The dissolution efficiency for different stream liming methods

1986 ◽  
Vol 31 (3-4) ◽  
pp. 827-837 ◽  
Author(s):  
H. U. Sverdrup
Keyword(s):  
Stream Liming ◽  
Dissolution Efficiency

The Dissolution Efficiency for Different Stream Liming Methods

1986 ◽  
pp. 1881-1891 ◽  
Author(s):  
H. U. Sverdrup
Keyword(s):  
Stream Liming ◽  
Dissolution Efficiency

Development of Prolonged Delivery of Tramadol and Dissolution Translation by Statistical Data Treatment

2011 ◽  
Vol 4 (1) ◽  
pp. 1331-1337
Author(s):  
P B Parejiya ◽  
B S Barot ◽  
P K Shelat
Keyword(s):  
Drug Release ◽  
Study Data ◽  
Stability Study ◽  
Dissolution Time ◽  
Matrix Tablet ◽  
Burst Effect ◽  
The Matrix ◽  
The Mean ◽  
The Difference ◽  
Dissolution Efficiency

The present study was carried out to fabricate a prolonged design for tramadol using Kollidon SR (Polyvinyl acetate and povidone based matrix retarding polymer). Matrix tablet formulations were prepared by direct compression of Kollidon SR of a varying proportion with a fixed percentage of tramadol. Tablets containing a 1:0.5 (Drug: Kollidon SR) ratio exhibited a rapid rate of drug release with an initial burst effect. Incorporation of more Kollidon SR in the matrix tablet extended the release of drug with subsequent minimization of the burst effect as confirmed by the mean dissolution time, dissolution efficiency and f2 value. Among the formulation batches, a direct relationship was obtained between release rate and the percentage of Kollidon SR used. The formulation showed close resemblance to the commercial product Contramal and compliance with USP specification. The results were explored and explained by the difference of micromeritic characteristics of the polymers and blend of drug with excipients. Insignificant effects of various factors, e.g. pH of dissolution media, ionic strength, speed of paddle were found on the drug release from Kollidon-SR matrix. The formulation followed the Higuchi kinetic model of drug release. Stability study data indicated stable character of Batch T6 after short-term stability study.

scholarly journals Evolution of physicochemical properties of quick lime at converter-smelting temperature

2021 ◽  
Vol 40 (1) ◽  
pp. 32-39
Author(s):  
Mengxu Zhang ◽  
Jianli Li ◽  
Zhengliang Xue ◽  
Renlin Zhu ◽  
Qiqiang Mou ◽  
...  
Keyword(s):  
Boundary Migration ◽  
Average Diameter ◽  
Dissolution Behavior ◽  
Grain Boundary Migration ◽  
Average Pore ◽  
Quick Lime ◽  
Volume Stability ◽  
Steel Making ◽  
Dissolution Efficiency ◽  
Lime Reactivity

Abstract The volume stability caused by the hydration of f-CaO is one of the main obstacles to the comprehensive utilization of steel-making slag. In view of the f-CaO produced by incomplete dissolution of lime, it is necessary to strengthen the dissolution behavior of lime in the converter process. The reactivity of lime determines the dissolution efficiency and is closely related to its microstructure. The experimental results show that the reactivity and porosity of quick lime decrease and the average diameter of pore increases with an increase in temperature. The CaO crystals gradually grow up under the action of grain boundary migration. When the temperature increased from 1,350 to 1,600°C, the lime reactivity decreased from 237.60 to 40.60 mL, the porosity decreased from 30.55 to 15.91%, the average pore diameter increased from 159.10 to 1471.80 nm, and the average CaO particle size increased from 0.33 to 9.61 µm. The results indicate that reactivity is decreased because of the deformation and growth of CaO crystals and the decrease in porosity in reactive lime. This will cause an obstacle to the dissolution of lime and is not conducive to the control of f-CaO in slag.

Dissolution of Sulfates and Sulfides Field Scales by Developed Scale Dissolver

2021 ◽  
Author(s):  
Hany Gamal ◽  
Salaheldin Elkatatny ◽  
Dhafer Al Shehri ◽  
Mohamed Bahgat
Keyword(s):  
Oil And Gas ◽  
Flow Characteristics ◽  
Compositional Analysis ◽  
Oil And Gas Industry ◽  
Acid System ◽  
Gas Industry ◽  
Petroleum Production ◽  
Study Results ◽  
Temperature Levels ◽  
Dissolution Efficiency

Abstract Oil and gas industry deals with fluid streams with different ions and concentrations that might cause scale precipitation. The scale precipitation, will thereafter, affect the fluid flow characteristics. Many problems will be raised by the scale deposition that affects the overall petroleum production. This paper aims to develop a non-corrosive acid system with high dissolution efficiency for field complex scales that have sulfates and sulfides minerals. The paper provided a series of lab analysis that covers the compositional analysis for the collected scale sample, and evaluating the developed acid system for compatible and stable properties, dissolution efficiency, and the corrosive impact. A field scale sample that has a composite chemical composition of paraffin, asphaltene, sulfides and sulfates compounds with different weight percentages by employing the diffraction of X-ray technology. Developing the new scale dissolver was achieved by specific compositional study for the organic acids to achieve high dissolution efficiency and low corrosive impact for the field treatment operations. The study results showed the successful scale removal for the developed dissolver at low temperature of 95 and 113 °F for surface treatment jobs. The dissolution efficiency recorded 62 and 71 % for 17 hours at the temperature levels respectively. The fluid showed a stable and compatible performance and has a pH of 12. The corrosion test was conducted without any scale inhibitors and the results showed the low corrosion effect by 0.0028 lbm/ft2. The obtained successful results will help to dissolve such complex field scales, maintain the well equipment, and maintain the petroleum production from scale issues.

Stimulation of Wells Damaged by Barite Present in Filter Cake or Scale

SPE Journal ◽  
2021 ◽  
pp. 1-11
Author(s):  
Igor Ivanishin ◽  
Hisham A. Nasr-El-Din ◽  
Dmitriy Solnyshkin ◽  
Artem Klyubin
Keyword(s):  
High Temperature ◽  
Filter Cake ◽  
Ethylenediaminetetraacetic Acid ◽  
Solid Phase ◽  
Barium Carbonate ◽  
Process Analysis ◽  
Drilling Fluid ◽  
Field Application ◽  
X Ray ◽  
Dissolution Efficiency

Summary High-temperature (HT) deep carbonate reservoirs are typically drilled using barite (BaSO4) as a weighting material. Primary production in these tight reservoirs comes from the network of natural fractures, which are damaged by the invasion of mud filtrate during drilling operations. For this study, weighting material and drilling fluid were sampled at the same drillsite. X-ray diffraction (XRD) and X-ray fluorescence analyses confirmed the complex composition of the weighting material: 43.2 ± 3.8 wt% of BaSO4 and 47.8 ± 3.3 wt% of calcite (CaCO3); quartz and illite comprised the rest. The drilling fluid was used to form the filter cake in a high-pressure/high-temperature (HP/HT) filter-press apparatus at a temperature of 300°F and differential pressure of 500 psig. Compared with the weighting material, the filter cake contained less CaCO3, but more nondissolvable minerals, including quartz, illite, and kaolinite. This difference in mineral composition makes the filter cake more difficult to remove. Dissolution of laboratory-grade BaSO4, the field sample of the weighting material, and drilling-fluid filter cake were studied at 300°F and 1,000 to 1,050 psig using an autoclave equipped with a magnetic stirrer drive. Two independent techniques were used to investigate the dissolution process: analysis of the withdrawn-fluid samples using inductively coupled plasma-optical emission spectroscopy, and XRD analysis of the solid material left after the tests. The dissolution efficiency of commercial K5-diethylenetriaminepentaacetic acid (DTPA), two K4-ethylenediaminetetraacetic acid (EDTA), Na4-EDTA solutions, and two “barite dissolvers” of unknown composition was compared. K5-DTPA and K4-EDTA have similar efficiency in dissolving BaSO4 as a laboratory-grade chemical and a component of the calcite-containing weighting material. No pronounced dissolution-selectivity effect (i.e., preferential dissolution of CaCO3) was noted during the 6-hour dissolution tests with both solutions. Reported for the first time is the precipitation of barium carbonate (BaCO3) when a mixture of BaSO4 and CaCO3 is dissolved in DTPA or EDTA solutions. BaCO3 composes up to 30 wt% of the solid phase at the end of the 6-hour reaction, and can be dissolved during the field operations by 5 wt% hydrochloric acid. Being cheaper, K4-EDTA is the preferable stimulation fluid. Dilution of this chelate increases its dissolution efficiency. Compared with commonly recommended solutions of 0.5 to 0.6 M, a more dilute solution is suggested here for field application. The polymer breaker and K4-EDTA solution are incompatible; therefore, the damage should be removed in two stages if the polymer breaker is used.

Physicochemical Evaluation of Brands of Amlodipine Besylate Tablets.

2020 ◽  
Vol 1 (5) ◽  
pp. 24-33
Author(s):  
C.A. Anyanwu-Ndulewe ◽  
◽  
L.E. Mogbolu ◽  
M.A. Oladunni ◽  
A.A. Adepoju-Bello
Keyword(s):  
Hardness Test ◽  
Drug Market ◽  
The United States ◽  
Financial Strain ◽  
Average Weight ◽  
Dissolution Profile ◽  
Amlodipine Besylate ◽  
Disintegration Time ◽  
Physicochemical Evaluation ◽  
Dissolution Efficiency

Background: Hypertension is a chronic condition, and the cost of filling prescriptions has a potential of putting a financial strain on patients, hence the need for lower priced but bioequivalent generics. The Nigerian drug market is awash with generics of Amlodipine besylate, a first line drug in the treatment of hypertension, therefore, any prescribed alternative must be bioequivalent to the originator. Objectives: This study assessed the physicochemical properties of some brands in order to predict pharmaceutical and bioequivalence and invariably, the interchangeability with the innovator brand. Methods: Compendial parameters of average weight, friability, disintegration, drug content and dissolution profile of ten generic brands were evaluated using the United States Pharmacopeia (USP) as well as the non-official hardness test. Results: Two brands failed the test for hardness, while still keeping to the stipulated friability limit. All the brands met the required disintegration time, irrespective of the discordance of some brands in the breaking force and friability values. All brands were found to contain between 92.00 and 103.57% (w/w) of Amlodipine besylate. Two brands failed to achieve ≥75% dissolution expected at 30 minutes and this was reflected in the low f2 values of 35.06% and 28.73%. The dissolution curves displayed a similarity for two brands, which was also corroborated by the high percentage dissolution efficiency (DE) of 92.00%, as well as the f1 and f2 values, compared to the innovator brand. Conclusion: Although the parameters used may predict therapeutic equivalence, interchangeability with the comparator brand is subject to relevant bioequivalence studies.

Phospholipid-containing films for improved drug release

2021 ◽  
pp. 30-33
Author(s):  
Jiahao Huang ◽  
◽  
Shawn Wettig
Keyword(s):  
Water Solubility ◽  
Aqueous Media ◽  
Active Pharmaceutical Ingredients ◽  
Natural Sources ◽  
Pharmaceutical Ingredients ◽  
Alternative Approach ◽  
Poor Water Solubility ◽  
Dissolution Efficiency ◽  
Oral Films ◽  
Liquid Liquid Phase Separation

Phospholipids from natural sources can delay liquid-liquid phase separation and improve supersaturation for active pharmaceutical ingredients with poor water-solubility in aqueous media. Researchers have developed oral films containing phospholipids to enhance the dissolution efficiency of hydrophobic pharmaceutical ingredients. Phospholipid-based oral films provide an alternative approach for compounding pharmacies to formulate drugs with poor water solubility.

Experimental Methods for the Evaluation of the Efficiency of an Innovative Sulfur-Dissolving Product in HP-HT Conditions

2021 ◽  
Author(s):  
Ivan Maffeis ◽  
Alberto Renato de Angelis ◽  
Riccardo Guernelli ◽  
Ettore Croce ◽  
Luigi Romano
Keyword(s):  
Elemental Sulfur ◽  
Liquid Product ◽  
Active Phase ◽  
Crystal Form ◽  
Experimental Investigations ◽  
Physical Interaction ◽  
Laboratory Equipment ◽  
Complete Representation ◽  
Before And After ◽  
Dissolution Efficiency

Abstract During production from sour gas reservoirs, precipitation of elemental sulfur can take place in production tubing, resulting in plugging of the well and stop of production. Injection in tubing of products devoted to dissolving sulfur can be an efficient solution for plug removal and production restoring. Traditionally, organic solvents (like toluene) are employed for solid sulfur dissolution. In the present work, experimental investigations have been performed on a particular innovative liquid product designed as active phase for wellbore injection or near wellbore applications. The analyses about the behavior of the considered product were conducted at HP-HT conditions. For this purpose, PVT laboratory equipment was employed, being able to reproduce the conditions of interest for the formation of elemental sulfur plug in well. An important preliminary optimization phase on the experimental setup was necessary to assure the correct management of studied liquid substance and solid sulfur. Integration of main outcomes with other kind of analyses allowed to depict a complete representation of the behavior: microscopy analysis of the liquid phase and high-resolution tomography of solid sulfur before and after the interaction were employed. A key point of the experimental characterization is the reproduction of significant involved phenomena. A preliminary effort was necessary for reproducing the realistic crystal form expected during the precipitation of solid sulfur in well. The dissolution efficiency of the liquid product is evaluated by observing its physical interaction with sulfur in a HP-HT cell. Particular attention was paid to correctly handling employed substances at the considered pressure and temperature conditions. A detailed description of the optimized equipment used in laboratory is provided. Several dissolution tests have been conducted at different temperature and pressure conditions, aiming to observe the dependence of the dissolution efficiency on the thermodynamic parameters. A visual qualitative analysis was performed on both the liquid product and the solid plug, before and after the interaction in cell. This allowed to deepen the comprehension of the dynamics of sulfur dissolution, which takes place not only from the top face of the plug, but also from preferential paths (fractures) present inside the plug itself. The presence of sulfur crystals dispersed in the liquid product after sampling from the cell is also evident at the end of the tests. The studied novel sulfur-dissolving liquid active phase is a candidate for remedial job injection at well in case of plugging due to solid elemental sulfur precipitation. The analyses here presented allowed to characterize the dissolution potential of this product. An optimized workflow was designed, including different kind of experimental disciplines.

scholarly journals A Novel Low-Temperature Non-Corrosive Sulfate/Sulfide Scale Dissolver

2020 ◽  
Vol 12 (6) ◽  
pp. 2455
Author(s):  
Hany Gamal ◽  
Salaheldin Elkatatny ◽  
Dhafer Al Shehri ◽  
Mohamed Bahgat
Keyword(s):  
Low Temperature ◽  
Corrosion Rate ◽  
High Performance ◽  
Oil And Gas ◽  
Ethylenediaminetetraacetic Acid ◽  
Gas Production ◽  
Operating Conditions ◽  
Superior Performance ◽  
X Ray ◽  
Dissolution Efficiency

The oil and gas production operations suffer from scale depositions. The scale precipitations have a damaging impact on the reservoir pores, perforations, downhole and completion equipment, pipeline network, wellhead chokes, and surface facilities. Hydrocarbon production possibly decreased because of the scale accumulation in the well tubular, leading to a well plugging, this requires wells to be shut-in in severe cases to perform a clean-out job. Therefore, scale deposition is badly affecting petroleum economics. This research aims to design a scale dissolver with low cost, non-damaging for the well equipment and has a high performance at the field operating conditions. This paper presents a novel non-corrosive dissolver for sulfate and sulfide composite scale in alkaline pH and works at low-temperature conditions. The scale samples were collected from a production platform from different locations. A complete description of the scale samples was performed as X-ray diffraction (XRD) and X-ray fluorescence (XRF). The new scale dissolver was prepared in different concentrations to examine its dissolution efficiency for the scale with time at low temperatures. The experimental design studied the solid to fluid ratio, temperature, solubility time, and dissolution efficiency in order to achieve the optimum and most economic performance of solubility in terms of high dissolution efficiency with the smallest possible amount of scale dissolver. A solubility comparison was performed with other commercial-scale-dissolvers and the corrosion rate was tested. The experimental work results demonstrated the superior performance of the new scale dissolver. The new scale dissolver showed a solubility efficiency of 91.8% at a low temperature of 45 °C and 79% at 35 °C. The new scale dissolver showed a higher solubility ratio for the scale sample than the ethylenediaminetetraacetic acid (EDTA) (20 wt. %), diethylenetriamine pentaacetic acid (DTPA) (20 wt. %), and HCl (10 wt. %). The corrosion rate for the new non-corrosive dissolver was 0.01357 kg/m2 (0.00278 lb./ft²) which was considered a very low rate and non-damaging for the equipment. The low corrosive effect of the new dissolver will save the extra cost of adding the corrosion inhibitors and save the equipment from the damaging effect of the corrosive acids.

A new class of electrolytes based on magnesium bis(diisopropyl)amide for magnesium–sulfur batteries

2019 ◽  
Vol 55 (43) ◽  
pp. 6086-6089 ◽  
Author(s):  
Xinghe Zhao ◽  
Yuanying Yang ◽  
Yanna NuLi ◽  
Dongyu Li ◽  
Yurui Wang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Ionic Conductivity ◽  
New Class ◽  
Dissolution Efficiency

A new class of electrolytes for Mg–S batteries prepared by a facile in situ reaction of magnesium bis(diisopropyl)amide (MBA) with AlCl3, which show reasonable ionic conductivity and relatively high anodic stability on stainless steel, close to 100% Mg deposition–dissolution efficiency and high cycling reversibility and compatibility with the S cathode.

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