Variability in Thermal Performance and Measured Heat Rate in Fossil-Fuelled Power Plants

Author(s):  
F L Carvalho ◽  
F H D Conradie ◽  
H Kuerten ◽  
F J McDyer

The paper examines the variability of key parameters in the operation of ten thermal power plants in various commercial grid environments with a view to assessing the viability of ‘on-demand’ plant performance monitoring for heat rate declaration. The plants of various types are limited to coal- and oil-fired units in the capacity range of 305–690 MW generated output. The paper illustrates the influence of control system configuration on effective and flexible power plant management. The analysis of variability indicates that there is a reasonable probability of achieving adequately stable operating periods within the normal operating envelope of grid dispatch instructions when thermal performance monitoring and display can be undertaken with a high confidence level. The levels of variability in fuel quality, which were measured during nominally constant levels of fuel input and generated output, range from about +1 per cent for oil-fired plants to about ±5 per cent for coal-fired power plants. The implications of adopting on-line monitoring of unit heat rate as an input to the generation ordering and unit commitment process are potentially significant cost and energy conservation benefits for utilities having a high proportion of coal- and oil-fired generation.

Author(s):  
Komandur S. Sunder Raj

The objectives of an effective power plant performance monitoring program are several-fold. They include: (a) assessing the overall condition of the plant through use of parameters such as output and heat rate (b) monitoring the health of individual components such as the steam generator, turbine-generator, feedwater heaters, moisture separators/reheaters (nuclear), condenser, cooling towers, pumps, etc. (c) using the results of the program to diagnose the causes for deviations in performance (d) quantifying the performance losses (e) taking timely and cost-effective corrective actions (f) using feedback techniques and incorporating lessons learned to institute preventive actions and, (g) optimizing performance. For the plant owner, the ultimate goals are improved plant availability and reliability and reduced cost of generation. The ability to succeed depends upon a number of factors such as cost, commitment, resources, performance monitoring tools, instrumentation, training, etc. Using a case study, this paper discusses diagnostic techniques that might aid power plants in improving their performance, reliability and availability. These techniques include performance parameters, supporting/refuting matrices, logic trees and decision trees for the overall plant as well as for individual components.


Author(s):  
Michael McClintock ◽  
Kenneth L. Cramblitt

Monitoring thermal performance in the current generation of combined cycle power plants is frequently a challenge. The “lean” plant staff and organizational structure of the companies that own and operate these plants frequently does not allow the engineering resources to develop and maintain an effective program to monitor thermal performance. Additionally, in many combined cycle plants the highest priority is responding to market demands rather than maintaining peak efficiency. Finally, in many cases the plants are not designed with performance monitoring in mind, thus making it difficult to accurately measure commonly used indices of performance. This paper describes the performance monitoring program being established at a new combined cycle plant that is typical of many combined cycle plants built in the last five years. The plant is equipped with GE 7FA gas turbines and a GE reheat steam turbine. The program was implemented using a set of easy-to-use spreadsheets for the major plant components. The data for the calculation of indices of performance for the various components comes from the plant DCS system and the PI system (supplied by OSIsoft). In addition to the development of spreadsheets, testing procedures were developed to ensure consistent test results and plant personnel were trained to understand, use and maintain the spreadsheets and the information they produce.


Author(s):  
Masoud Darbandi ◽  
Hamid Reza Khorshidi Behzadi ◽  
Vahid Farhangmehr ◽  
Gerry E. Schneider

The use of air-cooled steam condenser (ACSC) in thermal power plants has become so normal since a few decades ago. It is because there are so many valuable advantages with the ACSC implementation, e.g., little dependency on water consumption and benefiting from the forced convection heat transfer instead of the natural one to condense the steam. However, the thermal performance of an ACSC can be readily defected by the ambient wind; specifically, when the ambient temperature is high. This research work benefits from the computational fluid dynamics tool to study the details of ACSC’s thermal performance in such undesirable ambient windy conditions. Furthermore, this work suggests an effective remedy to increase the heat rate from the proposed ACSC. Evidently, the flow rate of cold air through the heat exchangers of proposed ACSC has direct influence in heat transfer rate from the heat exchangers of ACSC. One remedy to achieve higher cold air flow rates through these heat exchangers is to improve the design of its fans or blowers. However, for an ACSC already in service, one should look for other cost-effective remedies. So, if one wishes to improve the performance of those fans without changing their design one should pay attention to some other simple ways with little costs to implement them. This work suggests to tune up the pitch angles of blades of ACSC’s fans properly. The details of implementing this remedy are presented in this paper.


Author(s):  
Nynar Ayodhi ◽  
Y. Radhakrishnamurthy

Achieving rated capacity and economical operation of existing thermal power plants are vital issues for utilities. Plants nearing their design life are likely to show declining trend in availability as well as increasing trend in operation and maintenance costs due to ageing. Constraints in system adequacy, decreasing trend in efficiency and poor reliability are key issues to be addressed while planning life extension. 4×110 MW power plant located in southern part of India has been taken up for renovation and modernization. Pressure parts failures mainly accounted for the reduced availability of the units. The exit gas temperature in boiler was on the higher side leading to operation of the units with reduced efficiency. Change in fuel quality over the years as compared to what has been considered during design was a constraint in achieving rated capacity. The poor heat rate of turbine necessitated incorporation of the state-of-art design to achieve better heat rate. Improvements required in control and instrumentation system were also addressed in the renovation and modernization. Improvements in plant load factor, availability and unit heat rate could be achieved in the two units where renovation and modernization has been completed. The details of the renovation and modernization of these units are discussed in this paper.


Author(s):  
Helmer Andersen

Fuel is by far the largest expenditure for energy production for most power plants. New tools for on-line performance monitoring have been developed for reducing fuel consumption while at the same time optimizing operational performance. This paper highlights a case study where an online performance-monitoring tool was employed to continually evaluate plant performance at the Kalaeloa Combined Cycle Power Plant. Justification for investment in performance monitoring tools is presented. Additionally the influence of various loss parameters on the cycle performance is analyzed with examples. Thus, demonstrating the potential savings achieved by identifying and correcting the losses typically occurring from deficiencies in high impact component performance.


Author(s):  
Vijiapurapu Sowjanya ◽  
Robert Craven ◽  
Sastry Munukutla

Real-time performance monitoring of coal-fired power plants is becoming very important due to the impending deregulation of the electric power industry. Performance testing is made to be real-time by changing the traditional output loss method to include an estimation of coal composition based on the Continuous Emission Monitoring System (CEMS) data. This paper illustrates the robustness of the calculations by introducing a variance into each of the calculation inputs to access its effect on the final outputs of heatrate, boiler efficiency and coal flow. Though the original study was over five power plants this paper presents results for the two most diverse coals.


Author(s):  
Olivier Le Galudec ◽  
James Oszewski ◽  
John Preston ◽  
David Thimsen

In the field of Power Generation, Operators — Plant Owners, Utilities, IPPs … — have had to face severe constraints linked not only with price of electricity and cost of fuel, but also with more and more demanding environmental constraints. It appears that the next atmospheric emission coming under scrutiny is CO2. Some small scale laboratory size experiments and pilot scale tests demonstrating the ability to capture CO2 before it reaches the atmosphere have already been conducted, and some industrial scale demonstrators are already at the permitting stage and will soon reach construction. In order to anticipate the needs of Performance Tests within this coming market, ASME decided to form a new committee in order to prepare and deliver ASME Performance Test Code – PTC 48 “Overall Plant Performance with Carbon Capture” test code. This new code may be seen as an evolution of ASME PTC 46 “Performance Test Code on Overall Plant Performance” 1996 (currently under revision), which goes beyond the sole verification of components to provide guidelines for testing a full Plant. Capturing CO2 from fuel–fired power plants will have a significant impact on net capacity and net heat rate of the plant. Such plants will, in addition to the Power Block and Steam Generator, also include systems not commonly included in non-CO2 capture power plants. The addition of an ASU (Air Separation Unit, for oxy-combustion with CO2 capture) and/or CPU (CO2 Purification Unit, for oxy-combustion or post-combustion CO2 capture) has made necessary the preparation of a dedicated test code based upon same guiding principle than PTC 46, i.e. treating the plant globally as a “Black Box”. This approach allows correction of output and efficiency at the plant interfaces, but at the exclusion of internal parameters. It is anticipated that the code can inform development of regulations that define the rules and obligations of Operators. Currently, the proposed PTC 48 aims at fossil fuel fired Steam-electric power plants using either post-combustion CO2 capture or oxy-combustion with CO2 capture technologies. Combined cycles and Integrated Gasification Combined Cycles — IGCCs — are not addressed.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Zhongfu Tan ◽  
Liwei Ju ◽  
Xiaobao Yu ◽  
Huijuan Zhang ◽  
Chao Yu

In order to reduce thermal power generation cost and improve its market competitiveness, considering fuel quality, cost, creditworthiness, and sustainable development capacity factors, this paper established the evaluation system for coal supplier selection of thermal power and put forward the coal supplier selection strategies for thermal power based on integrated empowering and ideal matter-element extension models. On the one hand, the integrated empowering model can overcome the limitations of subjective and objective methods to determine weights, better balance subjective, and objective information. On the other hand, since the evaluation results of the traditional element extension model may fall into the same class and only get part of the order results, in order to overcome this shortcoming, the idealistic matter-element extension model is constructed. It selects the ideal positive and negative matter-elements classical field and uses the closeness degree to replace traditional maximum degree of membership criterion and calculates the positive or negative distance between the matter-element to be evaluated and the ideal matter-element; then it can get the full order results of the evaluation schemes. Simulated and compared with the TOPSIS method, Romania selection method, and PROMETHEE method, numerical example results show that the method put forward by this paper is effective and reliable.


2013 ◽  
Vol 416-417 ◽  
pp. 2110-2113
Author(s):  
Xing Liu

This paper, focusing on the practical moving condition of the thermal power plants, studied in detail that how to did the curve fitting according to the units data collected from Tianjin Dagang Power Plant; studied the each fuel loss in the process of start-stop the units and their calculation methods; and put forward that fuel consumption and life expenditure while starting and stopping the units should be considered when using peak-load regulation; worked out the GA program and proved GAs accuracy and superiority through the calculation examples, and showed that GA had great practical and research meaning.


2021 ◽  
Author(s):  
Flávio Leite Loução Junior ◽  
Marlon Sproesser Mathias ◽  
Claudia Sagastizábal ◽  
Luiz-Rafael Santos ◽  
Francisco Nogueira Calmon Sobral

In partnership with CCEE, CEPEL and RADIX as industrial partners, in 2021 the study group focused on the dynamics of hourly prices when industrial consumers are demand responsive, as a follow-up of the industrial problem tackled in 2018 and 2019, on ``Day-ahead pricing mechanisms for hydro-thermal power systems''. Demand response is currently being tested by the Brazilian independent system operator and by the trading chamber, ONS. The program considers reductions of consumption of some clients as an alternative to dispatching thermal power plants out of the merit order. The day-ahead problem of finding optimal dispatch and prices for the Brazilian system is modelled as a mixed-integer linear programming problem, with non-convexities related to fixed costs and minimal generation requirements for some thermal power plants. The work focuses on the point of view of an individual hydro-power generator, to determine business opportunities related to adhering to a demand response program.


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