Performance Evaluation of a SOFC-GT Hybrid System With Ejectors for the Anode and Cathode Recirculations

2017 ◽  
Author(s):  
Jinwei Chen ◽  
Kuanying Gao ◽  
Maozong Liang ◽  
Huisheng Zhang
Keyword(s):  
Fuel Cell ◽  
Hybrid System ◽  
Flow Rate ◽  
Low Cost ◽  
Cell System ◽  
Operating Conditions ◽  
Momentum Balance ◽  
Fuel Flow ◽  
Inlet Conditions ◽  
Safety Range

The recirculation of the anode and cathode exhaust has huge benefits on the fuel cell system, for instance, keeping proper operating conditions of the reformer and preheating the inlet air which reduces the recuperator size. Furthermore, the ejectors used for the fuel cell recirculation are more reliable and low-cost in maintenance than high temperature blowers. In this paper, an anode and cathode recirculation scheme, both equipped with ejectors, was designed in a Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) hybrid system. Additionally, a blower was added between the compressor and the heat exchanger to overcome the significant pressure loss caused by the cathode ejector. This configuration separates the compressor from the fuel cell and turbine components, introducing more flexibility in system modification. The investigations were conducted to analyze the performance of the hybrid system with anode and cathode ejectors in this paper. Firstly, the ejector model was established based on the energy, mass and momentum balance equations. Furthermore, it was validated that the ejector model was consistent with the reference data. Secondly, the stand-alone performance of the anode and cathode ejectors was analyzed. The geometry parameters of the ejectors were determined based on the design conditions. Then the off-design performance was analyzed based on the designed ejectors geometry. The results show that the performance of the ejectors is greatly influenced by the inlet conditions of the primary and secondary fluid mass flow rate. Finally, the anode and cathode ejectors were integrated into the SOFC-GT hybrid system. Meanwhile, the off-design and dynamic behaviors of the whole SOFC-GT hybrid system with anode and cathode ejectors for recirculation loops were analyzed. In the end, the results show that the designed ejectors can effectively satisfy the demands of the SOFC-GT system with anode and cathode recirculation loops. And the safety range of relative fuel flow rate is from 0.42 to 1.22 when the rotator speed is constant.

Performance Evaluation of an SOFC-GT Hybrid System With Ejectors for the Anode and Cathode Recirculations

2019 ◽  
Vol 16 (4) ◽  
Author(s):  
Jinwei Chen ◽  
Kuanying Gao ◽  
Maozong Liang ◽  
Huisheng Zhang
Keyword(s):  
Fuel Cell ◽  
Hybrid System ◽  
Rotational Speed ◽  
Low Cost ◽  
Dynamic Performance ◽  
Load Condition ◽  
System A ◽  
Fuel Flow ◽  
Primary Fluid ◽  
Component Models

The ejectors used for the fuel cell recirculation are more reliable and low cost in maintenance than high-temperature blowers. In this paper, an anode and cathode recirculation scheme, equipped with ejectors, was designed in a solid oxide fuel cell-gas turbine (SOFC-GT) hybrid system. The ejector model, SOFC model, and other component models and the validation were conducted to investigate the performance of the hybrid system with anode and cathode ejectors. The geometric parameters of the ejectors were designed to perform the anode and cathode recirculation loops according to the design conditions of the hybrid system with a blower-based recirculation loop. The cathode ejector geometries are much larger than the anode ejector. In addition, the sensitivity analysis of the primary fluid for the standalone anode and cathode ejectors is investigated. The results show that the ejector can recirculate more secondary fluid by reducing the ejector outlet pressure. Then, the anode and cathode ejectors were integrated into the SOFC-GT hybrid system. A blower gets involved downstream, and the compressor is necessary to avoid high expensive cost of redesigning compressor. The off-design and dynamic performance were characterized after integrating the anode and cathode ejectors into the hybrid system. The dynamic and off-design performances show that the designed ejectors are effectively integrated into the anode and cathode recirculation loops to replace the blower-based recirculation loops. The safety range of relative fuel flow rate is 0.62–1.22 in the fixed rotational speed strategy, and it is 0.53–1.1 in the variable rotational speed strategy. The variable rotational speed strategy can ensure higher system efficiency, which is more than 61% at a part-load condition.

Exergy Analysis of a Hybrid Micro Gas Turbine Fuel Cell System Based on Existing Components

2012 ◽  
Author(s):  
D. P. Bakalis ◽  
A. G. Stamatis
Keyword(s):  
Fuel Cell ◽  
Hybrid System ◽  
Exergy Analysis ◽  
Cell System ◽  
System Component ◽  
Utilization Factor ◽  
Fuel Cell Stack ◽  
Micro Gas Turbine ◽  
Partial Load ◽  
Set Up

A hybrid system based on an existing recuperated microturbine and a pre-commercially available high temperature tubular solid oxide fuel cell is modeled in order to study its performance. Individual models are developed for the microturbine and fuel cell generator and merged into a single one in order to set up the hybrid system. The model utilizes performance maps for the compressor and turbine components for the part load operation. The full and partial load exergetic performance is studied and the amounts of exergy destruction and efficiency of each hybrid system component are presented, in order to evaluate the irreversibilities and thermodynamic inefficiencies. Moreover, the effects of various performance parameters such as fuel cell stack temperature and fuel utilization factor are investigated. Based on the available results, suggestions are given in order to reduce the overall system irreversibility. Finally, the environmental impact of the hybrid system operation is evaluated.

Experimental and Theoretical Performance Analysis of a High Temperature PEM Fuel Cell Fed With LPG Using a Compact Steam Reformer

2011 ◽  
Author(s):  
Nicola Zuliani ◽  
Rodolfo Taccani ◽  
Robert Radu
Keyword(s):  
High Temperature ◽  
Fuel Cell ◽  
Cell System ◽  
Operating Conditions ◽  
Steam Reformer ◽  
Fuel Cell Performance ◽  
Fuel Processor ◽  
Balance Of Plant ◽  
Energy Balances ◽  
High Temperature Pem

High temperature PEM (HTPEM) fuel cell based on polybenzimidazole polymer (PBI) and phosphoric acid, can be operated at temperature between 120°C and 180°C. Reactants humidification is not required and CO content up to 1% in fuel can be tolerated, affecting only marginally performance. This is what makes HTPEM fuel cells very attractive, as low quality reformed hydrogen can be used and water management problems are avoided. This paper aims to present the preliminary experimental results obtained on a HTPEM fuel cell fed with LPG using a compact steam reformer. The analysis focus on the reformer start up transient, on the influence of the steam to carbon ratio on reformate CO content and on the single fuel cell performance at different operating conditions. By analyzing the mass and energy balances of the fuel processor, fuel cell system, and balance-of-plant, a previously developed system simulation model has been used to provide critical assessment on the conversion efficiency for a 1 kWel system. The current study attempts to extend the previously published analyses of integrated HTPEM fuel cell systems.

Theoretical Analysis on the Autothermal Reforming Process of Ethanol as Fuel for a Proton Exchange Membrane Fuel Cell System

2006 ◽  
Vol 4 (4) ◽  
pp. 468-473 ◽  
Author(s):  
Alessandra Perna
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Cell System ◽  
Autothermal Reforming ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Hydrogen Yield ◽  
Fuel Cell System ◽  
Exchange Membrane

The purpose of this work is to investigate, by a thermodynamic analysis, the effects of the process variables on the performance of an autothermal reforming (ATR)-based fuel processor, operating on ethanol as fuel, integrated into an overall proton exchange membrane (PEM) fuel cell system. This analysis has been carried out finding the better operating conditions to maximize hydrogen yield and to minimize CO carbon monoxide production. In order to evaluate the overall efficiency of the system, PEM fuel cell operations have been analyzed by an available parametric model.

Evaluation of Cathode Air Flow Transients in a SOFC/GT Hybrid System Using Hardware in the Loop Simulation

2014 ◽  
Author(s):  
Nana Zhou ◽  
Chen Yang ◽  
David Tucker
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Mass Flow ◽  
Cell System ◽  
Department Of Energy ◽  
Dynamic Responses ◽  
Partial Recovery ◽  
Fuel Cell System ◽  
Air Mass

Thermal management in the fuel cell component of a direct fired solid oxide fuel cell gas turbine (SOFC/GT) hybrid power system, especially during an imposed load transient, can be improved by effective management and control of the cathode air mass flow. The response of gas turbine hardware system and the fuel cell stack to the cathode air mass flow transient was evaluated using a hardware-based simulation facility designed and built by the U.S. Department of Energy, National Energy Technology Laboratory (NETL). The disturbances of the cathode air mass flow were accomplished by diverting air around the fuel cell system through the manipulation of a hot-air bypass valve in open loop experiments. The dynamic responses of the SOFC/GT hybrid system were studied in this paper. The evaluation included distributed temperatures, current densities, heat generation and losses along the fuel cell over the course of the transient along with localized temperature gradients. The reduction of cathode air mass flow resulted in a sharp decrease and partial recovery of the thermal effluent from the fuel cell system in the first 10 seconds. In contrast, the turbine rotational speed did not exhibit a similar trend. The collection of distributed fuel cell and turbine trends obtained will be used in the development of controls to mitigate failure and extend life during operational transients.

scholarly journals Fuel Cell designing with optimal high speed air compressor

2021 ◽  
pp. 29-38
Author(s):  
Nabeel Ahsan ◽  
Mahrukh Mehmood ◽  
Asad A. Zaidi
Keyword(s):  
Fuel Cell ◽  
High Speed ◽  
Proton Exchange Membrane ◽  
Cell System ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Air Compressor ◽  
Different Types ◽  
Input Parameters ◽  
Turbo Compressor

This paper discusses different air management technologies for fuel cell systems. Two different types of compressors are analyzed for Proton-exchange membrane fuel cells (PEMFC). Some important criteria are analyzed thoroughly for the selection of turbo compressor among different types of compressors illustrated with the help of matrix representations. The impacts of various input parameters for Fuel Cell (FC) are also explained thoroughly. Later the numerical modeling of an automobile fuel cell system using a high speed turbo-compressor for air supply is explained. The numerical model incorporates the important input parameters related with air and hydrogen. It also performed energy and mass balances across different components such as pump, fan, heat-exchanger, air compressor and also keeps in consideration the pressure drop across the flow pipes and various mechanical parts. The model is solved to obtain the characteristics of the FC system at different operating conditions. Therefore, it can be concluded that the high speed turbo compressor with a turbo-expander can have significant effects on the overall system power and efficiency.

scholarly journals An experimental investigation of solid oxide fuel cell performance at variable operating conditions

2016 ◽  
Vol 20 (5) ◽  
pp. 1421-1433 ◽  
Author(s):  
Ismet Tikiz ◽  
Imdat Taymaz
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Cell Performance ◽  
Oxide Fuel ◽  
Nitrogen Flow ◽  
Cell Temperature ◽  
Hydrogen Flow ◽  
Fuel Cell Performance

Cell temperature and selection of the reactant gases are crucial parameters for the design and optimization of fuel cell performance. In this study, effect of operating conditions on the performance of Solid Oxide Fuel (SOFC) has been investigated. Application of Response Surface Methodology (RSM) was applied to optimize operations conditions in SOFC. For this purpose, an experimental set up for testing of SOFC has been established to investigate the effect of Hydrogen, Oxygen, Nitrogen flow rates and cell temperature parameters on cell performance. Hydrogen flow rate, oxygen flow rate, nitrogen flow rate and cell temperature were the main parameters considered and they were varied between 0.25 and 1 L/min, 0.5 and 1 L/min, 0 and 1 L/min and 700-800 oC in the analyses respectively. The maximum power density was found as 0.572 W/cm2 in the experiments.

Active, Reactive and Harmonic compensation control of grid interfaced fuel cell system

2012 ◽  
Vol 13 (4) ◽  
Author(s):  
Gitanjali Mehta ◽  
S. P. Singh ◽  
Ram Dayal Patidar
Keyword(s):  
Fuel Cell ◽  
Reactive Power ◽  
Active Power Filter ◽  
Cell System ◽  
Active Power ◽  
Operating Conditions ◽  
Voltage Source ◽  
Filter Function ◽  
Load Current ◽  
Power Filter

Abstract This paper presents the modelling and control of grid interfaced fuel cell distributed generation system with embedded active filter function. The features of active power filter have been incorporated in the control circuit of the current controlled-voltage source inverter interfacing the fuel cell to the grid. Thus the same inverter is utilised to inject power generated from fuel cell source to the grid and to act as shunt active power filter to compensate for load current harmonics, load reactive power demand and load current imbalance. Thus, after compensation, the grid current is sinusoidal and in-phase with grid voltage. Simulation in MATAB and experimentation using DSP is carried out to verify the operation and the control principle. The results are obtained for different operating conditions with varying load demands to prove the effectiveness of the entire system.

scholarly journals The effects of operating conditions on the performance of a direct carbon fuel cell

2013 ◽  
Vol 34 (4) ◽  
pp. 187-197 ◽  
Author(s):  
Andrzej Kacprzak ◽  
Rafał Kobyłecki ◽  
Zbigniew Bis
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Gas Flow ◽  
Air Flow ◽  
Operating Conditions ◽  
Cell Performance ◽  
Fuel Particle ◽  
Air Flow Rate ◽  
Direct Carbon Fuel Cell ◽  
Fuel Particles

Abstract The influences of various operating conditions including cathode inlet air flow rate, electrolyte temperature and fuel particles size on the performance of the direct carbon fuel cell DCFC were presented and discussed in this paper. The experimental results indicated that the cell performance was enhanced with increases of the cathode inlet gas flow rate and cell temperature. Binary alkali hydroxide mixture (NaOH-LiOH, 90-10 mol%) was used as electrolyte and the biochar of apple tree origin carbonized at 873 K was used as fuel. Low melting temperature of the electrolyte and its good ionic conductivity enabled to operate the DCFC at medium temperatures of 723-773 K. The highest current density (601 A m−2) was obtained for temperature 773 K and air flow rate 8.3×106 m3s−1. Itwas shown that too low or too high air flow rates negatively affect the cell performance. The results also indicated that the operation of the DCFC could be improved by proper selection of the fuel particle size.

Critical flow rate of anode fuel exhaust in a PEM fuel cell system

2006 ◽  
Vol 156 (2) ◽  
pp. 512-519 ◽  
Author(s):  
Wenhua H. Zhu ◽  
Robert U. Payne ◽  
Bruce J. Tatarchuk
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Pem Fuel Cell ◽  
Cell System ◽  
Critical Flow ◽  
Fuel Cell System ◽  
Critical Flow Rate
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