Morphology Of Wax Crystals Research Articles

Morphology of Wax Crystals Affects the Rheological Properties and Thermal Conductivity of Waxy Oils

Morphology of Wax Crystals Affects the Rheological Properties and Thermal Conductivity of Waxy Oils

Higher alcohol acetoacetate aluminum chelates as pour point depressant and impedance reducing agent of biodiesel-diesel blends

The use of additives to improve the shortcomings of biofuels in application is one of the most economical and effective methods. In this study, a new type of tridentate higher alcohol acetoacetate aluminum chelate additive was synthesized originally and then synchronously used as pour point depressant and resistance reducing agent. The low temperature fluidity of biodiesel-diesel blends, including cloud point, cold filter plugging point and pour point could be reduced by the maximum of 6, 7 and 12 °C for B20 (20 vol% biodiesel + 80 vol% diesel), and 5, 5 and 9 °C for biodiesel after the treatment of higher alcohol acetoacetate aluminum chelate additive, named as C16-acac-Al. Furthermore, the impedance modulus determined by electrochemical impedance spectroscopy of the blends were greatly reduced after the treatment of C16-acac-Al, especially noiseless-free in the low frequency region, and the effects of temperature change on electrochemical impedance spectroscopy of treated blends was explored. At length, the mechanism on how the morphology of wax crystals affect electrochemical impedance spectroscopy of treated blends as well as the effect mechanism of the synthetic additives improving the low temperature fluidity of blends were put forward.

Controllable synthesis, characterization, and evaluation of poly (lauryl methacrylate-soybean oil) as a lubricant additive

Traditional free radical polymerization has poor controllability, and traditional petroleum-based lubricant additives have adverse effects on the environment. Poly (lauryl methacrylate (LMA)-soybean oil (SBO)) (P(LMA-SBO) was synthesized using Salen-Cu(II) complex as a catalyst and azodiisobutyronitrile (AIBN) as an initiator by the Schlenk techniques. The structure of P(LMA-SBO) was characterized by infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H NMR), and gel permeation chromatography (GPC) followed by evaluating the solidification point depression performance by the Chinese standard method GB/T 510-2018, and the wax crystal morphology was studied by optical microscopy. The results show the catalytic activity could be 22.88 × 104 g·mol−1·h−1 and the number average molecular weight (M n) of the copolymer is 8.71 × 104 with a low dispersity (Ɖ) of 1.37 under the optimal conditions, which indicates good controllability of the polymerization. Adding 1.0%(w) P(LMA-SBO) to the lubricating oil fraction (350–500 °C) could reduce the solidification point by 15 °C. Therefore, the Salen-Cu (II) catalyst was successfully applied to the controlled polymerization of LMA and SBO. The vegetable oil-based solidification point depressant of P(LMA-SBO) could be used as a potential alternative to replace the traditional solidification point depressant in the future.

Synergistic Catalysis of Water-Soluble Exogenous Catalysts and Reservoir Minerals during the Aquathermolysis of Heavy Oil.

Oil serves as the essential fuel and economic foundation of contemporary industry. However, the use of traditional light crude oil has exceeded its supply, making it challenging to meet the energy needs of humanity. Consequently, the extraction of heavy oil has become crucial in addressing this demand. This research focuses on the synthesis of several water-soluble catalysts that can work along with reservoir minerals to catalyze the hydrothermal cracking process of heavy oil. The goal is to effectively reduce the viscosity of heavy oil and lower the cost of its extraction. Based on the experimental findings, it was observed that when oil sample 1 underwent hydrothermal cracking at a temperature of 180 °C for a duration of 4 h, the amount of water added and catalyst used were 30% and 0.2% of the oil sample dosage, respectively. It was further discovered that the synthesized Mn(II)C was able to reduce the viscosity of oil sample 1 by 50.38%. The investigation revealed that the combination of Mn(II)C + K exhibited a significant synergistic catalytic impact on reducing viscosity. Initially, the viscosity reduction rate was 50.38%, which climbed to 61.02%. Subsequently, when catalyzed by the hydrogen supply agent isopropanol, the rate of viscosity reduction rose further to 91.22%. Several methods, such as freezing point analysis, thermogravimetric analysis, DSC analysis, component analysis, gas chromatography, wax crystal morphology analysis, and GC-MS analysis, were conducted on aqueous organic matter derived from heavy oil after undergoing different reaction systems. These analyses confirmed that the viscosity of the heavy oil was decreased. By studying the reaction mechanism of the model compound and analyzing the aqueous phase, the reaction largely involves depolymerization between macromolecules, breakdown of heteroatom chains, hydrogenation, ring opening, and other related consequences. These actions diminish the strength of the van der Waals force and hydrogen bond in the recombinant interval, impede the creation of a grid-like structure in heavy oil, and efficiently decrease its viscosity.

Preparation and Performance Evaluation of a New Type of Polyethylene-vinyl Acetate/Polystyrene Microsphere Composite Pour Point Depressant for Waxy Crude Oil.

Polymer/inorganic nanocomposite pour point depressant (PPD) is a research hotspot in the field of waxy crude oil pipelining. However, the inorganic nanoparticles need to be organically modified to improve their organic compatibility, and the inorganic nanoparticles are harmful to crude oil refining. In this work, organic PSMS with an average size of 1.4 μm was first synthesized by dispersion polymerization. Then, a new type of EVA/PSMS composite PPD was prepared by melt blending. The effects of the PSMS, EVA PPD, and composite PPD on the pour point, rheological properties, and wax precipitating properties of a specific waxy crude oil were investigated. It was found that adding 50-200 ppm of PSMS alone slightly improves the crude oil rheology through a spatial hindrance effect, while adding 20 ppm of EVA PPD greatly improves the crude oil rheology by modifying the wax crystal morphology. Compared with EVA PPD, adding 20 ppm composite PPD improves the crude oil rheology further, and the rheological improving ability first enhances and then weakens with increasing the PSMS content in the composite PPD (0-10 wt %). At the PSMS content in the composite PPD 5 wt %, the EVA/PSMS 5% composite PPD makes the wax crystal aggregates more compact, thus showing the strongest rheological improving ability. The EVA molecules could adsorb on the PSMS and form the composite particles, which further regulate the wax crystal morphology and then improve the crude oil rheology further.

Synthesis of terpolymer from Helianthus annuus (natural oil) and evaluation as pour point depressant and viscosity reducer on Indian crude oil

Pour Point Depressant is introduced to crude oil at ppm level to overcome transportation problem of crude oil because of its complex chemical structure. Synthesized PPDs improve flow property, viscosity and also improve its numerous parameters to improve performance of crude oil. Low molecular weight and high molecular weight, copolymer having better PPD types. In present work, synthesized Terpolymer, from natural source, was formed from the reaction with Helianthus annuus oil and ester of Erucic Acid with various fatty alcohol. It was evaluated for its properties on Indian waxy crude oils, i.e., From Limbodra well. Structure and molecular weight of synthesized polymer was confirmed by Spectral data and Gel permeation chromatography (GPC). Also its effect on crude oil was evaluated by Rheological studies, SARA Analysis, Pour point depressant effect. Cross–polarizing microscopic studies were performed to study changes in morphology of wax crystals in crude oil with and without additive. A zero friction advanced Rheometer AR-500 was used to determine the viscosity by applying Bingham plastic-flow model.

A genome-wide association study identifies genes associated with cuticular wax metabolism in maize.

The plant cuticle is essential in plant defense against biotic and abiotic stresses. To systematically elucidate the genetic architecture of maize (Zea mays L.) cuticular wax metabolism, 2 cuticular wax-related traits, the chlorophyll extraction rate (CER) and water loss rate (WLR) of 389 maize inbred lines, were investigated and a genome-wide association study (GWAS) was performed using 1.25 million single nucleotide polymorphisms (SNPs). In total, 57 nonredundant quantitative trait loci (QTL) explaining 5.57% to 15.07% of the phenotypic variation for each QTL were identified. These QTLs contained 183 genes, among which 21 strong candidates were identified based on functional annotations and previous publications. Remarkably, 3 candidate genes that express differentially during cuticle development encode β-ketoacyl-CoA synthase (KCS). While ZmKCS19 was known to be involved in cuticle wax metabolism, ZmKCS12 and ZmKCS3 functions were not reported. The association between ZmKCS12 and WLR was confirmed by resequencing 106 inbred lines, and the variation of WLR was significant between different haplotypes of ZmKCS12. In this study, the loss-of-function mutant of ZmKCS12 exhibited wrinkled leaf morphology, altered wax crystal morphology, and decreased C32 wax monomer levels, causing an increased WLR and sensitivity to drought. These results confirm that ZmKCS12 plays a vital role in maize C32 wax monomer synthesis and is critical for drought tolerance. In sum, through GWAS of 2 cuticular wax-associated traits, this study reveals comprehensively the genetic architecture in maize cuticular wax metabolism and provides a valuable reference for the genetic improvement of stress tolerance in maize.

Experimental study of the effects of a magnetic field/magnetic field-ferromagnetic nanocomposite pour point depressant on wax deposition.

A magnetic field and pour point depressant, as a new avenue for improving the submarine pipeline flow of waxy oils, has attracted increasing attention along with the development of efficient wax mitigation techniques. Although advances have been made recently in understanding the rheological behavior and crystallization properties of waxy oils, the effect of magnetic field and pour point depressants on wax deposition remains an open question. In this work, a ferromagnetic nanocomposite pour point depressant (FNPPD) was prepared. The variations in wax deposition mass and component under the effect of different magnetic treatments and magnetic field-FNPPDs were investigated using cold fingers and high-temperature gas chromatography. It was evident that both the high-intensity and high-frequency magnetic fields generated by the magnet and magnetic coil can effectively reduce the deposition mass and have a long-term magnetic history effect. The synergistic effect of magnetic fields and FNPPDs concurrently reduced the thickness/mass and wax content in the deposition layer, as compared to the individual use of magnetic fields or FNPPDs. The wax precipitation properties and wax crystal morphology of waxy oils under the action of the magnetic field were characterized by differential scanning calorimetry, focused beam reflectance measurement and polarizing microscopy experiments, and the mechanism of the magnetic field was elaborated from the perspective of crystallization kinetics by combining the fitting analysis of Avrami and size-independent growth model.

Analyzing the Role of Wax Crystal Morphology in Wax Inhibition Using Polymeric Additive

Analyzing the Role of Wax Crystal Morphology in Wax Inhibition Using Polymeric Additive

Resource utilization of expired progesterone medicines as flow improver for waxy crude oils

At present, the treatment of expired medicines mainly involves burning, which means waste of resources and carbon dioxide emissions, and it does not comply with the concept of resource recycling. In this study, in order to explore the resource utilization pathways of expired medicines, progesterone drugs were evaluated as crude oil flow improvers as an example. The results shows that progesterone injection (PI) and progesterone capsule (PC) both act as viscosity reducer and pour point depressant in different crude oil, and 500 ppm PI and 300 ppm PC are the best dosage respectively. 500 ppm PI can reduce the viscosity of HN oil sample by 60.40%, and depress the pour point by 8.5 °C. 300 ppm PC can reduce the viscosity of HN oil by 54.7%, and depress the pour point by 10.9 °C. Furthermore, through DSC and wax crystal morphology analysis, the possible mechanism of this expired medicine as crude oil flow improver was further discussed. Finally, considering the costs of concentration, transportation, treatment, processing and other links, the possible cost of crude oil flow improver was summed up, and its market feasibility was analyzed. This study provides a reference case for the resource utilization of expired medicines.

Fatty alcohols, a minor component of the tree tobacco surface wax, are associated with defence against caterpillar herbivory.

Despite decades of research resulting in a comprehensive understanding of epicuticular wax metabolism, the function of these almost ubiquitous metabolites in plant-herbivore interactions remains unresolved. In this study, we examined the effects of CRISPR-induced knockout mutations in four Nicotiana glauca (tree tobacco) wax metabolism genes. These mutations cause a wide range of changes in epicuticular wax composition, leading to altered interactions with insects and snails. Three interaction classes were examined: chewing herbivory by seven caterpillars and one snail species, phloem feeding by Myzus persicae (green peach aphid) and oviposition by Bemisia tabaci (whitefly). Although total wax load and alkane abundance did not affect caterpillar growth, a correlation across species, showed that fatty alcohols, a minor component of N. glauca surface waxes, negatively affected the growth of both a generalist caterpillar (Spodoptera littoralis) and a tobacco-feeding specialist (Manduca sexta). This negative correlation was overshadowed by the stronger effect of anabasine, a nicotine isomer, and was apparent when fatty alcohols were added to an artificial lepidopteran diet. By contrast, snails fed more on waxy leaves. Aphid reproduction and feeding activity were unaffected by wax composition but were potentially affected by altered cutin composition. Wax crystal morphology could explain the preference of B. tabaci to lay eggs on waxy wild-type plants relative to both alkane and fatty alcohol-deficient mutants. Together, our results suggest that the varied responses among herbivore classes and species are likely to be a consequence of the co-evolution that shaped the specific effects of different surface wax components in plant-herbivore interactions.

The dynamic changes of mango (Mangifera indica L.) epicuticular wax during fruit development and effect of epicuticular wax on Colletotrichum gloeosporioides invasion.

Mango fruits are susceptible to diseases, such as anthracnose, during fruit development, leading to yield reduction. Epicuticular wax is closely related to resistance of plants to pathogenic bacterial invasion. In this study, the effect of mango fruit epicuticular wax on the invasion of Colletotrichum gloeosporioides was investigated, followed by to understand the changes of wax chemical composition and crystal morphology during mango fruit development using GC-MS and SEM. Results showed that the epicuticular wax of mango fruits can prevent the invasion of C. gloeosporioides, and 'Renong' showed the strongest resistance to C. gloeosporioides. The wax content of four mango varieties first increased and then decreased from 40 days after full bloom (DAFB) to 120 DAFB. In addition, 95 compounds were detected in the epicuticular wax of the four mango varieties at five developmental periods, in which primary alcohols, terpenoids and esters were the main wax chemical composition. Furthermore, the surface wax structure of mango fruit changed dynamically during fruit development, and irregular platelet-like crystals were the main wax structure. The present study showed the changes of wax content, chemical composition and crystal morphology during mango fruit development, and the special terpenoids (squalene, farnesyl acetate and farnesol) and dense crystal structure in the epicuticular wax of 'Renong' fruit may be the main reason for its stronger resistance to C. gloeosporioides than other varieties. Therefore, these results provide a reference for the follow-up study of mango fruit epicuticular wax synthesis mechanism and breeding.

Oil-Soluble Exogenous Catalysts and Reservoir Minerals Synergistically Catalyze the Aquathermolysis of Heavy Oil.

Oil is the "blood" and economic lifeblood of modern industry, but traditional light crude oil has been over-consumed, and it has been difficult to meet human demand for energy, so the exploitation of heavy oil is particularly important. In this paper, an oil-soluble catalyst was synthesized to catalyze the pyrolysis reaction of heavy oil in collaboration with reservoir minerals, so as to achieve efficient viscosity reduction of heavy oil and reduce production costs. The experimental results showed that Zn(II)O + K had the best synergistic viscosity reduction effect after the aquathermolysis of No. 1 oil sample under the reaction conditions of 180 °C, 4 h, 30% of water, and 0.2% of catalyst, respectively, and the viscosity reduction rate was 61.74%. Under the catalysis of the isopropanol system, the viscosity reduction rate was increased to 91.22%. A series of characterizations such as freezing point, thermogravimetric analysis, DSC analysis, component analysis, gas chromatography, wax crystal morphology analysis, and GC-MS analysis of aqueous organic matter were carried out on heavy oil after reaction by different reaction systems, and it could be verified that the viscosity of heavy oil was reduced. Finally, through the study of the reaction mechanism of the model compound, combined with the aqueous phase analysis, it can be clearly found that the depolymerization between macromolecules, the breaking of heteroatom chains, hydrogenation, ring opening, and other effects mainly occur during the reaction, thereby weakening the van der Waals force and hydrogen bond of the recombinant interval, inhibiting the formation of grid structure in heavy oil and effectively reducing the viscosity of heavy oil.

A 3-Ketoacyl-CoA Synthase 10 (KCS10) Homologue from Alfalfa Enhances Drought Tolerance by Regulating Cuticular Wax Biosynthesis.

Cuticular wax, forming the first line of defense against adverse environmental stresses, comprises very long-chain fatty acids (VLCFAs) and their derivatives. 3-Ketoacyl-CoA synthase (KCS) is a rate-limiting enzyme for VLCFA biosynthesis. In this study, we isolated KCS10, a KCS gene from alfalfa, and analyzed the effect of gene expression on wax production and drought stress in transgenic plants. MsKCS10 overexpression increased compact platelet-like crystal deposition and promoted primary alcohol biosynthesis through acyl reduction pathways in alfalfa leaves. Overexpression of MsKCS10 induced the formation of coiled-rodlet-like crystals and increased n-alkane content through decarbonylation pathways in tobacco and tomato fruits. Overexpression of MsKCS10 enhanced drought tolerance by limiting nonstomatal water loss, improving photosynthesis, and maintaining osmotic potential under drought stress in transgenic tobacco. In summary, MsKCS10 plays an important role in wax biosynthesis, wax crystal morphology, and drought tolerance, although the mechanisms are different among the plant species. MsKCS10 can be targeted in future breeding programs to improve drought tolerance in plants.

A comprehensive assessment for the structural change of waxy crude oils induced by pour point depressant beneficiation

In the petroleum industry, the solid paraffins that precipitate out from a waxy crude oil complicate the low-temperature flow characteristics, causing major difficulties in pipeline transportation. Pour point depressants (PPDs) are often utilized to improve the flow characteristics of crude oils by modifying the morphology and structure of wax crystals, becoming a great technical and economic interest. The improving mechanism of PPDs on the structure of gelled waxy crude oil can be attributed to the nucleation, co-crystallization, and adsorption effect to the precipitated wax crystals, preventing the waxy structure from growing further and forming a volume spanning network. Many previous works about the PPDs’ effect have merely focused on the pour point, apparent viscosity, and yield strength depressing ability, while other structural properties have rarely been comprehensively evaluated. The objective of this study is to comprehensively reveal the change of the wax particle structure in oils benefitted with PPDs. The structure of gelled oils doped with PPDs was found to become less elastic and more susceptible to shear perturbation with a lower linear deformation range of 0.42% and a longer relaxed time scale of 3000 s. Large amplitude oscillatory shear (LAOS) tests show that the nonlinear viscoelastic behaviors can be weakened by PPDs, whereas the third harmonic value obtained by Fourier-transform analysis increases after adding PPDs, indicating that the sensitivity to applied load are strengthened. Meanwhile, the value of yield strain increases to about 8.7%, and the irreversible plastic deformation zone becomes relatively broader (brittleness index I increases to 70.9), which mean a more ductile fracture induced by PPDs would occur when yielding. Although the additive PPDs weaken the structural strength and the non-Newtonian characteristics (kinetic index of n1 increases to 0.8), the characteristic of thixotropy is obviously strengthened, and the doped crude oils exhibit a faster structural breakdown process after yielding. All these novel changes for structural features explored in this paper provide theoretical guidance into understanding the practical engineering problems of accelerated process for the pipeline restart flow benefitted with PPDs.

Effect of nanocomposite pour point depressant EVAL/CNT on flow properties of waxy crude oil

The nanocomposite EVAL-CNT was produced by chemical grafting in the solution system through the esterification of ethylene-vinyl alcohol copolymer (EVAL) and carboxylated multi-walled carbon nanotubes (O-MWCNT), and its structural properties were characterized. The improvement of the rheological properties of the waxy oil system by the novel pour point depressant was investigated using macroscopic rheological measurements and microscopic observations. The results showed that EVAL-CNT nanocomposite pour point depressant (PPD) could significantly reduce the pour point and improve the low temperature fluidity of crude oil and had better performance than EVAL-GO at the same addition level. The best effect was achieved at the dosing concentration of 400 ppm, which reduced the pour point by 13 °C and the low-temperature viscosity by 85.4%. The nanocomposites dispersed in the oil phase influenced the precipitation and crystallization of wax molecules through heterogeneous crystallization templates, which led to the increase of wax crystal size and compact structure and changed the wax crystal morphology, which had a better effect on the rheological properties of waxy oil.

An Insight Into Wax Precipitation, Deposition, and Prevention Stratagem of Gas-Condensate Flow in Wellbore Region

Abstract Unlike conventional waxy crude oil, the condensate undergoes a complex phase evolution process in high-temperature and high-pressure conditions of a deep gas-condensate reservoir, which makes it more difficult to predict and prevent the wax precipitation. This study measured the component composition, physical properties, and carbon number distribution of the closed sampled condensates from the wellbore region. The fluid component in wells was corrected by combining with the gas–oil ratio of the actual production data. The wellbore temperature and pressure profiles were accurately predicted using the corrected component, and the phase envelope relationship of gas-condensate flow was reasonably determined. A cold finger apparatus was designed to test the wax deposition characteristics. The main test unit consists of a completely closed high-pressure autoclave and a cold finger with a maximum 140 °C temperature-tolerant and 16,000 psi pressure-tolerant ability. The wax deposition characteristics were formulated, including wax appearance temperature (WAT), critical conditions for wax deposition, wax crystal morphology, and wax deposition rate. The primary mechanisms causing wax deposition in the wellbore region of deep gas-condensate reservoirs are still thermal diffusion and molecular diffusion. A wax crystal improved wax inhibitor consisting of hydrocarbons and polymers was collected and employed. The wax crystal improved wax inhibitor showed remarkable wax prevention performance, reducing WAT by up to 80% and achieving a 90% wax inhibiting rate within the experimental measurement concentrations. These results offer insights into the wax precipitation behavior, wax deposition characteristics, and wax prevention of the condensates.

Modified and Unmodified Jatropha Curcas Seed Oils as Pour Point Depressants for a Nigerian Waxy Crude Oil

Transportation of waxy crude oil faces great challenges in pipelines, however, pour-point depressant could be employed to improve flow properties of waxy crude oil by modifying the morphology and structure of wax crystals. In this paper, modified and unmodified jatropha curcas seed oils was used as a green pour point depressants to evaluate the flow properties of a Nigerian waxy crude oil. Jatropha curcas seed oil (49.5%) was extracted using petroleum ether and the oil was analyzed for oil quality parameters (acid value, iodine value, free fatty acid and saponification value) and subsequently modified using diethanolamine and ethylene glycol to give fatty amides and glycol esters with sulphamic acid (2% and 10% respectively) as catalysts. The modified products were characterized using Fourier transform infra-red (FT-IR) spectroscopy. The modified and unmodified Jatropha seed oils were used treat a Nigerian waxy crude oil to determine their effects on the pour point of the said crude oil. This was done by determining the viscosity and pour point of the crude oil before and after it is dosed with different concentrations of the modified and unmodified Jatropha oils. The results revealed the efficiency of the fatty amides to reduce the pour point and viscosity of the crude oil from 180C to 150C and from 3.49 cst. to 2.0 cst respectively. Both ethylene glycol-modified Jatropha seed oil and the unmodified Jatropha seed oil were able to also depress the pour point of the crude oil to the same degree showing that modification with ethylene glycol did not improve the ability of ordinary Jatropha seed oil to act as pour point depressant.

Exploration of the fundamental factor for the synergistic modification of model waxy oil by EVA and asphaltene: An experiment and simulation study

It has been well documented that the synergistic effect of polymer pour point depressant (PPD) and asphaltenes improves the low-temperature rheology of waxy oil. However, the fundamental factor of this synergistic effect has been little studied. In this paper, we innovatively combine macroscopic rheology experiment, mesoscopic particle size test and microscopic molecular dynamics simulation, supplemented by crystallization exotherm test and wax crystal morphology observation, to investigate the effect of solvent composition on the synergistic modification ability between ethylene-vinyl acetate (EVA) PPD and asphaltene, and then reveal the fundamental factor of this synergistic effect. The results showed that the EVA's adsorption on the asphaltene surface is the key element influencing their synergistic effects. With the deterioration of asphaltene dispersion in the solvent, the ability of asphaltene and EVA to synergistically improve the low-temperature rheology of model waxy oil increases and then decreases. When the aromatic component in the solvent was too high, a large number of aromatic solvent molecules were distributed around the asphaltene molecules through π-π conjugation, which interfered with the adsorption of EVA on asphaltene due to the existence of spatial site resistance. When the content of saturated hydrocarbon component in the solvent was too high, the self-aggregation tendency of asphaltenes led to a decrease in the number of adsorption sites on their surfaces, resulting in the decline of the adsorption efficiency of EVA on the asphaltene surface, and the synergistic modification effect between them was reduced. This work offers fresh ideas for the design of waxy crude oil PPD, which is crucial for the efficient pipeline transmission of waxy crude oil.

Impact of Paraffin Composition on the Interactions between Waxes, Asphaltenes, and Paraffin Inhibitors in a Light Crude Oil

The effect of wax molecular weight distribution on the efficacy of two alpha olefin-maleic anhydride paraffin inhibitors (PIs) having different densities of alkyl side-chains were examined in light West Texas crude in the absence and presence of asphaltenes. Interpretation of the data was aided by cross-polarization microscopy. Primary differences in wax crystal morphology appear to be driven by the composition of the wax, with secondary differences being associated with the choice of PI. In the absence of asphaltenes, the effect of wax composition on PI performance (i.e., reducing oil viscosity and wax appearance temperature) is greater for the PI having the higher chain density, with the one having the lower chain density being generally more effective regardless of the wax composition. These differences are diminished in the presence of asphaltenes such that the PI having the higher chain density is somewhat more effective. Trends in both morphology and viscosity suggest a steric effect associated with wax composition that is lessened on interaction of the PIs with asphaltenes.