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DC Field | Value | Language |
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dc.contributor.advisor | Swartz, Christopher | - |
dc.contributor.author | Ewaschuk, Christopher | - |
dc.date.accessioned | 2014-10-14T20:24:45Z | - |
dc.date.available | 2014-10-14T20:24:45Z | - |
dc.date.issued | 2014 | - |
dc.identifier.uri | http://hdl.handle.net/11375/16095 | - |
dc.description.abstract | The scheduling of the converter aisle of a nickel smelting plant is a non-trivial task with significant consequences to plant profitability and production. An optimization-based scheduling formulation is developed using a continuous-time paradigm to accurately represent event timings. The formulation accounts for environmental restrictions on sulfur dioxide emissions using event timing constraints. The formulation includes novel semi-continuous modeling to represent flash furnaces which operate with a continuous inlet flow and intermittent discrete material removal, as well as, a novel sequencing and symmetry-breaking scheme to account for identical units operating in parallel. A rolling horizon feature is included in the formulation to accommodate multi-period optimization. Tightening constraints are developed and used to improve the computational performance of the optimization and demonstrate the capacity of the proposed methodology to function as a real-time decision-support tool. A solution procedure is presented where an aggregate model is used to bound the objective function of the master problem in a two layer optimization scheme. Finally, a novel multi-tiered procedure is presented to enhance the optimization solution by re-optimizing for objectives of decreasing priority in order to minimize task start times and penalize deviations in the furnace flow rate. To address the closed-loop properties of scheduling, a reactive scheduling mechanism is included to allow for rescheduling to account the impact of process disturbances on the operating schedule. A methodology for reducing radical scheduling changes due to the optimization during reactive scheduling is presented. The reactive scheduling algorithm utilizes a tiered optimization approach that progressively increases the degrees of freedom available, as required, in order to achieve a feasible production schedule. The use of the reactive scheduling algorithm demonstrates the ability to reject disturbances and transition plant operation in an agile manner. | en_US |
dc.language.iso | en | en_US |
dc.subject | Scheduling | en_US |
dc.subject | Rolling-Horizon | en_US |
dc.subject | Continuous-time formulation | en_US |
dc.subject | Semi-continuous | en_US |
dc.subject | Production Planning | en_US |
dc.subject | Nickel Smelting Converting | en_US |
dc.subject | Mixed-Integer Linear Programming | en_US |
dc.subject | Tiered Optimization | en_US |
dc.title | Optimal Scheduling of Converter Aisle Operation in a Nickel Smelting Plant | en_US |
dc.type | Thesis | en_US |
dc.contributor.department | Chemical Engineering | en_US |
dc.description.degreetype | Thesis | en_US |
dc.description.degree | Master of Applied Science (MASc) | en_US |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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Ewaschuk_Christopher_M_finalsubmission201408_MASc.pdf | Optimal Scheduling of Converter Aisle Operation in a Nickel Smelting Plant | 3.69 MB | Adobe PDF | View/Open |
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