Failure analysis steam turbine in sugar factory thermal power plant: a Review

Generating electricity from thermal energy is one of the main ways of generating electricity. However, it must be generated in the most efficient and effective way. Due to the urgency of electricity generation, it is essential that it is produced in the most efficient way to minimize losses, maximise output, optimise resource utilisation and reduce overall costs of the power plant. These outputs are even more critical in the current era where sustainability has become the top priority. A thermal power plant is a converter of fossil fuels to electricity in which steam is used during a cycle to spin a turbine driving generator to produce electricity. It is important to maintain a power plant if it runs without failure. Reliability analysis is a standard tool for designing, scheduling and maintaining any system. Reliability of a power plant refers to the ability to generate electricity efficiently and more cost-effectively with an acceptable quality assurance. This paper provides an in-depth analysis of power generation in a sugar factory by steam turbine and the reasons for steam turbine failure. It also analyzes the maintenance models employed to enhance steam turbine availability in thermal power plants.


Introduction
The use of fossil fuels in power generation combined with low pollution in traditional thermal power plants is becoming a hot topic around the world.Energy availability and sustainability scenario has become a hot topic in many countries around the world due to the increased need to improve living standards, increase productivity and maintain a clean environment.Energy use is good for productivity, quality of products, costs and quality of life, but the use of fossil fuels has a negative impact on our environment.The basic concepts of power generation have been refined to improve the power generation efficiency by using modern waste heat recovery (WSR) and cogeneration technologies.
The turbine and generator set is one of the most important devices in the thermal power plant of sugar factory.In order for a power plant to be efficient, cost-effective and long-lasting, it is necessary to maintain it if it runs without failure.Over time, reliability analysis has become a standard tool for the design, planning of operation and maintenance for sugar factory power plant.Reliability of a thermal power plant relates to the possibility of provide electricity effectively and cheaply with a reasonable level of quality assurance.In a 2 currently thermal power plant system, it can be classified as a generation system, a transmission system and a distribution system.It can be considered independent or in combination of the pyramidal functional areas.The scope of this work is limited to evaluation of generation reliability.Most critical components are located in the generation system.Therefore, reliability analysis is necessary for frequently failing components.The primary objective is to define a methodology to enhance the reliability of sugar factory steam turbine.Reliability concepts are used as a guide for ranking maintenance strategies for the critical constituents of the sugar factory steam turbines.The reliability of a system can be determined through the Deterministic and Probabilistic approach to system reliability analysis.Deterministic approach of system reliability analysis deals with understanding the reasons why a system fails and how to plan to prevent such failure from occurring or reoccurring.This involves analysis such as previous failure report, understanding the scientific theory behind such failure, role and level of maintenance policies, etc.A power plant's role is to supply electricity, efficiently and with reasonable assurance of continuity and good quality to its customers.Today's power plant is a very large, complex and highly integrated power plant.Electric power plants may be divided into appropriate subsystems or function areas such as generating, transmitting and distributing electricity.Reliability studies can be done independently or in combination of all three functional domains.A steam turbine component in thermal power plant is shown below.In this paper, we used Boolean function technique to assess the reliability of an industrial problem relating to a sugar manufacturing plant.We found life of components, electricity consumption and developed maintenance schedule, and found its impact on system.We also looked at the main challenges in turbine maintenance; with special emphasis on steam turbine performance parameters we also studied recent methods of reliability analysis as well as maintenance of steam turbines.
A power plant's dependability depends on its capacity to deliver electricity in an efficient, cost-effective manner with a fair level of quality assurance.Generating, transmitting, and distributing energy are the three functional areas of a modern power plant system.The system may be analyzed singly or in conjunction with the other two functional domains.The assessment of generation reliability is the sole focus of this investigation.Since the generating system contains the majority of the crucial components, a reliability analysis of those parts that frequently fail is required.

Parts of thermal plant
Typically, a cogeneration plant in a sugar refinery is made up of both main and minor components.The following is a summary of the significant and insignificant components typically present in a cogeneration plant in a sugar factory:

Major Parts:
 Boiler: The bagasse, a byproduct of the sugar production process, is burned in the boiler to produce high-pressure steam. Steam Turbine: The steam turbine transforms thermal energy from high-pressure steam into kinetic energy that powers the turbine generator. Turbine and Generator: The turbine generators in sugar factory are connected, and the turbine generator transforms the kinetic energy of the turbine into electrical energy. Condenser: The condenser transforms the exhaust steam from the turbine into water, which is then sent back to the boiler for further transformation into steam. Cooling tower: The tower is used to cool the condenser water and eliminate extra heat produced during condensation. Fuel Storage and Handling System: Bagasse, the main fuel used in the boiler, can be stored in this system's storage facilities for fuel handling and storage.In order to move the bagasse from the storage to the boiler, conveying systems are also used. Ash Handling System: This system collects and discards the ash left behind after bagasse is burned in the boiler. Water Treatment Plant: This facility is in charge of cleaning and disinfecting the water utilized in the cooling and boiler systems. Electrical Substation: The electrical substation collects the electricity produced by the turbine generator and, if necessary, distributes it to different areas of the sugar factory and the grid.

Minor Parts:
 Pumps and Valves: Several pumps and valves have been placed throughout the facility to provide proper fluid circulation and control, including condensate, steam, and water.
 Instrumentation and Control System: This system, which monitors and regulates the functioning of the cogeneration plant, is made up of sensors, meters, control panels, and automation software. Exhaust Gas System: The exhaust gas system controls the release of exhaust gases from the boiler and is made up of components including flue gas stacks, dampers and fans. Air Preheater: The air preheater increases system efficiency by preheating the atmospheric combustion able air using waste heat from the flue gases. Feed water system: This system, which comprises feed water heaters, deaerators, and pumps, provides water to the boiler. Steam Distribution System: This system, which consists of pipes, valves, and steam traps, transfers steam from the boiler to several sugar mill processes. Generator Transformer: Using a greater voltage that is suited for transmission and distribution, the generator transformer raises the electrical voltage generated by the turbine generator. Control Room: The control room is home to the operator consoles, control panels, and monitoring tools that enable operators to oversee and manage plant operations.It is crucial to keep in mind that the precise layout and parts of a cogeneration plant in a sugar mill can change based on elements like plant size, technical improvements, and particular needs of the facility.

Review on reliability analysis of thermal power plant
J. Kuzelka, Martin Nesladek, Maxim lutovinor [1] computer models of fatigue fracture development in a steam turbine rotor blade groove explored.For example, in the ST design process, the thermo-mechanical fatigue mechanism handled by utilising advanced prediction approaches.Drazan Kozak, Marko katinic [2] analysed a case study of a moving blade failure in a steam turbine due to corrosion fatigue.One of the main reasons for steam turbine rotor blade failure, according to research, is corrosion fatigue.J A Rodriguez, J C Garcia, E Alonso, Y E Hamzaoui, J M Rodriguez G Urquiza [3] worked on estimating steam turbine blade failure probability using the improved Monte Carlo approach.M. Nurbanasari, Abdurrachim [4] discovered a crack in a steam turbines first stage blade.Investigate into the first stage blade failure of a 55 MW steam turbine.The blade, which manufactured of stainless steel 17-4 PH, lasted 12 years before breaking.D. N. Dewangan, Manoj Kumar Jha, Y. P. Banjare [5] looked at the thermal power plant's steam turbines dependability.Unreliable and unpredictable failure of a power plant caused by fault modes such as steam creates vibration, unbalance of rotating elements and misalignment shaft of the steam turbine, rotor malfunction, oil film absence in bearing, etc. M. Mehdizadeh, F. Khodabakhshi [6] Performed failure study of a steam turbine journal bearing's interfering part.As such delicate components of steam turbines, journal bearings are highly vulnerable to failure through various mechanisms of wear, fatigue, and crush while in use.Andrzej M. Rusin [7] studied technical parameters important for last few years' operation of steam turbines.In this paper author assess the technical fundamentals require for in long-term operation of power units.Detailed analyses have conducted for steam turbine components.Suk Joo Bae , Byeong Min Mun , Woojin Chang , Brani Vidakovic [9] designed Condition-based maintenance is designed to take maintenance actions only when there is an imminent evidence of failure for a monitoring system.Komal, D. Chang, and S. yeob Lee [10] analyzed fuzzy reliability analysis of dualfuel steam turbine propulsion system in LNG carriers considering data uncertainty.H. P. Jagtap, A. K. Bewoor, R. Kumar, M. H. Ahmadi, and L. Chen [11] found performance and availability turbo generator system and subsystem to improve maintenance schedule of a thermal power plant using particle swarm optimization.C. R. Vishnu and V. Regikumar [12] research on choosing a reliability-based maintenance strategy in processing plants: a case studyIn order to implement Reliability Centred Maintenance in process plants, this study suggests a broad strategy.The advantages of conventional maintenance plans are all included in RCM, a recently developed maintenance strategy.N. Gupta, A. Kumar, and M. Saini [13] investigated reliability and maintainability of generator in thermal power plant turbine power plant using RAMD.Z. Hameed and J. Vatn [14] found significant RAMS problems for the 10 MW reference wind turbine.The operational phase's feedback will serve as the foundation for conducting finite element and fatigue load assessments to identify the regions vulnerable to greater stress concentration.S. Kiran, K. P. Prajeeth, B. Sreejith, and M. M. [15] evaluated reliability and risk based maintenance in a process industry.Results indicate that the methodology identify the critical elements and improving the availability of the system.F. Corvaro, G. Giacchetta, B. Marchetti, and M. Recanati [16] studied in reliability, availability, maintainability for reciprocating compressors API 618.Sanjay Gupta, S. K. Gupta [17] analyzed sugar cane mills and its components by Orthogonal Matrixes for reliability of sugar factory.A. Mariajayaprakash, T. Senthilvelan [18] found failure and optimize boiler of sugar factory by FMEA and Taguchi concept.Abdossaber Peiravia, M. A. Aardakan [19] optimized different duplication reliability analysis of reliability by Markov-based model.Amit Kumara [20] measured reliability of sugar factory thermal power plant by mathematical modelling.Suyog S. Patil, Rajkumar B. P., Ravinder K. [21] evaluated common practise to a system's failure modes, along with its causes and effects, using the failure causes, effects, and instancy.To get over the drawbacks of the conventional FMECA, a number of Multi-Criteria Decision-Making techniques have emerged.The ExJ-PSI model, which combines MCDM techniques and incorporates expert opinions also suggested as a new integrated model in this research.Anatoly L. [22] analyzed thermal power plant generator unit by a multi-state Markov model for a short-term reliability.South Asian association [23] found cogeneration scope in Sugar refinery and paper manufacturing company.Demet O.U., B. Turkali [24] derived maintenance models for steam turbine and power plant critical components by using a DBN based reactive maintenance model.Dusmanta K. M., P. K. Sadhu [25] optimized deterministic and stochastic approach for thermal power plant safety it's reliability also decide suitable maintenance model for it.Marko c. [26] substituted reliability analysis model of nuclear power plant for wind power system and check it's performance and effects methodology of the power system reliability.Hanumant J., A. Bewoor [27] found importance of boiler furnace system in steam thermal power plant by markov-based using PSO.Howard C., S. Wang [28] assessed reliability of water-cooled multi system and found running of it.Hyeonmin K., J. T. Kim [29] evaluated failure Rate of any system and subsystem updates it by considering prognostics in probabilistic safety.Ching C. K., Jau C. K. [30] found available time and comparative analysis of available systems and its subsystem.The above figure illustrates the various failure analysis techniques used to evaluate thermal power plant systems, such as Monte Carlo, FMEA, RAMS and FTA.There are many ways to identify the failure of various sub-systems and components.The majority of the reviewers focus on system reliability, availability, and maintainability.Through the reference papers, it is possible to observe frequent failures and stoppages of thermal power plants and their sub-

Fundamental study of thermal power plant
In the published literature, the failure analysis is limited to steam leakage, rotor vibration and rotor imbalance.However, thanks to the use of AI and machine overall system failure analyses, none of the previous researchers mention the system failure analysis. Through the literature, it observed that very little study is available on reliability analysis of steam turbines by using artificial intelligence and machine learning. Most of the researchers are concentrated on predictable failure analysis of steam turbines and its subsystems but little work reported on Pre Failure detection. From the survey, it noticed that less work is available on leakages in steam turbines. The guidelines for selection of proper maintenance strategy of identified important components of steam turbines to increase the reliability of the system. Most of the researchers concentrated on steam turbine blade failure because of corrosion but few work reported on analysis of the mechanisms and sub-systems of steam turbines. More research is required to find out the effect of vibration on the steam turbine system and sub system. The research work related to availability improvement of existing components of steam turbines has little in published literature.

Conclusion
This paper contributes to understanding the significance of steam turbine and failure causes of steam turbines and its subsystems.The suggested literature work provides information on steam turbine maintenance models, steam turbine repair schedule and importance of artificial intelligence and machine learning.We also know how; this is crucial for failure free and increased availability of steam turbines in the thermal power plant.

Fig :- 1
Fig :-1 Literature Review and its Synthesis reasons.The most common reasons for stoppages and failures of thermal power plants are turbine section and their subsystems such as turbine blades; generator; bearings & corrosion piping; sensors; governor; steam sealing leakage; rotor vibration; imbalance of rotor & valve etc.