Steam Turbine Driving Compressor for Gas-Steam Combined Cycle Power Plant

2009 ◽  
Author(s):  
Wancai Liu ◽  
Hui Zhang
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Combined Cycle ◽  
Thermodynamic Process ◽  
Combined Cycle Power Plant ◽  
Steam Cycle

Gas turbine is widely applied in power-generation field, especially combined gas-steam cycle. In this paper, the new scheme of steam turbine driving compressor is investigated aiming at the gas-steam combined cycle power plant. Under calculating the thermodynamic process, the new scheme is compared with the scheme of conventional gas-steam combined cycle, pointing its main merits and shortcomings. At the same time, two improved schemes of steam turbine driving compressor are discussed.

Performance Modeling of Unfired Steam Cycle Using Single and Dual Pressure Once-Through Steam Generator

2011 ◽  
Author(s):  
Emad Hamid ◽  
Mike Newby ◽  
Pericles Pilidis
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Low Cost ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Low Carbon ◽  
Performance Simulation ◽  
Actual Performance ◽  
Combined Cycle Power Plant ◽  
Steam Cycle

The high thermal efficiency and the use of low carbon content fuel (e.g., natural gas) have made the Combined Cycle Power Plant (CCPP) one of the best choices for power generation due to its benefits associate with low cost and low environmental impact. The performance of Unfired Steam Cycle (USC) as a part of the CCPP has significant impact on the performance of the whole power plant as it provides the CCPP with around one third of the total useful power. An accurate performance simulation of the USC is therefore necessary to analyze the effects of various operating parameters on the performance of combined cycle power plant. In this paper, a performance simulation approach for an unfired steam cycle using single and dual pressure-level of an OTSG is presented. The developed modeling method has been applied to the performance simulation of an existing unfired steam cycle power generation unit installed at Manx Electricity Authority and the results are promising. A comparison between simulated and actual performance at design and off design operating conditions of the same USC has shown a remarkable agreement with errors values below 1%.

Flexible Combined Cycle Gas Turbine Power Plant Utilising Organic Rankine Cycle Technology

2016 ◽  
Author(s):  
Michael Welch ◽  
Nicola Rossetti
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Exhaust Gas ◽  
Operational Flexibility

Historically gas turbine power plants have become more efficient and reduced the installed cost/MW by developing larger gas turbines and installing them in combined cycle configuration with a steam turbine. These large gas turbines have been designed to maintain high exhaust gas temperatures to maximise the power generation from the steam turbine and achieve the highest overall electrical efficiencies possible. However, in today’s electricity market, with more emphasis on decentralised power generation, especially in emerging nations, and increasing penetration of intermittent renewable power generation, this solution may not be flexible enough to meet operator demands. An alternative solution to using one or two large gas turbines in a large central combined cycle power plant is to design and install multiple smaller decentralised power plant, based on multiple gas turbines with individual outputs below 100MW, to provide the operational flexibility required and enable this smaller power plant to maintain a high efficiency and low emissions profile over a wide load range. This option helps maintain security of power supplies, as well as providing enhanced operational flexibility through the ability to turn turbines on and off as necessary to match the load demand. The smaller gas turbines though tend not to have been optimised for combined cycle operation, and their exhaust gas temperatures may not be sufficiently high, especially under part load conditions, to generate steam at the conditions needed to achieve a high overall electrical efficiency. ORC technology, thanks to the use of specific organic working fluids, permits efficient exploitation of low temperatures exhaust gas streams, as could be the case for smaller gas turbines, especially when working on poor quality fuels. This paper looks at how a decentralised power plant could be designed using Organic Rankine Cycle (ORC) in place of the conventional steam Rankine Cycle to maximise power generation efficiency and flexibility, while still offering a highly competitive installed cost. Combined cycle power generation utilising ORC technology offers a solution that also has environmental benefits in a water-constrained World. The paper also investigates the differences in plant performance for ORC designs utilising direct heating of the ORC working fluid compared to those using an intermediate thermal oil heating loop, and looks at the challenges involved in connecting multiple gas turbines to a single ORC turbo-generator to keep installed costs to a minimum.

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.

A Parametric Study Method of Enhancing the Efficiency of Gas Turbine Combined Cycle Power Plant

2013 ◽  
Author(s):  
Jingjin Ji ◽  
Bo Sun ◽  
Dequan Zuo ◽  
Lei He
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
State Of The Art ◽  
Structure Design ◽  
Combined Cycle ◽  
Parameters Optimization ◽  
Cycle Performance ◽  
Feed Water ◽  
Combined Cycle Power Plant

At the present time, with the ever-increasing energy price, gas steam combined-cycle power plant is well received and favored by Chinese local investors due to its quickly-start and stop, high operational flexibility, high thermal efficiency, clean exhaust flue gas, short construction period characteristics. Recent researches make many efforts on the optimization of gas turbine intake system, main equipment parameters matching, and cold side of steam turbine to increase the overall performance of combined cycle. In the paper, we focused on a kind of triple-pressure reheat combined cycle equipped with a state of the art gas turbine, which is gradually entering Chinese market. An accurate overall combined cycle model was built up for the purpose of increasing the efficiency by means of steam parameters optimization. The influence of steam pressures and temperatures of each sections, feed-water regenerative heating and fuel preheating on combined cycle performance are evaluated with the model, the restriction factors such as temperature difference of heat recovery steam generator (HRSG) and steam turbine structure design were also considered. A set of optimum parameters are obtained for combined cycle equipped with a state of the art gas turbine by using the proposed method on enhancing combined cycle performance equipped with a certain type of gas turbine.

Gas Turbine Bottoming Cycles: Triple-Pressure Steam Versus Kalina

1995 ◽  
Vol 117 (1) ◽  
pp. 10-15 ◽  
Author(s):  
C. H. Marston ◽  
M. Hyre
Keyword(s):  
Monte Carlo ◽  
Power Plant ◽  
Gas Turbine ◽  
Mass Fraction ◽  
Combined Cycle ◽  
Kalina Cycle ◽  
Combined Cycle Power Plant ◽  
Pressure Steam ◽  
Plant Configuration ◽  
Steam Cycle

The performance of a triple-pressure steam cycle has been compared with a single-stage Kalina cycle and an optimized three-stage Kalina cycle as the bottoming sections of a gas turbine combined cycle power plant. A Monte Carlo direct search was used to find the optimum separator temperature and ammonia mass fraction for the three-stage Kalina cycle for a specific plant configuration. Both Kalina cycles were more efficient than the triple pressure steam cycle. Optimization of the three-stage Kalina cycle resulted in almost a two percentage point improvement.

Analytical Approach to Steam Turbine Heat Transfer in a Combined Cycle Power Plant

2004 ◽  
Author(s):  
Howard M. Brilliant ◽  
Anil K. Tolpadi
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Combined Cycle ◽  
Temperature Measurements ◽  
Flow Conditions ◽  
Transfer Coefficients ◽  
Local Flow ◽  
Combined Cycle Power Plant

Combined cycle units have become very popular in recent years as a source of power generation. Such units have a gas turbine as the topping cycle and a steam turbine as the bottoming cycle and can reach combined cycle efficiencies as high as 60%. The exhaust from the gas turbine is passed through a heat exchanger in which steam is generated for the steam turbine. This combined arrangement makes it less polluting as well. An important element of a combined cycle power plant is the steam turbine, which is the subject of this paper. Improvements to the design of advanced steam turbines require an improved understanding of the heat transfer within the various components of the unit. Physics-based ANSYS models for typical GE high pressure and intermediate pressure units have been developed. Components such as the rotor, diaphragm, and shells have been analyzed. The boundary conditions were derived from full-load, steady state flow analyses, steam turbine performance code outputs and computational fluid dynamics (CFD) analyses to develop normalized (non-dimensional) local flow conditions, with the normalizing parameters based on key cycle parameters. These normalized local flow conditions and cycle parameters were then used to define local transient boundary temperatures and heat transfer coefficients for input to the thermal ANSYS models. Transient analyses of components were performed. The results were compared with temperature measurements taken during the complete cycle of an operational steam turbine to validate and improve the methodology, and were applied to structural models of the components to predict their thermal growth and the net impact on the clearance between the rotor and diaphragms and other secondary flow paths in the steam turbine, including the packing seals. This paper will focus on the thermal modeling of a typical steam turbine. It will discuss the process used (summarized above) and the basic equations employed in the analyses. Results will be compared with shell temperature measurements obtained during the start up of a steam turbine in the field. Implications of the thermal results on power systems operation will be discussed. Plans for future improvements will be presented.

Repowering a Steam Turbine-Generator Power Plant Through Heat Recovery Type Combined Cycle: Selection of the Cycle — A Case Study

1996 ◽  
Author(s):  
H. A. Bazzini
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Heat Rate ◽  
Combined Cycle ◽  
Feed Water ◽  
Turbine Generator ◽  
Water Heaters ◽  
Selection Of ◽  
Steam Cycle

Much of the steam-turbine based, power generating units all over the word are more than 30 years old now. Within a few years they will face the possibility of retirement from service and replacement. Nonetheless some of them are firm candidates for repowering, a technology able to improve plant efficiency, output and reliability at low costs. This paper summarizes a study performed to establish the feasibility to repower a 2 × 33 MW steam turbine power plant and the procedure followed until selection of the steam cycle more suitable to the project. The preferred solution is compared with direct replacement of the units by a new combined cycle. Various repowering options were reviewed to find “beat recovery” type repowering as the best solution. That well-known technology consists of replacing the steam generator by a gas turbine coupled to an HRSG, supplying steam to the existing steam turbine. Three “GT+HRSG+ST” arrangements were considered. Available gas turbine-generators — both industrial and aero-derivative type —, were surveyed for three power output ranges. Five “typical” gas turbine-generator classes were then selected. Steam flow raised at the HRSG, gross and net power generation, and heat exchanging surface area of the HRSG, were calculated for a broad range of usually applied, steam turbine throttle conditions. Both single pressure and double pressure steam cycles were considered, as well as supplemental fire and convenience of utilizing the existing feed water heaters. Balance of plant constraints were also reviewed. Estimates were developed for total investment, O&M costs, fuel expenses, and revenues. Results are shown through various graphics and tables. The route leading to the preferred solution is explained and a sensitivity analysis added to validate the selection. The preferred solution, consisting in a Class 130 gas turbine in arrangement 1–1–2, a dual-pressure HRSG and a steam cycle without feed-water heaters, win allow delivering 200 MW to the grid, with a heat rate of 7423 kJ/kW-hr. Investment was valued at $MM77.0, with an IRR of 15.3%. Those figures compare well with the option of installing a new GTCC unit: with a better heat rate but an investment valued at $MM97.5, its IRR will only be 12.4%.

On-Line Performance Monitoring and Diagnostics for Large Combined Cycle Power Plant

2016 ◽  
Author(s):  
B. Chudnovsky ◽  
L. Levin ◽  
A. Talanker ◽  
V. Mankovsky ◽  
A. Kunin
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Performance Monitoring ◽  
Combined Cycle ◽  
Plant Performance ◽  
Combined Cycle Power Plant ◽  
Large Size ◽  
On Line

Diagnostics of large size combined-cycle power plant components (such as: Gas Turbine, HRSG, Steam Turbine and Condenser) plays a significant role in improving power plant performance, availability, reliability and maintenance scheduling. In order to prevent various faults in cycle operation and as a result a reliability reduction, special monitoring and diagnostic techniques is required, for engineering analysis and utility production management. In this sense an on-line supervision system has developed and implemented for 370 MW combined-cycle. The advanced diagnostic methodology is based on a comparison between actual and target conditions. The actual conditions are calculated using data set acquired continuously from the power plant acquisition system. The target conditions are calculated either as a defined actual best operation (Manufacturer heat balances) or by means of a physical model that reproduces boiler and plant performance at off-design. Both sets of data are then compared to find the reason of performance deviation and then used to monitor plant degradation, to support plant maintenance and to assist on-line troubleshooting. The performance calculation module provides a complete Gas Turbine, HRSG and Steam Turbine island heat balance and operating parameters. This paper describes a study where an on-line performance monitoring tool was employed for continuously evaluating power plant performance. The methodology developed and summarized herein has been successfully applied to large size 360–370 MW combined cycles based on GE and Siemens Gas Turbines, showing good capabilities in estimating the degradation of the main equipment during plant lifetime. Consequently, it is a useful tool for power plant operation and maintenance.

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