983 ◽  
Vol 23 (01) ◽  
pp. 11-20 ◽  
Author(s):  
Syed M. Hussaini ◽  
Jamal J. Azar
Keyword(s):  
Particle Size ◽  
Rheological Properties ◽  
Flow Rate ◽  
Carrying Capacity ◽  
Transport Model ◽  
Drilling Fluid ◽  
Fluid Velocity ◽  
Drilling Mud ◽  
Pressure Losses ◽  
Drilling Muds

Abstract Experiments are conducted with actual drilling muds to study the behavior of drilled cuttings in a vertical annulus. The effect of parameters such as particle size, flow rate, apparent viscosity, and yield point to plastic viscosity ratio on mud-carrying capacity are studied. The applicability of a semiempirical transport model developed by Zeidler also is investigated. It has been shown that in vertical annuluses, the fluid annular velocity has a major effect on the carrying capacity of muds, while the other parameters have an effect only at low to medium fluid annular velocities. We also conclude that Zeidler's semiempirical formulations for the prediction of drilled cuttings behavior are valid with certain limitations. Introduction One of the most important functions of a drilling fluid is to transpose the drilled particles (cuttings) generated by the drill bit to the surface through the wellbore annulus. This commonly is called the "carrying capacity" of drilling mud. Factors affecting the ability of drilling muds to lift cuttings arefluid rheological properties and flow rate,particle settling velocities,particle size and size distribution, geometry, orientation, and concentration,penetration rate of drill bits,rotary speed of drillstring,fluid density.annulus inclination, anddrillpipe position in the wellbore (eccentricity) and axially varying flow geometry. With the advent of deeper drilling and better bit designs, the demand for expending most of the energy at the bit has made it necessary to minimize the pressure losses in the annulus. These pressure losses depend on the fluid velocity, fluid density, and particle concentration. By control of these factors, pressure losses can be minimized. The particle slip velocity is an important factor and is defined as the velocity at which a particle tends to settle in a fluid because of is own weight. The velocity depends on the particle size, its geometry, its specific weight, and fluid rheological properties. The carrying capacity of muds also is affected by the velocity profile in the annulus. With all these variables acting simultaneously, the determination of carrying capacity of a mud becomes a complicated problem. An optimal drilling fluid is expected to lift the cuttings from the wellbore, suspend them when circulation is stopped, and drop them at the surface. Failure to achieve this performance often leads to problems that are costly and performance often leads to problems that are costly and time-consuming to solve. To avoid such problems, the previously mentioned parameters are to be considered in previously mentioned parameters are to be considered in the design of an optimal drilling fluid. Previous Investigations Previous Investigations SPEJ P. 11

A New Device for Field Recovery of Barite From Drilling Mud: I. Theory and Laboratory Results

1965 ◽  
Vol 5 (01) ◽  
pp. 6-14 ◽  
Author(s):  
R.F. Burdyn
Keyword(s):  
Particle Size ◽  
Specific Gravity ◽  
Drilling Fluid ◽  
Outer Cylinder ◽  
Maximum Amount ◽  
Rheological Parameters ◽  
Drilling Fluids ◽  
Concentric Cylinder ◽  
Drilling Technology ◽  
Operating Equation

Abstract The inadequate use of centrifugation to economically recover solids from weighted drilling fluids reflects the need for better equipment and techniques for this purpose. Laboratory studies in the development of an improved separator are described in which an operating equation is derived and tested. Results show that the concentric cylinder geometry employed effectively separates barite from a suspension and that the operating equation provides a good approximation for scale-up. Introduction Our current drilling technology frequently requires a high-density drilling fluid obtained by addition of barite. In the course of drilling, formation solids which are too fine to be removed either by screening or settling become suspended in the drilling fluid and gradually the volume of solids in the mud increases. The volume fraction of solids must be limited (if a satisfactory set of rheological parameters are to be maintained). A centrifugal separator provides an economical way of accomplishing this. The barite recovery process can be considered as a separation of two solids. One, the light solids, composed of formation and added solids, has a specific gravity of 2.6 to 2.7; the other, barite, has a specific gravity of 4.2 to 4.3. This density difference, plus the fact that the average light-solids particle size is much smaller than the average barite particle size, permits separation by a centrifuge. In drilling fluids some of the coarse particles of the light-solids-range will settle faster than fine particles of the barite-particle range. As a result a complete separation of the two species is not possible. Since the object of the process is not merely recovering the maximum amount of barite but includes as well removing the maximum amount of light solids, an optimum barite recovery efficiency exists. From a practical standpoint this optimum cannot be determined in the field for each drilling fluid system, and in practice the separation is less than optimum, with some sacrifice of barite. Drilling technology has included centrifugal separators for barite recovery for more than a decade. Results have been reported by a number of investigators indicating that the process is practical and economical. The decision to use a centrifuge is based on economics in which direct cost savings and the indirect benefits in rig time derived from improvement of the drilling fluid are important factors. One would expect that centrifugal separation of barite from drilling fluids would significantly affect barite consumption; however, this is not the case. The Minerals Yearbook shows an annual domestic barite consumption in the drilling industry of nearly I million tons. By rough estimate there are perhaps 80 separators presently in field use. Assuming half of these in use at any one time, operating an, average of four hours per day, at recovery rates averaging 3,000 lb of barite per hour, total annual recovery is about 90,000 tons. This is less than 10 per cent of the total barite used. I conservatively estimate that barite consumption in drilling operations can be reduced by 30 per cent through greater utilization of centrifugal separators. To encourage more wide- spread acceptance of centrifugal separators in the drilling industry, improved equipment and techniques would be very desirable. The present paper, covering theory and results obtained from a laboratory model, is the first in a series on the development of an improved mud separator for field use. THE CONCENTRIC CYLINDER GEOMETRY AS A SEPARATING DEVICE Consider the geometry shown in Fig. 1, consisting of two concentric cylinders separated by an annular space. These are arranged so that the outer cylinder is fixed and the inner one can be rotated about its axis on shafts sealed against the ends of the outer cylinder. SPEJ P. 6ˆ

scholarly journals Biomass Pretreatment and Enzymatic Hydrolysis Dynamics Analysis Based on Particle Size Imaging

2018 ◽  
Vol 24 (5) ◽  
pp. 517-525 ◽  
Author(s):  
Dimitrios Kapsokalyvas ◽  
Arnold Wilbers ◽  
Ilco A.L.A. Boogers ◽  
Maaike M. Appeldoorn ◽  
Mirjam A. Kabel ◽  
...  
Keyword(s):  
Particle Size ◽  
Enzymatic Hydrolysis ◽  
Length Distribution ◽  
Particle Morphology ◽  
Large Field ◽  
Microscopy Method ◽  
Particle Length ◽  
Biomass Particles ◽  
Pretreatment Severity

AbstractParameters such as pretreatment method, enzyme type and concentration, determine the conversion efficiency of biomass’ cellulose and hemicellulose to glucose and mainly xylose in biomass-based fuel production. Chemical quantification of these processes offers no information on the effect of enzymatic hydrolysis (EH) on particle morphology. We report on the development of a microscopy method for imaging pretreated biomass particles at different EH stages. The method was based on acquiring large field of view images, typically 20×10 mm2 containing thousands of particles. Morphology of particles with lengths between 2 μm and 5 mm could be visualized and analyzed. The particle length distribution of corn stover samples, pretreated with increasing amounts of sulfuric acid at different EH stages, was measured. Particle size was shown to be dependent on pretreatment severity and EH time. The methodology developed could offer an alternative method for characterization of EH of biomass for second generation biofuels and visualization of recalcitrant structures.

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