An Evaluation of Solubility of Wax and Asphaltene in Crude Oil for Improved Flow Properties Using a Copolymer Solubilized in Organic Solvent with an Aromatic Hydrocarbon
Wax and asphaltene are high molecular weighted compounds that contribute to the stability of crude oil at a dispersed state. Transportation of crude oil along pipelines from the oil rig to the refineries causes fluctuation of temperature which will lead to the coagulation of wax and flocculation of asphaltenes. This paper focuses on the prevention of wax and asphaltene precipitate deposition on the inner surface of the pipelines by using a wax inhibitor and an asphaltene dispersant. The novelty of this prevention method is the combination of three substances; a wax inhibitor dissolved in a wax inhibitor solvent and an asphaltene solvent, namely, ethylene-vinyl acetate (EVA) copolymer dissolved in methylcyclohexane (MCH) and toluene (TOL) to inhibit the precipitation and deposition of wax and asphaltene. The objective of this paper was to optimize the percentage composition of each component in this inhibitor which can maximize the viscosity reduction of crude oil. The optimization was divided into two stages which are the laboratory experimental stage in which the viscosity of crude oil samples containing inhibitor of different component compositions is tested at decreasing temperatures and the data optimization stage using response surface methodology (RSM) to design an optimizing model. The results of experiment proved that the combination of 50% EVA + 25% MCH + 25% TOL gave a maximum viscosity reduction of 67% while the RSM model proved that the combination of 57% EVA + 20.5% MCH + 22.5% TOL gave a maximum viscosity reduction of up to 61%.
[1] B. Wei, “Recent advances on mitigating wax problem using polymeric wax crystal modifier,” J. Pet. Explor. Prod. Technol., vol. 5, no. 4, pp. 391–401, 2015.
[2] A. K. Norland, “Organic flow assurance, pour point depressant development through experimental design,” University of Stavanger, Norway, 2012.
[3] A. J. Hennessy, A. Neville, K. J. Roberts, “An examination of additive-mediated wax nucleation in oil pipeline environments,” J. Cryst. Growth, vol. 198–199, no. 1, pp. 830-837, 1999.
[4] K. S. Pedersen, H. P. Ronningsen, “Influence of wax inhibitors on wax appearance temperature, pour point, and viscosity of waxy crude oils,” Energ. Fuel, vol. 17, no. 2, pp. 321–328, 2003.
[5] R. Hoffmann, L. Amundsen, “Influence of wax inhibitor on fluid and deposit properties,” J. Petrol. Sci. Eng., vol.107, pp. 12–17, 2013.
[6] A. M. Al-Sabagh, M. R. Noor El-Din, R. E. Morsi, M. Z. Elsabee, “Styrene-maleic anhydride copolymer esters as flow improvers of waxy crude oil,” J. Disper. Sci. Technol., vol. 30, no. 3, pp. 420–426, 2009.
[7] H. P. Soni, Kiranbala, D. P. Bharambe, “Performance-based designing of wax crystal growth inhibitors. Energ. Fuels, vol. 22, pp. 3930–3938. 2008.
[8] A. Borthakur, D. Chanda, S. R. Dutta Choudhury, K. V. Rao, B. Subrahmanyam, “Alkyl fumarate vinyl acetate copolymer as flow improver for high waxy Indian crude oils,” Energ. Fuels, vol. 10 no. 3, pp. 844–848. 1996.
[9] W. Leube, M. Monkenbusch, D. Schneiders, D. Richter, D. Adamson, L. Fetters, “Wax crystal modification for fuel oil by self-aggregating partially crystallizable hydrocarbon block copolymers,” Energ. Fuels, vol. 14, no. 2, pp. 419–430. (2000).
[10] M. Monkenbusch, D. Schneiders, D. Richter, L. Willner, W. Leube, L, Fetters, “Aggregation behaviour of PE-PEP copolymers and the winterization of diesel fuel,” Physica B Condens Matter., vol. 276-278, pp. 941–943, 2000
[11] H. S. Ashbaugh, L. J. Fetters, D. H. Adamson, R. K. Prud'homme, “Flow improvement of waxy crude oil mediated by self-aggregating partially crystallizable diblock copolymers,” J. Rheol., vol. 46, pp. 763–776, 2002.
[12] D. Schwahn, D. Richter, P. J. Wright, C. Symon, L. J. Fetters, M. Lin, “Self-assembling behaviour in decane solution of potential wax crystal nucleators based on poly(co-olefins),” Macromolecules, vol. 35, no. 3, pp. 861–870. 2002.
[13] M. D. C. Garcia, “Cryde oil wax crystallization. The effect of heavy n-paraffins and flocculated asphaltenes,” Energ. Fuels, vol. 14, no. 5, pp. 1043–1048. 2000.
[14] J. Tinsley, R. Prud'homme, X. Guo, D. Adamson, S. Susan, D. Amin, ”Effects of polymers on the structure and deposition behaviour of waxy oils,” Int. Symp. Oilfield Chem. Houston, Texas: Society of Petroleum Engineers, 2007.
[15] R. A. El-Ghazawy, R. K. Farag, “Synthesis and characterization of novel pour point depressants based on maleic anhydride-alkyl acrylates terpolymers,” J. Appl. Polym. Sci., vol. 115, pp. 72–78, 2010
[16] N. Halim, S. Ali, M. Nadeem, P. A. Hamid, I. M. Tan, “Synthesis of wax inhibitor and assessment of squeeze technique application for Malaysian waxy crude,” SPE Asia Pacific Oil and Gas Conf. Exhib, Jakarta, Indonesia: Society of Petroleum Engineers, 2011.
[17] K. S. Wang, C. H. Wu, J. L. Creek, P. J. Shuler, Y. Tang, “Evaluation of effects of selected wax inhibitors on paraffin deposition,” J. Petrol. Sci. Technol., vol. 21, no. 3-4, pp. 369–379, 2003.
[18] D. Gentili, C. Khalil, N. Rocha, E. Lucas, Evaluation of polymeric phospheric ester-based additives as inhibitors of paraffin depositions. SPE Latin American and Caribbean Petrol. Eng. Conf. Rio de Janeiro: Society of Petroleum Engineers, 2005.
[19] S. E. Kudaibergenov, A. G. Didukh, Z. E. Ibraeva, L. A. Bimendina, F. Rullens, M. Devillers, A regular, hydrophobically modified polyampholyte as novel pour point depressant. J. Appl. Polym. Sci., vol. 98, no. 5, pp. 2101–2108. 2005.
[20] A. L. C. Machado, E. F. Lucas, The influence of vinyl acetate content of the poly(ethylene-co-vinyl acetate) (EVA) additive on the viscosity and the pour point of a Brazilian crude oil. J. Petrol. Sci. Technol., vol. 19, no. 1-2, pp. 197–204, 2001.
[21] H. S. Ashbaugh, X. Guo, D. Schwahn, R. Prud'homme, D. Richter, L. J. Fetters, "Interaction of paraffin wax gels with ethylene/vinyl acetate co-polymers," Energ. Fuels, vol. 19, no. 1, pp. 138–144, 2005.
[22] J. B. Taraneh, G. Rahmatollah, A. Hassan, D. Alireza, “Effect of wax inhibitors on pur point and rheological properties of Iranian wax crude oil,” Fuel Process. Technol., vol. 89, no. 10, pp. 973–977, 2008.
[23] J. W. Qian, G. R. Qi, D. L. Han, S. L. Yang, Influence of incipient chain dimension of EVA flow improver on the rheological behaviour of crude oil. Fuel, vol. 75, no. 2, pp. 161–163, 1996.
[24] J. W. Qian, G. H. Zhou, W. Y. Yang, Y. L. Xu, Studies on pour point depression of EVA polymers in solvent mixtures containing wax. J. Appl. Polym. Sci., vol. 83, no. 4, pp. 815–821. 2002.
[25] M. Lashkarbolooki, F. Esmaeilzadeh, D. Mowla, “Mitigation of wax deposition by wax-crystal modifier for Kermanshah crude oil,” J. Disper. Sci. Technol., vol. 32, no. 7, pp. 975–985, 2011.
[26] M. N. Bouts, R. J. Wiersma, H. M. Muijs, A. J. Samuel, “An evaluation of new asphaltene inhibitors; laboratory study and field testing,” J. Petrol. Technol., vol. 47, no. 9, 1995.
[27] M. A. Buriro, M. T. Shuker, Minimizing asphaltene precipitation in Malaysian reservoir. SPE Saudi Arabia Section Technical Symp. Exhib. Al-Khobar, Saudi Arabia: Society of Petroleum Engineers, 2013.
[28] L. C. M. Palermo, N. F. Souza Jr., H. F. Louzada, M. C. M. Bezerra, L. S. Ferreira, E. F. Lucas, “Development of multifunctional formulations for inhibition of waxes and asphaltene depositions,” Braz J. Petrol. Gas, vol. 7, no. 4, pp. 181–192, 2013.
[1] B. Wei, “Recent advances on mitigating wax problem using polymeric wax crystal modifier,” J. Pet. Explor. Prod. Technol., vol. 5, no. 4, pp. 391–401, 2015.
[2] A. K. Norland, “Organic flow assurance, pour point depressant development through experimental design,” University of Stavanger, Norway, 2012.
[3] A. J. Hennessy, A. Neville, K. J. Roberts, “An examination of additive-mediated wax nucleation in oil pipeline environments,” J. Cryst. Growth, vol. 198–199, no. 1, pp. 830-837, 1999.
[4] K. S. Pedersen, H. P. Ronningsen, “Influence of wax inhibitors on wax appearance temperature, pour point, and viscosity of waxy crude oils,” Energ. Fuel, vol. 17, no. 2, pp. 321–328, 2003.
[5] R. Hoffmann, L. Amundsen, “Influence of wax inhibitor on fluid and deposit properties,” J. Petrol. Sci. Eng., vol.107, pp. 12–17, 2013.
[6] A. M. Al-Sabagh, M. R. Noor El-Din, R. E. Morsi, M. Z. Elsabee, “Styrene-maleic anhydride copolymer esters as flow improvers of waxy crude oil,” J. Disper. Sci. Technol., vol. 30, no. 3, pp. 420–426, 2009.
[7] H. P. Soni, Kiranbala, D. P. Bharambe, “Performance-based designing of wax crystal growth inhibitors. Energ. Fuels, vol. 22, pp. 3930–3938. 2008.
[8] A. Borthakur, D. Chanda, S. R. Dutta Choudhury, K. V. Rao, B. Subrahmanyam, “Alkyl fumarate vinyl acetate copolymer as flow improver for high waxy Indian crude oils,” Energ. Fuels, vol. 10 no. 3, pp. 844–848. 1996.
[9] W. Leube, M. Monkenbusch, D. Schneiders, D. Richter, D. Adamson, L. Fetters, “Wax crystal modification for fuel oil by self-aggregating partially crystallizable hydrocarbon block copolymers,” Energ. Fuels, vol. 14, no. 2, pp. 419–430. (2000).
[10] M. Monkenbusch, D. Schneiders, D. Richter, L. Willner, W. Leube, L, Fetters, “Aggregation behaviour of PE-PEP copolymers and the winterization of diesel fuel,” Physica B Condens Matter., vol. 276-278, pp. 941–943, 2000
[11] H. S. Ashbaugh, L. J. Fetters, D. H. Adamson, R. K. Prud'homme, “Flow improvement of waxy crude oil mediated by self-aggregating partially crystallizable diblock copolymers,” J. Rheol., vol. 46, pp. 763–776, 2002.
[12] D. Schwahn, D. Richter, P. J. Wright, C. Symon, L. J. Fetters, M. Lin, “Self-assembling behaviour in decane solution of potential wax crystal nucleators based on poly(co-olefins),” Macromolecules, vol. 35, no. 3, pp. 861–870. 2002.
[13] M. D. C. Garcia, “Cryde oil wax crystallization. The effect of heavy n-paraffins and flocculated asphaltenes,” Energ. Fuels, vol. 14, no. 5, pp. 1043–1048. 2000.
[14] J. Tinsley, R. Prud'homme, X. Guo, D. Adamson, S. Susan, D. Amin, ”Effects of polymers on the structure and deposition behaviour of waxy oils,” Int. Symp. Oilfield Chem. Houston, Texas: Society of Petroleum Engineers, 2007.
[15] R. A. El-Ghazawy, R. K. Farag, “Synthesis and characterization of novel pour point depressants based on maleic anhydride-alkyl acrylates terpolymers,” J. Appl. Polym. Sci., vol. 115, pp. 72–78, 2010
[16] N. Halim, S. Ali, M. Nadeem, P. A. Hamid, I. M. Tan, “Synthesis of wax inhibitor and assessment of squeeze technique application for Malaysian waxy crude,” SPE Asia Pacific Oil and Gas Conf. Exhib, Jakarta, Indonesia: Society of Petroleum Engineers, 2011.
[17] K. S. Wang, C. H. Wu, J. L. Creek, P. J. Shuler, Y. Tang, “Evaluation of effects of selected wax inhibitors on paraffin deposition,” J. Petrol. Sci. Technol., vol. 21, no. 3-4, pp. 369–379, 2003.
[18] D. Gentili, C. Khalil, N. Rocha, E. Lucas, Evaluation of polymeric phospheric ester-based additives as inhibitors of paraffin depositions. SPE Latin American and Caribbean Petrol. Eng. Conf. Rio de Janeiro: Society of Petroleum Engineers, 2005.
[19] S. E. Kudaibergenov, A. G. Didukh, Z. E. Ibraeva, L. A. Bimendina, F. Rullens, M. Devillers, A regular, hydrophobically modified polyampholyte as novel pour point depressant. J. Appl. Polym. Sci., vol. 98, no. 5, pp. 2101–2108. 2005.
[20] A. L. C. Machado, E. F. Lucas, The influence of vinyl acetate content of the poly(ethylene-co-vinyl acetate) (EVA) additive on the viscosity and the pour point of a Brazilian crude oil. J. Petrol. Sci. Technol., vol. 19, no. 1-2, pp. 197–204, 2001.
[21] H. S. Ashbaugh, X. Guo, D. Schwahn, R. Prud'homme, D. Richter, L. J. Fetters, "Interaction of paraffin wax gels with ethylene/vinyl acetate co-polymers," Energ. Fuels, vol. 19, no. 1, pp. 138–144, 2005.
[22] J. B. Taraneh, G. Rahmatollah, A. Hassan, D. Alireza, “Effect of wax inhibitors on pur point and rheological properties of Iranian wax crude oil,” Fuel Process. Technol., vol. 89, no. 10, pp. 973–977, 2008.
[23] J. W. Qian, G. R. Qi, D. L. Han, S. L. Yang, Influence of incipient chain dimension of EVA flow improver on the rheological behaviour of crude oil. Fuel, vol. 75, no. 2, pp. 161–163, 1996.
[24] J. W. Qian, G. H. Zhou, W. Y. Yang, Y. L. Xu, Studies on pour point depression of EVA polymers in solvent mixtures containing wax. J. Appl. Polym. Sci., vol. 83, no. 4, pp. 815–821. 2002.
[25] M. Lashkarbolooki, F. Esmaeilzadeh, D. Mowla, “Mitigation of wax deposition by wax-crystal modifier for Kermanshah crude oil,” J. Disper. Sci. Technol., vol. 32, no. 7, pp. 975–985, 2011.
[26] M. N. Bouts, R. J. Wiersma, H. M. Muijs, A. J. Samuel, “An evaluation of new asphaltene inhibitors; laboratory study and field testing,” J. Petrol. Technol., vol. 47, no. 9, 1995.
[27] M. A. Buriro, M. T. Shuker, Minimizing asphaltene precipitation in Malaysian reservoir. SPE Saudi Arabia Section Technical Symp. Exhib. Al-Khobar, Saudi Arabia: Society of Petroleum Engineers, 2013.
[28] L. C. M. Palermo, N. F. Souza Jr., H. F. Louzada, M. C. M. Bezerra, L. S. Ferreira, E. F. Lucas, “Development of multifunctional formulations for inhibition of waxes and asphaltene depositions,” Braz J. Petrol. Gas, vol. 7, no. 4, pp. 181–192, 2013.
@article{"International Journal of Chemical, Materials and Biomolecular Sciences:76432", author = "S. M. Anisuzzaman and Sariah Abang and Awang Bono and D. Krishnaiah and N. M. Ismail and G. B. Sandrison", title = "An Evaluation of Solubility of Wax and Asphaltene in Crude Oil for Improved Flow Properties Using a Copolymer Solubilized in Organic Solvent with an Aromatic Hydrocarbon", abstract = "Wax and asphaltene are high molecular weighted compounds that contribute to the stability of crude oil at a dispersed state. Transportation of crude oil along pipelines from the oil rig to the refineries causes fluctuation of temperature which will lead to the coagulation of wax and flocculation of asphaltenes. This paper focuses on the prevention of wax and asphaltene precipitate deposition on the inner surface of the pipelines by using a wax inhibitor and an asphaltene dispersant. The novelty of this prevention method is the combination of three substances; a wax inhibitor dissolved in a wax inhibitor solvent and an asphaltene solvent, namely, ethylene-vinyl acetate (EVA) copolymer dissolved in methylcyclohexane (MCH) and toluene (TOL) to inhibit the precipitation and deposition of wax and asphaltene. The objective of this paper was to optimize the percentage composition of each component in this inhibitor which can maximize the viscosity reduction of crude oil. The optimization was divided into two stages which are the laboratory experimental stage in which the viscosity of crude oil samples containing inhibitor of different component compositions is tested at decreasing temperatures and the data optimization stage using response surface methodology (RSM) to design an optimizing model. The results of experiment proved that the combination of 50% EVA + 25% MCH + 25% TOL gave a maximum viscosity reduction of 67% while the RSM model proved that the combination of 57% EVA + 20.5% MCH + 22.5% TOL gave a maximum viscosity reduction of up to 61%.
", keywords = "Asphaltene, ethylene-vinyl acetate, methylcyclohexane, toluene, wax.", volume = "11", number = "10", pages = "688-8", }
