Optimization of MHD Generator Based Combined Cycle Efficiency

2005 ◽  
Author(s):  
M. H. Saidi ◽  
A. A. Mozafari ◽  
H. D. Rezaei ◽  
A. J. Dehkordy
Keyword(s):  
Pressure Ratio ◽  
Combined Cycle ◽  
Second Law ◽  
Exergy Destruction ◽  
Mhd Generator ◽  
Pros And Cons ◽  
Combined Cycles ◽  
Power Generation Systems ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

Energy crisis has directed scientific efforts to increase the efficiency of power generation systems. Thermodynamic optimization of MHD (Magneto Hydrodynamic) generator based combined cycles due to their high operating temperatures may seriously reduce exergy, destruction and improve the second law efficiency. In this research a combined cycle, comprising of MHD cycle as topping and gas turbine cycle as bottoming cycle has been simulated and analyzed and its pros and cons have been exposed. The first and second law efficiencies have been estimated from the operating pressures and temperatures of the system. To calculate the second law efficiency, the entropy generation of all components of the combined cycle has been parametrically calculated. Furthermore, the optimal pressure ratio and working temperature for both cycles are represented. The influence of pressure loss in pipeline and the effect of heat exchanger performance on the cycle efficiency have been considered as well.

Evaluation of the Compression-Intercooled Reheat-Gas-Turbine-Combined Cycle

1984 ◽  
Author(s):  
Ivan G. Rice
Keyword(s):  
Gas Turbine ◽  
Thermodynamic Analysis ◽  
Pressure Range ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Time Increase ◽  
Efficiency Loss ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency ◽  
Turbine Output

Interest in the reheat-gas turbine (RHGT) as a way to improve combined-cycle efficiency is gaining momentum. Compression intercooling makes it possible to readily increase the reheat-gas-turbine cycle-pressure ratio and at the same time increase gas-turbine output; but at the expense of some combined-cycle efficiency and mechanical complexity. This paper presents a thermodynamic analysis of the intercooled cycle and pinpoints the proper intercooling pressure range for minimum combined-cycle-efficiency loss. At the end of the paper two-intercooled reheat-gas-turbine configurations are presented.

Thermodynamics of an Isothermal Gas Turbine Combined Cycle

1984 ◽  
Vol 106 (4) ◽  
pp. 743-749 ◽  
Author(s):  
M. A. El-Masri ◽  
J. H. Magnusson
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Extraction Process ◽  
Combined Cycle ◽  
Peak Temperature ◽  
Combined Cycles ◽  
Isothermal Gas ◽  
Technological Constraints ◽  
Cycle Efficiency ◽  
Steam Cycle

The isothermal (or multiple-reheat) gas turbine performs the combustion/work extraction process at a sustained, elevated temperature. This has distinct thermodynamic advantages in combined cycles for given peak temperature constraints. A thermodynamic model for this cycle is developed. Although based on a simple CO/CO2/O2 chemcial system the results are applicable to other reactants and dilutants. Combined cycle efficiency is reported for different gas turbine pressure ratios, peak temperatures, reactant dilution and steam cycle conditions. The range of parameters investigated starts from present-day advanced technologies and examines the potential of higher pressures and temperatures. Balances of thermodynamic availability are used to interpret the results. They show that for a given steam cycle and gas turbine pressure ratio, increasing peak temperature beyond a certain value provides sharply diminishing return. This is because the reduction in combustion irreversibility is offset by increased heat transfer irreversibility. Higher pressure ratios or steam cycle temperatures can raise this optimum peak temperature. In view of the various technological constraints, the authors’ conclusion is that an isothermal gas turbine with a peak temperature and pressure-ratio of about 1600K and 100:1, respectively, represents the most promising next step in technology. Coupled with existing advanced steam cycles this should provide efficiencies in the 60 percent range.

EFFECT OF AMBIENT TEMPERATURE ON THE PERFORMANCE OF A COMBINED CYCLE POWER PLANT

2013 ◽  
Vol 37 (4) ◽  
pp. 1177-1188 ◽  
Author(s):  
Arvind Kumar Tiwari ◽  
Mohd. Muzaffarul Hasan ◽  
Mohd. Islam
Keyword(s):  
Power Plant ◽  
Ambient Temperature ◽  
Thermal Power ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Exergy Destruction ◽  
Combined Cycle Power Plant ◽  
Combined Cycle Plant ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

The aim of the present paper is to examine the effect of ambient temperature on the performance of a combined cycle power plant. For this work, the combined cycle plant chosen is NTPC (National Thermal Power Corporation) Dadri, India where a gas unit of 817 MW is installed. The effect of ambient temperature on combined cycle efficiency, gas turbine cycle efficiency, exergy destruction in different components, exergy loss via exhaust and air fuel ratio at lower and higher turbine inlet temperature are reported. The results show that the net decrease in combined cycle efficiency is 0.04% and the variation in exergy destruction of different plant components is up to 0.35% for every °C rise in ambient temperature.

Thermodynamic Performance Assessment of Gas Turbine Trigeneration System for Combined Heat Cold and Power Production

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Abdul Khaliq ◽  
Rajesh Kumar
Keyword(s):  
Gas Turbine ◽  
Thermal Energy ◽  
Pressure Ratio ◽  
Energy Ratio ◽  
Second Law ◽  
Exergy Destruction ◽  
Thermodynamic Performance ◽  
Second Law Analysis ◽  
Process Heat ◽  
Gas Turbine Cycle

The thermodynamic performance of the combustion gas turbine trigeneration system has been studied based on first law as well as second law analysis. The effects of overall pressure ratio and process heat pressure on fuel utilization efficiency, electrical to thermal energy ratio, second law efficiency, and exergy destruction in each component are examined. Results for gas turbine cycle, cogeneration cycle, and trigeneration cycle are compared. Thermodynamic analysis indicates that maximum exergy is destroyed during the combustion and steam generation process, which represents over 80% of the total exergy destruction in the overall system. The first law efficiency, electrical to thermal energy ratio, and second law efficiency of trigeneration system, cogeneration system, and gas turbine cycle significantly varies with the change in overall pressure ratio but the change in process heat pressure shows small variations in these parameters. Results clearly show that performance evaluation of the trigeneration system based on first law analysis alone is not adequate and hence more meaningful evaluation must include second law analysis.

Second-Law Analysis in a Steam Power Plant for Minimization of Avoidable Exergy Destruction

2010 ◽  
Author(s):  
Tapan K. Ray ◽  
Pankaj Ekbote ◽  
Ranjan Ganguly ◽  
Amitava Gupta
Keyword(s):  
Work Performance ◽  
Operating Conditions ◽  
Performance Criteria ◽  
Second Law ◽  
Feed Water ◽  
Exergy Destruction ◽  
Actual Performance ◽  
Time Operation ◽  
Major Equipment ◽  
Cycle Efficiency

Performance analysis of a 500 MWe steam turbine cycle is performed combining the thermodynamic first and second-law constraints to identify the potential avenues for significant enhancement in efficiency. The efficiency of certain plant components, e.g. condenser, feed water heaters etc., is not readily defined in the gamut of the first law, since their output do not involve any thermodynamic work. Performance criteria for such components are defined in a way which can easily be translated to the overall influence of the cycle input and output, and can be used to assess performances under different operating conditions. A performance calculation software has been developed that computes the energy and exergy flows using thermodynamic property values with the real time operation parameters at the terminal points of each system/equipment and evaluates the relevant rational performance parameters for them. Exergy-based analysis of the turbine cycle under different strategic conditions with different degrees of superheat and reheat sprays exhibit the extent of performance deterioration of the major equipment and its impact to the overall cycle efficiency. For example, during a unit operation with attemperation flow, a traditional energy analysis alone would wrongly indicate an improved thermal performance of HP heater 5, since the feed water temperature rise across it increases. However, the actual performance degradation is reflected as an exergy analysis indicates an increased exergy destruction within the HP heater 5 under reheat spray. These results corroborate to the deterioration of overall cycle efficiency and rightly assist operational optimization. The exergy-based analysis is found to offer a more direct tool for evaluating the commercial implication of the off-design operation of an individual component of a turbine cycle. The exergy destruction is also translated in terms of its environmental impact, since the irretrievable loss of useful work eventually leads to thermal pollution. The technique can be effectively used by practicing engineers in order to improve efficiency by reducing the avoidable exergy destruction, directly assisting the saving of energy resources and decreasing environmental pollution.

scholarly journals Thermodynamic Analysis of Different Configurations of Combined Cycle Power Plants

2015 ◽  
Vol 5 (2) ◽  
pp. 89
Author(s):  
Munzer S. Y. Ebaid ◽  
Qusai Z. Al-hamdan
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Maximum Efficiency ◽  
Specific Work ◽  
Slight Effect ◽  
Turbine Engine ◽  
Gas Turbine Cycle ◽  
Cycle Efficiency

<p class="1Body">Several modifications have been made to the simple gas turbine cycle in order to increase its thermal efficiency but within the thermal and mechanical stress constrain, the efficiency still ranges between 38 and 42%. The concept of using combined cycle power or CPP plant would be more attractive in hot countries than the combined heat and power or CHP plant. The current work deals with the performance of different configurations of the gas turbine engine operating as a part of the combined cycle power plant. The results showed that the maximum CPP cycle efficiency would be at a point for which the gas turbine cycle would have neither its maximum efficiency nor its maximum specific work output. It has been shown that supplementary heating or gas turbine reheating would decrease the CPP cycle efficiency; hence, it could only be justified at low gas turbine inlet temperatures. Also it has been shown that although gas turbine intercooling would enhance the performance of the gas turbine cycle, it would have only a slight effect on the CPP cycle performance.</p>

Evolution and Future Trend of Large Frame Gas Turbines: A New 1600 Degree C, J Class Gas Turbine

2012 ◽  
Author(s):  
Satoshi Hada ◽  
Masanori Yuri ◽  
Junichiro Masada ◽  
Eisaku Ito ◽  
Keizo Tsukagoshi
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Standard Condition ◽  
Development Program ◽  
Combined Cycle ◽  
Component Technology ◽  
Extensive Experience ◽  
National Project ◽  
Cycle Efficiency

MHI recently developed a 1600°C class J-type gas turbine, utilizing some of the technologies developed in the National Project to promote the development of component technology for the next generation 1700°C class gas turbine. This new frame is expected to achieve higher combined cycle efficiency and will contribute to reduce CO2 emissions. The target combined cycle efficiency of the J type gas turbine will be above 61.5% (gross, ISO standard condition, LHV) and the 1on1 combined cycle output will reach 460MW for 60Hz engine and 670MW for 50Hz engine. This new engine incorporates: 1) A high pressure ratio compressor based on the advanced M501H compressor, which was verified during the M501H development in 1999 and 2001. 2) Steam cooled combustor, which has accumulated extensive experience in the MHI G engine (> 1,356,000 actual operating hours). 3) State-of-art turbine designs developed through the 1700°C gas turbine component technology development program in Japanese National Project for high temperature components. This paper discusses the technical features and the updated status of the J-type gas turbine, especially the operating condition of the J-type gas turbine in the MHI demonstration plant, T-Point. The trial operation of the first M501J gas turbine was started at T-point in February 2011 on schedule, and major milestones of the trial operation have been met. After the trial operation, the first commercial operation has taken place as scheduled under a predominantly Daily-Start-and-Stop (DSS) mode. Afterward, MHI performed the major inspection in October 2011 in order to check the mechanical condition, and confirmed that the hot parts and other parts were in sound condition.

Evaluation of Using Supercritical Rankine Cycles in Integrated Coal Gasification Combined Cycles (IGCC)

2017 ◽  
Author(s):  
Henry A. Long ◽  
Ting Wang ◽  
Arian Thomas
Keyword(s):  
Coal Gasification ◽  
Energy Resource ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Modern World ◽  
Integrated Gasification Combined Cycle ◽  
Combined Cycles ◽  
Reduce Emissions ◽  
Integrated Gasification ◽  
Cycle Efficiency

Coal is a prominent energy resource in the modern world, particularly in countries with emerging economies. In order to reduce emissions, it is necessary to find a way to utilize coal in a cleaner manner, such as through supercritical and ultra-supercritical Rankine cycles and the Integrated Gasification Combined Cycle (IGCC). Two approaches — raising the boiler pressure and using a reheat scheme — have been proven to notably increase the Rankine cycle efficiency. Thus, this study aims to investigate the effects of implementing reheat and supercritical or ultra-supercritical pressure in the bottom Rankine cycle on the IGCC cycle efficiency. First, reference cases of a standalone Rankine cycle were studied with single and double reheat, including boiler pressure levels from subcritical to ultra-supercritical conditions, followed by similar combined cycle cases, and finally IGCC systems. The results indicate that the notable efficiency enhancement in the standalone subcritical Rankine cycle do not prevail in the studied IGCC systems. Thus, it is not economically worthwhile to implement supercritical or ultra-supercritical bottom Rankine cycles in IGCC applications.

The Reheat Gas Turbine With Steam-Blade Cooling—A Means of Increasing Reheat Pressure, Output, and Combined Cycle Efficiency

1982 ◽  
Vol 104 (1) ◽  
pp. 9-22 ◽  
Author(s):  
I. G. Rice
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Expansion Ratio ◽  
Combined Cycle ◽  
Gas Generator ◽  
Exhaust Temperature ◽  
Blade Cooling ◽  
Cycle Efficiency ◽  
Turbine Blading

The reheat (RH) pressure can be appreciably increased by applying steam cooling to the gas-generator (GG) turbine blading which in turn allows a higher RH firing temperature for a fixed exhaust temperature. These factors increase gas turbine output and raise combined-cycle efficiency. The GG turbine blading will approach “uncooled expansion efficiency”. Eliminating cooling air increases the gas turbine RH pressure by 10.6 percent. When steam is used (injected) as the blade coolant, additional GG work is also developed which further increases the RH pressure by another 12.0 percent to yield a total increase of approximately 22.6 percent. The 38-cycle pressure ratio 2400° F (1316° C) TIT GG studied produces a respectable 6.5 power turbine expansion ratio. The higher pressure also noticeably reduces the physical size of the RH combustor. This paper presents an analysis of the RH pressure rise when applying steam to blade cooling.

Effect of Bottoming Cycle Alternatives on the Performance of Combined Cycle

2003 ◽  
Author(s):  
R. Yadav
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Positive Influence ◽  
Combined Cycle ◽  
Exhaust Temperature ◽  
Compressor Pressure Ratio ◽  
Topping Cycle ◽  
Steam Parameters ◽  
Cycle Efficiency ◽  
Steam Cycle

The increase in efficiency of combined cycle has mainly been caused by the improvements in gas turbine cycle efficiency. With the increase in firing temperature the exhaust temperature is substantially high around 873 K for moderate compressor pressure ratio, which has positive influence on steam cycle efficiency. Minimizing the irreversibility within the heat recovery steam generator HRSG and choosing proper steam cycle configuration with optimized steam parameters improve the steam cycle efficiency and thus in turn the combined cycle efficiency. In this paper, LM9001H gas turbine, a state of art technology turbine with modified compressor pressure ratio has been chosen as a topping cycle. Various bottoming cycles alternatives (sub-critical) coupled with LM9001H topping cycle with and without recuperation such as dual and triple pressure steam cycles with and without reheat have been chosen to predict the performance of combined cycle.

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