Experimental investigation and modelling of wax deposition inhibition in pipeline transportation of crude oil

Wax deposition causes serious problems in crude oil flow assurance due to the long chain n-paraffin. The application of wax inhibitors is an effective method to prevent wax formation and deposition. In this thesis, seven commercial groups of wax inhibitors were introduced and their performances were...

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Main Author:	Norida, Ridzuan
Format:	Thesis
Language:	English
Published:	2016
Subjects:	QD Chemistry TP Chemical technology
Online Access:	http://umpir.ump.edu.my/id/eprint/15834/13/Experimental%20investigation%20and%20modelling%20of%20wax%20deposition%20inhibition%20in%20pipeline%20transportation%20of%20crude%20oil.pdf
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spelling	my-ump-ir.158342021-11-23T06:29:51Z Experimental investigation and modelling of wax deposition inhibition in pipeline transportation of crude oil 2016-09 Norida, Ridzuan QD Chemistry TP Chemical technology Wax deposition causes serious problems in crude oil flow assurance due to the long chain n-paraffin. The application of wax inhibitors is an effective method to prevent wax formation and deposition. In this thesis, seven commercial groups of wax inhibitors were introduced and their performances were evaluated through cold finger and rheological methods. From both methods, poly(ethylene-co-vinyl acetate) (EVA) showed the highest inhibition performance based on the reduction of the wax deposit amount and the decrement of the crude oil viscosity value. To substantiate even further in the wax inhibitor selected, molecular dynamics (MD) simulation was introduced to understand the interaction between wax crystals and wax inhibitor at the molecular level. The interaction of wax crystals with inhibitors were analysed through radial distribution function (rdf) value which described the structure of inhibitor in wax crystals. MD simulations confirmed the increased percentage of inhibition efficiency (PIE) of the experimental study using EVA. Thus, EVA had inhibited the formation of n-octacosane wax solid of crude oil better than poly(maleic anhydride-alt-1-octadecene) (MA). N-octacosane wax crystal is a long chain molecule of crude oil and it has a strong van der Waals (vdW) interaction between the carbonyl group in EVA and hydrogen atoms in the n-octacosane. This increases its solubility. In addition, EVA has strong vdW interaction via the oxygen atom in the vinyl acetate functional group with the hydrogen atom in n-octacosane, resulting in a higher probability value of inhibition (gxy(r)). Design of experiment (DOE) was used to screen four possible factors that contribute to the n-paraffin wax formation. The factor of cold finger temperature (B) was identified as the most significant factor of wax problem, followed by experimental duration (C), rotational speed (A) and inhibitor concentration (D). The combination effect between factors B and C showed the highest percentage of contribution of wax deposit formation. The optimisation of wax deposit formation was achieved using response surface methodology (RSM). The optimised conditions were obtained at 1.5 h and 25°C. The minimum value of wax crystal formation achieved after the optimisation and transformation was 0.0042 g. This value shows over 150-fold decrement of wax formation expression compared to prior the optimisation process. Therefore, the model obtained from RSM is useful to provide an insight for engineers or researchers to estimate wax formation at other conditions. 2016-09 Thesis http://umpir.ump.edu.my/id/eprint/15834/ http://umpir.ump.edu.my/id/eprint/15834/13/Experimental%20investigation%20and%20modelling%20of%20wax%20deposition%20inhibition%20in%20pipeline%20transportation%20of%20crude%20oil.pdf pdf en public phd doctoral Universiti Malaysia Pahang Faculty of Chemical & Natural Resources Engineering
institution	Universiti Malaysia Pahang Al-Sultan Abdullah
collection	UMPSA Institutional Repository
language	English
topic	QD Chemistry TP Chemical technology
spellingShingle	QD Chemistry TP Chemical technology Norida, Ridzuan Experimental investigation and modelling of wax deposition inhibition in pipeline transportation of crude oil
description	Wax deposition causes serious problems in crude oil flow assurance due to the long chain n-paraffin. The application of wax inhibitors is an effective method to prevent wax formation and deposition. In this thesis, seven commercial groups of wax inhibitors were introduced and their performances were evaluated through cold finger and rheological methods. From both methods, poly(ethylene-co-vinyl acetate) (EVA) showed the highest inhibition performance based on the reduction of the wax deposit amount and the decrement of the crude oil viscosity value. To substantiate even further in the wax inhibitor selected, molecular dynamics (MD) simulation was introduced to understand the interaction between wax crystals and wax inhibitor at the molecular level. The interaction of wax crystals with inhibitors were analysed through radial distribution function (rdf) value which described the structure of inhibitor in wax crystals. MD simulations confirmed the increased percentage of inhibition efficiency (PIE) of the experimental study using EVA. Thus, EVA had inhibited the formation of n-octacosane wax solid of crude oil better than poly(maleic anhydride-alt-1-octadecene) (MA). N-octacosane wax crystal is a long chain molecule of crude oil and it has a strong van der Waals (vdW) interaction between the carbonyl group in EVA and hydrogen atoms in the n-octacosane. This increases its solubility. In addition, EVA has strong vdW interaction via the oxygen atom in the vinyl acetate functional group with the hydrogen atom in n-octacosane, resulting in a higher probability value of inhibition (gxy(r)). Design of experiment (DOE) was used to screen four possible factors that contribute to the n-paraffin wax formation. The factor of cold finger temperature (B) was identified as the most significant factor of wax problem, followed by experimental duration (C), rotational speed (A) and inhibitor concentration (D). The combination effect between factors B and C showed the highest percentage of contribution of wax deposit formation. The optimisation of wax deposit formation was achieved using response surface methodology (RSM). The optimised conditions were obtained at 1.5 h and 25°C. The minimum value of wax crystal formation achieved after the optimisation and transformation was 0.0042 g. This value shows over 150-fold decrement of wax formation expression compared to prior the optimisation process. Therefore, the model obtained from RSM is useful to provide an insight for engineers or researchers to estimate wax formation at other conditions.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Norida, Ridzuan
author_facet	Norida, Ridzuan
author_sort	Norida, Ridzuan
title	Experimental investigation and modelling of wax deposition inhibition in pipeline transportation of crude oil
title_short	Experimental investigation and modelling of wax deposition inhibition in pipeline transportation of crude oil
title_full	Experimental investigation and modelling of wax deposition inhibition in pipeline transportation of crude oil
title_fullStr	Experimental investigation and modelling of wax deposition inhibition in pipeline transportation of crude oil
title_full_unstemmed	Experimental investigation and modelling of wax deposition inhibition in pipeline transportation of crude oil
title_sort	experimental investigation and modelling of wax deposition inhibition in pipeline transportation of crude oil
granting_institution	Universiti Malaysia Pahang
granting_department	Faculty of Chemical & Natural Resources Engineering
publishDate	2016
url	http://umpir.ump.edu.my/id/eprint/15834/13/Experimental%20investigation%20and%20modelling%20of%20wax%20deposition%20inhibition%20in%20pipeline%20transportation%20of%20crude%20oil.pdf
_version_	1783732003100688384

Experimental investigation and modelling of wax deposition inhibition in pipeline transportation of crude oil

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