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

2021 ◽  
Vol 11 (3) ◽  
pp. 3611-3625

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.

Author(s):  
William Iheanyi Eke ◽  
Sampson Kofi Kyei ◽  
Ozioma Achugasim ◽  
Joseph Atubokiki Ajienka ◽  
Onyewuchi Akaranta

AbstractWax crystallization and deposition is a major flow assurance problem in production and transportation of waxy crude oil. Conventional flow improvers are mainly high molecular weight synthetic polymers, many of which are eco-toxic. Bio-based flow improvers derived from natural products are promising as inexpensive, eco-friendly alternatives to existing products. In this study, natural cashew nut shell liquid (CNSL) extracted from waste shells of Anacardium occidentale was esterified with polyethylene glycol (PEG). CNSL derivative reduced the pour point of waxy crude oil by 12 °C at 1000 ppm. The effects of CNSL derivatives on wax crystal morphology and micro-structure were studied by cross-polarized microscopy. Micrographs were processed and analyzed with ImageJ software. Addition of CNSL derivatives to oil resulted in changes in wax crystal morphology and micro-structure evidenced by a reduction in average crystal Feret diameter and aspect ratio and increase in boundary fractal dimension, indicative of formation of increasing number of smaller, rounder crystals. Effect of the additives on flow properties of the waxy oil was determined using a co-axial cylinder rotational viscometer. Dynamic viscosity of oil at shear rate of 17 s−1 was reduced by 79.7–90.5%. CNSL-PEG esters show good prospects as low-cost additives for production, storage and pipeline transportation of waxy crude oil.


SPE Journal ◽  
2021 ◽  
pp. 1-13
Author(s):  
Biswadeep Pal ◽  
Tarun Kumar Naiya

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.


2018 ◽  
Vol 57 (25) ◽  
pp. 8612-8619 ◽  
Author(s):  
Yongwen Ren ◽  
Long Fang ◽  
Zhaojun Chen ◽  
Hui Du ◽  
Xiaodong Zhang

2017 ◽  
Vol 39 (8) ◽  
pp. 1165-1171 ◽  
Author(s):  
Na Li ◽  
GuoLiang Mao ◽  
XianZhi Shi ◽  
ShiWei Tian ◽  
Yang Liu

2021 ◽  
Vol 11 (5) ◽  
pp. 2287-2297
Author(s):  
Sivakumar Pandian ◽  
Patel Chintan Dahyalal ◽  
Shanker Krishna ◽  
S. Hari ◽  
Deepalakshmi Subramanian

AbstractTransportation of heavy crude oil through pipelines poses a great challenge in oil and gas industry. Crude oil chokes the pipelines when the temperature drops below the pour-point temperature. In the present study, a bio-based additive, i.e., Cashew Nut Shell Liquid (CNSL) has been tested as a flow improver for heavy crude. CNSL was obtained from waste cashew nut shell by means of mechanical extraction, and it was completely characterized. Similarly, the crude oil used in the study was characterized for its physio-chemical properties. Also, the crude oil was subjected to Saturates, Aromatics, Resins and Asphaltene analysis and Fourier Transform Infra-Red analysis. The raw and additive-treated crude oil with different CNSL dosages were subjected to pour-point and rheology measurements and optical micro-imaging analysis which indicated a remarkable improvement in flow whereby an optimum dose of 2000 ppm was observed. Furthermore, the effects of different parameters like shear rate, concentration of the flow improver and the effect of temperature on the crude oil flowability were studied. The process variables were optimized by means of Taguchi method, and the percentage contribution of each parameter was identified with the help of ANOVA table. The results indicate that a remarkable improvement in flow was observed at an optimum dose of 2000 ppm. The contribution of the concentration was found to be around 53%, whereas the contributions of the shear rate and the temperature were only 18.08 and 28.91%, respectively. Therefore, it has been observed that CNSL flow improvers extracted from cheap reasonable resources are more effective as they are cost-effective and eco-friendly when compared to conventional additives.


Author(s):  
Rituraj Singh ◽  
Prasenjit Talukdar

In the aura of this research we developed the grafted nanocomposite pour point depressant by culmination of a set of monomers namely acrylamide, maleic anhydride, styrene, and octadecyl methacrylate and further grafted to nano silica for improving the flow properties and thereby decrease the temperature of pour point value of the NorthEast Indian waxy based crude oil. Moreover, to emphasize and understand the central effects of different concentrations of synthesized nanocomposite pour point depressants on the pour point of waxy crude oil, several important experiments were undergone and later its results were compared with the commercial pour point depressant. In addition, the rheological props of the sample crude were also analyzed with and without additives. The results shows that the synthesized nanocomposite has more effectively reduced the viscosity as well as pour point of the sample to desired value when compared to that of the commercially used pour point depressant.


2012 ◽  
Vol 524-527 ◽  
pp. 1844-1847 ◽  
Author(s):  
Hong Zhang ◽  
Wen Fa Xiao

The situation of low temperature crude oil pipeline carrying is universal. The rapid developing of pipe line supposes higher asking on new carrying technology. The problem of long distance carrying at normal temperature of high waxy crude oil is impel to resolve and its potential social economic profit is obvious. As the pipeline is designed at high production period of field so there must have low carrying situation at beginning and ending time. At the situation the high waxy crude oil and high pour point crude oil will face on great resistance and blockage problem. Further more the pipeline has to make great energy expense on high temperature carrying. So take new carrying technology to realize atmosphere temperature carrying is crucial of resolving low temperature carrying. The method of adding chemical pour point depressant(PPD)/flow improver additives (FIA) into crude oil directly was widely used at present. The progress of the additives and its study methods was summarized in the paper and supply some reference for the technology of PPD/FIA.


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