Chapter 2 REVIEW OF RELATED LITERATURE
Introduction TC-700 is one of the critical gas compressor-driver steam turbine at Petron Bataan Refinery (PBR). During years of its operation, there are instances where it suffered drop in performance due to deposition or fouling of steam turbine blades caused by abnormal steam quality. This prompts the management of PBR to implement strict condition monitoring in order for early detection and assessment of signs of performance drop. However, difficulties of analyzation of condition monitoring arises due to the fact that the turbine’s operating point is always varying to match the process requirements. Steam turbine also cannot be tested offgrid because it operates at 24/7. This prompted an idea to develop a quick and trendable monitoring technique for easy turbine performance assessment using empirical quantities derived from other steam turbine operating parameters.
Related Readings ASME/ANSI PTC 6S Report “Simplified Procedure for Routine Performance Tests of Steam Turbines” is a guideline to perform developing procedures of monitoring steam turbine performance. This includes data in determining turbine cycle heat rate, power capacity, high pressure (HP) and intermediate pressure (IP) section efficiencies, turbine stage pressures and flow capacities, Albert, (2000). The procedures will determine trends of operating efficiency, trouble detection, and test data for evaluation of efficiency changes of
steam turbine operation. In order to have a reliable result in conducting the procedures, precision instruments must be installed at critical test points, ASME PTC-6S (2003). Related Literature Steam Turbine Steam Turbines is a type of Heat Engine where heat is extracted from the steam then converting it to mechanical work. The steam turbine, however, differs from other type of heat engine (i.e. steam engine, internal combustion engine) on the manner of converting the heat energy to mechanical work. The heat energy is transformed into Kinetic (Velocity) Energy which is then transformed to mechanical work. The Kinetic Energy is produced by the steam passing to a small opening. The Mechanical work is then produced by striking (impulse) or leaving (reaction) a movable part, Terrell Croft (1923). At Saudi Aramco, steam turbines are used as a prime mover to drive generators, gas compressors and pumps. Nozzles and Blades are the two main components of Steam turbine to convert steam heat energy to mechanical work. The rotating parts are the blades while the stationary or non-moving parts the nozzles. Pressure and Temperature comprises the heat energy stored in the steam. As the steam passes the nozzle, the steam velocity increases while the pressure drops. The kinetic energy of the steam will strike the blades causing them to move thus generating a mechanical work. The blades are aligned around the circumference of the rotating wheel while the nozzles are aligned along the inside circumference of the stationary wheel just around the same radius of the blades, Saudi Aramco (2003). Steam turbines converts the heat energy of steam into mechanical work. Steam heat energy is defined by its pressure and temperature. Given these properties, enthalpy, entropy
and state can be determined using steam diagrams. The steam will pass thru a small opening converting the pressure energy to kinetic energy. During this process, the temperature and pressure decreases. The developed kinetic energy moves the blades of the turbine thus spinning the wheel. The spinning wheel is now the mechanical work. Steam turbine has many purpose mainly as a driver of equipment such as pumps, generators, fans and blowers and compressors. The steam turbine has an advantage of converting directly the heat energy to mechanical work compared to electric motors where the heat must be transformed to mechanical work (thru generators) then to electricity and finally to mechanical work again. For applications of steam turbine driving compressors and/or pumps, steam turbine has an advantage to quickly adopt to the varying process load by speed control (thru turbine governor) and steam flow, Revalo, 2016. Steam Turbine Performance Steam Turbine Performance is a way of evaluating the turbine design and installation and will provide an indication when a turbine maintenance is required. In conventional method, steam turbine performance is generally related to the amount of energy available. The amount of energy available is computed with the help of Mollier Diagram by plotting the actual steam parameters. Mollier diagram is a plot of enthalpy versus entropy with constant pressure and temperature lines, Saudi Aramco (2003). Monitoring systems such as vibration, lubrication, material erosion and cracking, bearing condition, turbine load and speed are not turbine performance indicators. However, analytical techniques can be assumed using theses parameters can be implemented for identifying potential steam turbine performance problems, ASME PTC-6S (2003).
The overall turbine performance is a function of the average performance of the turbine stages which is related to the velocity ratio. The velocity ratio is the blade velocity (Vb) over steam jet velocity (Vj). Blade velocity at meters per second (m/sec) can be obtained using the formula: Vb = (πDN)/60000, where D is wheel pitch diameter in meters, N is revolutions per minute (RPM). Steam jet velocity at meters per second (m/sec) can be obtained using the formula: Vj = (44.72)*sqrt(h1-h2), where h1 and h2 are steam inlet and outlet enthalpy respectively in kilojoules per kilogram (kJ/kg), Saudi Aramco (2003).
From:
Saudi Aramco (2003), Engineering Encyclopedia - Determining Steam
Turbine Performance Characteristics. Page 7 Steam turbine performance is basically the mechanical steam turbine efficiency. Which further described as on how the available heat, that is the heat absorbed by the steam turbine is converted to mechanical work. Not all the heat absorbed by the steam turbine is converted to mechanical work due to heat loss, steam leakages and other types of inefficiencies which falls on the steam turbine design, Revalo, 2016 Steam Turbine Blade Deposition (Fouling) Blade surface deposition is due to the impurities found in the feedwater, water, steam generator, desuperheating water that flows with the steam and enters the steam turbine. The
impurities dissolve in the superheated and wet steam depending on the pressure and temperature. The steam losses its pressure and temperature as it passes the turbine thus loosing also its impurity dissolving characteristic. The impurities then precipitate and adheres to the turbine blades. The effect of the deposition is a drop in steam turbine performance. The loss of performance will depend on the deposit’s thickness, location and the surface roughness. The performance loss is due to the change of the basic profile of the nozzles which attributes to changes in flow, energy distribution, and the aerodynamic profiles, Otakar Jonas, Lee Machemer, 2008. Deposition on turbine which decreases the performance are formed by precipitation from superheated steam, evaporation of moisture on surfaces above saturation temperature, deposition of metal oxides and adsorption of gases and dissolved impurities in superheated and wet steam onoxidized surface, Otakar Jonas, Joyce Mancini, Jonas, Inc., 2001. The deposits on the steam turbine blades increases the inter-stage pressure. Steam turbine deposition can happen on a very short instance given a poor steam purity. Normally, improper steam water purification process leads to this problem. Amorphous silica (SiO2) is the most common fouling compound. There are several causes of steam turbine deposition where most famous are entrainment, attemperating water impurity, boiler water salts vaporization, localized silica saturation and turbine velocity. Prevention or minimizing of steam turbine deposition of silica can be realized by proper purification of boiler water using water treatment facilities such as reverse osmosis and by increasing the number of blowdown activity in order to lower the silica level of the steam. Online water washing can remove water soluble deposits that adhered onto the steam turbine blades, however for non-water soluble steam turbine blades and nozzle deposits such as silica, water washing normally do
no improvement on restoring steam turbine performance which would require steam turbine opening and blasting to remove the adhered deposits, GE water, 2012.
from: http://www.gewater.com/handbook/boiler_water_systems/fig18-1.jsp
from: http://www.gewater.com/handbook/boiler_water_systems/fig18-2.jsp Experiences by the author suggests that the main cause of performance degradation of steam turbines as a driver of compressors and generators is blade deposition or fouling. Issues such as blade erosion due to particles or droplets of water impinging the blades are minor issue and insignificant. In PBR, boiler water is subjected to the process called reverse osmosis which apparently purifies the boiler water before entering the steam generators.
However, reverse osmosis alone does not solve the problem of turbine blade deposition since the reverse osmosis equipment are continuously online and properly maintained. Mitigations such as continuous or frequent steam blow down helped to alleviate the issue of blade deposition. Other source of water going into the steam is during attemperating where water is injected or sprayed on the steam line in order the steam to desuperheat thus lowering the temperature. At lower temperature, the steam loses some of its dissolving capabilities which could worsen the problem. Many instances, during continuous operation, the required capacity of the driven equipment will not be reached because of decrease in performance of the steam turbine. Monitoring each steam turbine parameters are tedious due to the continuously varying operating point as required by the process. Therefore, by just trending each parameter will not efficiently or proficiently know the current steam turbine performance, Revalo, 2016. Steam turbine performance curve Water rate (or steam rate) is generally the basis of performance guarantee of manufacturers of steam turbine due to the fact that this is dependent on varying steam conditions and principally, because all other performance values are determined from it. In addition, average purchasers of turbine think about the economics in terms of water rate. However, if inlet and outlet steam conditions are available, water rate is meaningless, Terrell Croft (1923). Theoretical steam rate (TSR) is the required steam in producing the horsepower of an ideal machine. Actual Steam Rate (ASR) which is also called as water rate is the steam needed per actual horsepower of real steam turbine. TSR can be computed ideally by subtracting the inlet and exhaust enthalpy at pressures of isentropic condition then converting
to work units (i.e. Btu to ft-lb). ASR is equal to the steam turbine efficiency multiplied by TSR. TSR tables are very useful and alternative method in calculating steam rates by not using Mollier diagram, Saudi Aramco (2003). Steam turbine performance curve using Mollier chart is seemingly difficult to use due to the obvious reason of difficulty of reading, plotting and computing from it. Steam rate is easier to visualize since it graphs the power versus the steam flow. Under theoretical condition (no drop in turbine performance) and by using steam rate, steam flow is linearly and directly proportional with the steam turbine power delivered. Manufacturers provides a guarantee Actual Steam Rate graph where the turbine efficiency is already considered. The actual steam rate provided by the manufacturer is a best way to see if the steam turbine still on par with the guaranteed performance. For these reason, steam rate is best be applied for steam turbine and generator setup where the generator will measure the power delivered by the turbine and by knowing the steam flow rate, it will be easily being compared to the actual steam rate provided by the manufacturer or vendor. For applications such as pump and compressor where the steam turbine is the driver, power produced by the steam turbine is not immediately known due to the fact that the pumps and compressors do not directly reveal the power. Graphs of steam rate for different steam turbine speed is also provided. Also for special applications such as steam turbines having extractions have its steam rate chart. Steam rate chart also has an extension for hand valves which adds steam flow if open, Revalo, 2016. Condition Monitoring Condition monitoring is the identification of a machine’s condition while in operation. Condition monitoring of steam turbines is important because it allows detection of
the machine’s possible wear. It also is used to detect leakages which can affect the lifespan of the steam turbine. Some examples of condition monitoring for steam turbines are: Plotting first stage pressure versus steam flow: detection of steam path fouling; and Trending if gland condenser vacuum: detection of contamination of oil system, Firsthoffer, 2011. Essential to a successful condition monitoring is the identification of correct parameters to measure and how to interpret them. There are two methods of condition monitoring. One is the trend monitoring wherein machine parameter readings are taken regularly. The other one is condition checking wherein machine parameter readings are taken just at a single instance. The advantage of the former is it gives the technician or engineer time for preparing for a possible machine problem. Other types of condition monitoring, Revalo, 2016. Related Study Steam Turbine Steam turbine consists of expansive components (i.e. nozzles and stators) which are connected to the stationary frame of the turbine casing and primary concerns with the conversion of heat energy to kinetic energy, and the rotor blades which converts the kinetic energy to mechanical energy. The blade system consists the expansive components and rotor blades. Airfoil, spacer and shroud typically components of the steam turbine blade. In the paper by Jolanta Baran, eco-design for manufacturing turbine blades and packages which will lead to a decrease in power consumption to produce the product thus helping the environment, Baran, 2016.
The basic parts of steam turbines are the rotating part and the stationary part. The rotating part composed of the shaft and turbine wheel with the blades; and the stationary part composes the casing and with the nozzles installed. The combination of the nozzle and blades essentially converts the heat energy of the steam into a mechanical work. Construction and manufacturing of these parts utilizes an amount of energy. By designing each of this part with a purpose in mind, less energy will be spent in producing these parts. Advances in design such as the airfoil profile and material could be made used in order to achieve this goal of decreasing of environmental impact on producing steam turbine parts. Other parts or system can also be improved such as interstage sealing, governor valve and bearings can also be improved for a better design with the goal of low production cost and longer life of parts, Revalo, 2016 Steam Turbine Performance Performance testing versus performance monitoring: performance monitoring uses indices variations by periodic calculations or surveillance while the performance test is conducted in a controlled condition (i.e. PTC 6S). Standards or codes for performance monitoring are limited to calculation of significant indices which could indicate steam turbine performance and monitoring their operating trends comparing them to the reference indices. Performance monitoring mainly beneficial due to short period of performance gathering activity. Performance testing is not practical due to preparations and pre-requisites it requires. However, performance monitoring is less accurate than performance testing due to the data conditioning. Ultimately, detection of performance variation is for performance monitoring while absolute values of performance indices is for performance testing, KIM et al., 2014.
Performance testing is prescribed by ASME in order to know the actual operating condition of the steam turbine after an interval of time. During performance testing, the steam turbine will be tested to the design condition and the data of the test will be compared from the guaranteed design specification. Controlled variables must be maintained during performance testing which follows that there are a lot of preparation and resources needed in order to perform this activity. Performance monitoring is the other way around and complements the performance testing. By performance monitoring, the steam turbine condition is checked using online instruments during the equipment is at actual operation. Although not at controlled condition, performance monitoring can trend specific parameters and analyzing them in order to gain an indication or hint of what is the current condition of the steam turbine. A good performance monitoring implementation will lengthen the interval of the prescribed performance test which is an economical saving to the plant, Revalo, 2016. Steam Turbine Blade Deposition (Fouling) Common steam turbine faults are: (1) solid particle erosion at the first stage of steam turbine; (2) overflow valve leakage; (3) deposition and fouling in 2 nd, 3rd and 4th stages; (4) damaging of shell and seals; (5) normal wearing and aging; and (6) gassing and fouling in the condenser of power plants. Specifically, fouling or deposition normally is coming from the boiler then transported to the superheated steam by three types of mechanisms which are: carry-over mechanically, vaporous carry-over and attemperators or desuperheater. The notch of fouling and deposition is dependent to the steam generator drum pressure, efficiency of separation, desuperheating, and other factors. Fouling or deposition causes a decrease in steam turbine performance. This is due to the changing of blade profile and increasing of surface roughness. Different depositing or fouling compound can be found at different steam
turbine parts and depends on the temperature of the location. Fouling and deposition can be generally reduced by improving of water purification and reduction of desuperheating or attemperating, C. Karlsson et al., 2008. Steam turbine fouling and deposition has an adverse effect on the steam turbine performance. Many instances that the plant operators are already into their radar that there will be an eminent performance degradation of the steam turbine in the future due to deposition and fouling. But solving this issue is very complicated especially if the plant is old and an upgrade of boiler water purification technology will be economically unfeasible. The main attributor of steam turbine performance degradation due to deposition or fouling is the changing of the aerodynamic profile of the blades and nozzles which affects the generation of kinetic energy by the nozzle and mechanical work by the blades. Many types of depositing and fouling compound has been identified which adheres at the turbine blades. The location of the deposition or fouling along the steam path is dictated by the actual temperature and pressure on that location where the depositing or fouling compound separates to the steam. Improving the water quality and reducing the source of the depositing and fouling compound are ways to alleviate the problem, Revalo, 2016. Steam turbine performance curve Steam turbine efficiency is basically dependent to it’s the mechanical condition relative to the design. As the condition of the turbine deteriorates, efficiency of the steam turbine drops proportionally thus the steam turbine will not operate as per its published performance curve. There are three key areas to improve in order to increase the steam turbines efficiency which are: improving of combustion which has something to with the heat balance of the cycle; improvement of aerodynamics of turbine blades in order to increase the
life and performance; and improvement of materials for longer life and to cope to a higher operating temperature. Computer optimized steam turbine operation and improvement in material had continuously making the goal reaching 50 percent efficiency. Improved nozzle profiles are overcoming the problem of losses on the stationary blades. More efficient blades are also realized due to computer aided design. Redesigning of turbine sidewall contours at high pressure side and the reduction of wet steam at low pressure side have increase the turbine efficiency by 10 percent and reduced downtimes and cost of maintenance. There are four causes of decreasing of steam turbine efficiency and performance which are: deposits and fouling in the steam paths; nozzle and bucket surface erosion; mechanical damage of nozzles and buckets because of foreign material; leakages of steam in the packing seals. Deterioration due to aging is also a factor on the degradation of steam turbine efficiency. Mass and energy balance of steam cycle could increase the overall power plant efficiency by: Superheating which increases the thermal efficiency; Further reduction of condensing pressure and temperature which increases power cycle efficiency; Reheating which increases thermal efficiency and also decrease the chances of wet steam at the low pressure side thus protecting the last blades from erosion; increasing of feed water temperature which decreases the heat added by the steam generator; decreasing the pressure drop at the reheater which increase the available steam energy entering the intermediate section of the steam turbine; decreasing of pressure drop at the extraction which leads to lower heat input by the reheater; reduction of makeup water by repairing the source of leakage of water; reducing the turbine exhaust pressure which has something to do with the design; air preheating at the steam generator use of the available heat source in order to use less fuel consumed; sub-cooling
which increase the turbine heat rate when applied to a power cycle, Joseph A. MacDonald, 2003. Steam turbine performance curve is a document provided by the original equipment manufacturer as a tool to know or see if the actual steam turbine performance is still at par to the guaranteed operating condition. Steam turbine performance would basically decrease upon its aging and a new turbine performance curve can be developed after performance testing. During the design phase, there are many areas with regards to the steam turbine design could increase or improve the steam turbine efficiency. Steam turbine as a part of a power cycle, improvements on the other equipment will improve the thermal efficiency of the cycle thus producing more work using less heat input, Revalo, 2016 Condition Monitoring Seven key steam turbine parameters: inlet flow, inlet pressure, first stage pressure, hot reheat pressure, cross-over pressure, high pressure efficiency index, and intermediate pressure efficiency index if trended over time and interpreted properly will give a steam turbine diagnosis of deterioration. Different combinations of these parameters will lead to an early warning or identification of the steam turbine issues which are: solid particle erosion in the high pressure steam turbine; solid particle erosion in the intermediate pressure steam turbine; deposition and peening in high pressure turbine; deposition and peeing in intermediate pressure turbine; deposition in intermediate pressure turbine; rubbing in the intermediate pressure steam turbine; and deposition and damages in the intermediate pressure steam turbine. Accuracy of data is a must for proper interpretation. Because of such, there is a need to verify and trending of data before starting the analysis. An understanding of changes of each of the seven parameters one at time is essential for an easier and correct
interpretation since there are more than one change happens at a time. The main strategy to be adopted in order to know if a deterioration is eminent is to see the historical pattern of trend of each of the seven parameters (i.e. increasing, decreasing or stable). Comparing of the seven parameters to its corresponding guaranteed design values is also a plus. Real time diagnosis of fault is more important for steam turbines in power generation. Analysis of the inferences of the trend of each seven parameters such as increasing, decreasing or constant provides a relationship of steam turbine fault condition, L. Sivakumar, S. Devi, 2014.
from: Applied Soft Computing (730-741) - Implementation of VLSI model as a tool in diagnostics of slowly varying process parameters which affect the performance of steam turbine PTC PM addresses steam turbine performance monitoring and PTC 6 or 6S are for performance testing. Performance testing and performance monitoring are complimentary to each other where the results of PTC 6 or 6S are reliably accepted as official yet too much
resources are needed. Improved performance monitoring will reduce the frequency of performance tests. Condition based maintenance or sometimes called predictive maintenance can save money by the reduction of the testing activities, KIM et al., 2014.
from: Hyeonmin Kim, Man Gyun Na, Gyunyoung Heo, 2014, Application of monitoring, diagnosis, and prognosis in thermal performance analysis for nuclear power plants. Fault detection and diagnosis is a way to identify, isolate and detect faults. Initially, it will determine the fault by fault detection. Then after the fault has been identified, isolating the fault determines the location of the fault. Then follows the fault identification which describes the fault’s characteristics. Online monitoring is the other designation to fault detection and diagnosis and applied to monitor the system continuously during operation. Model-based method and model-free method are the two classifications of fault detection and diagnosis. Model-free method is further classified into multivariate (data-driven) and univariate (signal-based). Model-based fault detection and diagnosis is a mathematical model used to represent the system’s normal behavior. Faults are detected and diagnosed by comparing the actual condition to the predicted or theoretical condition using a model.
Multivariate fault detection and diagnosis also into the relationships of correlated measurements of parameters. However, relationships may be developed in an implicit methodology by training an empirical model through analysis of fault free training data obtained at normal operations. The empirical model is used to estimate the values of new measurements then faults are detected and diagnosed by analyzing the residuals. Univariate method fault detection and diagnosis decide by comparison of features or spectrum from a signal to the desired baseline values. Data-driven fault detection and diagnosis and signal based fault detection and diagnosis methods are mostly used in various industries, Jianping Ma, Jin Jiang,2010. Several steam turbine operating parameters, if analyzed properly will complement every established condition monitoring program. Many studies are already being performed in the area of steam turbine fault detection and diagnosis where frameworks are created to formulate working programs to automatically notify or alert human operators of impending problem or issue the steam turbine currently being experienced. The program can immediately shut down the steam turbine in order to protect the safety of the operators and lessen the impact of the problem mechanically; and alert the maintenance team in order to properly schedule the maintenance to be conducted thus decreasing the maintenance cost. As prescribed by PTC 6S, the steam turbine must undergo occasional performance testing to test the steam turbine if the actual performance still at par with the guaranteed performance provided by the original equipment manufacturer of the steam turbine. This prescription becomes an issue to plant operators because of the required planning and resources needed to conduct the testing only for the purpose of knowing if the performance of the steam turbine is still at par with the design condition guaranteed by the original equipment manufacturer.
Performance testing interval could be decreased if online performance monitoring by trending will be implemented measuring different steam turbine parameters which could also give a valuable insight whether the steam turbine is actually operating reasonably below its previous performance, Revalo, 2016. Synthesis and Justification This research will provide a simplification of notification or a quick tool in order to detect steam turbine performance degradation thru introduction of empirically derived quantity from the selected steam turbine operating parameters. By trending this quantity, performance degradation can be easily being detected even the selected parameters are continuously changing due to the changing requirement of the process. By eliminating the noise of the continuously changing measurement of the selected parameters, analyzing will be quick and just visual by observing the trend which also no need for further calculation. Deposition or fouling in steam turbine blades is the major cause of early degradation of steam turbine performance. If not properly managed, the effect to the steam turbine is quick and still, if partially mitigated, a gradual deposition to the steam turbine nozzles and blades will still manifest. TC-700 of Petron Bataan Refinery is suffering with this type of problem. This steam turbine drives the un-spared and critical compressor of Fluid Catalytic Cracker (FCC) unit. Performance testing just as prescribed by ASME PTC-6S cannot be implemented due to the fact that FCC cannot be shut down due to the apparent economic loss. Therefore, performance monitoring is the only way to have an idea or a hint of possible gradual degradation of steam turbine performance. The performance monitoring will complement the already established condition monitoring of the steam turbine. There are already established researches on the area of early fault detection and diagnosis using
different methods and developing a software which basically analyzes and compare different steam turbine parameters. Past studies establish a method by using advanced approaches such as neural, heuristic and fuzzy logic in performing analysis in determining the problem. This study is different due to the fact that it is a quick and simple trend representation of overall steam turbine performance. It will use simple manipulation of steam turbine parameters in order to come up with an empirically derived quantity which is trendable and can be exported to Excel. This will serve an early detection which should notify the Reliability Engineers of Petron Bataan Refinery to perform an in depth analysis of the steam turbine. Theoretical Framework Hyeonmin Kim, Man Gyun Na and Gyunyoung Heo have a research study on Application of monitoring, diagnosis, and prognosis in thermal performance analysis for nuclear power plants. This study made light of implementation an in-situ or basically a performance monitoring model for nuclear power plants. Turbine faults are referred to the work of K. C. Cotton, 1998 to his book “Evaluating and Improving Steam Turbine Performance,” where diagnostics matrix for steam turbine monitoring was presented. Steam Turbine performance degradation due to blade deposition and fouling was well presented by GE Water, 2012. Jianping Ma, Jin Jiang,2010 further explains the purpose of condition monitoring in fault detection and diagnosis which to be used for nuclear power plants.
References Terrell Croft (1923), Steam Turbine Principles and Practice, 4th Edition
Saudi Aramco (2003), Engineering Encyclopedia - Steam Turbines Saudi Aramco (2003), Engineering Encyclopedia - Determining Steam Turbine Performance Characteristics. ASME PTC 6S REPORT (2003), Procedures for Routine Performance Tests of Steam Turbines. http://www.plant-maintenance.com/articles/steam_turbine_analysis.shtml http://www.maintenanceworld.com/wp-content/uploads/2013/07/jqme3.pdf W.E.Forsthoffer (2011), Forsthoffer's Best Practice Handbook for Rotating Machinery Otakar Jonas, Lee Machemer, 2008, Proceedings of the Thirty-Seventh Turbomcachinery Symposium - Steam Turbine Corrosion and Deposits Problems and Solutions Otakar Jonas, Joyce Mancini, Jonas, Inc., 2001, Materials Performance - Steam Turbine Problems and Their Field Monitoring. Forsthoffer’s best practice Handbook for Rotating Machinery by William E. Firsthoffer. Publisher” Elsevier, Ltd. Massachusetts, USA. 2011 GE
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L. Sivakumar, S. Devi, 2014, Applied Soft Computing (730-741) - Implementation of VLSI model as a tool in diagnostics of slowly varying process parameters which affect the performance of steam turbine Jolanta Baran,2016, Energy Conversion and Management - Redesign of steam turbine rotor blades and rotor packages - Environmental analysis within systematic eco-design approach Hyeonmin Kim, Man Gyun Na, Gyunyoung Heo, 2014, Application of monitoring, diagnosis, and prognosis in thermal performance analysis for nuclear power plants. Jianping Ma, Jin Jiang,2010, Progress in Nuclear Energy - Applications of fault detection and diagnosis methods in nuclear power plants: A review Joseph A. MacDonald, 2003, Increasing Steam Turbine Power Generation Efficiency Energy Tech Magazine K. C. Cotton, “Evaluating and Improving Steam Turbine Performance,” 2nd ed., Cotton Fact Inc., 1998, pp.332.
