Combined-Cycle Start-Up Procedures: Dynamic Simulation and Measurement

2016 ◽  
Author(s):  
Nicolas J. Mertens ◽  
Falah Alobaid ◽  
Bernd Epple ◽  
Hyun-Gee Kim
Keyword(s):  
Power Plant ◽  
Dynamic Simulation ◽  
Steam Generator ◽  
Heat Recovery ◽  
Thermal Stresses ◽  
Measurement Data ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Start Up ◽  
Fast Start

The daily operation of combined-cycle power plants is increasingly characterized by frequent start-up and shutdown procedures. In addition to the basic requirement of high efficiency at design load, plant operators therefore acknowledge the relevance of enhanced flexibility in operation — in particular, fast start-ups — for plant competitiveness under changing market conditions. The load ramps during start-up procedure are typically limited by thermal stresses in the heat recovery steam generator (HRSG) due to thick-walled components in the high pressure circuit. Whereas conventional HRSG design is largely based on simple steady-state models, detailed modelling and dynamic simulation of the relevant systems are necessary in order to optimize HRSG design with respect to fast start-up capability. This study investigates the capability of a comprehensive process simulation model to accurately predict the dynamic response of a triple-pressure heat recovery steam generator with reheater from warm and hot initial conditions to the start-up procedure of a heavy-duty gas turbine. The commercial combined-cycle power plant (350 MWel) was modelled with the thermal-hydraulic code Apros. Development of the plant model is based on geometry data, system descriptions and heat transfer calculations established in the original HRSG design. The numerical model is validated with two independent sets of measurement data recorded at the real power plant, showing good agreement.

scholarly journals Combined Cycle Power Plant Start-Up Effects and Constraints of the HRSG

1992 ◽  
Author(s):  
Akber Pasha
Keyword(s):  
Power Plant ◽  
Conceptual Design ◽  
Steam Generator ◽  
Heat Recovery ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Combined Cycle Power Plant ◽  
System A ◽  
Start Up ◽  
Total Plant

The heat recovery steam generator (HRSG) is an integral part of the combined cycle power plant which includes combustion turbine and steam turbine in addition to heat recovery steam generator. The start-up of the heat recovery steam generator, therefore, has an influence on the start-up of the total plant. The paper discusses various constraints, both external and internal, which affect the Steam Generator start-up and in turn influence the start-up of the total plant. Considerations in the design of the steam generator to accommodate the plant start-up requirements, along with the effect of the cyclic or base loaded operation are also discussed. The paper also presents a procedure which may be adopted in the conceptual design of the plant for an optimized system, a system which can accommodate the total plant start-up requirements without undue constraints on the availability of the full plant output.

Simulation and Optimization of Combined Cycle Power Cycles Through HRSG’s Heat Exchangers Arrangement and Parameters for Exergy and Cost

2012 ◽  
Author(s):  
Ravin G. Naik ◽  
Chirayu M. Shah ◽  
Arvind S. Mohite
Keyword(s):  
Power Plant ◽  
Steam Generator ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Second Law Of Thermodynamics ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Exergetic Efficiency ◽  
Power Cycles ◽  
Combined Cycle Power Plant

To produce the power with higher overall efficiency and reasonable cost is ultimate aim for the power industries in the power deficient scenario. Though combined cycle power plant is most efficient way to produce the power in today’s world, rapidly increasing fuel prices motivates to define a strategy for cost-effective optimization of this system. The heat recovery steam generator is one of the equipment which is custom made for combined cycle power plant. So, here the particular interest is to optimize the combined power cycle performance through optimum design of heat recovery steam generator. The case of combined cycle power plant re-powered from the existing Rankine cycle based power plant is considered to be simulated and optimized. Various possible configuration and arrangements for heat recovery steam generator has been examined to produce the steam for steam turbine. Arrangement of heat exchangers of heat recovery steam generator is optimized for bottoming cycle’s power through what-if analysis. Steady state model has been developed using heat and mass balance equations for various subsystems to simulate the performance of combined power cycles. To evaluate the performance of combined power cycles and its subsystems in the view of second law of thermodynamics, exergy analysis has been performed and exergetic efficiency has been determined. Exergy concepts provide the deep insight into the losses through subsystems and actual performance. If the sole objective of optimization of heat recovery steam generator is to increase the exergetic efficiency or minimizing the exergy losses then it leads to the very high cost of power which is not acceptable. The exergo-economic analysis has been carried to find the cost flow from each subsystem involved to the combined power cycles. Thus the second law of thermodynamics combined with economics represents a very powerful tool for the systematic study and optimization of combined power cycles. Optimization studies have been carried out to evaluate the values of decision parameters of heat recovery steam generator for optimum exergetic efficiency and product cost. Genetic algorithm has been utilized for multi-objective optimization of this complex and nonlinear system. Pareto fronts generated by this study represent the set of best solutions and thus providing a support to the decision-making.

scholarly journals Thermodynamic analysis of heat recovery steam generator in combined cycle power plant

2007 ◽  
Vol 11 (4) ◽  
pp. 143-156 ◽  
Author(s):  
Kumar Ravi ◽  
Krishna Rama ◽  
Rama Sita
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Steam Generator ◽  
Heat Recovery ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Combined Cycle Power Plant ◽  
Pressure Steam ◽  
Turbine Output

Combined cycle power plants play an important role in the present energy sector. The main challenge in designing a combined cycle power plant is proper utilization of gas turbine exhaust heat in the steam cycle in order to achieve optimum steam turbine output. Most of the combined cycle developers focused on the gas turbine output and neglected the role of the heat recovery steam generator which strongly affects the overall performance of the combined cycle power plant. The present paper is aimed at optimal utilization of the flue gas recovery heat with different heat recovery steam generator configurations of single pressure and dual pressure. The combined cycle efficiency with different heat recovery steam generator configurations have been analyzed parametrically by using first law and second law of thermodynamics. It is observed that in the dual cycle high pressure steam turbine pressure must be high and low pressure steam turbine pressure must be low for better heat recovery from heat recovery steam generator.

Fast start-up analyses for Benson heat recovery steam generator

Energy ◽  
2012 ◽  
Vol 46 (1) ◽  
pp. 295-309 ◽  
Author(s):  
Falah Alobaid ◽  
Stefan Pfeiffer ◽  
Bernd Epple ◽  
Chil-Yeong Seon ◽  
Hyun-Gee Kim
Keyword(s):  
Steam Generator ◽  
Heat Recovery ◽  
Heat Recovery Steam Generator ◽  
Start Up ◽  
Fast Start

scholarly journals Simulation of a Heat Recovery Steam Generator Operating in a Combined Cycle Plant

2013 ◽  
Author(s):  
Raphael Duarte ◽  
Sandro Ferreira ◽  
Rafael Barbosa
Keyword(s):  
Heat Exchanger ◽  
Power Plant ◽  
Steam Generator ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Computational Models ◽  
Structural Changes ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Energy Potential

The heavy duty gas turbines evolution led to higher combined cycle efficiencies. Thus, more complex heat recovery steam generators were developed in order to maximize the use of that energy potential. Therefore, computational models capable to predict the operational conditions of the equipment may be needed in order to analyze the system behavior for different situations. This article describes a computational model able to simulate the off-design behavior of a heat recovery steam generator (HRSG) operating in a combined cycle power plant. The model was developed so that it can be used in both model-based diagnostics systems and performance evaluation systems. Each heat exchanger inside the HRSG was designed individually and arranged according to the analyzed equipment. The computer code’s architecture was built in such a way that it can be easily changed, allowing the analysis of other HRSG’s configurations with simple structural changes, given the program’s modularity. In order to deal with the lack of details of the power plant equipment, which means not enough geometrical information of each heat exchanger, a generic algorithm tool was used to calibrate the heat exchangers models using only the measured data of the power plant SCADA. The developed program was validated against operational data from a real plant and showed satisfactory results, confirming the robustness of this model.

Application of GPA to Combined Cycle Gas Turbine Plants

2004 ◽  
Author(s):  
A. I. Zwebek ◽  
P. Pilidis
Keyword(s):  
Power Plant ◽  
Path Analysis ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Steam Generator ◽  
Heat Recovery ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
A New Technique ◽  
Gas Turbine Cycle

This paper investigates the possibility of applying a new technique called Gas/Steam Path Analysis (GSPA), that is based on the principles of Gas Path Analysis (GPA), to gas as well as steam turbine plants (as one unit) that are main parts of a combined cycle power plant by way of simulation. In order to facilitate this investigation two pieces of software were developed at Cranfield University. With this technique, it was possible to monitor the major components of the combined cycle, and hence predict the faults that may occur within the cycle beforehand. Faults looked at were, fouling and erosion of gas and steam turbine units, heat recovery steam generator degradation (scaling and/or ashe deposition), and condenser degradation. The obtained results from GSPA calculations of the cases investigated showed that “GSPA” technique can be equally applied to either gas turbine cycle, steam turbine cycle, or to the combination of the two in a form of combined cycle. The procedure, assumptions made, and the results obtained are presented and discussed herein.

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