T. T. Khidr

Synthesis and Evaluation of Copolymers as Pour-point Depressants

Abstract α-Olefin maleic anhydride copolymers were prepared by reacting C8 or C14 olefin with maleic anhydride, then esterified with dodecyl or NAFOL 1822B alcohol, purified and characterized through average molecular weight, polydispersity index, and infrared spectroscopy. A waxy crude oil (pour point = 21°C and wax content = 18.9 wt%) was treated with the four synthesized additives as pour-point depressants and determined using x-ray diffractometer. It is found that the x-ray diffraction patterns of waxes with additives are remarkably different from those without additives. The NAFOL 1822B ester of 1-tetradecene maleic anhydride copolymer also show stronger interaction with the wax than NAFOL 1822B ester of 1-octene copolymer, dodecyl ester of 1-tetradecene maleic anhydride copolymer, and dodecy ester of 1-octene maleic anhydride copolymer. These effects can be attributed to the chain length of side hydrocarbon. The wax solubilization is a function of copolymer.

Preparation the Esters of Oleic Acid-Maleic Anhydride Copolymer and Their Evaluation as Flow Improvers for Waxy Crude Oil

Five comb-like copolymers derived from oleic acid-maleic anhydride were prepared and then esterified by long-chain fatty alcohol (POMA Cn), where n = 18, 20, 22. These polymers were characterized by FTIR and 1H NMR analysis. The molecular weight was determined by using gel permeation chromatography (GPC). The prepared copolymers were investigated as flow improvers and pour point depressants (PPD) for crude oil. From the evaluation, it was found that, the maximum depression of PP was obtained by (POMA2 C22) with long-chain alcohol (C22–OH) from 27°C to 15°C (ΔPP3000ppm = −12°C). On the other side, it was remarked that no depression obtained by (POMA2 C18), which esterified by alcohol (C18–OH) at the same condition. The depression of pour point effectiveness was discussed on the light of polymers structure, molecular weights, and their concentrations. By analysis the results of the rheological flow properties, it was found that the POMA2 C22 enhanced the Bingham yield values (τβ). The τβ for crude oil without additives against 15, 27, and 39°C were 0.286, 0.131, and 0.075 Pa respectively, whereas the τβ for the treated crude oil with POMA2 C22 were 0.027, 0.022 and 0.010 Pa at 3000 ppm at the same temperatures. By using the photomicrography analysis, it was found that, the wax morphology was greatly modified to fine dispersed crystals of compact size.

EFFECT OF ABIETIC ACID DERIVATIVE SURFACTANTS ON CALORIFIC VALUE AND FLOW OF CRUDE OIL AND SOME DISTILLATES

ABSTRACT A series of abietic monoester and amide have been prepared by esterification of abietic acid with long chain alcohol blend (Nafol 20+), polyethylene glycol (PEG 400, 600, 1000 and 4000) and hexadecylamine. The abietic diester derivatives were prepared by esterification of abietic–maleic anhydride adduct with Nafol 20+ only or polyethylene glycol-1000 and Nafol 20+. These reactions were carried out to prepare eight abietic acid derivatives. The products were purified and characterized by FTIR and 1H NMR analyses. The surface-active properties of these compounds were correlated with their effect on pour point and calorific values of crude oil. From the results, it has been found that the compound EA23-MN, which has the more negative value of ΔG ad, exhibited maximum pour point depression and increases the calorific values of crude oil and some distillates.

Synthesis and Evaluation of Some Novel Polymeric Surfactants Based on Aromatic Amines Used as Wax Dispersant for Waxy Gas Oil

Dicarboxy methyl ethoxylated aniline and 1,3‐dicarboxy methoxy benzene were synthesized as intermediate monomers to prepare six polyester surfactants. The first three of them were obtained by polyesterification of dicarboxy methoxy ethoxylated (EO=10) aniline with polyethylene glycol (M. wt.; 400, 600, 1000). The product named as An E10 400, An E10 600, and An E10 1000. The later three was obtained by polyesterification of 1, 3 dicarboxymethoxy benzene with the same PEG at different molecular weights. The product named as; R 400, R 600, and R 1000. These polyesters were characterized by FT.ir, and GPC. These polyesters were evaluated as pour point depressants of a mixed blend of Egyptian Western desert gas oil, (PP=18oC). The obtained data showed that, the maximum reduction of pour point was obtained with An E10 1000 (ΔPP=15°C) and R 1000 (ΔPP=18°C) regarding to the two groups of polyesters respectively. Blends from these compounds were done. From the results, it was found that, the blend IV exhibit the maximum depression of pour point, (ΔPP=24°C). The photomicrographic investigation for the change of wax crystals morphology and size as the results of using the pour point dispersants was carried out after the treatment by the blends. The photomicrographic pictures showed a great modification of wax crystals was obtained as a result of dispersion of wax by the additives. The results were compared with a commercial additive at 1000 ppm. It was found that, its ΔPP=18°C. This work was extended to study the surface active properties of these polyesters at liquid/air interface. The obtained data were used to explain the discrepancy of these polyesters toward pour point depression.

Pour Point Depressant Additives for Waxy Gas Oil

Abstract Eight pour point depressants were synthesized to study flow properties for paraffin gas oil. Anhydride copolymers were prepared making use of the copolymerization of acrylate (R1Ac) of different alkyl chains R1 = C14, C18, Nafol 20+A (Cav = 21), and Nafol 1822C (Cav = 22) with maleic anhydride (MA) and terpolymers were prepared by the reaction Nafol 20+A acrylate (Cav = 21), maleic anhydride, and (R2 Ac), where R2 = C4/C8. The additives were purified and characterized by Fourier transform infrared (FTIR) spectroscopy and gel permeation chromatography (GPC). The prepared additives show dual functions as both wax dispersants and pour point depressants. Photomicrographs showed that wax morphology was greatly modified to fine dispersed crystals of compact size according to additive type of treatment.

Polymeric Nonionic Surfactants as a Pour Point Depressant

Polymeric nonionic surfactants with the same hydrophobic moieties C18E68 and C18E136 were prepared. The surface properties of the synthesized surfactants and the critical micelle concentration, surface excesses concentration and the minimum surface area were evaluated and discussed. The efficiency of the prepared polymeric surfactants as pour point for fuel oil was discussed in absence and in presence of commercial additive. The most of the prepared additives showed a good performance toward improving the flow properties of the tested fuel oil. Then the rheological data were further determined through shear rate-viscosity measurements.

Synthesis of Some Additives and Study Effect of Gas Oil Composition on Flow Properties

Nine additives were prepared by esterification of dibasic acid (succinic, adipic, sebacic acid) and polyethylene glycol (Mol.wt.=600, 1000, 4000). These additives were characterized by infrared spectral analysis, average molecular weight and polydispersity index. Their influence on the depression of pour point for two type of paraffin gas oils (G1 and G2) were investigated, blends of paraffin gas oils G1 and G2 by different ratio, when their untreated and treated by additives were evaluated as pour point depressant in comparison with the original paraffin gas oils G1 and G2. The effect of additive type and gas oil composition on wax crystal modification were studied using the photo micrographic analysis. Diethoxylate (eo=182) sebacate with blend gas oil No. 3 has achieved the best performance as pour point depressant. The photo micrographic analysis showed that, the wax morphology was greatly modified to fine dispersed crystals of compact size. A correlation between the pour point depression and the extent of wax modification was detected.

Studies on the Influence of Cationic Surfactant Chemical Additives on Wax Deposition

Abstract Wax deposition studies were carried out to investigate the modification of wax crystals when gas oil was doped with some polymeric surfactant chemical additives. These additives were synthesized via esterification of chloroacetic acid and different alcohols to corresponding esters that were quaternized with polytriethanol amine and polyvinylpyridine to give polycationic surfactants. The surface activities of these polymers were evaluated using standard methods. Properties such as pour point depression data and average carbon number were studied. The behavior of the mixtures of the prepared surfactants on the depression of pour point was determined. The results given indicated that these additives are good surfactants and low temperature improvers for gas oil.

Synergistic effect between surfactants and polyacrylates-maleicanhydride copolymers to improve the flow properties of waxy crude oil

ABSTRACT Four copolymers were prepared by copolymerization of octadecyl acrylate with maleic anhydride abbreviated as [ODM], the resulted copolymer was reacted with octadecylalcohol [ODMSA], hexadecylamine [ODMCA], benzyl alcohol [ODMBA] and aniline [ODMAn]. Three oil-soluble surfactants were also prepared by esterification of mono, di and tri ethanolamine with oleic acid, abbreviated as [MEAO, DEAO and TEAO]. These compounds were purified and characterized by FTIR, 1H-NMR and GPC. The prepared copolymers were evaluated individually and mixed with the oil-soluble surfactants and evaluated as flow improvers and pour point depressants for waxy crude oil. It was found that, the polymer with aromatic side chain [ODMBA] exhibited the maximum pour point depression ΔPP = 24°C at concentration 1000 ppm, while the minimum pour point depression was obtained by [ODMCA] which pronounced ΔPP = 15°C at 1000 ppm. Furthermore, the blend [B4] between [ODMBA] and oil-soluble surfactant [TEAO] achieved extra depression of pour point (ΔPP = 30°C). The rheological properties of the treated and untreated crude oil with the polymeric additives were also investigated and it was found that Bingham yield value (τB) was decreased from 1.63 Pa at 32°C to 0.3 Pa at the same temperature and 500 ppm concentration of [ODMBA]. GRAPHICAL ABSTRACT

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

ABSTRACT 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 (Γmax), and the minimum surface area (Amin). 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.