Pour Point Depressant of Fuel Oil Using Non-ionic Surfactants

Paraffin wax deposition from fuel oil at low temperature is one of the serious and long-standing problems in petroleum industry. The addition of pour point depressants (PPD) has been proved to be an efficient way to inhibit wax deposition. The influence of PPD on wax precipitation at low temperature was investigated. A different ethoxylated nonionic surfactants were prepared by reacting natural fatty acids (myristic acid and palmitic acid) with polyethylene glycol of different molecular weight. The synthesized nonionic surfactants were confirmed by NMR and FTIR spectroscopy. The surface properties of the synthesized surfactants, including the critical micelle concentration, effectiveness (π_CMC), maximum surface excess (Г_max), and minimum surface area (A_min) were determined. The efficiency of ethoxylated nonionic surfactants was evaluated as cloud and pour point depressant for fuel oil was discussed. The results indicate that C₁₆E₇ surfactant posse's good cloud and pour point depressing performance. The effect of additive type and compatibility additive with natural wax dispersant on the wax crystallization behavior at low (0°C) was evaluated. Photomicrographs showed that wax morphology was greatly modified to fine dispersant crystal of compact size. Correlation between wax modification and pour point depression appear to be merely qualitative in such heterogeneous fuel systems.     

Synthesis,interface activity and oil flooding experiment with an authentic sandstone microscopic model of cationic gemini surfactant

In this work, a series of cationic gemini surfactants with different hydrophobic tails were prepared and characterized by element analysis, IR spectra, and ¹H NMR spectra. The influencing factors of physic-chemical properties of these surfactants were carefully studied. The critical micelle concentration (CMC) of all the surfactants ranged from 3.87 × 10^?4 mol L^?1 to 8.97 × 10^?4 mol L^?1 and the values (γ_cmc) also ranged from 28.62 mN m^?1 to 34.07 mN m^?1 at CMC level by surface tension experiments. The consequences of the oil/water interface tension experiments indicated that all these prepared surfactants could lower oil/water interface tension to ultra-low with the combination of Na₂CO₃. C₁₂-2-C₁₂, and C₁₄-2-C₁₄ were chosen as the representative to evaluate the displacement efficiency in the oil flooding experiments using authentic sandstone microscopic model. The results showed that these surfactants could effectively improve the displacement efficiency by 10–20%.     

Effect of polar head surfactants on the demulsification of crude oil

Surfactants can act as demulsifiers to neutralize the stabilizing effect of natural emulsifiers in crude oil. Here, the effect of polar head group of surfactants with identical hydrophobic chain C₁₂ (SLES, SLS, C₁₂E₂₃, BKC, C₁₂E₇) on the demulsification of crude oil emulsion and its effect on water separation rate were studied at different temperature. The activation energy for destabilization was calculated. The results indicate that the rate of water separation increases with temperature and surfactant concentration. The emulsion destabilising activation energy decreases as the concentration of the surfactant increases. The Interfacial Tension (IFT) study showed that when the reduction in IFT was the highest, the water separation rate and efficiency achieved was the highest.     

Effect of chemical structure on the cloud point of some new non-ionic surfactants based on bisphenol in relation to their surface active properties

A series of non-ionic surfactants were prepared from bisphenol derived from acetone (A), acetophenone (AC) and cyclohexanone (CH). The prepared bisphenols were ethoxylated at different degrees of ethylene oxide (27, 35, 43). The ethoxylated bisphenols were non-esterified by fatty acids; decanoic, lauric, myristic, palmitic, stearic, oleic, linoloic and linolinic. Some surface active properties for these surfactants were measured and calculated such as, surface tension [γ], critical micelle concentration [CMC], minimum area per molecule [A_min], surface excess [C_max], free energy of micellization and adsorption [ΔG_mic] and [ΔG_ads]. At a certain temperature, the cloud point was measured for these surfactants. From the obtained data it was found that; the cloud point is very sensitive to the increase of the alkyl chain length, content of ethylene oxide and degree of unsaturation. The core of bisphenol affected the cloud point sharply and they are ranked regarding bisphenol structure as BA > BCH > BAC. By inspection of the surface active properties of these surfactants, a good relation was obtained with their cloud points. The data were discussed on the light of their chemical structures.     

Effect of salinity on the IFT between aqueous surfactant solution and crude oil

The effect of salts and different surfactants on the equilibrium as well as dynamic interfacial tension (DIFT) between crude oil and water was investigated. Three different types of surfactants with identical hydrophobic chain length C₁₂: Sodium Lauryl Ether Sulphate (SLES), Dodecyl Trimethyl Ammonium Bromide (DTAB), Polyoxyethylene (23) lauryl ether (C₁₂E₂₃) were used in this study. SLES shows better synergism of salt and surfactant mixture amongst the surfactants studied. The order of synergism of salts with the surfactant observed was MgCl₂>CaCl₂> NaCl. The results obtained from partition coefficient study show that the addition of salts favours the partition of surfactants into the oil phase hence reduce IFT more effectively. DIFT results reveal that, salt accelerates the surfactant migration towards the interface, hence, reducing the t^* value.     

The effect of cationic surfactant additives on flow properties of crude oil

Pretreatment of the crude oil with flow improver or pour point depressants has received the greatest acceptance due to its simplicity and economy. Three cationic surfactants Bola form based on urea were prepared by quaternization reaction with alkyl dihalides of different chain length (hexayl, decyl-, and dodecyl-dibromide). The prepared compounds (U6, U10, and U12) were evaluated as surface active agents as well as pour point depressant for crude oil compared to monosurfactant (U12a) corresponding to (U12). The surface parameters of each synthesized surfactant were calculated from their surface tension profile including the critical micelle concentration, maximum surface excess (Γ_max), and the minimum surface area (A_min). The free energies of micellization (ΔG°_mic) and adsorption (ΔG°_ads) were also calculated. Its pour point and viscosity decreased significantly after adding surfactants. FTIR studies of crude-surfactant mixture showed remarkable decrease in concentration of viscosity enhancing groups such as alkanes, alcoholic, and acidic groups, indicating the effectiveness of both the surfactants.     

联结基对磺酸盐型双子表面活性剂的界面张力和起泡性能的影响

 合成了一系列具有支状疏水链的新型磺酸盐型双子表面活性剂D₂C_n（D为疏水基仲辛基,C为联结基中亚甲基,n=2,4,6,8）,考察了联结基对其表面活性的影响。结果表明,D₂C_n系列双子表面活性剂溶液的临界表面张力γ_CMC与临界胶束浓度CMC值均随联结基长度的增加而增大;辽河原油加入D₂C_n系列双子表面活性剂溶液后的油-水界面张力随着联结基团长度的增加先增加后降低。D₂C_n系列双子表面活性剂具有良好的泡沫性能,随着联结基长度的增加,初始起泡体积降低,泡沫半衰期先增加后降低;随着温度的增加,泡沫半衰期显著下降,初始起泡体积先增加后降低。     

The influence of sulfur on the structural-dynamic parameters of petroleum systems studied by the NMR technique

A number of crude oils, fuel oils, and asphalts containing sulfur with a concentration in the range of 0.16–4.61 wt % were studied by the nuclear magnetic resonance technique. The NMR relaxation parameters were measured with a 08/PC laboratory NMR relaxometer made in-house according to TU 25-4823764.0031-90 and a computerized portable proton magnetic resonance analyzer. A multiexponential character of the spinecho envelope was revealed for all samples, which was deconvoluted into three exponentials having relaxation times of T _2A, T _2B, and T _2C. The obtained high-resolution NMR spectra of crude oil, fuel oil, and asphalt show that sulfur contributes to the width of all spectral lines. The slope of the T _1A, T _1B, T _1C, T _2A, T _2B, and T _2C plots varies depending on the temperature range of the measurement in all cases, thereby indicating a change in the activation energy E _Ai of molecular motion. All of the activation energies increase with an increase in the sulfur concentration. Over the entire range of measurement temperatures, there is one activation energy for crude oils and two activation energies E _A¹ and E _A² for fuel oils, with the low-temperature activation energies having higher values. An analysis of the asphalt revealed five, not two, activation energies or intervals of constant E _B² values (structurally-dynamically ordered phases of the shells of asphalt structure units).     

季铵盐型Gemini 表面活性剂水溶液的表面和油-水界面特性

 用 DCAT-21型表面张力及接触角仪测定了不同结构的季铵盐型 Gemini 表面活性剂 C_n-s-C_n·2Br 溶液的表面张力和界面张力变化,为选择一种较好的表面活性剂作为驱油剂提供基础。结果表明,烷基链长n 均为12时,随联接基团数s 的增加,季铵盐型 Gemini 表面活性剂降低表面和界面张力能力减小。s 相同时,随着烷基链长n 增加,Gemini 表面活性剂的临界胶束浓度（CMC）减小。加入无机盐可以进一步降低 Gemini 表面活性剂的 CMC 值。季铵盐型 Gemini 表面活性剂的 CMC 值较类似结构的单链单头普通表面活性剂的 CMC 值低,且达到最低界面张力时的浓度比单链单头普通表面活性剂低2个数量级。Gemini表面活性剂的高表面活性主要由其特殊的分子结构所决定。     

Anionic cocogem surfactants containing propyl-2-ol groups: Synthesis,surface properties and antibacterial activity against SRB bacteria

Cocogem surfactants are synthesized based on the neutralization reaction of higher monocarboxylic acids (octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid) and 2:1 mol of N,N'-bis(propyl-2-ol)ethylenediamine). Krafft temperatures of these surfactants and colloidal chemical properties of their aqueous solutions were determined by using tensiometric and conductometric measurements. Surface activity parameters of cocogem surfactants, critical micelle concentration (CMC), counter-ion binding degree (β), the surface tension reduction effectiveness (π_CMC), excess concentration of surface (Γ_max), as well as area per molecule at the interface (A_min), Gibbs free energy (ΔG_ad and ΔG_mic) values of adsorption and micellar formation processes are calculated. The size of the aggregates formed by anionic cocogem surfactants in an aqueous solution was determined by the DLS method. It was defined that cocogem surfactants have antibacterial properties against SRB, which is considered to be the most dangerous for the oil industry.     

SURFACE AND THERMODYNAMIC PARAMETERS OF THE ANIONIC COLLECTOR FOR OIL SEPARATION BY FLOTATION

Used lubricating/cooling fluid represents a source of waste water pollution. The objective of the present work is to improve the application of flotation technique for the removal of synthetic emulsifiable oil. Anionic surfactant of the structure H₂₅C₁₂ Ø_OHSO₃ Ba has been synthesized and used a collector for oil. From surface tension-concentration curves in aqueous solution at 25, 35, and 45°C, surface excess concentration and area/molecule at surface saturation, critical micelle concentration, efficiency, and thermodynamic parameters of adsorption and micellization have been calculated. The effect of electrolyte on the surface properties of collector is studied. Several parameters affecting the performance of the flotation processes are investigated including electrolyte, collector concentrations, and temperatures are studied and optimum conditions are determined. The results are discussed according to surface and thermodynamic properties of collector and kinetic parameters.     

Hexa-triethanolamine oleate esters as pour point depressant for waxy crude oils

New crystal modifier surfactants were developed by esterification of hexa-triethanolamine with oleic acid to prepare mono, di, and tri-esters. The synthesized esters were confirmed by IR spectroscopy and the molecular weight of the major compound in the reaction mixture was determined by MS analysis. Surface properties of the synthesized modifiers, including critical micelle concentration (CMC), effectiveness (π_cmc), maximum surface excess (Ί_max) and minimum surface area (A_min) were determined at 30 °C. The synthesized esters were evaluated as flow improver (FI) and pour point depressant (PPD). Hexa-triethanolamine mono-oleate was most efficient for crude oil (I), and hexa-triethanolamine tri−oleate was most efficient for crude oil (II).     

Synthesis of polymeric additives based on itaconic acid and their evaluation as pour point depressants for lube oil in relation to rheological flow properties

Modification of the wax crystal habit practical interest during transportation processing of lube oil at low temperature. Various pour point depressant (PPD) additives can facilitate this modification by different mechanisms. Comb shaped polymer additives are known to depress the pour point of lube oil by providing different nucleation sites for the precipitation of wax. This paper describes performance based design, synthesis, characterization and evaluation of comb shaped polymeric additives. Alkyl itaconates were prepared by the esterification of itaconic acid with different saturated alcohols C₁₆/C₁₈/NAFOL 20+A (C_av = 20)/NAFOL 1822 B (C_av = 22). The four synthesized monomers were characterized and copolymerized with styrene in different molar ratios. All the products were characterized by infra-red (FTIR), Nuclear Magnetic Resonance (NMR) Spectroscopy and Gel permeation chromatography (GPC). Rheological properties of lube oil (with and without additives) were studied by Brookfield viscometer. In this study the additives based on itaconic acid were evaluated as good PPD and rheology modifiers.     

Preparation and evaluation of some amide ether carboxylate surfactants

A homologous series of new mild surfactants, namely: Alkyl amide ether carboxylates surfactants (AEC) RCO–NHCH₂CH₂O (CH₂CH₂O)₆CH₂COONa, were synthesized by esterification, amidation, ethoxylation and carboxymethylation reaction steps of fatty acids (Lauric, Myristic, palmitic, stearic, oleic or linoleic). The chemical structures of the prepared compounds were confirmed using different spectroscopic techniques, FTIR spectroscopy, mass spectra and HNMR. The surface properties including surface and interfacial tensions, foaming height, emulsification power, calcium ion stability, stability to hydrolysis and critical micelle concentration (cmc) were determined. The study of their surface properties showed their stability in hard water and in acidic and alkaline media. These compounds have high calcium ion stability. The low foaming power could have an application in the dyeing auxiliary industry. The lower values of the interfacial tension values indicate the ability of using these surfactants in several applications as corrosion inhibitors and biocides. The data revealed various advantages and potentials as a main surfactant as well as co- surfactants.     

The Preparation and Characterization of Some Novel Quaternary Iminium Salts Based on Schiff-base as a Corrosion Inhibitor

Abstract

Novel quaternary iminium compounds, namely, N-(4-methoxybenzylidene)-N-benzyldodecyliminium chloride (I_a), N-(4-methoxybenzylidene)-N-benzylhexadecyl iminium chloride (I_b), N-(4-methoxybenzylidene)-N-benzyloctadecyliminium chloride (I_c), and N-benzylidene-N-benzyldodecyliminium chloride, were prepared. The surface properties such as surface and interfacial tension, foaming, and emulsifying power of these surfactants were investigated. The surface parameters including critical micelle concentration (CMC), maximum surface excess (Γ_max), minimum surface area (A_min), efficiency (PC₂₀), and effectiveness (π_CMC) were calculated. Free energy of micellization (ΔG°_mic) and adsorption (ΔG°_ads) were calculated.     

Evaluation and application of surfactants synthesized from asphalt components

The synthesis, characterization, surface activity and applications of nonionic surfactants derived from the asphalt components (maltenes M) are presented. These compounds were synthesized by the sulfonation of (maltene), then the prepared maltene sulfonic acid (MS) was reacted with hexadecylamine giving maltene sulfonamide product (A) which undergoes an alkali-catalyzed ethoxylation at (135–150 °C). Several surfactants (M-10 to M-40) were formed with different ethylene oxide units (from 10 up to 40) and were characterized by molecular weight determinations, elemental analyses and FTIR analysis. Surface tension, as a function of concentration of the surfactants in the aqueous media, was measured at 25 °C. From these measurements, the critical micelle concentration (CMC), the maximum surface excess concentration (Г_max), Minimum area per molecule (A_min), effectiveness of surface reduction (П_CMC) and the efficiency (pC20) were calculated. The prepared surfactants were applied as emulsifying agents for making asphalt emulsions. Storage stability, (Saybolt Furol) viscosity, settlement (water content difference %), coating ability and water resistance were measured. The results indicated that M-20 (maltene sulfonamide ethoxylated with 20 units of ethylene oxides) gives a maximum stability.     

Thermophysical interface properties of crude oil and aqueous solution containing sulfate anions: experimental and modeling approaches

Abstract

Sulfate anion is well-known for being one of the most active agents to be injected into the oil reservoirs and being capable of not only altering the interfacial properties of crude oil but also enhancing the water solution properties in oil recovery. In the current study, the effects of temperature and pressure were studied on interfacial tension (IFT) as well as the adsorption behavior of two different solutions containing sulfate anion using experimental measurements and modeling approaches. Although it was expected that IFT values of the studied systems might decrease as temperature increased due to the improvement in the molecule mobility and solubility of crude oil in water, which consequently might lead to the reduction in its free energy, the reverse trend was observed. The measured dynamic IFT values and adsorption behavior revealed that surface excess concentration of natural surfactants (Г_NS) can be considered as the most effective parameter on interpreting IFT behavior as a function of temperature.     

Resolution of water in crude oil emulsion by some novel aromatic amine polyesters

In this work, three aromatic amines (p-toluidine, p-nitroaniline and p-chloroaniline) were chosen as bases for the repatriation of some nonionic polyesters. These amines were ethoxylated with different total number of ethylene oxide units 6, 12, 18. The prepared ethoxylated amine diols were polyesterified with maleic anhydride and polypropylene oxide polyethylene oxide block copolymers in polyesterification reaction. The demulsification efficiency of these demulsifiers was investigated using the bottle test. The effects of the molecular weight, concentration, asphaltene content, water content, Hydrophile Lipophile Balance (HLB) and temperature on the demulsification efficiency were investigated. The surface active properties were correlated with their demulsification efficiency. It was found that, NAE₁₈D gave the best result in the demulsification process. The demulsification efficiency was discussed on the light of surface active properties, interfacial tension and the factors affecting the demulsification. The surface-active properties of the prepared demulsifiers were measured at 60 °C.     

油田用于CO2起泡的表面活性剂的研究现状

介绍了油田用CO_2泡沫的发展过程,以及对用作起泡剂的表面活性剂的要求。重点介绍了国内外CO_2泡沫用表面活性剂的发展现状,现场用于CO_2泡沫的水溶性表面活性剂的种类,用于CO_2泡沫的溶于CO_2的表面活性剂的研究现状,并总结了CO_2泡沫在现场的应用情况。     

Distribution of <Emphasis Type="Italic">n</Emphasis>-Alkanes in the Products of Electric Dewaxing of Diesel Fuel

The distribution of n-alkanes in summer diesel fuel and products of its electric and urea dewaxing, dewaxed diesel (DWD) and slack wax, has been studied. Quantitative changes in the groups of low- C_7–14, middle- C_15–18, and high-melting C₁₉₊n-alkanes in the diesel, DWD, and slack wax have been shown. By the combination of the DWD yield, selectivity of removal of high-melting n-alkanes from the initial diesel fuel, and cold flow properties of DWD, electric dewaxing is a promising process.