MW Combined Cycle Power Plant Research Articles

Dynamic process simulation of a 780 MW combined cycle power plant during shutdown procedure

The share of variable renewables in power generation is increasing due to the push to reduce emissions, and the flexibility of conventional power plants has become a major concern. There are many ways to increase the flexibility of existing power plants and implement a more flexible system for the future, such as a fast start-up procedure and higher load change rates. In this study, a 2D dynamic process simulation model of a reference combined cycle power plant is presented to increase the flexibility of cyclic operation by investigating, for the first time in the literature, the shutdown procedure using APROS software. The 780 MWel Tambak Lorok reference combined cycle power plant consists of the GE 9HA.02 heavy-duty gas turbine and a three-stage horizontal heat recovery steam generator with reheat. Several steps were considered to improve the accuracy of the developed dynamic process simulation model, including varying the steam leakage to the atmosphere to control how much thermal energy remains in the heat recovery steam generator, changing the shape loss coefficients of the tubes to achieve higher or lower recirculation, and decoupling the reheater and the intermediate pressure drum. The developed model is validated with real data from three different combined cycle power plants in different countries with various capacities. The comparison shows that the developed dynamic simulation model can accurately represent the real behaviour of natural convection in the heat recovery steam generator. The main outcome was to provide detailed information on the shutdown procedure of large-scale combined cycle power plants, addressing the aspect of the development of new start-up strategies to reduce the time required for the start-up procedure.

Energy and exergy assessment of 750 MW combined cycle power plant: A case study

As global energy demand continues to rise, the imperative to explore and enhance energy generation from existing resources intensifies. Combined cycle power plants (CCPPs) have emerged as a promising solution to improve efficiency and electricity production. In this study, we present a comprehensive analysis of the thermodynamic performance of a 750 MW CCPP located in Assiut, Egypt, with a focus on its energy and exergy efficiency. Our investigation reveals critical insights into the CCPP's operational dynamics. Notably, the combustion chambers emerge as the primary contributors to exergy destruction, accounting for 53.3 % of the total exergy loss. Heat recovery steam generators (HRSGs) follow closely at 32 %, while compressors, steam turbines, gas turbines, and cooling systems contribute 5.3 %, 5 %, 2.3 %, and 1.7 %, respectively. These findings pinpoint specific areas where exergy losses are most significant, offering valuable guidance for targeted improvements in CCPP performance. Furthermore, we report that the overall energy efficiency of the entire plant stands at 34.6 %, with an exergy efficiency of 33.5 %. In summary, our study provides a comprehensive scientific assessment of the thermodynamic performance of a 750 MW CCPP. The specific insights into exergy destruction and efficiency metrics not only contribute to our understanding of CCPPs but also offer actionable recommendations for optimizing the operation of gas turbine based CCPPs. These findings hold significance in the broader context of energy sustainability and environmental considerations.

Sustainable operations of a combined cycle power plant using artificial intelligence based power prediction

Combined Cycle Power Plants (CCPP) are an effective method for Power generation due to their high thermal efficiency, low fuel consumption, and low greenhouse emissions. However, investing millions into building a power plant without knowledge of the power generation capacity seems unproductive. With the help of AI, we have tried to eliminate this conundrum. The present study focuses on the prediction of power produced by a 747 MW Combined Cycle Power Plant (CCPP) using a Back Propagation Neural Network (BPNN) and compares its results with the actual data from CCPP. BPNN is a regression-based prediction technique that is utilized in this study to develop a predictive model and train it using the following input features: Ambient Temperature, Ambient Pressure, Mass Flow rate of fuel in Gas Turbine 1, and Mass Flow rate of fuel in Gas Turbine 2. The Predictive Model with 10 neurons in the hidden layer was found to be most effective with Mean Squared Error (MSE) value, for the validation dataset, of 0.0063237. CCPP is also analyzed through a thermodynamic model, developed using EES. A detailed energy analysis is carried out and the results were compared with predicted and actual data. It was found that the thermal efficiency and total power generation of actual, predicted, and simulated models were 27.541% & 667.32 MW, 28.238% & 683.48 MW and 28.201% & 683.16 MW, respectively. A parametric study was further carried out to investigate the significance of operating parameters on power output and it was concluded that the temperatures across the Gas turbines have a significant impact on the performance of CCPP. Finally, Methane was replaced by 3 different fuels, one by one, and the effect of each fuel was investigated thermodynamically. It was found that the Lower Heating Value (LHV) of fuel was an important parameter in achieving a higher power output. It can be summarized from this research work that predictive models do have accuracy and such data science techniques can be used as a substitute for extensive thermodynamic calculations.

Growth and Yield Performance of Green Capsicum (Capsicum Annuum L.) As Influenced by Vermicompost Application Grown at Rooftop Of Chandpur Area

A pot experiment was conducted during rabi season during 2020-21 at a rooftop of Chandpur 150 MW Combined Cycle Power Plant (CCPP) Area in Chandpur Sadar upazila under Chandpur district to study the impact of different dosages of vermicompost (VC) on the growth and yield parameters of green capsicum plants (Capsicum annuum L.). It was laid out in a randomized complete block design (RCBD) with three replications each of six treatments viz. T1: 0 ton VC ha-1 (control), T2: 2.5 ton VC ha-1, T3: 5 ton VC ha-1, T4: 7.5 ton VC ha-1, T5: 10 ton VC ha-1, and T6:15 ton VC ha-1. Results revealed that maximum plant height (38.53 cm), number of leaf plant-1 (80), and highest number of branches plant-1 (6) were recorded in T5 followed by T3. The highest values for rest of the growth and yield parameters were found from the plant receiving VC at the rate of 5 ton ha-1 (T3), such as, longest leaf per plant (12.84 cm), highest number of branches plant-1 (6), maximum girth (3.53 cm), maximum number of fruits plant-1(7), average fruit weight (44.75 g fruit-1), maximum weight of fresh (320.28 g fruits plant-1) and dry (4.43 g fruits plant-1); and maximum total fresh (109.40 g) and dry weight (21.03 g) of plants. Highest fruit length (18.97 cm) and diameter of fruit (7.30 cm) were recorded in T5 and T4, respectively. Almost all of the growth and yield parameters were observed lowest in control (T1). Study indicates that supreme dose of VC 15 ton ha-1 in T6 yielded lower performance compare to 10 and 5 ton VC ha- 1. Considering the overall performance, it may be concluded that vegetative growth and yielding capacity of green capsicum plants can be boosted up by applying vermicompost at the rate of 10 ton ha-1 and 5 ton ha-1, respectively. This new information will be beneficial for growers, researcher and relevant workers. J. Biodivers. Conserv. Bioresour. Manag. 2021, 7(2): 13-22

Comparative evaluation of Integrated Solar combined cycle plant with cascade thermal storage system for different heat transfer fluids

The existing conventional combined cycle power plant(s) are generally not getting the schedules for supply of power because of the high price of Natural Gas and are forced to remain idle or to run on part load. On the other side, the focus is on the capacity addition of power generation units based on the alternate sources mainly solar to counter the ill effects on environment through fossils fuel-based plant(s). In such a scenario, the combined cycle power plant(s) with its integration with solar (ISCC) can pave the way forward to provide an optimal solution to tap most of the power generation through solar power and to ensure grid stability through utilising the installed combined cycle power plant(s) at part or full load. It will be a win-win situation for solar plants as well as combined cycle power plants. This study presents an integration of Linear Fresnel collector solar system and latent heat cascade storage system with a 328.10 MW combined cycle power plant of north India for operating it as integrated solar combined cycle (ISCC). The present work discusses the configurations of integration of solar power generation cycle with the combined cycle power generation and presents the analysis of the performance of these integration configurations including the operation of gas turbine(s) at full load or part load. A MATLAB code is used for simulation to analyse the performance of ISCC by varying direct normal irradiation at different part-load condition of gas turbine with different heat transfer fluids such as water and molten salt, then also compare the performance of latent heat cascade thermal storage system with oil & molten salt as HTF. The effect of cascade thermal storage has also been analysed on the plant performance. The efficiency of ISCC with molten salt as HTF is 50.87% which is more than with water as HTF by 1.51%. The present study also brings out the saving of the fuel to figure out the financial benefit. However, the financial model has not been developed in the present work due to the dynamics of the price of natural gas internationally. The study also presents the analysis of the enhanced fuel-saving ratio and reduced emissions.

Exergy, Economical and Environmental analysis of a natural gas Direct Chemical Looping Carbon capture and Formic acid-based hydrogen storage system

Chemical looping combustion is one of the novel technologies in energy, which can co-generate hydrogen and power with an efficient carbon capture process to control the system’s emission. This system’s carbon capture process is one of the main processes to achieve the United nations’ environmental goals and other climate change control agencies. This paper aims to study Designing a Natural Gas Direct Chemical Looping Carbon capture and Formic acid Hydrogen storage system for a combined cycle power plant and analyze it with energy, exergy, and environmental factors. The model was implemented on a 500 MW combined cycle power plant unit in Iran, and the results show that if the model is implemented on the plant, overall energy efficiency can be increased by 33%. Furthermore, according to the references, the carbon emissions decreased more than 93%, which is an achievable target using the Chemical looping combustion.

Life Cycle Assessment of a combined cycle power plant in Indonesia

This paper presents the Life Cycle Assessment (LCA) of a 640 MW combined cycle power plant located in West Java, Indonesia. The power plant adopts the dual-fuel firing system, in which both natural gas and high-speed diesel fuels are used. The LCA was performed using the open-source LCA software OpenLCA version 1.9. A functional unit of 1 kWh of electricity generation was used in calculating the environmental impacts. The system boundary was modeled using the gate-to-gate system, which includes all inputs and outputs for the following subsystems: fuel storage, water preparation, electricity production, and supporting subsystems. The life cycle inventory (LCI) used data gathered from July 2018 to June 2019. The CML-IA baseline method was used to perform the life cycle impact assessment (LCIA), providing results for ten midpoint impact categories. All impact categories were normalized using World 2000 normalization factors. The result shows that the most significant impact categories are acidification potential (AP), eutrophication potential (EP), and global warming potential (GWP), respectively. The largest acidification source is nitrogen oxide emission from the combustion chamber, with a percentage of 80.32%. Regarding the combustion stage, the post-combustion method is recommended to remove nitrogen oxide from exhaust gases to lower the AP impact category.

Optimization of CCGT operating modes at variable loads taking into account equivalent operating hours

The optimal control of the operating modes of combined cycle power plants is a difficult scientific and practical task, due to the difficulty of taking into account the real technical condition of the equipment, the particularities of the operating modes of a combined cycle gas turbine (with one or two operating gas turbines) and other factors. To determine the optimal regime of combined cycle unit with heat recovery steam generator at variable loads, the method of calculating equivalent operating hours (equivalent operating time) was used, based on the accumulation of damageability from creep and low-cycle fatigue of the main equipment of the combined cycle unit (gas, steam turbines and heat recovery steam generators). The equivalent operating hours and economic parameters of the 450 MW combined cycle power plant were calculated and the optimal operating mode of the main equipment was determined while reducing the load during night off-peak hours.

Heat Rate Gap and Cost Analysis Due to Increase of Condenser Pressure in A 660 MW Combined Cycle Power Plant

A condenser is one of the main equipment in a Combined Cycle Power Plant (CCPP) cooling system which has a great influence on steam turbine output and thermal efficiency of the whole power plant as well. The objective of this study is to analyze the effect of increase in condenser pressures on the heat rate and electricity production costs. The primary data is acquired from the DCS. These data are then compared to those of the best performance operating data. The differences of these two data of 23 parameters, are then integrated with the impact factor to gain the heat rate loss. Based on the heat rate loss, then the cost of electricity production is established accordingly. The study concludes that the increase of condenser pressure from 2.41 inHgA to 2.82 inHgA results in increase of plant heat rate 19.55 kcal/kWh. The 5 great parameters to contribute to this loss are: HP and LP steam flows, condenser pressure, stack temperatures of HRSG 1.3 and 1.2. Meanwhile, the cost of production rises up from 751 IDR/kWh to 805 IDR/kWh

Thermodynamics Performance Evaluation in Combined Cycle Power Plant by Using Combined Pinch and Exergy Analysis

In this paper, combination between pinch and exergy analysis for a 326 MW Combined Cycle Power Plant (CCPP) at Tanjung Priok is performed. These cycles are made of a gas turbine, a steam turbine and Heat Recovery Steam Generator (HRSG). In addition to analyze the performance of each component (compressor, combustion chamber, turbine, heat recovery steam generator) of the Combined Cycle Power Plant CCPP Tanjung Priok, this study also analyzes the impact of changes in the operating costs of the power plant after optimizing the parameters (pinch point and steam drum pressure). By using exergy analysis, the initial data used to analyze the performance and identified which components of the system that has the potential to do the performance improvement. The experience-based values for the pressure of the high-pressure and the low-pressure drum are selected and held constant during this step. One of the initial steps taken in the optimization of this system is to determine the optimum temperature difference in the heat exchange process that occurs in heat recovery steam generator (The value for the pinch point is varied in the range of 5 to 40 °C in steps of 0.5 °C). Then, through the developed optimization process, other optimal operating parameters were identified. The optimized combined cycle was compared with the Initial data. The application results of combined pinch and exergy analysis (CPEA) in the power plant showed that the net power could be increased by 2.67% and the exergetic efficiency could be increased from 45.9% to 47.1%.

Energy and Exergy Analysis for Unit13E1 of Benghazi Combined Cycle Power Plant

Presented in this paper, an exhaustive energy-exergy analysis of a 476 MW combined cycle power plant located in Benghazi-Libya, as an example to illustrate the utility and importance of exergy analysis compared with energy analysis. The proposed power plant cycle was simplified into sub-systems and modelled. These models of mass, energy and exergy balance equations were applied to each sub-system and farther validated by the manufacturer’s data at design operating condition. The results indicate that, the power plant has an overall energy and exergy efficiencies of 55.0% and 52.0% respectively. The total exergy destruction rate is found to be 444.2 MW (48.3 % of fuel input exergy). Significant exergy destruction rate is found to occur in the combustion chamber which contributes a major share of 340.7 MW (37.06%), followed by heat recovery steam generator with 35.7MW (4. %). Moreover, the results of the exergy analysis are compared with those of energy analysis. The comparison is quite of interest. The exergy analysis is much more enlightening, because the dissipations and efficiencies measured with availability are true one, where as those measured with energy are erroneous and misleading. The benefit of this study has enabled us to identify sites where loss of useful energy (exergy) takes place in a power plant and its performance can be evaluated. The results presented here are of real practical value in many ways, they can be valuable for the academic research interest.

IECP — an approach for integrated environmental and cost evaluation of process design alternatives and its application to evaluate different NOx prevention technologies in a 125 MW thermal power plant

This paper proposes a methodology, IECP (integrated environmental and cost potential), for the integrated environmental and cost evaluation of a process design option. It is designed for a quick quantitative evaluation of a design option at different levels of process synthesis or retrofit applications. A hazard based approach, Pro-hazard, has been developed for the quantitative evaluation of environmental potential of design options by using a cradle-to-gate life cycle assessment. This assigns an environmental potential index to a design option by comparing its environmental performance with respect to the base option. To quickly evaluate the cost of the resulting option a simple approach, Eco-index, has been developed. It gives a cost potential index to a specific design option by comparing its unit operating and fixed cost with respect to that of the base option. In the IECP framework, both the environmental potential and cost potential indices for a design option are combined by assigning an appropriate weighting factor to each index, which gives an integrated index, IECP, for the design option. In this paper, the IECP methodology has been combined with a process simulator, Aspen HYSYS, to obtain the necessary data to quickly and accurately determine the IECP index. The applicability of the proposed IECP approach has been demonstrated through a case study for the selection of potential NOx prevention options in a 125 MW combined cycle power plant from a large number of options related to flue gas recirculation, steam and water injection to the furnace.

Condensate system modelling in real time for a training power plant simulator

In this paper, the basis of the models of the condensate water and the air cooled condenser are presented. The models are part of a full scope simulator of a 450 MW combined cycle power plant. The simulator is executed in real time and is intended to be a support for the training of the operators of the Comisian Federal de Electricidad (the Mexican utility company). The simulator is presently in the final acceptance tests stage and is programmed to be in commercial operation in 2010. Here, are included a summary of the modelling methodology used to develop the referred models and the mathematical fundaments used to obtain the main equations. The tendencies of selected variables during a transient are displayed and analysed in order to probe the validity of the new generic models.

Availability Analysis of Gas Turbines Used in Power Plants

The availability of a complex system, such as a gas turbine, is strongly associated with its parts reliability and maintenance policy. That policy not only has influence on the parts’ repair time but also on the parts’ reliability affecting the system degradation and availability. This study presents a method for reliability and availability evaluation of gas turbines installed in an electric power station. The method is based on system reliability concepts, such as functional tree development, application of failure mode and effects analysis to identify critical components for improvement of system reliability, and reliability and maintainability evaluation based on a historical failure database. The method also proposes the application of Reliability Centered Maintenance concepts to improve complex system maintenance policies aimed at the reduction of unexpected failure occurrences in critical components. The method is applied to the analysis of two F series gas turbines, each with an output of 150 MW, installed in a 500 MW combined cycle power plant. The reliability and availability of the turbines are simulated based on a five-year failure database. The availability analysis shows different results for each turbine, one presenting 99% and the other 96% availability, indicating differences in their systems installation and operation.

Thermodynamic Simulation of A Combined Cycle Power Plant At Part-Load Operation

A 355 MW combined-cycle power plant has been modeled andsimulated at part loads. Results of a sensitivity analysis of the effect ofhigh pressure (HP) on the combined-cycle performance are presented.The best combination of process parameters of steam leaving the steamgenerator that will give optimum performance of the combined-cyclepower plant were determined at part load operation. Results for theoptimum values of thermal efficiency and power output, together withvalues of the decision variables, are presented. At part loads, the plantdemands lower values of HP pressure to get a suitable dry steam at thesteam turbine exit. The combined cycle gives higher power output withhigh efficiency at full load comparatively at partial loads.

Thermodynamic Simulation of A Combined Cycle Power Plant At Part-Load Operation

ABSTRACT A 355 MW combined-cycle power plant has been modeled and simulated at part loads. Results of a sensitivity analysis of the effect of high pressure (HP) on the combined-cycle performance are presented. The best combination of process parameters of steam leaving the steam generator that will give optimum performance of the combined-cycle power plant were determined at part load operation. Results for the optimum values of thermal efficiency and power output, together with values of the decision variables, are presented. At part loads, the plant demands lower values of HP pressure to get a suitable dry steam at the steam turbine exit. The combined cycle gives higher power output with high efficiency at full load comparatively at partial loads.

Exergy analysis of a 420 MW combined cycle power plant

Combined cycle power plants (CCPPs) have an important role in power generation. The objective of this paper is to evaluate irreversibility of each part of Neka CCPP using the exergy analysis. The results show that the combustion chamber, gas turbine, duct burner and heat recovery steam generator (HRSG) are the main sources of irreversibility representing more than 83% of the overall exergy losses. The results show that the greatest exergy loss in the gas turbine occurs in the combustion chamber due to its high irreversibility. As the second major exergy loss is in HRSG, the optimization of HRSG has an important role in reducing the exergy loss of total combined cycle. In this case, LP-SH has the worst heat transfer process. The first law efficiency and the exergy efficiency of CCPP are calculated. Thermal and exergy efficiencies of Neka CCPP are 47 and 45.5% without duct burner, respectively. The results show that if the duct burner is added to HRSG, these efficiencies are reduced to 46 and 44%. Nevertheless, the results show that the CCPP output power increases by 7.38% when the duct burner is used. Copyright © 2007 John Wiley & Sons, Ltd.

Optimization of combined cycle power plants using evolutionary algorithms

This paper deals with the application of an evolutionary algorithm to the minimization of the product cost of complex combined cycle power plants. Both the design configuration (process structure) and the process variables are optimized simultaneously. The optimization algorithm can choose among several design options included in a superstructure of the power plant such as different gas turbine systems available at the market, up to three pressure levels for steam generation in the heat-recovery steam generator, supplementary firing, steam reheat, parallel arrangement of heat exchangers in the gas path, and steam injection into the gas turbine. For the assumptions and simplifications made in this study, a 240 MW combined cycle power plant with a large gas turbine (150 MW), a two-pressure heat recovery steam generator with a reheater but without supplementary firing is favored from an economic viewpoint. A detailed exergy analysis of selected intermediate solutions and the final optimal design identifies the magnitude, location and causes of the thermodynamic inefficiencies.

Thermally induced vibrations due to rub in real rotors

The analysis of the effects of the rotor-to-stator rub in the rotor dynamics field has produced many models, often nonlinear or with particular attention to chaotic behaviour, but with scarce correspondence with real rotors since Jeffcott-like rotors are mainly used without thermal transients, or sometimes real rotors are used but with very simple thermal modelling. One of the most remarkable aspects of the rotor-to-stator rub at operating speed is the possibility of observing spiral vibration phenomena in the synchronous vibration, i.e. the vibration vector changes its amplitude and rotates even at the rated speed. This is due to the combined effect of the contact forces which introduce heat and of the resulting thermal bow. The phenomenon is also called vector turning or thermally induced vibrations. It is interesting to analyse the dynamical behaviour of the machine: the spirals can have a self-propagating trend or conversely a self-correcting trend. The model presented in the paper for the analysis of the spiral vibration has a unique characteristic in that it allows real machines to be analysed, since it uses a fully assembled machine model (rotor, bearings and foundation) and implements a rather sophisticated thermal and contact model. The experimental validation of the proposed model is performed on data coming from a real machine: the generator of a 50 MW combined cycle power plant, in which unstable spiral vibrations were observed at the operating speed during a power increase.

The Taweelah A2 independent water and power project

Taweelah A2 is the first independent water and power project in Abu Dhabi under the government privatization policy. In response to the Abu Dhabi Water and Electricity Authority (ADWEA) request for proposals, CMS Energy prepared and submitted their offer in April 1998. Following clarifications, the Power and Water Purchase Agreement was signed on 3 October 1998. CMS appointed Mott MacDonald as their technical advisers for the tender and project phases. The Taweelah A2 plant will comprise a 720 MW combined cycle power plant and 50 migd MSF desalination plant. Three Siemens type V94.3a gas turbine generators with exhaust heat recovery boilers will supply steam to two back pressure steam turbine generators. Exhaust steam will be taken to four Hanjung 12.5 migd single deck cross tube MSF distillers, equal in capacity to the largest units ever built. Carbon dioxide gas recovered from the distiller air ejectors will be used for remineralizing the distillate. Seawater will be drawn from an existing intake channel serving the complete complex. The boilers are designed for a high level of supplementary firing to meet the wide variations in electrical load on the Abu Dhabi grid, with full water output. Construction of the US $750 million project, located between the existing Taweelah A1 and B stations, began in April 1999. First power production is scheduled in May 2000, first water production in May 2001 and completion in August 2001. The plant will be owned and operated by Emirates CMS Power, jointly owned by CMS and ADWEA. This paper describes the desalination and power plant and outlines the power and water purchase aspects of the project. The high thermal efficiency of the combined cycle and MSF plant minimizes fuel consumption, heat rejection and atmospheric emissions, making this one of the best plants in the region from an environmental standpoint.