Optimization of Advanced Liquid Natural Gas-Fuelled Combined Cycle Machinery Systems for a High-Speed Ferry

2012 ◽  
Author(s):  
Kari Anne Tveitaskog ◽  
Fredrik Haglind
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Dynamic Network ◽  
Combined Cycle ◽  
Working Fluid ◽  
Power Requirement ◽  
Pressure Steam ◽  
Combined Cycles ◽  
Liquid Natural Gas ◽  
Steam Cycle

This paper is aimed at designing and optimizing combined cycles for marine applications. For this purpose, an in-house numerical simulation tool called DNA (Dynamic Network Analysis) and a genetic algorithm-based optimization routine are used. The top cycle is modeled as the aero-derivative gas turbine LM2500, while four options for bottoming cycles are modeled. Firstly, a single pressure steam cycle, secondly a dual-pressure steam cycle, thirdly an ORC using toluene as the working fluid and an intermediate oil loop as the heat carrier, and lastly an ABC with inter-cooling are modeled. Furthermore, practical and operational aspects of using these three machinery systems for a high-speed ferry are discussed. Two scenarios are evaluated. The first scenario evaluates the combined cycles with a given power requirement, optimizing the combined cycle while operating the gas turbine at part load. The second scenario evaluates the combined cycle with the gas turbine operated at full load. For the first scenario, the results suggest that the thermal efficiencies of the combined gas and steam cycles are 46.3% and 48.2% for the single pressure and dual pressure steam cycles, respectively. The gas ORC and gas ABC combined cycles obtained thermal efficiencies of 45.6% and 41.9%, respectively. For the second scenario, the results suggest that the thermal efficiencies of the combined gas and steam cycles are 53.5% and 55.3% for the single pressure and dual pressure steam cycles, respectively. The gas ORC and gas ABC combined cycles obtained thermal efficiencies of 51.0% and 47.8%, respectively.

scholarly journals Applying Kalina Technology to a Bottoming Cycle for Utility Combined Cycles

1987 ◽  
Author(s):  
A. L. Kalina ◽  
H. M. Leibowitz
Keyword(s):  
Combined Cycle ◽  
Cycle Performance ◽  
Working Fluid ◽  
Water Mixture ◽  
Pinch Point ◽  
Kalina Cycle ◽  
Pressure Steam ◽  
Combined Cycles ◽  
Steam Plant ◽  
Steam Cycle

A new power generation technology often referred to as the Kalina cycle, is being developed as a direct replacement for the Rankine steam cycle. It may be applied to any thermal heat source, low or high temperature. Among several Kalina cycle variations there is one that is particularly well suited as a bottoming cycle for utility combined cycle applications. It is the subject of this paper. Using an ammonia/water mixture as the working fluid and a condensing system based on absorption refrigeration principles the Kalina bottoming cycle outperforms a triple pressure steam cycle by 16 percent. Additionally, this version of the Kalina cycle is characterized by an intercooling feature between turbine stages, diametrically opposite to normal reheating practice in steam plants. Energy and mass balances are presented for a 200 MWe Kalina bottoming cycle. Kalina cycle performance is compared to a triple pressure steam plant. At a peak cycle temperature of 950° F the Kalina plant produces 223.5 MW vs. 192.6 MW for the triple pressure steam plant, an improvement of 16.0 percent. Reducing the economizer pinch point to 15° F results in a performance improvement in excess of 30 percent.

Parametric study on the performance of combined power plant of steam and gas turbines

2021 ◽  
pp. 1-18
Author(s):  
Mohammad Almajali ◽  
Omar Quran
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Parametric Study ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Design Parameters ◽  
Pressure Steam ◽  
Reheat Steam ◽  
Steam Cycle

Abstract This paper deals with aspects of the combined power and power (CPP) plants. Such plants consist of two major parts; the steam turbine and gas turbine plants. This study investigates the efficiency of CPP under the effect of several factors. CPP plants can achieve the highest thermal efficiency obtained with turbomachinery up to date. In this cycle, the anticipated waste thermal energy of the exhaust of gas turbine is used to generate a high pressure steam to empower the steam turbine in the steam cycle. By systematically varying the main design parameters, their influence on the CPP plant can be revealed. A comprehensive parametric study was conducted to measure the influence of the main parameter of the gas and steam cycles on the performance of CPP. The results exhibit that the overall plant thermal efficiency is significantly greater than that of either the two turbines. Due to the high thermal efficiency, a significant reduction in the greenhouse effect can be achieved. It is found that regenerative steam cycle will reduce the overall efficiency of combined cycle. On the other hand, using reheat steam cycle in the CPP plant will lead to an increase in both the thermal efficiency of the plant and the dryness factor of steam at exit of the steam turbine.

Analysis of a Combined Cycle Plant Using a Small Particle Receiver to Drive a Primary Brayton Cycle

2015 ◽  
Author(s):  
Matthew Miguel Virgen ◽  
Fletcher Miller
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Small Particle ◽  
Power Plants ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Working Fluid ◽  
Brayton Cycle ◽  
Efficiency Gains ◽  
Steam Cycle

All current commercial CSP plants operate at relatively low thermodynamic efficiency due to lower temperatures than similar conventional plants and due to the fact that they all employ Rankine conversion cycles. We present here an investigation on the effects of adding a bottoming steam power cycle to a hybrid CSP plant based on a Small Particle Heat Exchange Receiver (SPHER) driving a gas turbine as the primary cycle. Due to the high operating temperature of the SPHER being considered (over 1000 Celsius), the exhaust air from the primary Brayton cycle still contains a tremendous amount of exergy. While in the previous analysis this fluid was only used in a recuperator to preheat the Brayton working fluid, the current analysis explores the potential power and efficiency gains from instead directing the exhaust fluid through a heat exchanger to power a Rankine steam cycle. Not only do we expect the efficiency of this model to be competitive with conventional power plants, but the water consumption per kilowatt-hour will also be reduced by nearly two thirds as compared to most existing concentrating solar thermal power plants as a benefit of having air as the primary working fluid, which eliminates the condensation step present in Rankine-cycle systems. Coupling a new steam cycle model with the gas-turbine CSP model previously developed at SDSU, a wide range of cases were run to explore options for maximizing both power and efficiency from the proposed CSP combined cycle gas turbine (CCGT) plant. Due to the generalized nature of the bottoming cycle modeling, and the varying nature of solar power, special consideration had to be given to the behavior of the heat exchanger and Rankine cycle in off-design scenarios. The trade-offs of removing the recuperator for preheating the primary fluid are compared to potential overall power and efficiency gains in the combined cycle case.

Efficiency Entitlement for Bottoming Cycles

2006 ◽  
Author(s):  
Douglas C. Hofer ◽  
S. Can Gulen
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
New Method ◽  
Working Fluid ◽  
Generating Capacity ◽  
Topping Cycle ◽  
Cycle Efficiency ◽  
Steam Cycle

A significant portion of the new electrical generating capacity installed in the past decade has employed heavy-duty gas turbines operating in a combined cycle configuration with a steam turbine bottoming cycle. In these power plants approximately 1/3 of the power is generated by the bottoming cycle. To ensure that the highest possible combined cycle efficiency is realized it is important to optimize the bottoming cycle efficiency and doing so requires a solid understanding of the efficiency entitlement. This paper describes a new technique for calculating the theoretical efficiency entitlement for a bottoming cycle that corresponds to the maximum possible bottoming cycle work and maximized combined cycle work and efficiency. This new method accounts for the decrease in ideal efficiency as the gas turbine exhaust is cooled as it transfers heat energy to the working fluid in the bottoming cycle. The new definition is compared to conventional definitions, including that of Carnot and an Exergy based second law efficiency, and shown to provide a simple and accurate analytical expression for the entitlement efficiency in a bottoming cycle. For representative cycle conditions, the entitlement efficiency for the bottoming cycle is calculated to be ∼45% compared to the Carnot efficiency for the same conditions of ∼67%. Although the new method is applicable to any power cycle obtaining its heat input from the exhaust stream of a topping cycle, special attention is given to the steam bottoming cycle traditionally used in modern gas turbine combined cycle power plants. Comparisons are made between the ideal bottoming cycle and variants of a steam cycle including a single pressure non-reheat and a three pressure reheat cycle. These comparisons explore the unavoidable loss in efficiency associated with constant temperature heat addition that occurs in the steam cycle.

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.

Concept for a Combustion System in Oxyfuel Gas Turbine Combined Cycles

2013 ◽  
Author(s):  
Sven Gunnar Sundkvist ◽  
Adrian Dahlquist ◽  
Jacek Janczewski ◽  
Mats Sjödin ◽  
Marie Bysveen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Combustion Stability ◽  
Working Fluid ◽  
Outlet Temperature ◽  
Exhaust Gas ◽  
Combustion System ◽  
Combined Cycles

A promising candidate for CO2 neutral power production is Semi-Closed Oxyfuel Combustion Combined Cycles (SCOC CC). Two alternative SCOC-CCs have been investigated both with recirculation of the Working Fluid (CO2 and H2O) but with different H2O content due to different conditions for condensation of water from the Working Fluid. The alternative with low moisture content in the re-circulated Working Fluid has shown highest thermodynamic potential and has been selected for further study. The necessity to use recirculated exhaust gas as the Working Fluid will make the design of the gas turbine quite different from a conventional gas turbine. For a combined cycle using a steam Rankine cycle as a bottoming cycle it is vital that the temperature of the exhaust gas from the Brayton cycle is well suited for steam generation that fits steam turbine live steam conditions. For oxyfuel gas turbines with a combustor outlet temperature of the same magnitude as conventional gas turbines a much higher pressure ratio is required (close to twice the ratio as for a conventional gas turbine) in order to achieve a turbine outlet temperature suitable for combined cycle. Based on input from the optimized cycle calculations a conceptual combustion system has been developed, where three different combustor feed streams can be controlled independently: the natural gas fuel, the oxidizer consisting mainly of oxygen plus some impurities, and the re-circulated Working Fluid. This gives more flexibility compared to air-based gas turbines, but introduces also some design challenges. A key issue is how to maintain high combustion efficiency over the entire load range using as little oxidizer as possible and with emissions (NOx, CO, UHC) within given constraints. Other important challenges are related to combustion stability, heat transfer and cooling, and material integrity, all of which are much affected when going from air-based to oxygen-based gas turbine combustion. Matching with existing air-based burner and combustor designs has been done in order to use as much as possible of what is proven technology today. The selected stabilization concept, heat transfer evaluation, burner and combustion chamber layout will be described. As a next step the pilot burner will be tested both at atmospheric and high pressure conditions.

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.

Novel High-Performing Single-Pressure Combined Cycle With CO2 Capture

2010 ◽  
Vol 133 (4) ◽  
Author(s):  
Nikolett Sipöcz ◽  
Klas Jonshagen ◽  
Mohsen Assadi ◽  
Magnus Genrup
Keyword(s):  
Natural Gas ◽  
Electric Power ◽  
Gas Turbine ◽  
Co2 Capture ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
Working Fluid ◽  
Market Demand ◽  
Combined Cycles

The European electric power industry has undergone considerable changes over the past two decades as a result of more stringent laws concerning environmental protection along with the deregulation and liberalization of the electric power market. However, the pressure to deliver solutions in regard to the issue of climate change has increased dramatically in the last few years and has given rise to the possibility that future natural gas-fired combined cycle (NGCC) plants will also be subject to CO2 capture requirements. At the same time, the interest in combined cycles with their high efficiency, low capital costs, and complexity has grown as a consequence of addressing new challenges posed by the need to operate according to market demand in order to be economically viable. Considering that these challenges will also be imposed on new natural gas-fired power plants in the foreseeable future, this study presents a new process concept for natural gas combined cycle power plants with CO2 capture. The simulation tool IPSEpro is used to model a 400 MW single-pressure NGCC with post-combustion CO2 capture using an amine-based absorption process with monoethanolamine. To improve the costs of capture, the gas turbine GE 109FB is utilizing exhaust gas recirculation, thereby, increasing the CO2 content in the gas turbine working fluid to almost double that of conventional operating gas turbines. In addition, the concept advantageously uses approximately 20% less steam for solvent regeneration by utilizing preheated water extracted from heat recovery steam generator. The further recovery of heat from exhaust gases for water preheating by use of an increased economizer flow results in an outlet stack temperature comparable to those achieved in combined cycle plants with multiple-pressure levels. As a result, overall power plant efficiency as high as that achieved for a triple-pressure reheated NGCC with corresponding CO2 removal facility is attained. The concept, thus, provides a more cost-efficient option to triple-pressure combined cycles since the number of heat exchangers, boilers, etc., is reduced considerably.

Novel High-Perfoming Single-Pressure Combined Cycle With CO2 Capture

2010 ◽  
Author(s):  
Nikolett Sipo¨cz ◽  
Klas Jonshagen ◽  
Mohsen Assadi ◽  
Magnus Genrup
Keyword(s):  
Natural Gas ◽  
Electric Power ◽  
Gas Turbine ◽  
Co2 Capture ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
Working Fluid ◽  
Market Demand ◽  
Combined Cycles

The European electric power industry has undergone considerable changes over the past two decades as a result of more stringent laws concerning environmental protection along with the deregulation and liberalization of the electric power market. However, the pressure to deliver solutions in regard to the issue of climate change has increased dramatically in the last few years and given the rise to the possibility that future natural gas-fired combined cycle (NGCC) plants will also be subject to CO2 capture requirements. At the same time, the interest in combined cycles with their high efficiency, low capital costs and complexity has grown as a consequence of addressing new challenges posed by the need to operate according to market demand in order to be economically viable. Considering that these challenges will also be imposed on new natural gas-fired power plants in the foreseeable future, this study presents a new process concept for natural gas combined cycle power plants with CO2 capture. The simulation tool IPSEpro is used to model a 400 MW single-pressure NGCC with post-combustion CO2 capture, using an amine-based absorption process with Monoethanolamine. To improve the costs of capture the gas turbine, GE 109FB, is utilizing exhaust gas recirculation, thereby increasing the CO2 content in the gas turbine working fluid to almost double that of conventional operating gas turbines. In addition, the concept advantageously uses approximately 20% less steam for solvent regeneration by utilizing preheated water extracted from HRSG. The further recovery of heat from exhaust gases for water preheating by use of an increased economizer flow results in an outlet stack temperature comparable to those achieved in combined cycle plants with multiple pressure levels. As a result, overall power plant efficiency as high as that achieved for a triple-pressure reheated NGCC with corresponding CO2 removal facility is attained. The concept thus provides a more cost-efficient option to triple-pressure combined cycles since the number of heat exchangers, boilers, etc. is reduced considerably.

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.

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