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A scheduling model for a coal handling facility
Dissertation (MEng (Industrial Engineering))--University of Pretoria, 2006.
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University of Pretoria
2013
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| _version_ | 1867613669919031296 |
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| access_status_str | Open Access |
| author2 | Kruger, P.S. (Paul Stephanus), 1944- |
| author_browse | Kruger, P.S. (Paul Stephanus), 1944- |
| author_facet | Kruger, P.S. (Paul Stephanus), 1944- |
| collection | Thesis |
| dc_rights_str_mv | © 2004, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MEng (Industrial Engineering))--University of Pretoria, 2006. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/25388 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:39:49.883Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/25388 A scheduling model for a coal handling facility Kruger, P.S. (Paul Stephanus), 1944- marinda.swart@sasol.com Swart, Marinda Nlp linearization Sos1 variables Operational solution time Gams Event based scheduling Continuous time representation Facility Mixed integer non-linear programming Minlp Coal handling Scheduling UCTD Dissertation (MEng (Industrial Engineering))--University of Pretoria, 2006. The objective of this project is to develop an operational scheduling model for Sasol Mining’s coal handling facility, Sasol Coal Supply (referred to as SCS), to optimise daily operations. In this document, the specific scheduling problem at SCS is presented and solved using Mixed Integer Non-Linear Programming (MINLP) continuous time representation techniques. The most recent MINLP scheduling techniques are presented and applied to an example problem. The assumption is made that the results from the example problem will display trends which will apply to the SCS scheduling problem as well. Based on this assumption, the unit-specific event based continuous time formulation is chosen to apply to the SCS scheduling problem. The detail mathematical formulation of the SCS scheduling problem, based on the chosen technique, is discussed and the necessary changes presented to customise the formulation for the SCS situation. The results presented show that the first phase model does not solve within 72 hours. A solution time of more than three days is not acceptable for an operational scheduling model in a dynamic system like SCS. Various improvement approaches are applied during the second phase of the model development. Special Ordered Sets of Type 1 (SOS1) variables are successfully applied in the model to reduce the amount of binary variables. The time and duration constraints are restructured to simplify the structure of the model. A specific linearization and solution technique is applied to the non-linear equations to ensure reduced model solution times and reliable results. The improved model for one period solves to optimality within two minutes. This dramatic improvement ensures that the model will be used operationally at SCS to optimise daily operations. The scheduling model is currently being implemented at SCS. Examples of the input variables and output results are presented. It is concluded that the unit-specific event based MINLP continuous time formulation method, as presented in the literature, is not robust enough to be applied to an operational industrial-sized scheduling problem such as the SCS problem. Customised modifications to the formulation are necessary to ensure that the model solves in a time acceptable for operational use. However, it is proved that Mixed Integer Non-linear Programming (MINLP) can successfully be applied to optimise the scheduling of an industrial-sized plant such as SCS. Although more research is required to derive robust formulation techniques, the principle of using mathematical methods to optimise operational scheduling in industry can dramatically impact the way plants are operated. The optimisation of daily schedules at SCS by applying the MINLP continuous time scheduling technique, has made a significant contribution to the coal handling industry. Finally, it can be concluded that the SCS scheduling problem was successfully modelled and the operational scheduling model will add significant value to the Sasol Group. Industrial and Systems Engineering unrestricted 2013-09-06T21:06:56Z 2005-06-13 2013-09-06T21:06:56Z 2004-10-08 2006-06-13 2005-06-10 Dissertation Swart, M 2004, A scheduling model for a coal handling facility, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/25388 > http://hdl.handle.net/2263/25388 http://upetd.up.ac.za/thesis/available/etd-06102005-084721/ © 2004, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf application/pdf application/pdf application/vnd.ms-excel University of Pretoria |
| spellingShingle | Nlp linearization Sos1 variables Operational solution time Gams Event based scheduling Continuous time representation Facility Mixed integer non-linear programming Minlp Coal handling Scheduling UCTD A scheduling model for a coal handling facility |
| title | A scheduling model for a coal handling facility |
| title_full | A scheduling model for a coal handling facility |
| title_fullStr | A scheduling model for a coal handling facility |
| title_full_unstemmed | A scheduling model for a coal handling facility |
| title_short | A scheduling model for a coal handling facility |
| title_sort | scheduling model for a coal handling facility |
| topic | Nlp linearization Sos1 variables Operational solution time Gams Event based scheduling Continuous time representation Facility Mixed integer non-linear programming Minlp Coal handling Scheduling UCTD |
| url | http://hdl.handle.net/2263/25388 http://upetd.up.ac.za/thesis/available/etd-06102005-084721/ |