scholarly journals TopCycle: A Novel High Performance and Fuel Flexible Gas Turbine Cycle

2021 ◽  
Vol 13 (2) ◽  
pp. 651
Author(s):  
Simeon Dybe ◽  
Michael Bartlett ◽  
Jens Pålsson ◽  
Panagiotis Stathopoulos

High pressure humidified cycles can combine high operational flexibility and high thermal efficiency. The current work introduces such a cycle, namely TopCycle, which provides the necessary combustion infrastructure to operate on a wide fuel variety in a steam-rich atmosphere. The cycle configuration is presented in detail, and its operation is exemplified on the basis of simulation results. Operation at design condition results in electric efficiencies higher than 50% (lower heating value (LHV)) and power densities higher than 2100 kW/kgair (referred to intake air flow). A sensitivity analysis identifies the cycle performance as a function of representative parameters, which provide the basis for future operation and design improvements. As for any gas turbine cycle, TopCycle’s electric efficiency can be effectively improved by increasing the turbine inlet temperature, optimizing the economizer heat recovery, as well as elevating the working pressure. Finally, TopCycle’s performance is compared to a state-of-the-art combined cycle (CC) at equivalent operation parameters. The TopCycle operates at an elevated electric efficiency and considerably higher power density, which can be transferred into smaller plant footprint and dimensions and thus lower investment costs at equal power output in comparison to a CC.

2015 ◽  
Vol 5 (2) ◽  
pp. 89
Author(s):  
Munzer S. Y. Ebaid ◽  
Qusai Z. Al-hamdan

<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>


Author(s):  
Mayank Maheshwari ◽  
Onkar Singh

Abstract Performance of gas/steam combined cycle power plants relies upon the performance exhibited by both gas based topping cycle and steam based bottoming cycle. Therefore, the measures for improving the performance of the gas turbine cycle and steam bottoming cycle eventually result in overall combined cycle performance enhancement. Gas turbine cooling medium affects the cooling efficacy. Amongst different parameters in the steam bottoming cycle, the deaerator parameter also plays its role in cycle performance. The present study analyzes the effect of deaerator’s operating pressure being varied from 1.6 bar to 2.2 bar in different configurations of simple and reheat gas/steam combined cycle with different cooling medium for fixed cycle pressure ratio of 40, turbine inlet temperature of 2000 K and ambient temperature of 303 K with varying ammonia mass fraction from 0.6 to 0.9. Analysis of the results obtained for different combined cycle configuration shows that for the simple gas turbine and reheat gas turbine-based configurations, the maximum work output of 643.78 kJ/kg of air and 730.87 kJ/kg of air respectively for ammonia mass fraction of 0.6, cycle efficiency of 54.55% and 53.14% respectively at ammonia mass fraction of 0.7 and second law efficiency of 59.71% and 57.95% respectively at ammonia mass fraction of 0.7 is obtained for the configuration having triple pressure HRVG with ammonia-water turbine at high pressure and intermediate pressure and steam turbine operating at deaerator pressure of 1.6 bar.


Author(s):  
Lieke Wang ◽  
Mehdi Bahador ◽  
Simon Bruneflod ◽  
Mats Annerfeldt ◽  
Mats Björkman ◽  
...  

Siemens Oil & Gas introduced an enhanced SGT-800 gas turbine during 2010. The new power rating is 50.5 MW with a 38.3 % electrical efficiency (ISO) in simple cycle and the best in class combined-cycle performance of more than 55 %. The increased power and improved efficiency from the existing 47 MW rating are mainly obtained by improved compressor airfoil profiles and improved turbine aerodynamics and cooling air layout. The upgrade components in the gas turbine are interchangeable from the existing rating. The current paper is focused on the design modifications of the turbine parts and their validation and operation experience. For the turbine section, the main design modifications include the redesigned stage 1 with better aerodynamic and cooling performance, modified stage 3 for increased outlet area, etc. However, the turbine inlet temperature is not increased compared to the existing 47 MW rating. Comprehensive validation measures have been taken to make sure that the modifications meet the design targets, at both the component level and the system level. The results from the validation tests have confirmed the turbine performance in terms of aerodynamics, cooling, life time, etc. In addition, these results have given a strong basis for future upgrade, e.g., potential cooling air saving has been identified on several areas. The first SGT-800 with 50.5 MW rating was successfully operated and tested during the spring 2010 and the expected performance figures were confirmed. Up to January 2013, the fleet of this new rating has accumulated >40 000 Equivalent Operation hours (EOH), while the fleet leader has accumulated >16 000 EOH. A planned follow up inspection was made after 10 000 EOH by using borescope for the hot section, and it showed that all the turbine parts were in good condition.


Author(s):  
Dirk Therkorn ◽  
Martin Gassner ◽  
Vincent Lonneux ◽  
Mengbin Zhang ◽  
Stefano Bernero

Highly competitive and volatile energy markets are currently observed, as resulting from the increased use of intermittent renewable sources. Gas turbine combined cycle power plants (CCPP) owners therefore require reliable, flexible capacity with fast response time to the grid, while being compliant with environmental limitations. In response to these requirements, a new operation concept was developed to extend the operational flexibility by reducing the achievable Minimum Environmental Load (MEL), usually limited by increasing pollutant emissions. The developed concept exploits the unique feature of the GT24/26 sequential combustion architecture, where low part load operation is only limited by CO emissions produced by the reheat (SEV) burners. A significant reduction of CO below the legal limits in the Low Part Load (LPL) range is thereby achieved by individually switching the SEV burners with a new operation concept that allows to reduce load without needing to significantly reduce both local hot gas temperatures and CCPP efficiency. Comprehensive assessments of the impact on operation, emissions and lifetime were performed and accompanied by extensive testing with additional validation instrumentation. This has confirmed moderate temperature spreads in the downstream components, which is a benefit of sequential combustion technology due to the high inlet temperature into the SEV combustor. The following commercial implementation in the field has proven a reduction of MEL down to 26% plant load, corresponding to 18% gas turbine load. The extended operation range is emission compliant and provides frequency response capability at high plant efficiency. The experience accumulated over more than one year of successful commercial operation confirms the potential and reliability of the concept, which the customers are exploiting by regularly operating in the LPL range.


Author(s):  
S Kumar ◽  
O Singh

Successful gas turbine technology is based significantly upon the introduction of new blade materials with increased permissible temperature for gas turbine blades and/or the use of efficient means and methods of turbine blade cooling in order to achieve the highest possible turbine inlet temperature. The gas turbine blade cooling models found in literature indicate that the effect of radiation from elevated temperature gases is generally not considered. However, the radiative heat transfer always occurs owing to the presence of mainly carbon dioxide and water vapour in the combustion products. The present paper deals with the comparative study of transpiration-cooled gas turbine cycle performance with and without taking radiation effect for different coolants and permissible blade temperature. The thermodynamic evaluation shows that, with consideration of the radiation effect, the theoretical coolant requirement increases so as to be close to the actual requirement and hence the cycle performance is affected accordingly. The transpiration-cooled gas turbine cycle performance parameter variations are presented to exemplify the role of cooling technology, cooling means, and material development, taking the radiation effect into account.


2014 ◽  
Vol 592-594 ◽  
pp. 1487-1492
Author(s):  
Lord Jaykishan Nayak ◽  
Dhaneshwar Mahto

The present study deals with the effect of inlet air cooling on performance of simple combined cycle power plant (CCPP) .During hot days the density of air decreases, which reduce the mass flow rate of air in to compressor. The power consume by the compressor increases with increase in intake air temperature, which reduce net power output of gas turbine cycle. Mechanical refrigeration system at inlet of compressor has been used to reduce the inlet temperature of air to desired level. The performance analysis of CCPP was carried out using software developed in MATLAB.


Author(s):  
Hicham Abdallah ◽  
Bruno Facchini ◽  
Simon Harvey

A number of different innovative gas turbine cycles are currently being developed for future high performance power generation applications. Of particular interest are new cycles such as the Humid Air Turbine (HAT) cycle and the Chemically Recuperated Gas Turbine (CRGT) cycle. The HAT cycle has reached the stage of commercial demonstration, whereas the CRGT cycle is still in the research stage. Performance predictions for CRGT cycles show cycle performance levels higher than those of the basic Steam Injected (STIG) cycle, but lower than those of state-of-the-art combined cycles. Thus, CRGT cycles are most likely to be of interest for intermediate load operation or cogeneration. For such applications, part load performance is a key performance criterion. Part load operation is generally detrimental to power plant performance, and it is thus important to assess the part load performance of such a plant under various operating conditions. The emphasis of this paper is on the comparison of part load performance of various advanced cycles (STIG, CRGT, Combined Cycle). The results show that the part load performance levels of a CRGT cycle deteriorate less fast than those of a combined cycle, whereas part load behavior is similar to that of a STIG cycle. However, this study also indicates that CRGT part load performance is less attractive than published performance curves of Westinghouse’s innovative CHAT cycle, thus confirming that the key advantage of the CRGT cycle is the projected ultra-low emissions characteristics of the cycle.


Author(s):  
A.A. Filimonova ◽  
◽  
N.D. Chichirova ◽  
A.A. Chichirov ◽  
A.A. Batalova ◽  
...  

The article provides an overview of modern high-performance combined-cycle plants and gas turbine plants with waste heat boilers. The forecast for the introduction of gas turbine equipment at TPPs in the world and in Russia is presented. The classification of gas turbines according to the degree of energy efficiency and operational characteristics is given. Waste heat boilers are characterized in terms of design and associated performance and efficiency. To achieve high operating parameters of gas turbine and boiler equipment, it is necessary to use, among other things, modern water treatment equipment. The article discusses modern effective technologies, the leading place among which is occupied by membrane, and especially baromembrane methods of preparing feed water-waste heat boilers. At the same time, the ion exchange technology remains one of the most demanded at TPPs in the Russian Federation.


Author(s):  
Ragnhild E. Ulfsnes ◽  
Olav Bolland ◽  
Kristin Jordal

One of the concepts proposed for capture of CO2 in power production from gaseous fossil fuels is the semi-closed O2/CO2 gas turbine cycle. The semi-closed O2/CO2 gas turbine cycle has a near to stoichiometric combustion with oxygen, producing CO2 and water vapor as the combustion products. The water vapor is condensed and removed from the process, the remaining gas, primarily CO2, is mainly recycled to keep turbine inlet temperature at a permissible level. A model for predicting transient behavior of the semi-closed O2/CO2 gas turbine cycle is presented. The model is implemented in the simulation tool gPROMS (Process System Enterprise Ltd.), and simulations are performed to investigate two different issues. The first issue is to see how different cycle performance variables interact during transient behavior; the second is to investigate how cycle calculations are affected when including the gas constant and the specific heat ratio in compressor characteristics. The simulations show that the near to stoichiometric combustion and the working fluid recycle introduce a high interaction between the different cycle components and variables. This makes it very difficult to analytically predict the cycle performance during a transient event, i.e. simulations are necessary. It is also found that, except for the shaft speed calculation, the introduction of gas constant and specific heat ratio dependence on the compressor performance map will have only a minor influence on the process performance.


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