Synthesis, characterisation and pre-evaluation of a novel terpolymer as pour point depressants to improve the Malaysian crude oil flowability

Wax deposition is considered one of the most serious operational issues in the crude oil pipelines. This issue occurs when the crude oil temperature decreases below the temperature of wax appearance and paraffin wax starts to precipitate on the pipelines’ inner walls. As a result, the crude oil flow is impeded because of the precipitated wax. The use of polymeric pour point depressants has obtained significant interest among researchers as an approach of wax control for enhancing the flowability of the waxy crude oil. PPD of poly(behenyl acrylate -co-stearyl methacrylate-co- maleic anhydride) (BA-co-SMA-co-MA) was facilely synthesised by the use of free radical polymerisation. The variation of the PPD structure was studied by choosing several essential parameters like monomers ratio, reaction time, initiator concentration, and reaction temperature. Furthermore, viscosity measurement, pour point, and cold finger apparatus have been employed to evaluate the efficiency of the synthesised Polymer. The chemical structure of poly(BA-co-SMA-co-MA) has been identified through the use of Fourier transform infrared as well as nuclear magnetic resonance. The experimental findings demonstrated that the ideal conditions for obtaining the highest yield were 1.5% initiator concentration, reaction time and temperature of 8 h and 100 °C, respectively, and monomer ratio of 1:1:1 (BA:SMA:MA). Under these ideal conditions, the prepared terpolymer reduced the crude oil viscosity at 30 °C and 1500 ppm from 7.2 to 3.2 mPa.s. The cold finger experiment demonstrated that after poly(BA-co-SMA-co-MA) was used as a wax inhibitor, the maximum efficiency of paraffin inhibition of 45.6% was achieved at 200 rpm and 5 °C. Besides, the best performance in depressing the pour point by ΔPP 14 ℃ observed at the concentration of 1500 ppm, which can change the growth characteristics of wax crystals and delay the aggregation of asphaltene and resin, thus effectively improving the flowability of crude oil.

Pour point depressants for fuels based on tall oil fatty acid esters

С целью расширения области применения жирных кислот таллового масла – побочного продукта сульфатной варки целлюлозы (которые преимущественно состоят из непредельных С18-кислот), в том числе за счет получения различных синтетических продуктов на их основе, синтезированы соответствующие этиленгликолевый и додециловый эфиры. Изучена возможность применения указанных сложных эфиров в качестве депрессорных присадок для марок универсального топливного мазута и судового экологического топлива. Жирные кислоты этерифицированы 1-додеканолом и этиленгликолем в присутствии катализатора п-толуолсульфокислоты. Температуру текучести топлив определяли ручным методом по стандарту ASTM D97. Температура текучести топлива судового экологического снизилась с +21 до 0 °С при использовании 2% додецилового эфира жирных кислот в качестве присадки. Установлено, что синтезированные эфиры жирных кислот таллового масла снижают температуру текучести остаточных топлив на уровне, сравнимом с применением промышленно производимой депрессорной присадки, что позволяет расширить сырьевую базу присадок этого типа и сократить закупки по импорту, а также более глубоко использовать жирные кислоты таллового масла в органическом синтезе. In order to expand the field of application of tall oil fatty acids, a by-product of sulfate pulping (which mainly consist of unsaturated C18 acids), including the production of various synthetic products based on them, the corresponding ethylene glycol and dodecyl esters have been synthesized. The possibility of application the esters as pour point depressants for grades of universal fuel oil and marine ecological fuel has been studied. Fatty acids were esterified with 1-dodecanol and ethylene glycol in the presence of a p-toluenesulfonic acid as catalyst. The pour point of the fuels was determined manually according to the ASTM D97 standard. The pour point of ecological marine fuel decreased from +21 to 0 °C when using 2% dodecyl ester of fatty acids as an additive. It was found that the synthesized esters of tall oil fatty acids reduce the pour point of residual fuels at a level comparable to the use of a commercially produced depressant additive, which makes it possible to expand the feedstock base of this type of additives and reduce import purchases, as well as to use more extensively tall oil fatty acids in organic synthesis.

Predictive control of the starting pressure of the main oil pipeline

The article calculates the starting pressures and the time of safe shutdown of the pipeline during the transportation of high-viscosity and high pour point oils, the rheological properties of which depend on temperature. When the oil temperature decreases, its viscosity increases and paraffins are released, forming a strong structure, for which additional stress is necessary to shift. To start a stopped oil pipeline transporting oil with such characteristics, the pressure developed by the pumps may not be enough. In this regard, it is necessary to determine the safe time of stopping the oil pipeline. The relevance increases with an increase in the share of high-viscosity and high pour point oil in the total production volume. Predictive control, based on the analysis of data on the characteristics of the transported product and forecasting the nature of their changes, is an intelligent tool for managing the efficiency of technological transport enterprises. Predictive control allows you to choose the optimal way to ensure reliable and trouble-free operation of the main equipment of hydrocarbon transport systems.A numerical experiment was carried out for the effect of seasonal cooling devices to protect permafrost soils from thawing, at the time of a safe shutdown of the oil pipeline. The values of starting pressures have been determined. Dependence of the pressures on the duration of the safe shutdown of the pipeline has been established. It was revealed that due to the operation of seasonally operating cooling devices, the difference between the temperature soil and oil increases during cooling, and the cooling rate increases. More pressure will be required to launch such an oil pipeline.

Low-Temperature Rheology and Thermoanalytical Investigation of Lubricating Greases: Influence of Thickener Type and Concentration on Melting, Crystallization and Glass Transition

This study investigates crystallization, melting and glass transition of Li- and Ca-12-hydroxystearate greases in relation to the pour point of the corresponding oils. The base oils for the greases are mineral oil, polyalphaolefin, alkylated naphthalene, propylene glycol, and trimellitate. For the mineral oil-based greases the crystallization temperature Tc increases and the melting temperature Tm decreases upon addition of thickener. The pour point of the mineral oil then is 3 K below Tc and does not properly define the lowest application temperature for mineral oil (MO) based greases. Both thickeners induce a small increase of the glass transition temperature (1–3 K) of the synthetic oils polyalphaolefin, alkylated naphthalene, propylene glycol. The pour point of the base oils correlates well with the onset of the glass transition in the corresponding grease indicated by a sharp increase in grease viscosity. Pure trimellitate with unbranched alkyl chains does not crystallize upon cooling but shows noticeable supercooling and cold crystallization. As the percentage of thickener in corresponding greases increases, more oil crystallizes upon cooling 20 K above the crystallization temperature of the trimellitate without thickener (−44 °C). Here, the thickener changes the crystallization behavior from homogeneous to heterogeneous and thus acts as a crystallization nucleus. The pour point of the base oil does not provide information on the temperature below which the greases stiffen significantly due to crystallization.

Ni Rouges, ni Blancs. Quelques observations sur les insurrections paysannes durant la Guerre civile en Russie–Ukraine (1918–1922)

Cet article présente une synthèse des nouvelles connaissances sur la place de la paysannerie durant la Guerre civile en Russie de 1918 à 1922, obtenues grâce aux ouvertures des archives dans les années 1990 et leurs publications partielles par l’historien Viktor Danilov et le sociologue Teodor Shanin. Sans forcément bouleverser complètement l’image que l’on pouvait avoir précédemment sur cet épisode crucial de l’histoire russe du XXe siècle, elles la modifient ou la précisent sur bien des points. Tout d’abord, les soulèvements contre le pouvoir soviétique, bien plus nombreux qu’on ne le croyait précédemment, ont joué un rôle souvent décisif dans le déroulement de la Guerre civile et notamment dans la décision d’instaurer la NEP. Ni « Rouges » ni « Blancs », les paysans s’opposaient à la politique prédatrice des uns et des autres. Toutefois, ce que l’on trouve dans les archives, ce sont les récits des soulèvements dont beaucoup ont pour point de départ les réquisitions de blé par le pouvoir bolchevique, opérées par les détachements spéciaux, ou les enrôlements forcés dans l’Armée rouge. Ces révoltes sont d’envergures diverses. En effet, elles peuvent impliquer un seul village à des régions entières, quelques dizaines de personnes à plus de cent mille. Loin d’être monarchistes, les slogans des insurgés nous montrent un rejet de l’ancien régime et une adhésion aux soviets accompagnés d’un refus violent des bolcheviks, assimilés à des voleurs et des profiteurs. Les archives révèlent enfin dans le détail, certes la violence des insurgés, mais surtout celle de la répression massive dont ils furent les victimes.

Déstabiliser la binarité en archéologie : le cas des tombes 137 et 260 de la nécropole mérovingienne de Bossut-Gottechain

Le sexe est une « catégorie biologique, immuable et universelle ». Le genre est un « système socialement construit catégorisant de manière hiérarchique les sexes ». Depuis les premiers travaux se revendiquant de l’archéologie du genre dans les années 1980, les recherches récentes nous invitent à remettre en question ces définitions, à cesser de considérer le sexe comme une entité figée et à dépasser le modèle binaire du sexe et du genre. Ces réflexions peinent cependant à se frayer un chemin jusqu’à l’archéologie mérovingienne. En prenant pour point de départ deux sépultures particulières de la nécropole de Bossut-Gottechain (Belgique), cet article envisage de questionner la catégorisation binaire des sexes et des genres en archéologie.

Synthesis, characterization and evaluation of stearyl acrylate-co-behenyl acrylate copolymer as a pour point depressant of waxy crude oil

Pour point depressant (PPD) has the competitive advantage of lowering the temperature of the wax appearance (WAT) and crude oil viscosity. In this paper, a novel PPD of poly stearyl acrylate-co-behenyl acrylate (SA-co-BA) in various mass ratios (1:1, 2:1, 3:1, 1:2 and 1:3) was effectively synthesized by solution radical polymerization method, and characterized by fourier transform infrared FTIR, proton nuclear magnetic resonance NMR, x-ray diffraction XRD and scanning electron microscopy SEM. The SA-co-BA PPD was evaluated on Malaysian crude oil via the pour point, the rheological and cold finger analysis to prevent the wax deposition at low temperature and improve flowability. The findings showed that the mass ratio (1:1) at 1000 ppm has a positive effect on the pour point depression from 11 to 2 °C. It was investigated from the rheological measurement that the viscosity of crude oil increases as the temperature decreases. Whereas, the viscosity decreases as the shear rate increases and as shear rate increases, shear stress increases. The flowability performance of the crude by the mass ratio of 1:1 at 1000 of the SA-co-BA concentrations have improved by 89.76%. The highest paraffin inhibition efficiency PIE of wax deposited was obtained at 1:1 of the mass ratio by 44.14%, indicating the smallest amount of wax is formed. This finding is interestingly attributed to the acrylate groups that have a long alkyl chain. Thus, SA-co-BA copolymer was demonstrated to be an appreciable pour point depressant that can prevent the wax deposition at low temperature and increasing the flowability of Malaysian crude oil.