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dc.contributor.advisorBenkreira, Hadj
dc.contributor.advisorAl-Hengari, S.
dc.contributor.authorMohamed, Fathia A.B.
dc.date.accessioned2021-03-09T12:53:07Z
dc.date.available2021-03-09T12:53:07Z
dc.date.issued2019
dc.identifier.urihttp://hdl.handle.net/10454/18393
dc.description.abstractWaxy crude oils (1/3 of oil produced worldwide), pumping through pipelines considered risky operation due to the crude wax content (15-40 wt.%) and to the temperature at which wax supersaturates and precipitates, leading to the danger of pipe blockage, eventually resulting, in multimillion dollars loss in production and maintenance. This research undertaken to develop operational strategy of waxy crude pipelines, considering the crude and crude gel properties and flow conditions. The research problem was approached by characterizing the crude gel with and without additives using chromatography (GC), differential scanning calorimetry (DSC), cross polarised microscopy (CPM), controlled stress and oscillatory shear rheology (CSR and OSR), the principal parameters being the crude temperature and the rate at which the crude was cooled. GC and DSC were useful in establishing wax composition, content and wax appearance temperature (WAT). Control stress rheometer proved to be the most appropriate as it measured the reduction in apparent viscosity at full production (10-50 s-1 shear rate), near shutdown (1 s-1 ) and yielding when the oil was statically cooled. On this basis, it was established that the wax inhibitor was the most effective. CPM revealed that only the wax inhibitor changed the structure of the gel, disrupting its otherwise knitted crystal network. Dilution with the light crude oil merely reduced the wax content and the pour point depressant reduced the gelling temperature. OSR provided a check on CSR and confirmed the gelation temperature measured. CSR provided the yield stress measured, it also provided comprehensive data that can be used for theoretical modelling of this complex flow.en_US
dc.description.sponsorshipLibyan Petroleum Institute, Libyaen_US
dc.language.isoenen_US
dc.rights<a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>.eng
dc.subjectWaxy crude oilen_US
dc.subjectFlow assuranceen_US
dc.subjectPour pointen_US
dc.subjectFlow characteristicen_US
dc.subjectGelled oilen_US
dc.subjectYield stressen_US
dc.subjectWax depositionen_US
dc.subjectChemical inhibitorsen_US
dc.subjectMorphologyen_US
dc.subjectViscoelastic propertiesen_US
dc.titleAn Experimental Study on the Effects of Heat and Chemical Inhibitors on the Flow Behaviour of Waxy Crude Oils. The Effects of Heat and Chemical Inhibitors on the Rheological Properties of Waxy Crude Oils with regard to Pumping in Pipelinesen_US
dc.type.qualificationleveldoctoralen_US
dc.publisher.institutionUniversity of Bradfordeng
dc.publisher.departmentFaculty of Engineering and Informaticsen_US
dc.typeThesiseng
dc.type.qualificationnamePhDen_US
dc.date.awarded2019
refterms.dateFOA2021-03-09T13:01:09Z


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Appendix A( Microscopic result ...
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Appendix A
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Appendix B ( Dynamic cooling ...
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Appendix B
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Appendix C
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Appendix D
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Appendix E (pour temperature ...
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Appendix E
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Appendix F (DSC results)F.pdf
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Appendix F
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Appendix G (physical propertie ...
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Appendix G
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Appendix H (CVO calibration).pdf
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Appendix i (GC results).pdf
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Appendix I
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Appendix J
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Final thesis.pdf
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PhD Thesis

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