M.Ing. / The dissertation is an investigation on the implementation of new technologies (five off) in a coal pulverising with main aim to optimise mill maintenance interventions. The technologies in question are: • Stationary air throat replaced with a rotating throat assembly. • Hydro-pneumatic mill loading cylinders replaced with airbags. • Classifier cone modification. • Introduction of triton material for the mill spider guide plates. • High chrome mill grinding balls. Every maintenance intervention, even if planned, negatively affects a plant’s availability and reliability. A Babcock and Wilcox (B&W) at Kriel power station (ESKOM) was used for the testing of the mentioned technologies. The mill model/size is a B&W 10.8E mill. The aim of the introduction of new technology on a mill is to optimise the period between required maintenance activities. A higher availability will assist in achieving good plant maintenance performance indicators. It needs to be noted that the dissertation focussed on the financial and technical parameters of a specific modification. This in an effort to increase uptime and reduce costs as part of a business drive for bigger profit margins. The new technologies tested were thus evaluated from a technical and financial point of view. Each technology was implemented at different time periods and nowhere was any tests performed in parallel on a single mill. To get approval from an investment committee for release of money for tests/modifications, technical and financial assumptions need to be made regarding the performance parameters of the modification/change. Once a modification is being tested, actual plant data can be used as inputs into the execution phase of the modification as assumptions can be replaced with test data. A financial model was developed to “test” the financial feasibility of the proposed changes/modifications. With new technology successful implemented in the plant the current maintenance strategies for maintenance interventions can be re-evaluated as the proposed modifications removed historic barriers that determined the current used based maintenance intervals. An example is where a mill is taken from service to replace or repair the stationary air throat (typically every 5 000 operating hours). With the newly applied technology (rotating throat assemblies), there is no need for maintenance interventions every 5 000hrs as a rotating throat assembly can run without major interventions for 60 000hrs.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:7109 |
| Date | 22 June 2011 |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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