Prediction of Wax Precipitation Temperature in Petroleum Fluids

Onyejekwe Ifeanyichukwu Michael,Uwaezuoke Nnaemeka,Obibuike Ubanozie Julian,Duru Ugochukwu Ilozuruike

doi:10.11648/j.ogce.20210901.12

Onyejekwe Ifeanyichukwu Michael, Uwaezuoke Nnaemeka + Show 2 more

Open Access

https://doi.org/10.11648/j.ogce.20210901.12

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Abstract

The precipitation and deposition of wax has remained a major challenge that the oil industries is faced with during the production of waxy crude. This problem is simply an issue from the wellbore to the surface facilities. As a result of this, millions of dollars has been invested in remedial operations. In this research, a predictive model that uses thermodynamic relationship in predicting precipitation of wax has been developed. K-values for the solid-liquid equilibrium is described using solubility parameter, melting point temperature, enthalpy of fusion, and the molar volume for the components. The weight fraction was used to describe the wax mixture. Experimental data from three oil mixtures were used in comparing the model predicted wax appearance temperature (WAT). For oil mixA, the experimental value is 294.15K; Pauly et al predicted 302.15K while this work predicted 301.21K. For oil mixB, the experimental value is 300.15K; Pauly et al predicted 310.15K while this work predicted 308.91K. For oil mixC, the experimental value is 298.15K; Pauly et al predicted 302.15K while this work predicted 300.38K. The obtained results from this research confirmed the capability of the model in predicting Wax Appearance Temperature. A more conservative value for the WAT was predicted which is an improvement.

Highlights

The evaporation of volatile light end or drop in the system temperature is key to the precipitation of paraffin deposits in crude oils
As a result of changes in temperature, pressure and composition we have the formation of vapour, liquid and solid phases due to the wide volatility and melting point range of hydrocarbon component found in petroleum
The model predicted result was compared with experimental wax appearance temperature (WAT) data

Summary

Introduction

The evaporation of volatile light end or drop in the system temperature is key to the precipitation of paraffin deposits in crude oils. In order to address the safety, operational, and design of wax remediation systems, a fundamental understanding of the deposition behaviour of waxy crude is required. The groundbreaking research into the phenomenon of wax deposition is the application of fundamental science to model waxy-oil fluid systems, elucidating the controlling physical mechanisms of wax deposition and gel behaviour [1]. As a result of changes in temperature, pressure and composition we have the formation of vapour, liquid and solid phases due to the wide volatility and melting point range of hydrocarbon component found in petroleum. The precipitation of the heavy hydrocarbon components as wax crystals in the liquid and vapour phases is attributed to a drop in temperature. The development of thermodynamic model in describing wax precipitation and deposition is the recent attempts in solving the old problem of wax precipitation

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