30120140501013

258 views
146 views

Published on

Published in: Technology, Business
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
258
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
1
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

30120140501013

  1. 1. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING 6340(Print), ISSN 0976 – 6359(Online) Volume 5, Issue 1, January (2014), © IAEME AND TECHNOLOGY (IJMET) ISSN 0976 – 6340 (Print) ISSN 0976 – 6359 (Online) Volume 5, Issue 1, January (2014), pp. 122-131 © IAEME: www.iaeme.com/ijmet.asp Journal Impact Factor (2013): 5.7731 (Calculated by GISI) www.jifactor.com IJMET ©IAEME OPTIMISATION OF BINARY COGENERATIVE THERMAL POWER PLANTS WITH SOLID OXIDE FUEL CELLS ON NATURAL GAS Done J.Tashevski1, Risto V. Filkoski2, Igor K. Shesho3 Faculty of Mechanical Engineering, University “Ss Cyril and Methodius”, Karpos II bb, 1000 Skopje, Republic of Macedonia ABSTRACT The present paper deals with the issue of large capacity binary co-generative thermal power plants with high temperature solid oxide fuel cells (SOFC) on natural gas.A complex function with a number of variables is employed in order to optimize the operation cycle of this type of power plant from the energy and environmental standpoint. Characteristic parameters of such plant are calculated on a basis of the optimization results: basic dimensions; optimal number of modules; electrical power and unit efficiency of the fuel cell; electrical power and unit efficiency of the gas turbine facility; as well as electrical and thermal power of the steam turbine facility. A software package is created on a basis of the developed optimization procedure, consisting of a number of subprograms and functions, which is flexible for further development. For verification of the optimization procedure, the obtained calculation results are compared with operation parameters of a power plant of well-known manufacturer. Also, a comparison is performed between a binary cogeneration TPP with SOFC and a cogeneration plant without fuel cell, in terms of energy efficiency and environmental benefits. Key words: Binary Cogeneration Power Plant, Natural Gas, Solid Oxide Fuel Cell. 1. INTRODUCTION The power sector trends in the world are generally directed towards the development of thermal power plants (TPP) that should meet several main goals: high performance, reliability and flexible operation, reduced fuel consumption, reduced emission of harmful substances and profitability. Increasing energy demand causes growing permanent consumption of fossil fuels and gradual and continuous eradication of stocks of fuels. Therefore, it is necessary to find new sources of energy that can adequately replace the existing fuels, as well as new technical solutions for power generation that can operate on that kind of fuels. One of the prospective alternative fuels for this century is hydrogen. 122
  2. 2. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online) Volume 5, Issue 1, January (2014), © IAEME Fuel cells are electrochemical devices that convert directly the energy contained in the fuel matter into electricity with high efficiency and low environmental impact. In order to generate significant power, many single cells should be brought together by connecting them in series. There are various types of fuel cells, which differ from each other according to the type of electrolyte and fuel used. Solid oxide fuel cells (SOFC) are known as high temperature energy conversion devices, considerably higher than the other fuel cell types, making them suitable for application in stationary power and heat generation systems [1]. A detailed explanation of the function principles, materials used, performance efficiency and chemical reactions mechanism, including a unit cell chemistry and fuel conversion modeling approaches, is given in [2]. The development of the high-temperature SOFC, capable of operating at 1000 °C, has opened up intriguing possibilities for integrating it within the integrated gasification combined cycle [3]. Cycle performance calculations have already been undertaken [4,5]. The main problem with stationary fuel cells is that they are either not reliable enough or too expensive at the present time [6]. The SOFC appears ideal for the application in binary cogenerative power plant, because it can easily use fossil fuels (solid, liquid and gaseous), but also derived fuels rich with hydrogen, as well as pure hydrogen. High-temperature fuel cells are permanently developed and hybrid cycles with SOFC can offer overall system efficiencies of over 70% [2]. 2. HIGH-TEMPERATURE SOFC IMPLEMENTED IN A THERMAL POWER PLANT In the model binary cogenerative power plant with fuel cells (BCFC) high-temperature solid oxide fuel cell (SOFC) is applied, which operates at a temperature of 1000 °C and pressure up to 15 bar. This type of fuel cells is a product of Siemens-Westinghouse, a company which is specialized in manufacturing of tubular (cylindrical) fuel cells. Their model of individual fuel cells consists of standard components and with the following characteristics [6-9]: Diameter 0.4 m; Height 2 m; Power of individual cell unit 315 W; Power of a module 1.7 MW; Number of individual cells in one module 5600. For the modeling and calculation purpose, the modular solid oxide fuel cell is selected, based on an internal reforming of natural gas (up to 99 % methane) into hydrogen, which is a primary fuel for combustion in the fuel cells. 3. BINARY COGENERATION POWER PLANTS WITH SOFC Binary cogeneration thermal power plants with high-temperature SOFC (BCFC) are combined plants that comprise three thermal power units: high-temperature SOFC, gas turbine unit and cogeneration steam turbine power plant. In these plants electricity is generated in triple way: at the fuel cell inverter, as well as at the generators of the gas turbine and steam turbine plants. At the same time, thermal energy is obtained from the cogeneration steam power plant. The cogeneration steam power plant may be designed in different ways: as a condensing steam turbine unit with steam extraction for technological needs, as a unit with back-pressure steam turbine or as a unit with condensing and counter-pressure turbines. For the purpose of the analysis in the present work a BCFC unit is selected, with fuel cell power of 100 MW. The technology scheme of the natural gas BCFC power plant is presented in Fig. 2. 4. OPTIMISATION OF BCFC Optimisation of BCFC with SOFC is a very complex task due to the number of systems, components and functions needed for plant operation. These plants should fulfill high demanding requirements, such as economical operation, efficiency, reliability, durability, availability and 123
  3. 3. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online) Volume 5, Issue 1, January (2014), © IAEME flexibility in operation. Therefore, the optimization of these plants is necessarily related with many compromises. Figure 2. Schematic presentation of cogenerative power plant with SOFC on NG The analysis of BCFC clearly shows that operation of these plants depends on many factors. The fuel cell produces most of the electricity and is also the main component, which decisively affects the parameters that are going to be achieved in the gas-turbine and steam-turbine power plants. This means that proper optimization of the parameters in the fuel cell has a major influence to the optimization process of the entire plant. It must be noted that the significance of the parameters important for the gas-turbine and steam-turbine plants must not be neglected during optimization. 124
  4. 4. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online) Volume 5, Issue 1, January (2014), © IAEME The (important) parameters of plants with fuel cells vary depending on a number of influencing factors: the voltage of individual fuel cell, fuel composition, fuel utilization, oxidant composition, utilization of oxidant, the pressure in the fuel cell (compressor pressure ratio), the temperature of the fuel at the inlet into the fuel cell, temperature of oxidant at the fuel cell inlet and others. Therefore, a proper balancing of these variables is essential in order to achieve optimum operation of the plant. Apart of the mentioned variables related directly to the fuel cell, the variables that define the gas-turbine and steam-turbine plants significantly affect the operation of BCFC power plant. Some of them are: temperature in the gas turbine inlet, pressure and temperature of the superheated steam at the exit of the heat recovery steam generator (and at the steam turbine inlet), pressure and quantity (flow) of steam extraction for technological needs, pressure in the deaerator, condenser pressure, etc. The number of variables that affect the performance of BCFC defines also the number of variables in a function that is necessary to be optimized. A criteria of optimality is maximum total exergy efficiency of the BCFC, which indicates the overall efficiency of the BCFC. In many cases of practical variation calculations it is necessary to optimize a function that depends on many variables. The function in this case has the following general form [14-16]: η = η (VFC ,U g ,U o , Tgv , Tov , Π K , ( pI )∗ ) (2) where: VFC V - voltage of individual fuel cell, Ug % – fuel utilization, Uo % – oxidant utilization, Tgv K – fuel temperature at the fuel cell inlet, Tov K – temperature of oxidant at the fuel cell inlet, ΠC – compressor pressure ratio (pressure in the fuel cell), pI MPa – steam pressure at the outlet of heat recovery steam generator, ηex,BCFC – total exergy efficiency. The range of expected actual variation of the function η is (0,3-0,999) and, in any case its vale is less than 1, while the elementary range of the variation of variables is presented in Table 1. In order to eliminate the optimization errors, the most practical and also the most accurate approach is to apply the method of replacing each value for a particular variable and determining the value of the criterion for optimization for that value. It is possible only at optimization of plants for which there is not a program, created in advance, for calculation of certain parameters of the plant. Changing the values of the variables is possible by modifying the program for calculation of the plant. In case of BCFC change the values of important variables that affect the performance of the plant are changed, i.e. the total exergy efficiency of BCFC. This means that for each value of the variable the total exergy efficiency is calculated, and after the operation (multiple variation and iteration) a variant of the values is selected at which the highest total exergy efficiency is achieved. The input data for the optimization model given in Table 1, are subsequently changed with certain previously defined step, or appropriate (maximum, medium or standard) values given, at which it is known by previous analysis that the plant achieves the optimum efficiency [14, 15]. Optimization is performed for the cases of BCFC without additional combustion (excluding B1/B2) and with additional combustion (with B1/B2). After completion of power plants optimization the maximum value of total exergy efficiency is obtained, as well as corresponding optimum values of the variables (Table 2). It must be noted that in the case of the optimization procedure of the BCFC without burners B1 and B2, additional variable for the steam pressure at the exit of the heat recovery steam generator is included. The plant achieves a relatively low temperature of the flue gases exiting the air recuperator, which causes decrease of the temperature of the steam exiting the steam generator. Therefore, the pressure of the steam exiting the steam generator needs to be reduced in order to fulfill the necessary parameters of the steam turbine. 125
  5. 5. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online) Volume 5, Issue 1, January (2014), © IAEME Table 1. Input data for optimization model – a case of BCFC on natural gas [14,15]: Input data for modular fuel cell Power of modular SOFC PAC MW 100 (selection) Voltage of individual fuel cell VFC V 0,6 - 0,7 (step 0,1) Fuel utilization Ug % 93 - 98 (step 1) Oxidant utilization Uo % 75 - 85 (step 1) Fuel temperature at the inlet of SOFC Tgv K 773 - 823 (step 10) Oxidant temperature at the inlet of SOFC Tov K 973 - 1023 (step 10) Fuel composition (natural gas) Standard analysis Oxidant composition (air) 79 % N2, 21 % O2 Input data for gas turbine plant 1 - 15 (step 1) Compressor pressure ratio ΠC Air temperature at the compressor inlet t1 °C 15 (average) Temperature at the gas turbine inlet TiGT K 1770 (max)* Input data for steam turbine plant Steam pressure at the outlet of the heat recovery steam pI MPa 14 (standard - high) generator (HRSG) 1 – 10 (step 1)** Steam temperature at the outlet of the HRSG tI °C 560 (max-standard) Pressure of steam extraction for technology consumers pHC MPa 0,5 (selection) Deaerator pressure pD MPa 0.7 (standard-selec.) Condenser pressure pCO MPa 0.006 (standard) Specific quantity of steam extraction for HC αOT kg/kg 0.3 (selection) * Gas turbine technology, gas turbine G series, Mitsubishi heavy industries[17] ** The variable is a subject of optimization only in BCFC without additional burners Table 2. Optimization results of BCFC Variable Voltage of the individual fuel cell Utilization of gaseous fuel Utilization of oxidant Fuel temperature at the inlet of FC Oxidant temperature at the inlet of FC Compressor pressure ratio Steam pressure at the outlet of the HRSG Maximum value of the criteria Total exergy efficiency pI V % % K K MPa Without B1/B2 0.7 93 85 823 973 3 5 With B1/B2 0.7 93 85 823 973 9 - ηex,BCFC - 0.759 0.738 VFC Ug Uo Tgv Tov ΠC 5. CALCULATION OF BCFC For determining the electrical and total efficiencies of the BCFC power plant the exergy method is applied in the present case, which gives a realistic insight into the operational efficiency. By applying other (classical) method of determining the efficiency in which electricity and thermal energy are summarized, unrealistically high efficiency values are obtained [14]. After optimization performed, and on the basis of the determined optimal values of the variables, the results are estimated for all parameters characteristic for this type of plant, Table 3. From Table 3 it can be seen that the facility achieves high electrical efficiency and high exergy efficiency, which is mostly due to the high efficiency of the fuel cell itself. The total electric power of the plant is mainly generated in the fuel cell and a smaller part in the gas-turbine and steamturbine plant. 126
  6. 6. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online) Volume 5, Issue 1, January (2014), © IAEME Table 3. Output data (results) for BC with modular high-temperature SOFC: Output data (results) Without B1/B2 With condensing steam turbine (ST) with regulated steam extraction Fuel consumption in FC B kg/s Fuel consumption in B1 B1 kg/s Fuel consumption in B2 B2 kg/s Air flow in FC mv kg/s Gas flow at the FC outlet mg kg/s Gas flow at the GT inlet mg1 kg/s Gas flow at the inlet of the HRSG mg2 kg/s With B1/B2 3.29 62.03 65.32 - 3.29 0.978 0.012 62.03 65.322 66.301 66.313 Temperature at the outlet of the FC tgKD °C 1041.123 949,698 Power of the FC (E)* Efficiency of the FC (E) Number of individual FC PAC ηEFC nfc kW cells 100,000.00 0.635 327,278.670 100,000.00 0.635 327,278.670 Number of modules Area of the modular FC Length/Width nmfc Afcm afcm /bfcm mod m2 m 59 143.769 9.790/14.685 59 143.769 9.790/14.685 Power of the GTP (Е) Efficiency (Е) of GTP (+FC) Steam flow trough STP Steam flow for HC Power (Е) of STP Efficiency (Е) of STP Thermal power of STP Power (Е) of BCFC PEGTP ηEGTP mo mOT PESTP ηESTP QTSTP PE,BCFC kW kg/s kg/s kW kW kW 12,064.258 0.711 7.34 2.20 5,783.64 0.273 5,095.15 117,847.898 34,344.203 0.658 11.24 3.37 14,417.57 0.366 8,299.88 148,337.047 Efficiency (Е) of BCFC Total exergy efficiency With back-pressure steam turbine Power (Е) of BCFC with FC Efficiency (Е) of BCFC with FC Total exergy efficiency *(E) electrical ηE,BCFC ηex,BCFC - 0.748 0.759 0.724 0.738 PE,BCFC ηE,BCFC ηex,BCFC kW - 115,069.375 0.731 0.769 144,312.797 0.704 0.755 When applying a condensing steam turbine the electrical efficiency of the plant grows, but thermal utilization of available energy. On the other hand, applying counter-pressure steam turbine reduces electrical efficiency, but increments the total exergy. That means, certain reduction of the plant’s electrical power and increasing of the thermal power. Optimization procedure can be repeated for any power level, by defining the appropriate power of a modular fuel cell with suitable composition of the fuel and oxidant. The mathematical model with appropriate software package is composed of numerous complex calculation procedures, but there are also standard calculations for determination of properties of gas, steam, water etc. Selected and most important section of the results is presented in this paper. The model has ability to calculate other combinations of combined power plant and other variations of the BCFC. 127
  7. 7. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online) Volume 5, Issue 1, January (2014), © IAEME 5. VERIFICATION OF THE MATHEMATICAL MODEL RESULTS Assessment of the validity of the results obtained with the mathematical model is done using the data for a plant on gaseous fuel from literature sources [9, 10]. For comparison of the results obtained with the BCFC model for gaseous fuels, utilized data are relating to an existing plant with a power of 4 MW that runs on natural gas and is the product of one of the leading companies in this field Siemens Westinghouse, with assistance from the U.S. Company Heron [10]. The plant is a combination of a modular SOFC with high-temperature fuel cell and a gas-turbine plant. The results from the calculation are presented in Table 4. Comparison shows that the obtained model calculations are very close to the data of the selected plant. It must be noted that the plant under consideration is a combination of modular fuel cell and gas-turbine plant. However it does not diminish the reliability of the obtained results. Table 4. Comparison of the results of the optimization model application on BCFC on natural gas [10, 14]: Input data Power of SOFC PAC Voltage of individual fuel cells Vfc Fuel utilization Ug Oxidant (air) utilization Uo Temperature of fuel at the SOFC inlet Tgv Temperature of oxidant at the SOFC inlet Tov Fuel composition CH4 PCH4v C2H6 PC2H6v C3H8 PC3H8v CO2 PCO2v N2 PN2v Oxidant composition (air) O2 PO2ov N2 PN2ov Temperature of oxidant (air) at the compressor inlet t1 Compressor pressure ratio ΠC Model results Comparison power plant data Fuel consumption B Oxidant (air) mass flow rate mv Mole flow rate of gases at SOFC outlet nCO2 nH2O nO2 nN2 Total gas flow ng Mass flow rate of gases at SOFC outlet mg Gases composition at SOFC outlet CO2 PCO2KD H2O PH2OKD O2 PO2KD N2 PN2KD Power (Е) of the gas-turbine plant PEGTP Efficiency (Е) of the gas-turbine plant ηEGTP Power (Е) of the GT with SOFC PEBCPFC Efficiency (Е) of GT with SOFC ηEBCFC Specific consumption of heat (Е) qEBCFC 128 MW V % % K K % % % % % % % °C - 3.5 0.7 94 81.5 767 973 93.9 3.2 1.1 1.0 0.8 21 79 25 3.5 kg/s kg/s kmol/h kmol/h kmol/h kmol/h kmol/h kg/s % % % % kW kW kg/kWh 0.13 2.25 265 2.37 8.5 16.5 2.5 72.5 430 0.40 3,930 0.76 4,700 Results 0.129 2.251 22.429 44.384 6.807 192.768 266.39 2.370 8.419 16.661 2.555 72.365 428.84 0.388 3,928.83 0.766 4,696.82
  8. 8. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online) Volume 5, Issue 1, January (2014), © IAEME 6. COMPARISON BETWEEN BCFC ON COGENERATION TPP WITHOUT FUEL CELL NATURAL GAS AND BINARY In order to demonstrate the capabilities and good perspective of the BCFC, a comparison is made between a BCFC (with burners for additional combustion) and binary cogeneration power plant (BCPP) without fuel cells (classical cogeneration plant), with equal electrical and thermal power. From the obtained results, shown in Table 5, it can seen that BCFC achieve much higher total exergy efficiency compared to BCPP without fuel cells [14]. One of the major advantages of BCFC power plants (PP) over the other TPPs are environmental benefits. In order to assess the environmental benefits, two plants with the same electrical and thermal power are compared. BCFC plant with electric power of 500 MW and thermal power of 105 MW is smaller consumer of fuel compared with the BCPP with the same electrical and thermal power, which is directly reflected in reduction of emissions of harmful substances. Comparison of specific emissions of CO2 and NOx from BCFC power plant and BCPP is presented in Table 6, showing that the specific emissions from BCFC are about 20% smaller compared to the ones from BCPP. Table 5. Comparison between BCFC and BCPP: Parameter Unit BCFC with B1/B2 BCPP (without FC) Bvk Fuel consumption kg/s 14.94 19.1 PE Electrical power MW 500 500 Thermal power QT MW 105 105 ηE Electrical efficiency 0.68 0.54 ηvk Total exergy efficiency 0.73 0.58 Table 6. Specific emissions of CO2 and NOx from BCFC PP compared to BCPP: BCFC with B1/B2 BCPP (without FC) eCO2 g/kWh Specific emission of 294.58 375.00 CO2 eNOx g/kWh Specific emission of 0.32 0.40 NOx 7. CONCLUSION From the present work a conclusion can be drawn that the combined thermal power plants with BCFC achieve high efficiency, i.e. one of the highest efficiencies at the actual combined thermal power plants. Depending on the choice of cogeneration steam-turbine thermal power plant, efficiency varies within the limits of 70-75%. Important advantage of these facilities is the possibility for combined generation of electricity and thermal energy. Besides the abovementioned, these plants have other advantages: - They can use any type of fuel, including hydrogen - They can be built as large power objects and used as the basic source of electricity and thermal energy - They can be used as a completely independent source of electricity and thermal energy 129
  9. 9. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online) Volume 5, Issue 1, January (2014), © IAEME - Fuel cells operate at constant parameters and permanently supply the BCP with constant amount of thermal energy - There is a possibility for coupled regulation of the parameters before the gas-turbine and steam-turbine plants, as well as for an independent operation of one of these plants in the eventual failure of the other one - According to the current status, the fuel cells are characterized with a relatively long operational life, up to 70 000 hours - The harmful emission of gases is low, that means they are environmentally friendly - Fuel cell works completely quiet, because there are no rotation parts. The presented model allows fast and relatively simple optimization and calculation of power plants with FC. The accompanying program is simple to use, but the user must have prior knowledge in its use. In the following period, the effort will be put on the model improvement from the numerical and programming side and not so much by thermal aspect. When it comes to fuel cells, the most immediate drawback is their high cost, but if they reach the expectations that in this decade the price of fuel cells power plants will equal the price of other TPP, these plants will be very competitive on the energy market. The great interest of many companies taking advantage of fuel cells makes manufacturers of fuel cells to work on increasing their service life, i.e. reducing the spending of their components. REFERENCES 1. Colpan C.O., Thermal Modeling of Solid Oxide Fuel Cell Based Biomass Gasification Systems, PhD Thesis, Faculty of Graduate Studies and Research, Department of Mechanical and Aerospace Engineering, Carleton University, Ottawa, Canada, 2009. 2. Kee R.J., Zhu H., Goodwin D.G., Solid-oxide fuel cells (SOFC) with hydrocarbon and hydrocarbon-derived fuels, 30th Int. Symp. on Combustion, Chicago, Illinois, 2004. 3. Lawn C.J., Technologies for tomorrow’s electric power generation, Proc. ImechE Vol. 223 Part C: J. Mechanical Engineering Science, 2009, 2717-2742. 4. Ghosh S., De S., Thermodynamic performance study of an integrated gasification fuel cell combined cycle: an exergy analysis, Proc. ImechE, Part A: J. Power and Energy, 2003, 217 (A6), 575-581. 5. Ghosh S., De S., First and second law performance variations of a coal gasification fuel-cellbased combined cogeneration plant with varying load, Proc. ImechE, Part A: J. Power and Energy, 2004, 218 (A7), 477-485. 6. Wiens B., The Future of Fuel Cells, Ben Wiens Consulting Inc., 2010, http://www.benwiens.com/energy4.html (Site approached on 25 May, 2012) 7. Veyo S., Westinghouse SOFC field init status, Review Conference on Fuel Cell Technology, Chicago, 1999 8. George R., Westinghouse Program Overview, Second workshop on very high efficiency fuel cell/advanced turbine power cycles fuel cells 96, Morgantown energy technology center, USA, 1996 9. Veyo. S., Westinghouse fuel cell combined cycle systems, Second workshop on very high efficiency fuel cell/advanced turbine power cycles fuel cells 96, Morgantown energy technology center, USA, 1996 10. EG&G Technical Services, Inc, Fuel Cell Handbook, US Department of Energy, Morgantown, West Virginia, USA, 2004 11. O’Connel R., Fuel Cell – Revolutionary technology from the 19-th Century, SFA, London, 2000. 130
  10. 10. International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online) Volume 5, Issue 1, January (2014), © IAEME 12. Trippel C., Stilinger W., Operating a fuel cells using a landfill gas, Review Conference on Fuel Cell Technology, Chicago, 1999. 13. Tan-Ping Ch., SOFC system analysis, Review Conf. on Fuel Cell Technology, Chicago, 1999. 14. Tashevski D., Optimization of binary cogenerative power plants with height temperature fuel cells, Ph. D. thesis, University St. Ciril and Methodius, Mechanical faculty, Skopje, Macedonia, 2004 (in Macedonian). 15. Kehlofer R., Plancheler A., BBC combined cycle: Combined gas/steam turbine power plant, report, No. 10, Zurich, Switzerland, 1997. 16. Vujanovic B., Methods of optimization, Novi Sad, Serbia, 1980 (in Serbian). 17. ***, Gas turbine technology No.5 development of the G series gas turbine, Mitsubishi heavy industries Ltd, http://www.mhi.co.jp. 18. K. Balachander and Dr. P. Vijayakumar, “Economic Analysis, Modeling and Simulation of Photovoltaic Fuel Cell Hybrid Renewable Electric System for Smart Grid Distributed Generation System”, International Journal of Mechanical Engineering & Technology (IJMET), Volume 3, Issue 1, 2012, pp. 179 - 186, ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359. 19. Aram Mohammed Ahmed and Dr. Mohammad Tariq, “Thermal Analysis of a Gas Turbine Power Plant to Improve Performance Efficiency”, International Journal of Mechanical Engineering & Technology (IJMET), Volume 4, Issue 6, 2013, pp. 43 - 54, ISSN Print: 0976 – 6340, ISSN Online: 0976 – 6359. 131

×