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Fahad A Alsulaiman - One of the best experts on this subject based on the ideXlab platform.
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exergy analysis of parabolic trough solar collectors integrated with combined steam and organic rankine Cycles
Energy Conversion and Management, 2014Co-Authors: Fahad A AlsulaimanAbstract:In this paper, detailed exergy analysis of selected thermal power systems driven by parabolic trough solar collectors (PTSCs) is presented. The power is produced using either a steam Rankine Cycle (SRC) or a combined Cycle, in which the SRC is the Topping Cycle and an organic Rankine Cycle (ORC) is the bottoming Cycle. Seven refrigerants for the ORC were examined: R134a, R152a, R290, R407c, R600, R600a, and ammonia. Key exergetic parameters were examined: exergetic efficiency, exergy destruction rate, fuel depletion ratio, irreversibility ratio, and improvement potential. For all the cases considered it was revealed that as the solar irradiation increases, the exergetic efficiency increases. Among the combined Cycles examined, the R134a combined Cycle demonstrates the best exergetic performance with a maximum exergetic efficiency of 26% followed by the R152a combined Cycle with an exergetic efficiency of 25%. Alternatively, the R600a combined Cycle has the lowest exergetic efficiency, 20–21%. This study reveals that the main source of exergy destruction is the solar collector where more than 50% of inlet exergy is destructed, or in other words more than 70% of the total destructed exergy. In addition, more than 13% of the inlet exergy is destructed in the evaporator which is equivalent to around 19% of the destructed exergy. Finally, this study reveals that there is an exergetic improvement potential of 75% in the systems considered.
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energy and sizing analyses of parabolic trough solar collector integrated with steam and binary vapor Cycles
Energy, 2013Co-Authors: Fahad A AlsulaimanAbstract:In this study, solar field sizing and overall performance of different vapor Cycles are examined. The systems considered are parabolic trough solar collectors integrated with either a binary vapor Cycle or a steam Rankine Cycle (SRC). The binary vapor Cycle consists of an SRC as a Topping Cycle and an organic Rankine Cycle as a bottoming Cycle. Seven refrigerants are examined for the bottoming Cycle: R600, R600a, R134a, R152a, R290, R407c, and ammonia. This study reveals that significant reduction in the solar field size is gained due to the performance improvement when the binary vapor Cycle is considered as compared to a steam Rankine Cycle with atmospheric condensing pressure; however, SRC with vacuum pressure has the best performance and smallest solar field size. It further reveals that the R134a binary vapor Cycle has the best performance among the binary vapor Cycles considered and, thus, requires the smallest solar field size while the R600a binary vapor Cycle has the lowest performance. Finally, optimization shows that lowering the mass flow rate of the heat transfer fluid (HTF) per each solar collector row, within the range considered, results in a reduction of the required number of solar collector rows and, thus, in savings.
Onkar Singh - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic study of different configurations of gas steam combined Cycles employing intercooling and different means of cooling in Topping Cycle
Applied Thermal Engineering, 2019Co-Authors: Mayank Maheshwari, Onkar SinghAbstract:Abstract Various options for improving the performance of gas/steam combined Cycle, the performance enhancement can be achieved by increasing the turbine inlet temperature and/or increasing the Cycle pressure ratio along with intercooling for reducing compression work and reheating for increasing the expansion work. The present paper analyses eight novel configurations of the intercooled gas turbine based combined Cycles having the gas turbine blade cooled using closed loop cooling scheme. Combined Cycle configurations differ in respect to cooling medium being steam or ammonia-water, intercooling, reheating, single/dual/triple pressure heat recovery steam generator, steam turbine, and ammonia water turbine. The comparative evaluation of combined Cycle arrangements is based on thermodynamic modeling using first law and the second law of thermodynamics for the inlet temperature to turbine of 2000 K and ambient temperature of 303 K. Study aims at furnishing results for understanding the implications of modifications on the Cycle performance. The results show that maximum 1142 kJ/kg of work is obtained for ammonia concentration of 0.6 while the maximum Cycle efficiency of 53.87% and second law efficiency of 58.46% is obtained for ammonia concentration of 0.7 at Cycle pressure ratio of 40 for combined Cycle with triple pressure heat recovery vapor generator having ammonia-water Cycle at high pressure& intermediate pressure and Rankine Cycle at low pressure.
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comparative evaluation of different combined Cycle configurations having simple gas turbine steam turbine and ammonia water turbine
Energy, 2019Co-Authors: Mayank Maheshwari, Onkar SinghAbstract:Abstract Gas/steam combined Cycles have been increasingly used in power plants due to better energy utilization for getting better performance from them as compared to Brayton Cycle based gas turbine plant or the Rankine Cycle based steam turbine plant individually. However, there exists ample scope for further improvement in the performance of combined Cycles through variations in their arrangements. The present study deals with the thermodynamic analysis of different combined Cycle power plant configurations having the simple gas turbine with closed loop cooling of gas turbine blades and varying arrangements in the bottoming Cycle. The variation in the bottoming Cycle relies upon the effective utilization of energy available in the Topping Cycle. The bottoming Cycle considered uses steam Cycle or ammonia water Cycle or its combination. The comparison of eight different combined Cycle configurations considered in this study reveals that, the work output is maximum for simple gas turbine with bottoming Cycle having reheat ammonia water turbine and steam turbine, with an output of 638 kJ/kg of air, first and second law efficiency of 54.95% and 57.87% respectively for ammonia mass fraction of 0.7. The exergy loss is found to be maximum for the combustion chamber followed by heat recovery vapor generator.
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exergy analysis of intercooled reheat combined Cycle with ammonia water mixture based bottoming Cycle
Applied Thermal Engineering, 2017Co-Authors: Mayank Maheshwari, Onkar SinghAbstract:Abstract The present paper deals with exergy analysis of a combined Cycle with ammonia water mixture as the working fluid in the bottoming Cycle. The effect of varying ammonia mass fraction on the thermodynamic performance of various elements of the considered combined Cycle configuration is studied. The analysis reveals that as the ammonia mass fraction increases, the availability increases in low pressure gas turbine of the Topping Cycle, reheater, heat recovery vapor generator (HRVG), low pressure turbine, and decreases in economizer, refrigerant heat exchanger and absorber. Results obtained are useful as the exergy estimation indicates that amongst all thermodynamic elements in the considered combined Cycle, the maximum availability is destroyed in HRVG followed by low pressure gas turbine which is good input for designers to improve HRVG.
Mayank Maheshwari - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic study of different configurations of gas steam combined Cycles employing intercooling and different means of cooling in Topping Cycle
Applied Thermal Engineering, 2019Co-Authors: Mayank Maheshwari, Onkar SinghAbstract:Abstract Various options for improving the performance of gas/steam combined Cycle, the performance enhancement can be achieved by increasing the turbine inlet temperature and/or increasing the Cycle pressure ratio along with intercooling for reducing compression work and reheating for increasing the expansion work. The present paper analyses eight novel configurations of the intercooled gas turbine based combined Cycles having the gas turbine blade cooled using closed loop cooling scheme. Combined Cycle configurations differ in respect to cooling medium being steam or ammonia-water, intercooling, reheating, single/dual/triple pressure heat recovery steam generator, steam turbine, and ammonia water turbine. The comparative evaluation of combined Cycle arrangements is based on thermodynamic modeling using first law and the second law of thermodynamics for the inlet temperature to turbine of 2000 K and ambient temperature of 303 K. Study aims at furnishing results for understanding the implications of modifications on the Cycle performance. The results show that maximum 1142 kJ/kg of work is obtained for ammonia concentration of 0.6 while the maximum Cycle efficiency of 53.87% and second law efficiency of 58.46% is obtained for ammonia concentration of 0.7 at Cycle pressure ratio of 40 for combined Cycle with triple pressure heat recovery vapor generator having ammonia-water Cycle at high pressure& intermediate pressure and Rankine Cycle at low pressure.
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comparative evaluation of different combined Cycle configurations having simple gas turbine steam turbine and ammonia water turbine
Energy, 2019Co-Authors: Mayank Maheshwari, Onkar SinghAbstract:Abstract Gas/steam combined Cycles have been increasingly used in power plants due to better energy utilization for getting better performance from them as compared to Brayton Cycle based gas turbine plant or the Rankine Cycle based steam turbine plant individually. However, there exists ample scope for further improvement in the performance of combined Cycles through variations in their arrangements. The present study deals with the thermodynamic analysis of different combined Cycle power plant configurations having the simple gas turbine with closed loop cooling of gas turbine blades and varying arrangements in the bottoming Cycle. The variation in the bottoming Cycle relies upon the effective utilization of energy available in the Topping Cycle. The bottoming Cycle considered uses steam Cycle or ammonia water Cycle or its combination. The comparison of eight different combined Cycle configurations considered in this study reveals that, the work output is maximum for simple gas turbine with bottoming Cycle having reheat ammonia water turbine and steam turbine, with an output of 638 kJ/kg of air, first and second law efficiency of 54.95% and 57.87% respectively for ammonia mass fraction of 0.7. The exergy loss is found to be maximum for the combustion chamber followed by heat recovery vapor generator.
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exergy analysis of intercooled reheat combined Cycle with ammonia water mixture based bottoming Cycle
Applied Thermal Engineering, 2017Co-Authors: Mayank Maheshwari, Onkar SinghAbstract:Abstract The present paper deals with exergy analysis of a combined Cycle with ammonia water mixture as the working fluid in the bottoming Cycle. The effect of varying ammonia mass fraction on the thermodynamic performance of various elements of the considered combined Cycle configuration is studied. The analysis reveals that as the ammonia mass fraction increases, the availability increases in low pressure gas turbine of the Topping Cycle, reheater, heat recovery vapor generator (HRVG), low pressure turbine, and decreases in economizer, refrigerant heat exchanger and absorber. Results obtained are useful as the exergy estimation indicates that amongst all thermodynamic elements in the considered combined Cycle, the maximum availability is destroyed in HRVG followed by low pressure gas turbine which is good input for designers to improve HRVG.
P. Holbrow - One of the best experts on this subject based on the ideXlab platform.
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Modification and operation of the EPRI large-scale hot gas filter during the Grimethorpe Topping Cycle Experiment. Volume 2, Final report
1993Co-Authors: P. Holbrow, B. Langley, R. Andrews, R. ClarkAbstract:A reliable high temperature, high pressure (HTHP) gas clean up system is a critical component for many coal-fired-combined Cycle power generation systems. A device employing ceramic filter elements was constructed and operated at the Grimethorpe between 1986 and 1987, funded by EPRI. This report describes a subsequent programme of modification and operation-between 1990 and 1992 as part of the Grimethorpe Topping Cycle Project, when the PFB combustor at Grimethorpe was run in conjunction with a small gas turbine. The main requirement of the filter during this programme was to provide reliably about 7kg/s of clean PFBC flue gases containing less than 30 ppmw particulates to the gas turbine. However the opportunity was taken to undertake a further filter test programme with the following objectives: Establishing the durability of the filter elements; establishing the filter pressure drop, permeance and dust emissions as a function of time; and determining the characteristics of the pulse cleaning system. The filter was on line for 1508 hours. A variety of problems were experienced including pulse manifold failures and difficulties with element cleaning. Changes were made to the element hold down system and the final design, combined with a change of feed sorbent from limestone tomore » mite, resulted in more successful cleaning. Dust contaminations at the filter outlet were typically 0.3 ppmw during extended runs, with particles in the uncontaminated filter dust below 2.7{mu}m. A comprehensive measurement programme enabled the objectives of the programme to be achieved. Materials, aspects and durability of the elements are covered in separate report.« less
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Modification and operation of the EPRI large-scale hot gas filter during the Grimethorpe Topping Cycle experiment. Volume 1: Final report
1993Co-Authors: P. Holbrow, B. Langley, R. Andrews, R. ClarkAbstract:A reliable high temperature, high pressure (HTHP) gas clean up system is a critical component for many coal-fired combined Cycle power generation systems. A device employing ceramic filter elements was constructed and operated at the Grimethorpe PFBC Establishment between 1986 and 1987, funded by EPRI. This report describes a subsequent program of modification and operation between 1990 and 1992 as part of the Grimethorpe Topping Cycle Project, when the PFB combustor at Grimethorpe was run in conjunction with a small gas turbine. The main requirement of the filter during this program was to provide reliably about 7 kg/s of clean PFBC flue gases containing less than 30 ppmw particulates to the gas turbine. However the opportunity was taken to undertake a further filter test program with the following objectives: establishing the durability of the filter elements; establishing the filter pressure drop, permeance and dust emissions as a function of time; and determining the characteristics of the pulse cleaning system. The filter was on line for 1,508 hours. A variety of problems were experienced including pulse manifold failures and difficulties with element cleaning. Changes were made to the element hold down system, and the final design, combined with a change ofmore » feed sorbent from limestone to dolomite, resulted in more successful cleaning. Dust contaminations at the filter outlet were typically 0.3 ppmw during extended runs, with particles in the uncontaminated filter dust below 2.7 {mu}m. A comprehensive measurement program enabled the objectives of the program to be achieved. 10 refs., 132 figs., 36 tabs.« less
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operation and performance of the epri hot gas filter at grimethorpe pfbc establishment 1987 1992
1993Co-Authors: G. K. Burnard, J. Stringer, R.k. Clark, A. J. Leitch, P. HolbrowAbstract:This paper summarises and compares the operation and performance of the EPRI filter during the 1987 and 1991/92 periods of operation at the Grimethorpe PFBC Establishment. During the latter period the filter was operated as an integral component of the Grimethorpe Topping Cycle Project, which formed part of British Coal Corporation’s overall strategy in the development of their Topping Cycle.
Masoud Rokni - One of the best experts on this subject based on the ideXlab platform.
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performance comparison on repowering of a steam power plant with gas turbines and solid oxide fuel cells
Energies, 2016Co-Authors: Masoud RokniAbstract:Repowering is a process for transforming an old power plant for greater capacity and/or higher efficiency. As a consequence, the repowered plant is characterized by higher power output and less specific CO 2 emissions. Usually, repowering is performed by adding one or more gas turbines into an existing steam Cycle which was built decades ago. Thus, traditional repowering results in combined Cycles (CC). High temperature fuel cells (such as solid oxide fuel cell (SOFC)) could also be used as a Topping Cycle, achieving even higher global plant efficiency and even lower specific CO 2 emissions. Decreasing the operating temperature in a SOFC allows the use of less complex materials and construction methods, consequently reducing plant and the electricity costs. A lower working temperature makes it also suitable for Topping an existing steam Cycle, instead of gas turbines. This is also the target of this study, repowering of an existing power plant with SOFC as well as gas turbines. Different repowering strategies are studied here, repowering with one gas turbine with and without supplementary firing, repowering with two gas turbines with and without supplementary firing and finally repowering using SOFC. Plant performances and CO 2 emissions are compared for the suggested repowered plants.
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plant characteristics of an integrated solid oxide fuel cell Cycle and a steam Cycle
Energy, 2010Co-Authors: Masoud RokniAbstract:Plant characteristics of a system containing a solid oxide fuel cell (SOFC) Cycle on the top of a Rankine Cycle were investigated. A desulfurization reactor removes the sulfur content in the fuel, while a pre-reformer broke down the heavier hydrocarbons in an adiabatic steam reformer (ASR). The pre-treated fuel then entered to the anode side of the SOFC. The remaining fuels after the SOFC stacks entered a catalytic burner for further combusting. The burned gases from the burner were then used to produce steam for the Rankine Cycle in a heat recovery steam generator (HRSG). The remaining energy of the off-gases was reCycled back to the Topping Cycle for further utilization. Several parameter studies were carried out to investigate the sensitivity of the suggested plant. It was shown that the operation temperature of the desulfurization and the pre-reformer had no effect on the plant efficiency, which was also true when decreasing the anode temperature. However, increasing the cathode temperature had a significant effect on the plant efficiency. In addition, decreasing the SOFC utilization factor from 0.8 to 0.7, increases the plant efficiency by about 6%. An optimal plant efficiency of about 71% was achieved by optimizing the plant.