The Effect of Compositional Changes of Binary Mixtures of n-alkane solvents on the Precipitation of Heavy Organics from a Solution of Crude Oil Residue

Ga Udourioh,Mu Ibezim-Ezeani,Se Ofodile

doi:10.4314/jasem.v19i3.26

Ga Udourioh, Mu Ibezim-Ezeani + Show 1 more

Open Access

https://doi.org/10.4314/jasem.v19i3.26

Copy DOI

Abstract

The effect of precipitant compositional changes on the precipitation of heavy organics (HO) from a solution of crude oil residue using binary mixtures of n-alkane solvents was studied. Heavy organic precipitates were generated using different ratios of C5:C6, C6:C7 and C5:C7 n-alkane solvents. The result obtained showed that for binary mixtures at 1:0, 3:1, 2:1, 1:1, 1:2, 1:3 and 0:1 ratios, the weight percentage precipitates of C5:C6 were 11.19±0.45, 8.56±0.80, 5.62±0.58, 8.53±0.80, 5.83±1.29, 5.45±0.57 and 5.24±0.32; C5:C7 were 11.19±0.90, 5.63±0.52, 2.12±0.25, 4.51±0.65, 2.11±0.37, 1.67±0.40 and 0.97±0.05; and C6:C7 were 5.24±0.32, 3.37±0.08, 1.94±0.03, 3.39±0.60, 1.48±0.03, 1.43±0.03 and 0.97±0.05 respectively. The results have shown that the quantity of HO precipitate decreases with increasing quantity of higher carbon number of n-alkane solvent to a minimum value at 2:1 ratio. From the minimum value, it rises to a maximum at 1:1 ratio as the proportion of Cn+x to Cn (where C is carbon atom, n and x represent the number of carbon atom) increases. The quantity of HO precipitate decreases again to a minimum at 1:2 ratio as the proportion of Cn+x increases further, and finally to the lowest value at pure Cn+x. The conclusion is that the components of the crude oil residue undergo a three-stage phase transition as the volume ratios of the n-alkane solvents vary. This study can lead to a better understanding of the phase behavior of heavy organics under compositional changes and hence the prediction of heavy organic precipitation.Keywords: Heavy Organics, Precipitates, crude oil, binary mixtures, n-alkane.

Highlights

Deposition, flocculation and plugging of heavy organics on petroleum pipelines, tubular, pumps and other equipment during production and transportation of petroleum fluids is a major problem in the oil industry
Efforts have been directed towards precipitation of heavy organics in crude oil in the laboratory using single n-alkanes with the belief that results obtained would give a better understanding of the deposition phenomena, predict correctly the onset of organic deposition region and help to avoid getting to the region (Eduardo et al 2004; Chapman et al 2007; Saraji et al 2013)
The results of the experiments for the different ratios of C6:C7, C5:C7 and C5:C6 binary mixtures precipitated with approximately 1g of crude oil residue at room temperature and atmospheric equivalent pressure are given in Tables 1 to 3

Summary

Introduction

Deposition, flocculation and plugging of heavy organics on petroleum pipelines, tubular, pumps and other equipment during production and transportation of petroleum fluids is a major problem in the oil industry. In most cases it has caused blockage in the oil reservoirs, pipelines and other tubular production and processing facilities leading to reservoir damage and reduction of well productivity. Arterial blockage in the petroleum industry is mostly due to the deposition of heavy organics from petroleum fluids (Pacheco-Sanchez and Mansoori, 1997). According to Escobedo and Mansoori (1992), heavy organic deposition problem is one of the major factors that increases the production cost of petroleum products. Efforts have been directed towards precipitation of heavy organics in crude oil in the laboratory using single n-alkanes with the belief that results obtained would give a better understanding of the deposition phenomena, predict correctly the onset of organic deposition region and help to avoid getting to the region (Eduardo et al 2004; Chapman et al 2007; Saraji et al 2013)

Methods

Results

Conclusion