A modelling methodology to quantify the impact of plant anomalies on ID fan capacity in coal fired power plants

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dc.contributor.advisorRousseau, Pieter
dc.contributor.advisorGosai, Priyesh
dc.contributor.authorKhobo, Rendani Yaw-Boateng Sean
dc.date.accessioned2020-09-13T19:34:20Z
dc.date.available2020-09-13T19:34:20Z
dc.date.issued2020
dc.date.updated2020-09-13T19:34:02Z
dc.description.abstractIn South Africa, nearly 80 % of electricity is generated from coal fired power plants. Due to the complexity of the interconnected systems that make up a typical power plant, analysis of the root causes of load losses is not a straightforward process. This often leads to losses incorrectly being ascribed to the Induced Draught (ID) fan, where detection occurs, while the problem actually originates elsewhere in the plant. The focus of this study was to develop and demonstrate a modelling methodology to quantify the effects of major plant anomalies on the capacity of ID fans in coal fired power plants. The ensuing model calculates the operating point of the ID fan that is a result of anomalies experienced elsewhere in the plant. This model can be applied in conjunction with performance test data as part of a root cause analysis procedure. The model has three main sections that are integrated to determine the ID fan operating point. The first section is a water/steam cycle model that was pre-configured in VirtualPlantTM. The steam plant model was verified via energy balance calculations and validated against original heat balance diagrams. The second is a draught group model developed using FlownexSETM. This onedimensional network is a simplification of the flue gas side of the five main draught group components, from the furnace inlet to the chimney exit, characterising only the aggregate heat transfer and pressure loss in the system. The designated ID fan model is based on the original fan performance curves. The third section is a Boiler Mass and Energy Balance (BMEB) specifically created for this purpose to: (1) translate the VirtualPlant results for the steam cycle into applicable boundary conditions for the Flownex draught group model; and (2) to calculate the fluid properties applicable to the draught group based on the coal characteristics and combustion process. The integrated modelling methodology was applied to a 600 MW class coal fired power plant to investigate the impact of six major anomalies that are typically encountered. These are: changes in coal quality; increased boiler flue gas exit temperatures; air ingress into the boiler; air heater inleakage to the flue gas stream; feed water heaters out-of-service; and condenser backpressure degradation. It was inter alia found that a low calorific value (CV) coal of 14 MJ/kg compared to a typical 17 MJ/kg reduced the fan's capacity by 2.1 %. Also, having both HP FWH out of service decreased the fan's capacity by 16.2 %.
dc.identifier.apacitationKhobo, R. Y. S. (2020). <i>A modelling methodology to quantify the impact of plant anomalies on ID fan capacity in coal fired power plants</i>. (). ,Engineering and the Built Environment ,Department of Mechanical Engineering. Retrieved from http://hdl.handle.net/11427/32244en_ZA
dc.identifier.chicagocitationKhobo, Rendani Yaw-Boateng Sean. <i>"A modelling methodology to quantify the impact of plant anomalies on ID fan capacity in coal fired power plants."</i> ., ,Engineering and the Built Environment ,Department of Mechanical Engineering, 2020. http://hdl.handle.net/11427/32244en_ZA
dc.identifier.citationKhobo, R.Y.S. 2020. A modelling methodology to quantify the impact of plant anomalies on ID fan capacity in coal fired power plants. . ,Engineering and the Built Environment ,Department of Mechanical Engineering. http://hdl.handle.net/11427/32244en_ZA
dc.identifier.ris TY - Master Thesis AU - Khobo, Rendani Yaw-Boateng Sean AB - In South Africa, nearly 80 % of electricity is generated from coal fired power plants. Due to the complexity of the interconnected systems that make up a typical power plant, analysis of the root causes of load losses is not a straightforward process. This often leads to losses incorrectly being ascribed to the Induced Draught (ID) fan, where detection occurs, while the problem actually originates elsewhere in the plant. The focus of this study was to develop and demonstrate a modelling methodology to quantify the effects of major plant anomalies on the capacity of ID fans in coal fired power plants. The ensuing model calculates the operating point of the ID fan that is a result of anomalies experienced elsewhere in the plant. This model can be applied in conjunction with performance test data as part of a root cause analysis procedure. The model has three main sections that are integrated to determine the ID fan operating point. The first section is a water/steam cycle model that was pre-configured in VirtualPlantTM. The steam plant model was verified via energy balance calculations and validated against original heat balance diagrams. The second is a draught group model developed using FlownexSETM. This onedimensional network is a simplification of the flue gas side of the five main draught group components, from the furnace inlet to the chimney exit, characterising only the aggregate heat transfer and pressure loss in the system. The designated ID fan model is based on the original fan performance curves. The third section is a Boiler Mass and Energy Balance (BMEB) specifically created for this purpose to: (1) translate the VirtualPlant results for the steam cycle into applicable boundary conditions for the Flownex draught group model; and (2) to calculate the fluid properties applicable to the draught group based on the coal characteristics and combustion process. The integrated modelling methodology was applied to a 600 MW class coal fired power plant to investigate the impact of six major anomalies that are typically encountered. These are: changes in coal quality; increased boiler flue gas exit temperatures; air ingress into the boiler; air heater inleakage to the flue gas stream; feed water heaters out-of-service; and condenser backpressure degradation. It was inter alia found that a low calorific value (CV) coal of 14 MJ/kg compared to a typical 17 MJ/kg reduced the fan's capacity by 2.1 %. Also, having both HP FWH out of service decreased the fan's capacity by 16.2 %. DA - 2020_ DB - OpenUCT DP - University of Cape Town KW - Engineering KW - Induced Draft Fan KW - Draught plant KW - anomaly detection KW - Fan Capacity Limitations LK - https://open.uct.ac.za PY - 2020 T1 - A modelling methodology to quantify the impact of plant anomalies on ID fan capacity in coal fired power plants TI - A modelling methodology to quantify the impact of plant anomalies on ID fan capacity in coal fired power plants UR - http://hdl.handle.net/11427/32244 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/32244
dc.identifier.vancouvercitationKhobo RYS. A modelling methodology to quantify the impact of plant anomalies on ID fan capacity in coal fired power plants. []. ,Engineering and the Built Environment ,Department of Mechanical Engineering, 2020 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/32244en_ZA
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Mechanical Engineering
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.subjectEngineering
dc.subjectInduced Draft Fan
dc.subjectDraught plant
dc.subjectanomaly detection
dc.subjectFan Capacity Limitations
dc.titleA modelling methodology to quantify the impact of plant anomalies on ID fan capacity in coal fired power plants
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationlevelMSc
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