Quality management system to improve conveyor system performance : Lethabo Power Station as case study
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Eskom Lethabo Power Station experienced a number of ash plant conveyor failures that resulted in production loss and plant damages. This study was aimed at determining the root causes of the failures (technical, management system and process) that led to conveyor unreliability. The problem was verified by interviewing people working in the plant and by analysing financial, technical and process data. A hypothesis was made that the problem emanates from poor quality management practices; this was confirmed by carrying out root cause analyses on 10 major events that occurred. It was evident that the costs of poor quality in the ash plant were very high and requires urgent attention. A literature review was conducted to establish whether the quality management system complies with the requirements of ISO 9000 and total quality management (TQM). The survey found that the Eskom Lethabo Power Station partly complies with the requirements of ISO 9001 on an organisational level. However, the ash plant did not comply with the requirements of ISO 9000 in performing its daily duties. The plant quality documents and systems were evaluated to establish whether they could have prevented the incidents from occurring. It was found that the documentation and data records were inadequate. To determine the root causes of the technical quality problems, a brainstorming session was conducted using the nominal group technique to gather data as quickly as possible. The cause and effect analysis was designed to identify all potential causes of the problem. The Pareto analysis was used to prioritise the identified causes. The three factorial experiments were designed to measure process parameters (speed, mass, operating hours). Data was recorded using supervisory control and data acquisition (SCADA). The data was analysed using three factorial calculations. Data was validated by performing analysis of variance (ANOVA) calculations. The survey questionnaire (using the Likert scale) was designed to measure the level of adherence of the ash plant employees and management to the requirements of the ISO 9001 management system. The questionnaire measured the elements of the quality management system (QMS) requirements, its importance and its implementation at the ash plant. The pilot interview was conducted with five respondents who are part of the selected population, and the results suggested that managing supplier quality was a major contributor to quality problems The interview output was used to determine changes proposed to the ash plant QMS. All ideas were verified by the senior engineer and validated by the plant engineering manager.
- Engineering