Long term overheating and its effect on plant availability
- Authors: Madjoe, Sean Michael
- Date: 2015
- Subjects: Boilers - Efficiency , Coal-fired power plants , Heat - Transmission , Steam-boilers - Creep , Boilers - Testing
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/56161 , uj:16338
- Description: Abstract: This mini-dissertation investigates the impact that Long Term Overheating and Creep (LTOC) has on coal fired power stations and the availability implications thereof. The need for the investigation arose from a single coal fired power station, with multiple boilers with a total generating capacity of greater than 400MW, of which LTOC is the dominant boiler tube failure mechanism. For the purposes of the mini-dissertation, the power station was simply titled Power Station X. A summary is provided of the various boiler tube failure mechanisms as well as a brief description of availability. The mini-dissertation makes use of case studies in researching the matter of LTOC. It was seen that LTOC is a global matter, which is typically seen in ageing power stations. The major discussion points arising from the mini-dissertation is that of a boiler tube failure management program as well as correctly understanding the causes of boiler tube failures. With an adequate and correctly functioning boiler tube failure management program one can reduce and manage the occurrence of boiler tube failures. The second major discussion point arising from the mini-dissertation is that of correctly understanding the contributing factors to boiler tube failures. A lot of emphasis has been placed on the actual mechanisms and identification of failures, however the contributing factors and root cause has not been thoroughly investigated. Additionally one also has to identify the various areas prone to creep and the necessary remedial and mitigating actions for the removal and or replacement of such components, while keeping in mind the financial implication thereof. The mini-dissertation concludes with possible areas of future research as well as possible remedial actions that can be taken. , M.Ing. (Engineering Management)
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- Authors: Madjoe, Sean Michael
- Date: 2015
- Subjects: Boilers - Efficiency , Coal-fired power plants , Heat - Transmission , Steam-boilers - Creep , Boilers - Testing
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/56161 , uj:16338
- Description: Abstract: This mini-dissertation investigates the impact that Long Term Overheating and Creep (LTOC) has on coal fired power stations and the availability implications thereof. The need for the investigation arose from a single coal fired power station, with multiple boilers with a total generating capacity of greater than 400MW, of which LTOC is the dominant boiler tube failure mechanism. For the purposes of the mini-dissertation, the power station was simply titled Power Station X. A summary is provided of the various boiler tube failure mechanisms as well as a brief description of availability. The mini-dissertation makes use of case studies in researching the matter of LTOC. It was seen that LTOC is a global matter, which is typically seen in ageing power stations. The major discussion points arising from the mini-dissertation is that of a boiler tube failure management program as well as correctly understanding the causes of boiler tube failures. With an adequate and correctly functioning boiler tube failure management program one can reduce and manage the occurrence of boiler tube failures. The second major discussion point arising from the mini-dissertation is that of correctly understanding the contributing factors to boiler tube failures. A lot of emphasis has been placed on the actual mechanisms and identification of failures, however the contributing factors and root cause has not been thoroughly investigated. Additionally one also has to identify the various areas prone to creep and the necessary remedial and mitigating actions for the removal and or replacement of such components, while keeping in mind the financial implication thereof. The mini-dissertation concludes with possible areas of future research as well as possible remedial actions that can be taken. , M.Ing. (Engineering Management)
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Effects of condenser performance on thermal heat rate
- Authors: Narainsingh, Soomesh
- Date: 2014-03-17
- Subjects: Coal-fired power plants , Heat - Transmission , Condensers (Steam)
- Type: Thesis
- Identifier: uj:4346 , http://hdl.handle.net/10210/9695
- Description: M.Tech. (Mechanical Engineering) , Eskom fossil fuel power stations operate under various conditions and the ageing fleet of fossil fuel power stations are under strain due to the rising demand in electricity. The quest for cheaper electricity in growing businesses and bringing foreign investment into South Africa is significant for economic growth. Therefore, minimizing operation costs and improving availability, reliability and thermal heat rate are key objectives for the operation of the business. Thermal heat rate calculation is a method used to assess the performance of fossil fuel power stations. It provides an indication of the thermal performance which reflects the condition and operation of the plant. This dissertation refers to the tools used to measure the condenser performance and to identify the reason for unhealthy condenser performance and an increase in thermal heat rate. Problem: Poor condenser performance causes significant losses in generation and thermal heat rate in fossil fuel plants. Loss in generation and thermal heat rate is caused by condenser backpressure. This has an adverse effect on turbine thermal heat rate and henceturbine efficiency. The performance of the condenser affects the turbine performance to a large extent. Decreased condenser performance will increase the turbine thermal heat rate, i.e. kJ/kWh, because of the increased steam consumption per kWh of energy generated and therefore lowering the overall turbine efficiency. This will result in poor thermal heat rate efficiency resulting in an increased coal burn rate, i.e. kg/kWh, and an increased fuel bill and carbon foot print for the fossil fuel power station. The aim of this dissertation is to determine the effects of condenser performance on thermal heat rate and to provide the engineering and operating personnel with a guide for monitoring condenser back pressure in order to improve turbine thermal heat rate and turbine efficiency. Method and Procedure: Chapter 4 describes the method and procedure used for the pre and post outage evaluation to cost-effectively determine the current condition of the condenser and to quantify the increase in thermal heat rate due to condenser degradation. The pre and post outage evaluation offered an opportunity to evaluate and quantify the effectiveness of the maintenance program and the value of the capital layout undertaken during the scheduled Unit outage. Findings: Chapter 5 discusses the findings of the pre and post outage data analysis of the condenser using the EtaPRO system as the tool. Re-tubing 50% of the condenser inner loop tubes and cleaning the other 50% of the outer loop tubes demonstrated a decrease in condenser backpressure and therefore an improvement in thermal heat rate. This will also result in an improvement in turbine cycle efficiency and reduce coal cost.
- Full Text:
- Authors: Narainsingh, Soomesh
- Date: 2014-03-17
- Subjects: Coal-fired power plants , Heat - Transmission , Condensers (Steam)
- Type: Thesis
- Identifier: uj:4346 , http://hdl.handle.net/10210/9695
- Description: M.Tech. (Mechanical Engineering) , Eskom fossil fuel power stations operate under various conditions and the ageing fleet of fossil fuel power stations are under strain due to the rising demand in electricity. The quest for cheaper electricity in growing businesses and bringing foreign investment into South Africa is significant for economic growth. Therefore, minimizing operation costs and improving availability, reliability and thermal heat rate are key objectives for the operation of the business. Thermal heat rate calculation is a method used to assess the performance of fossil fuel power stations. It provides an indication of the thermal performance which reflects the condition and operation of the plant. This dissertation refers to the tools used to measure the condenser performance and to identify the reason for unhealthy condenser performance and an increase in thermal heat rate. Problem: Poor condenser performance causes significant losses in generation and thermal heat rate in fossil fuel plants. Loss in generation and thermal heat rate is caused by condenser backpressure. This has an adverse effect on turbine thermal heat rate and henceturbine efficiency. The performance of the condenser affects the turbine performance to a large extent. Decreased condenser performance will increase the turbine thermal heat rate, i.e. kJ/kWh, because of the increased steam consumption per kWh of energy generated and therefore lowering the overall turbine efficiency. This will result in poor thermal heat rate efficiency resulting in an increased coal burn rate, i.e. kg/kWh, and an increased fuel bill and carbon foot print for the fossil fuel power station. The aim of this dissertation is to determine the effects of condenser performance on thermal heat rate and to provide the engineering and operating personnel with a guide for monitoring condenser back pressure in order to improve turbine thermal heat rate and turbine efficiency. Method and Procedure: Chapter 4 describes the method and procedure used for the pre and post outage evaluation to cost-effectively determine the current condition of the condenser and to quantify the increase in thermal heat rate due to condenser degradation. The pre and post outage evaluation offered an opportunity to evaluate and quantify the effectiveness of the maintenance program and the value of the capital layout undertaken during the scheduled Unit outage. Findings: Chapter 5 discusses the findings of the pre and post outage data analysis of the condenser using the EtaPRO system as the tool. Re-tubing 50% of the condenser inner loop tubes and cleaning the other 50% of the outer loop tubes demonstrated a decrease in condenser backpressure and therefore an improvement in thermal heat rate. This will also result in an improvement in turbine cycle efficiency and reduce coal cost.
- Full Text:
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