Pour point depression and flow improvement of waxy crude oil using polyethylene glycol esters of cashew nut shell liquid

Abstract

Wax 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.

Evaluation of modified cashew nutshell liquid as natural surfactants for chemical flooding in sandstone oil reservoirs

“…In the oil and gas industry, cashew nutshell liquid and its derivatives have been found to be good corrosion inhibitors and flow improvers for waxy and heavy crude oil [7,12,31]. Polyethylene glycol and diethanolamine esters of natural cashew nutshell liquid as well as formaldehyde-novolac resins of distilled cashew nutshell liquid were effective as crude oil wax dispersants/inhibitors and pour point depressants [8,9,17,18] reported the extensive use of cardanol and cardol and their derivatives as additives for the production of surfactants, resins, and polymers. However, no study has reported the application of CNSL derivatives in chemical EOR processes.…”

Non‐catalytic esterification of palm fatty acid distillate with 2‐ethyl hexanol for high purity production of biolubricant ester

“…The addition of chemical additives (pour point depressants) or combining with other fluids having lower pour points can lessen the PP of the ester 60 . A study indicated that PP depressant reduces the PP of crude oil by 12 °C 61 . Meanwhile, chemical modifications could further reduce PP, such as epoxidation of fatty acid before esterification or epoxidation of the ester 13,49 …”

“…60 A study indicated that PP depressant reduces the PP of crude oil by 12 °C. 61 Meanwhile, chemical modifications could further reduce PP, such as epoxidation of fatty acid before esterification or epoxidation of the ester. 13,49 Viscosity is a measurement of the internal friction of a moving fluid.…”

Modification of discarded polypropylene mask and its utilization as crude oil flow improver

“…The microscopic morphological analysis of wax crystals in the saturated hydrocarbons of the crude oil before and after the addition of MPP2 was carried out using a polarized light microscope. 37 As depicted in Figure 7(a), it can be observed that prior to the addition of MPP2, the wax crystals exhibited flocculent morphology and were densely packed. Figure 7(b) shows a significant reduction in the amount of wax crystals and their dispersion after the addition of MPP2, indicating a clear reduction in wax crystal agglomeration.…”