JREE: Vol. 5, No. 3, (Summer 2018) 42-52 Research Article Journal of Renewable Energy and Environment Journal Homepage: www.jree.ir Modeling and Process Analysis of a Biomass Gasifier-Molten Carbonate Fuel Cell-Gas Turbine-Steam Turbine Cycle as a Green Hybrid Power Generator Hassan Ali Ozgoli * Department of Mechanical Engineering, Iranian Research Organization for Science and Technology (IROST), Sh. Ehsani Rad St., Enqelab St., Parsa Sq., Ahmadabad Mostoufi Rd., Azadegan Highway, Postal Code: 3313193685, Tehran, Iran. PAPER INFO Paper history: Received 05 June 2019 Accepted in revised form 28 September 2019 Keywords: Biomass Gasifier Molten Carbonate Fuel Cell Gas Turbine Steam Turbine Hybrid System ABSTRACT Fuel cell-based hybrid cycles that include conventional power generators have been created to modify energy performance and output power. In the present paper, integrated biomass gasification (IBG)-molten carbonate fuel cell (MCFC)-gas turbine (GT) and steam turbine (ST) combined power cycle is introduced as an innovative technique in terms of sustainable energy. In addition, biomass gasification has been explained and shown able to supply the required fuel to the energy generators to compensate for the consumption consequences of fossil fuels. In this system, a molten carbonate fuel cell generates electricity from syngas produced by biomass gasification. In addition, a gas cleaning process prepares adequate treatment before consumption in the fuel cell. Furthermore, for the justification of this system as a combined heat and power (CHP) cycle, a considerable amount of produced heat in the proposed process generates power in GT and ST bottoming cycles. Due to the energy targeting, modeling and simulation of the presented system were fulfilled by the Cycle-Tempo software, and the results showed about 42 MW output power and total efficiency of around 83 %. Further to that, parametric studies represented the durability of the generated power against ambient temperature variations. Finally, changes in total power and efficiency due to the fluctuation of the moisture content of biomass, pressure ratio, and inlet temperature of GT have also been demonstrated. 1. INTRODUCTION 1 Fuel cells have been developed for converting chemical energy into electrical energy directly and noiselessly. They represent a highly efficient electrochemical apparatus, which does not include the moving parts. In the high-temperature fuel cells, methane, hydrogen, and carbon monoxide may be used on the anode side. These kinds of fuel cells can use syngas produced from coal or biomass gasification process as fuel if it is sufficiently clean [1-6]. The Molten Carbonate Fuel Cell (MCFC) works at high temperatures (about 650 °C) with various privileges such as feasibility of heat recovery and integration into other power generators. In other words, high operating temperature leads to an increase in performance just like any other cogeneration multi-purpose opportunities from high-quality heat along with the electric power generation. In addition, integration of biomass gasification into a variety of combined cycles including gas turbines, fuel cells, and steam turbines has been shown in several studies as sustainable energy systems of the hybrid power generators [7-10]. The MCFC unit can be efficiently integrated into other power producers like a gas turbine, since the temperature of the MCFC exhaust gas is high enough. In a reference by Appleby and Foulkes [11], it is demonstrated that the combination of gas turbines and fuel cells could be taken into consideration. Although the studies on the integration of fuel cells and gas turbines have been initiated several decades ago [11], the attraction of fuel cell-gas turbine cycles has developed in more recent years. For example, Liese and Gemmen [12] and Agnew et al. [13] analyzed the performance *Corresponding Author’s Email: a.ozgoli@irost.org (H.A. Ozgoli) of these hybrid cycles. Moreover, the effects of the combination of hybrid cycles and biomass gasification were presented in the past [14]. Besides, several operational hybrid systems have already been implemented by different groups [15-17]. A hybrid high-temperature MCFC-MGT system, which uses biomass gasification compared with natural gas as its fuel, was presented by Azegami [18]. In this system, about 60 % of gas fuel has been supplied by biomass gasification. The maximum electrical efficiency of 52 % was obtained when the delivered power is 300 kW. In another study, the integration of atmospheric MCFC in hybrid conjunction with a GT and a steam cycle was shown by Steinfeld [19]. The energy efficiency of this system was shown to be more than 70 %. Supplied fuel in this hybrid system was obtained from natural gas, whose proportion is 95 % and, also, the amount of anode recycling is 5 %. A hybrid MCFC-MGT power cycle fueled by natural and biogas gas was presented by Huang et al. to evaluate the total cycle performance [20]. Results of this research showed that the MCFC and MGT outputs decreased due to an increase in the biogas flow rate. Finally, the range of overall power efficiency is between 39 % and 42 %. A parametric study for evaluating the performance of an MCFC–GT cycle was accomplished by Lunghi et al. [21]. This study illustrated that a fuel cell, which is optimized for stand-alone operation, should be investigated again where it works in a hybrid cycle. Moreover, by using advanced gas turbine systems such as air humidification or turbine inlet air cooling, CHP efficiency can reach higher than 58 %. The feasibility of biomass-based MCFC and gas micro turbine integration was conducted by Jurado and Valverde