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.

The Chemical Performance Evaluation for Pour Point Depressant (PPD) Testing, X Oil Field, Vietnam

Pour Point Depressant (PPD) Testing are used extensively to modify the crystallinity of hard waxes and to reduce the natural pour point of crude. The best PPD chemical and best dosage for crude oil treatment will be chosen based on the laboratory test results to: Reduce pour point of crude oil; Reduce viscosity of crude oil; Improve rheological properties of crude oil; Reduce wax deposition rate and pipeline restart pressure. The chemical performance evaluation for PPD, proposed to use at X Oil Field has been conducted in Crude oil and Petroleum products Lab. The following properties have been determined in laboratory for blank sample (which is a mixture of H1, H4 and H5 crude oil samples with ratio of 2.1:1.4:1.0) and sample treated by PPD (rundown crude oil sample): Pour Point (for blank sample and treated sample); Wax Appearance Temperature (WAT) and Wax Disappearance Temperature (WDT) (for blank sample); Dynamic Viscosity (for blank and treated samples); Yield Stress by Rheometer (for blank and treated samples) for 100 mins, 1000 mins and 02 days shut-in times; Wax Deposition Rate by Cold Finger for blank and treated samples; Restart Pressure by Restart Loop (for blank and treated samples) for 100 mins, 1000 mins and 02 days shut-in times.

Application of Synthesized Novel Biodegradable Pour-Point Depressant from Natural Source on Flow Assurance of Indian Waxy Crude Oil and Comparative Studies with Commercial Pour-Point Depressant

Summary Pour-point depressants (PPDs) were synthesized from natural sources and used in waxy crude oil transportation to reduce the pour point and improve flow. A biodegradable PPD (BPPD) was synthesized and tested to mitigate crude oil flow assurance problems in the present work. The transesterification process was used to synthesize coconut oil ethyl ester (COEE, termed as BPPD). Fourier transform electron spectroscopy (FTIR), proton nuclear magnetic resonance (H-NMR), and microscopic analysis were performed for better understanding of mechanisms for both BPPD and a commercially available PPD named PPD-A. The pour point of crude oil was reduced by 12 and 9°C after the addition of 800 ppm BPPD and PPD-A, respectively. The microscopic analysis confirms that the crystals of wax converted to very fine and dispersed particles during mixing of additives, which in turn increase flowability. BPPD performs better to reduce interfacial tension than PPD-A. The maximum reduction of 19% in interfacial tension was observed after the addition of 800 ppm BPPD. BPPD alters the wettability of the pipeline surface from intermediate wet to water-wet within 60 seconds, which results in reduced slip velocity and consequently lessens the deposition of wax. As a result, crude oils will not stick to the wall of the pipe surface and will experience less resistance to flow through pipelines. FTIR analysis indicated that long-chain alkane and aromatic groups are responsible for a higher pour point, and their concentration level was reduced after the addition of BPPD. The viscosity of crude oil was reduced by almost 94% after the addition of 800 ppm BPPD with crude oil, which in turn minimizes pumping costs for crude oil. As a result, the total project cost was reduced substantially. Biodegradability tests confirm that the BPPD is biodegradable and nontoxic. Due to its biodegradability and nontoxic nature, BPPD has a promising capacity to be used in the petroleum industry for easier pipeline transportation of waxy crude.

Comparison of pour point depressant (PPD) ethylene-vinyl acetate (EVA) and nano-montmorillonite

One of the problems with oil production is stuck of oil transportation flow in the pipeline caused by wax deposits. The high wax content in crude oil causes the oil viscosity value to increase so that crude oil has High Pour Point Oil (HPPO) properties. In this research, using crude oil sample with initial pour point of 31oC and viscosity of 556 cP. This samples are classified as heavy oil. Therefore, this sample is suitable for use as an experiment in this research. There are several methods to deal with HPPO. One chemical method used to overcome this problem is adding Pour Point Depressant (PPD) to crude oil. This PPD functions to decrease pour point value by binding wax crystals in crude oil. In this study, two types of PPD were compared, Ethylene-Vinyl Acetate (EVA) and Nano-Montmorillonite (Nano-MMT). Both can reduce the pour point value on crude oil, but PPD EVA shows a more excellent reduction than nano-MMT. The results show that EVA is better at binding crystals than nano-MMT. After the injection of 400 ppm EVA, the pour point value of crude oil could be decreased up to 24oC, and the viscosity also decreased by 185 cP.

Evaluation of Cashew Nut Shell Liquid Borate Ester as Pour Point Depressant for Flow Assurance of Waxy Crude Oil

The development of chemical solutions to wax problems by modifying renewable natural products is an innovative response to the need for cheaper, eco-friendly pour point depressants for waxy crude oil flow improvement. Natural cashew-nut shell liquid (CNSL) was extracted from shells of Anacardium occidentale and derivatized into the borate ester. Pour point of oil doped with 500ppm CNSL borate ester was reduced by -24oC. The effect of borate ester addition on wax morphology was studied by cross-polarized microscopy. Analysis of micrographs using ImageJ software showed a decrease in Feret diameter, aspect ratio, and boundary fractal dimension of wax crystals in doped oil and increased crystal circularity and solidity, indicating the evolution of smaller, rounder, regular structures with smoother, even surfaces. At 10oC, oil shear stress and dynamic viscosity were reduced by 27.6% and 24.6%, respectively. Pour point depressant and flow improvement effects of additive were related to changes in crystal morphology.