Optimize Performance Through Customization of Paraffin Inhibitor Molecular Structure

2021 ◽  
Author(s):  
Kiran Gawas ◽  
Chandrashekhar Khandekar ◽  
Katrina Akita ◽  
Janet Ngo ◽  
John Hazlewood
Keyword(s):  
Molecular Weight ◽  
Maleic Anhydride ◽  
High Molecular Weight ◽  
Gas Production ◽  
Performance Study ◽  
Oil Composition ◽  
Scanning Calorimetry ◽  
Test Conditions ◽  
Alpha Olefin ◽  
The Impact

Abstract Deposition of high molecular weight paraffins and subsequent plugging is one of the most prevalent flow assurance risks in both onshore and offshore oil and gas production. Several thermal (e.g., insulation, heat treatment), mechanical (e.g., pigging, cutting), and chemical (e.g., paraffin crystal modifiers, dispersants, and solvents) techniques are used for wax deposition prevention and remediation. Various chemistries such as long-chain poly alkyl acrylates, olefin vinyl acetate copolymers, alkyl phenol resins and esterified olefin maleic anhydride polymers are used as wax crystal modifiers. This study investigates the impact of the alpha olefin maleic anhydride co-polymers structure on the composition and deposition of paraffin. Eight different crude samples from condensates to black oils with API gravity in the range of 30 to 50° were studied. The focus of this research is on paraffin inhibitors’ effectiveness in reducing paraffin deposition that is driven by thermal driving force between the bulk oil and the pipe wall. Inhibitor performance was measured by cold finger testing. Three different alpha olefin (short, medium and long) maleic anhydrides esterified with different fatty alcohols with varying chain lengths were tested for performance. The impact of selected chemicals on amount and composition of paraffin deposit under different test conditions was studied. Wax deposit composition was characterized using high temperature gas chromatography (HTGC) and differential scanning calorimetry (DSC) techniques. Effect of pendant side chain length as well as the composition and molecular weight of the alpha-olefin backbone on paraffin inhibition is presented. Additionally, the impact of test conditions on the composition and hence the performance of the selected chemicals is investigated. We present our findings on selective inhibition of lower molecular weight paraffin depending on the composition of the oil, leaving a much harder deposit rich in high molecular weight paraffin. This is an important observation since a hard deposit would be extremely difficult to remediate in the field and should be avoided. In summary this work provides guidelines for tailoring paraffin inhibitor molecules based on crude oil composition and field conditions, through a systematic structure-performance study.

scholarly journals Physicochemical and Antifungal Properties of Clotrimazole in Combination with High-Molecular Weight Chitosan as a Multifunctional Excipient

Marine Drugs ◽  
2020 ◽  
Vol 18 (12) ◽  
pp. 591
Author(s):  
Bożena Grimling ◽  
Bożena Karolewicz ◽  
Urszula Nawrot ◽  
Katarzyna Włodarczyk ◽  
Agata Górniak
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Weight Ratio ◽  
Scanning Calorimetry ◽  
Minimal Inhibitory Concentrations ◽  
Dissolution Tests ◽  
Effective Combination ◽  
The Impact ◽  
High Molecular Weight Chitosan

Chitosans represent a group of multifunctional drug excipients. Here, we aimed to estimate the impact of high-molecular weight chitosan on the physicochemical properties of clotrimazole–chitosan solid mixtures (CL–CH), prepared by grinding and kneading methods. We characterised these formulas by infrared spectroscopy, differential scanning calorimetry, and powder X-ray diffractometry, and performed in vitro clotrimazole dissolution tests. Additionally, we examined the antifungal activity of clotrimazole–chitosan mixtures against clinical Candida isolates under neutral and acid conditions. The synergistic effect of clotrimazole and chitosan S combinations was observed in tests carried out at pH 4 on Candida glabrata strains. The inhibition of C. glabrata growth reached at least 90%, regardless of the drug/excipient weight ratio, and even at half of the minimal inhibitory concentrations of clotrimazole. Our results demonstrate that clotrimazole and high-molecular weight chitosan could be an effective combination in a topical antifungal formulation, as chitosan acts synergistically with clotrimazole against non-albicans candida strains.

Intraindividual Comparison of the Impact of two Selective Apheresis Methods (DALI and HELP) on the Coagulation System

2000 ◽  
Vol 23 (3) ◽  
pp. 199-206 ◽  
Author(s):  
U. Julius ◽  
G. Siegert ◽  
S. Gromeier
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Protein S ◽  
Binding Activity ◽  
Coagulation System ◽  
Factor Xii ◽  
High Molecular Weight Kininogen ◽  
Prothrombin Fragment ◽  
Intraindividual Comparison ◽  
The Impact

We performed an intraindividual comparison of the effect on the coagulation system of two selective apheresis procedures: Direct Adsorption of Lipoproteins (DALI) and Heparin-induced Lipoprotein Fibrinogen Precipitation (HELP). Six patients suffering from heterozygous familial hypercholesterolemia have been treated with 2 sessions of each procedure. Anticoagulation was carried out according to usual recommendations. Blood samples were taken before, immediately after and on the second day after the sessions. We assessed global coagulation tests (prothrombin time, activated partial thromboplastin time), fibrinogen, prothrombin fragment F 1 + 2 and a variety of factors (Factors II, V, VII, XIII, IX, X, XI, XII, XIIa; von Willebrand Factor; collagen-binding activity, prekallikrein, high-molecular weight kininogen) and antagonists (antithrombin III, protein S activity, free protein S). In fact, all parameters measured have been influenced by the apheresis treatment. Fibrinogen is lowered more by HELP, which also has a more definite impact on factors belonging to the prothrombin complex (II, VII, X). In contrast, the major effects of the DALI system have been seen on the intrinsic pathway of the coagulation system (IX, XI, prekallikrein, high-molecular-weight kininogen). With both systems, no increases in activated Factor XII or in prothrombin fragment F1 + 2 have been observed. These data provide a solid basis for individual adaptations of anticoagulant doses.

scholarly journals The Influence of the Use of Polymer Lining within the Roller Press Gravity Feeder on Briquette Quality

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2489
Author(s):  
Michał Bembenek
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Material Flow ◽  
Laboratory Tests ◽  
Polymer Materials ◽  
Roller Press ◽  
Fine Grained ◽  
The Impact ◽  
Ultra High Molecular Weight

When considering the operation of roller presses for the consolidation of fine-grained materials, the main problems are disturbances in the proper flow of the material and its bridging in gravity feeders. This is especially true for small and medium capacity presses, where the hoppers for dosing the material are narrow. This article presents innovative laboratory tests of the impact of using a polymer plate lining in the gravity feeder of a roller press. Polymer materials Polyacetal C (POM C) and Ultra-High-Molecular-Weight Polyethylene (UHMW-PE) were used for the tests. The influence of the use of plates on the material flow and quality of briquettes was investigated in comparison with the case where such plates were not used. The research showed an improvement in the flow of fine-grained materials in the feeder and an increase of the briquette strength indexes, as compared to those cases when polymer linings were not used in the feeder.

Stereocomplex electrospun fibers from high molecular weight of poly(L-lactic acid) and poly(D-lactic acid)

2020 ◽  
Vol 40 (2) ◽  
pp. 136-142 ◽  
Author(s):  
Homa Maleki ◽  
Hossein Barani
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Thermal Properties ◽  
High Molecular Weight ◽  
Chemical Properties ◽  
Electrospun Fibers ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Electrospinning Method

AbstractThe stereocomplex formation is a promising method to improve the properties of poly(lactide) (PLA)-based products due to the strong interaction of the side-by-side arrangement of the molecular chains. Recently, electrospinning method has been applied to prepare PLA stereocomplex, which is more convenient. The objective of the current study is to make stereocomplexed PLA nanofibers using electrospinning method and compare their properties and structures with pure poly(l-lactide) (PLLA) fibers. The stereocomplexed fibers were electrospun from a blend solution of high molecular weight PLLA and poly(d-lactide) (1:1 ratio). The morphology of the obtained electrospun fibers was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Differential scanning calorimetry was applied to study their thermal properties and crystallinity. Fourier transform infrared spectroscopy (FTIR) test was conducted on the samples to characterize their chemical properties. The SEM and AFM images indicated that smooth uniform fibers with a cylindrical structure were produced. Besides, the FTIR results and thermal properties confirmed that only stereocomplex crystallites formed in the resulting fibers via the electrospinning method.

scholarly journals The low-velocity impact and post-impact properties of ultra-high-molecular-weight polyethylene fiber weft plain knitted structural composites

2019 ◽  
Vol 14 ◽  
pp. 155892501983252
Author(s):  
Cuiyu Li ◽  
Rui Zhang ◽  
Jingyan Jia ◽  
Gaopan Wang ◽  
Yameng Shi
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Contact Force ◽  
Compression Strength ◽  
Impact Compression ◽  
Impact Properties ◽  
Damage Area ◽  
Post Impact ◽  
The Impact ◽  
Ultra High Molecular Weight

This study investigated the impact and post-impact behavior of different layer weft plain knitted composite materials based on modified ultra-high-molecular-weight polyethylene/epoxy composites. The modified ultra-high-molecular-weight polyethylene weft plain knitted composites with 8, 12, 16 layers were prepared by vacuum-assisted resin transfer molding process and then subjected to impact and post-impact compression test. The impact properties were analyzed using the contact force–deflection and energy–time curves, and the post-impact compression was analyzed using the compression strength–strain curves. It can be obtained that the maximum contact force, absorbed energy, and residual compression strength after impact of the 16-layer specimen are 81.40%, 74.18%, and 73.25% more than those in the 8-layer specimen. respectively. According to the ultrasonic C-scan tests for the impact samples, the 16-layer specimen had the least damage area after the impact test, and the 8-layer composites damage area was 117.45% more than the 16-layer specimen.

High Molecular Weight Polyethylene Nanospheres: Synthesis Physical and Mechanical Properties

2008 ◽  
Vol 8 (6) ◽  
pp. 3123-3135 ◽  
Author(s):  
Pradip Paik ◽  
Kamal K. Kar
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Particle Size ◽  
Electron Microscope ◽  
Elastic Modulus ◽  
High Molecular Weight ◽  
Melting Temperature ◽  
Ion Beam ◽  
Atomic Scale ◽  
Scanning Calorimetry

The high molecular weight (MW) polyethylene (PE) particles of particle size varied from macro to micron to nanometer were synthesized by Grignard reagent. The microscopy analysis (scanning electron microscope, SEM; transmission electron microscope, TEM; and atomic force microscope, AFM) shows the spherical shape of PE particles. The effects of particle size, varies from macro to nanometer scale on crystal structure, crystallinity (χc), glass transition temperature (Tg), melting temperature (Tm), surface roughness and mechanical properties were studied. Differential scanning calorimetry (DSC) experiments show that the nanoparticles of PE are highly crystalline (χc ≈ 72%). The crystal length of PE nanoparticles is found to be approximately 14 Å. Although the Gibbs-Thomson equation is explained the depression of melting temperature (ΔTm) by 5 °C, the impervious results of Tg are still not fully understood. The low roughness value (2 Å) proves the presence of "atomic-scale-chain" folding at the surface of PE nanoparticles. A novel protocol is developed, and the elastic modulus of individual nanospherical PE particles is computed from 'force-distance' mapping curves of AFM. Hemispherical tungsten (W) tip was fabricated from focused ion beam and used as an indenter to measure the mechanical properties. It is found that the nano sized PE particles have higher elastic modulus (E = 1.2–1.4 GPa) compared to the bulk or macro sized PE (E = 0.6–0.7 GPa). The results corroborate the robustness of our experiments, since, the analogous results for macro sized particles match well with the literature.

Nanoindentation properties of compression-moulded ultra-high molecular weight polyethylene

2003 ◽  
Vol 217 (5) ◽  
pp. 357-366 ◽  
Author(s):  
S P Ho ◽  
L Riester ◽  
M Drews ◽  
T Boland ◽  
M LaBerge
Keyword(s):  
Molecular Weight ◽  
Elastic Modulus ◽  
High Molecular Weight ◽  
Mechanical Response ◽  
Total Joint Replacement ◽  
Scanning Calorimetry ◽  
Nanomechanical Properties ◽  
Significant Difference ◽  
Ultra High Molecular Weight ◽  
Penetration Depths

This paper investigates the elastic modulus and hardness of untreated and treated compression-moulded ultra-high molecular weight polyethylene (UHMWPE) tibial inserts of a total knee replacement (TKR) prosthesis. Investigations were carried out at a nanoscale using a Nanoindenter™ at penetration depths of 100, 250 and 500 nm. The nanomechanical properties of surface and subsurface layers of the compression-moulded tibial inserts were studied using the untreated UHMWPE. The nanomechanical properties of intermediate and core layers of the compression-moulded tibial insert were studied using the cryoultrasectioned and etched UHMWPE treated samples. The cryoultrasectioning temperature (-150°C) of the samples was below the glass transition temperature, Tg(-122± 2°C), of UHMWPE. The measurement of the mechanical response of crystalline regions within the nanostructure of UHMWPE was accomplished by removing the amorphous regions using a time-varying permanganic-etching technique. The percentage crystallinity of UHMWPE was measured using differential scanning calorimetry (DSC) and the Tg of UHMWPE was determined by dynamic mechanical analysis (DMA). Atomic force microscopy (AFM) was used to assess the effect of surface preparation on the samples average surface roughness, Ra. In this study, it was demonstrated that the untreated UHMWPE samples had a significantly lower ( p<0.0001) elastic modulus and hardness relative to treated UHMWPE cryoultrasectioned and etched samples at all penetration depths. No significant difference ( p > 0.05) in elastic modulus and hardness between the cryoultrasectioned and etched samples was observed. These results suggest that the surface nanomechanical response of an UHMWPE insert in a total joint replacement (TJR) prosthesis is significantly lower compared with the bulk of the material. Additionally, it was concluded that the nanomechanical response of material with higher percentage crystallinity (67 per cent) was predominantly determined by the crystalline regions within the semi-crystalline UHMWPE nanostructure.

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