Investigation of Heavy Organics Precipitation from Nigerian Crude Oil Residue Using Binary Mixture of n-Alkane Solvents

So Anuchi,Uj Chukwu,Se Ofodile

doi:10.4314/jasem.v21i6.26

Abstract

The effects of mixing two n-alkane solvents on the precipitation of heavy organics in crude oil were carried out. The crude oil sample sourced from a major operative in Nigeria was distilled at 240 o C and used for the precipitation experiment. The binary mixture of n-alkane solvents (C 6 : C 10 , C 6 : C 16 , C 10 : C 14 , C 10 : C 16 , C 14 : C 16 ) was carried out in the solvent ratio of 0:1, 1:2, 1:1, 2:1, and 1:0 respectively. From the results, C6: C10 mixture shows an abrupt decrease in heavy organics precipitated from 1:0 volume ratio of C 6 : C 10 to 2:1 volume ratio of C 6 : C 10 and a further steady decrease were observed. The percentage volume increment of C6 in the mixture of C 6 : C 16 , also shows steady and an abrupt decrease in heavy organics precipitated, which indicates phase transitions occurring at 1:1 and 2:1 volume ratio points. The additions of C 10 to C 14 and C 10 to C 16 results to decrease in the weight percentage of heavy organics precipitated. While a slight decrease in weight percentage of heavy organics occurs during the addition of C 14 to C 16 . Precipitation experiment carried out using binary mixture shows a three-stage phase transition: solid-liquid, liquid-solid and solid-liquid in C 6 : C 16 at different volume ratios of the mixtures. Keywords : Binary mixture, heavy organics, crude oil residue, n-alkane solvents, precipitates

Highlights

The formation of heavy organics deposits during petroleum production can cause several technical issues including partial or total blockage of wellbores, pipelines, and damage to equipment (Salami et al 2016)
The aim of this work is to investigate the effects of mixing two n-alkane solvents (n-hexane (C6), ndecane (C10), n-tetradecane (C14), and n-hexadecane (C16)) on the quantity of heavy organics (HOs) precipitated from a Nigerian crude oil
Some of the HOs are soluble in the n-alkane diluted oil; using the single solvent of C6 n-alkane they appear in the liquid phase

Summary

Introduction

The formation of heavy organics deposits during petroleum production can cause several technical issues including partial or total blockage of wellbores, pipelines, and damage to equipment (Salami et al 2016). Heavy organics (HOs) are heavy components of crude oil, which fractions include saturates, aromatics, resins, and asphaltenes with vary polarity and solubility (Mansoori et al 2007). The mechanism of deposition of heavy organics from crude oil in the oilfield can be better understood by precipitation of HOs from oil in the laboratory using binary mixtures n-alkane than only the individual solvents. This is because the binary precipitation experiment gives a closer insight into understanding the susceptibility of petroleum to HOs precipitation in the oilfield (Achugasim; Ekpo 2015). The aim of this work is to investigate the effects of mixing two n-alkane solvents (n-hexane (C6), ndecane (C10), n-tetradecane (C14), and n-hexadecane (C16)) on the quantity of HOs precipitated from a Nigerian crude oil

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Conclusion