Surge Prevention Techniques for a Turbocharged Solid Oxide Fuel Cell Hybrid System

2021 ◽  
Author(s):  
Luca Mantelli ◽  
Mario L. Ferrari ◽  
Alberto Traverso
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbines ◽  
Control Strategies ◽  
Solid Oxide ◽  
Pollutant Emissions ◽  
Inlet Temperature ◽  
Oxide Fuel ◽  
Surge Margin ◽  
Compressor Inlet

Abstract Pressurized solid oxide fuel cell systems are one of the most promising technologies to achieve high efficiencies and reduce pollutant emissions. This study focuses on an innovative layout, based on an automotive turbocharger, which improves cost effectiveness at small size (<100 kW), despite reducing slightly the efficiency compared to micro gas turbines based layouts. This turbocharged system poses two main challenges. On one side, the absence of an electrical generator does not allow the direct control of the rotational speed. On the other side, the large volume of the fuel cell stack between compressor and turbine alters the dynamic behavior of the turbocharger during transients, increasing the risk of compressor surge. The pressure oscillations associated with surge are particularly detrimental for the system and could damage the materials of the fuel cells. The aim of this paper is to investigate different techniques to drive the operative point of the compressor far from the surge condition when needed, increasing its reliability. Using a system dynamic model, developed with the TRANSEO tool by TPG, the effect of different anti-surge solutions is simulated: (i) water spray at compressor inlet, (ii) compressor fogging, (iii) air bleed, (iv) recirculation and (iv) ejector-aided recirculation at compressor intake. The system is simulated with two different control strategies, i.e. constant fuel mass flow and constant turbine inlet temperature. Different solutions are evaluated based on surge margin behavior, both in the short and long terms, but also monitoring other relevant physical quantities of the system.

Surge Prevention Techniques for a Turbocharged Solid Oxide Fuel Cell Hybrid System

2021 ◽  
Author(s):  
L. Mantelli ◽  
M. L. Ferrari ◽  
A. Traverso
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Rotational Speed ◽  
Pressure Ratio ◽  
High Energy ◽  
Cell System ◽  
Solid Oxide ◽  
Pollutant Emissions ◽  
Inlet Temperature ◽  
Oxide Fuel

Abstract Pressurized solid oxide fuel cell (SOFC) systems are one of the most promising technologies to achieve high energy conversion efficiencies and reduce pollutant emissions. The most common solution for pressurization is the integration with a micro gas turbine, a device capable of exploiting the residual energy of the exhaust gas to compress the fuel cell air intake and, at the same time, generating additional electrical power. The focus of this study is on an alternative layout, based on an automotive turbocharger, which has been more recently considered by the research community to improve cost effectiveness at small size (< 100 kW), despite reducing slightly the top achievable performance. Such turbocharged SOFC system poses two main challenges. On one side, the absence of an electrical generator does not allow the direct control of the rotational speed, which is determined by the power balance between turbine and compressor. On the other side, the presence of a large volume between compressor and turbine, due to the fuel cell stack, alters the dynamic behavior of the turbocharger during transients, increasing the risk of compressor surge. The pressure oscillations associated with such event are particularly detrimental for the system, because they could easily damage the materials of the fuel cells. The aim of this paper is to investigate different techniques to drive the operative point of the compressor far from the surge condition when needed, reducing the risks related to transients and increasing its reliability. By means of a system dynamic model, developed using the TRANSEO simulation tool by TPG, the effect of different anti-surge solutions is simulated: (i) intake air conditioning, (ii) water spray at compressor inlet, (iii) air bleed and recirculation, and (iv) installation of an ejector at the compressor intake. The pressurized fuel cell system is simulated with two different control strategies, i.e. constant fuel mass flow and constant turbine inlet temperature. Different solutions are evaluated based on surge margin behavior, both in the short and long terms, but also monitoring other relevant physical quantities of the system, such as compressor pressure ratio and turbocharger rotational speed.

Performance Evaluation of Solid Oxide Fuel Cell Engines Integrated With Single/Dual-Spool Turbochargers

2011 ◽  
Vol 8 (6) ◽  
Author(s):  
So-Ryeok Oh ◽  
Jing Sun ◽  
Herb Dobbs ◽  
Joel King
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Control Strategies ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Operating Characteristics ◽  
Load Following ◽  
Fuel Flow

This study investigates the performance and operating characteristics of 5kW-class solid oxide fuel cell and gas turbine (SOFC/GT) hybrid systems for two different configurations, namely single- and dual- spool gas turbines. Both single and dual spool turbo-chargers are widely used in the gas turbine industry. Even though their operation is based on the same physical principles, their performance characteristics and operation parameters vary considerably due to different designs. The implications of the differences on the performance of the hybrid SOFC/GT have not been discussed in literature, and will be the topic of this paper. Operating envelops of single and dual shaft systems are identified and compared. Performance in terms of system efficiency and load following is analyzed. Sensitivities of key variables such as power, SOFC temperature, and GT shaft speed to the control inputs (namely, fuel flow, SOFC current, generator load) are characterized, all in an attempt to gain insights on the design implication for the single and dual shaft SOFC/GT systems. Dynamic analysis are also performed for part load operation and load transitions, which shed lights for the development of safe and optimal control strategies.

Examination of Ambient Pressure Effects on Hybrid Solid Oxide Fuel Cell Turbine System Operation Using Hardware Simulation

2006 ◽  
Author(s):  
David Tucker ◽  
Larry Lawson ◽  
John VanOsdol ◽  
Jordan Kislear ◽  
Ayodeji Akinbobuyi
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Dynamic Models ◽  
Ambient Pressure ◽  
Pressure Vessels ◽  
Solid Oxide ◽  
Inlet Pressure ◽  
Inlet Temperature ◽  
Oxide Fuel ◽  
Compressor Inlet

The effect of ambient inlet air pressure variations on the compressor performance in a direct fired solid oxide fuel cell gas turbine hybrid power system has been studied using the Hybrid Performance (Hyper) project hardware simulation facility at the U.S. Department of Energy, National Energy Technology Laboratory (NETL). The Hyper facility at NETL makes use of a high speed numerical model which controls a burner and a series of pressure vessels and piping to collectively simulate a direct-fired, high-temperature fuel cell. The hardware simulating the fuel cell is integrated into the system with a modified single shaft turbine driven compressor and a pair of recuperates to provide cathode air preheat from the turbine exhaust. Orifice plates were employed at the compressor inlet of the facility to parametrically vary the inlet pressure. The compressor inlet temperature for all tests conducted was held within a 2 Kelvin range. Variation in inlet pressure was shown to have a significant effect on many hybrid system performance parameters. Some system parameters were shown to have a linear dependency on the inlet pressure, leading to the implementation of correction factors. Similar dependence of compressor discharge pressure and temperature on compressor inlet pressure was predicted by dynamic models based on isentropic compression principles. Transient operation was also impacted by changes in compressor inlet pressure. Startup profiles are shown against the compressor stall line for indication of changes in surge margin.

Thermodynamic and dynamic analysis off a wind-powered off-grid industrial building integrated with solid oxide fuel cell and electrolyzer for energy management and storage

2021 ◽  
pp. 1-30
Author(s):  
Pegah Mottaghizadeh ◽  
Mahshid Fardadi ◽  
Faryar Jabbari ◽  
Jacob Brouwer
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Wind Farm ◽  
Control Strategies ◽  
Storage System ◽  
Energy Storage System ◽  
Solid Oxide ◽  
System Level ◽  
Industrial Building ◽  
Oxide Fuel

Abstract In this study, an islanded microgrid system is proposed that integrates identical stacks of solid oxide fuel cell and electrolyzer to achieve a thermally self-sustained energy storage system. Thermal management of the SOEC is achieved by use of heat from the SOFC with a heat exchanger network and control strategies. While the SOFC meets the building electricity demand and heat from its electrochemical reactions is transferred to the SOEC for endothermic heat and standby demands. Each component is physically modelled in Simulink and ultimately integrated at the system level for dynamic analyses. The current work simulates a system comprised of a wind farm in Palm Springs, CA coupled with the SOEC (for H2 generation), and an industrial building powered by the SOFC. Results from two-weeks of operation using measured building and wind data showed that despite fluctuating power profiles, average temperature and local temperature gradients of both the SOEC and SOFC were within desired tolerances. However, for severe conditions of wind power deficit, H2 had to be supplied from previous windy days' storage or imported.

scholarly journals Thermoeconomic Optimization of a Hybrid Photovoltaic-Solid Oxide Fuel Cell System for Decentralized Application

2019 ◽  
Vol 9 (24) ◽  
pp. 5450
Author(s):  
Alexandros Arsalis ◽  
George E. Georghiou
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Cell System ◽  
Solid Oxide ◽  
Small Scale ◽  
Inlet Temperature ◽  
Oxide Fuel ◽  
Optimization Strategy ◽  
Commercial Building ◽  
Autonomous Operation

A small-scale, decentralized hybrid system is proposed for autonomous operation in a commercial building (small hotel). The study attempts to provide a potential solution, which will be attractive both in terms of efficiency and economics. The proposed configuration consists of the photovoltaic (PV) and solid oxide fuel cell (SOFC) subsystems. The fuel cell subsystem is fueled with natural gas. The SOFC stack model is validated using literature data. A thermoeconomic optimization strategy, based on a genetic algorithm approach, is applied to the developed model to minimize the system lifecycle cost (LCC). Four decision variables are identified and chosen for the thermoeconomic optimization: temperature at anode inlet, temperature at cathode inlet, temperature at combustor exit, and steam-to-carbon ratio. The total capacity at design conditions is 70 and 137.5 kWe, for the PV and SOFC subsystems, respectively. After the application of the optimization process, the LCC is reduced from 1,203,266 to 1,049,984 USD. This improvement is due to the reduction of fuel consumed by the system, which also results in an increase of the average net electrical efficiency from 29.2 to 35.4%. The thermoeconomic optimization of the system increases its future viability and energy market penetration potential.

Thermodynamic Performance of a Gas Turbine Plant Combined With a Solid Oxide Fuel Cell

2008 ◽  
Author(s):  
Yousef Haseli ◽  
Ibrahim Dincer ◽  
Greg F. Naterer
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Compression Ratio ◽  
Solid Oxide ◽  
Specific Power ◽  
Inlet Temperature ◽  
Oxide Fuel ◽  
Turbine Inlet Temperature ◽  
Energy And Exergy

This paper undertakes a thermodynamic analysis of a high-temperature solid oxide fuel cell, combined with a conventional recuperative gas turbine. In the analysis the balance equations for mass, energy and exergy for the system as a whole and its components are written, and both energy and exergy efficiencies are studied for comparison purposes. These results are also verified with data available in the literature for typical operating conditions, the predictive model of the system is validated. The energy efficiency of the integrated cycle is obtained to be as high as 60.55% at the optimum compression ratio. These model findings indicate the influence of different parameters on the performance of the cycle and irreversibilities therein, with respect to the exergy destruction rate and/or entropy generation rate. The results show that a higher ambient temperature would lead to lower energy and exergy efficiencies, and lower net specific power. Furthermore, the results indicate that increasing the turbine inlet temperature results in decreasing both the energy and exergy efficiencies of the cycle, whereas it improves the total specific power output. However, an increase in either the turbine inlet temperature or compression ratio leads to a higher rate of irreversibility within the plant. It is shown that the combustor and SOFC contribute predominantly to the total irreversibility of the system; about 60 percent of which takes place in these components at a typical operating condition, with 31.4% for the combustor and 27.9% for the SOFC.

Safety Analysis of a Solid Oxide Fuel Cell/Gas Turbine Hybrid System Fueled With Gasified Biomass

2015 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaojing Lv ◽  
Chaohao Lu ◽  
Xinjian Zhu ◽  
Yiwu Weng
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Safety Performance ◽  
Solid Oxide ◽  
The Other ◽  
Inlet Temperature ◽  
Oxide Fuel ◽  
Compressor Surge

The effect of biomass gas on the safety performance of a solid oxide fuel cell (SOFC)/micro gas turbine (GT) hybrid system was studied with consideration of the fuel cell working temperature, fuel cell temperature gradient requirement, compressor surge zone, and turbine inlet temperature (TIT). The safety performance of the hybrid system on the design condition and off-design condition was also analyzed. Results show that the hybrid system is good adaptability to low concentrations of biomass gas. The electrical efficiency could reach 50% with different biomass gases and is higher than the other combined power systems that used biomass gas. The wood chip gas (WCG) would make the fuel cell or GT easier overheat than the other three gases. The cotton wood gas (CWG) and corn stalk gas (CSG) are easy to cause the TIT too low or the compressor surge. In the safety zone, considering the hybrid system load adjustment range, the effecting order (from large to small, following is same) is WCG, grape seed gas (GSG), CSG, and CWG. Considering the hybrid system electric efficiency, the effecting order is WCG, GSG, CWG, and CSG.

scholarly journals Ammonia-based Solid Oxide Fuel Cell for zero emission maritime power: a case study

2022 ◽  
Vol 334 ◽  
pp. 06007
Author(s):  
Simona Di Micco ◽  
Mariagiovanna Minutillo ◽  
Luca Mastropasqua ◽  
Viviana Cigolotti ◽  
Jack Brouwer
Keyword(s):  
Fuel Cell ◽  
Diesel Engine ◽  
Solid Oxide Fuel Cell ◽  
High Energy ◽  
Propulsion System ◽  
Solid Oxide ◽  
Pollutant Emissions ◽  
Optimal Size ◽  
Oxide Fuel ◽  
Heavy Fuel Oil

Implementing environmentally friendly fuels and high efficiency propulsion technologies to replace the Internal Combustion Engine (ICE) fueled by fossil fuels such as Heavy Fuel Oil (HFO) and Marine Gas Oil (MGO) on board ships represents an attractive solution for maritime power. In this context, fuel cells can play a crucial role, thanks to their high energy efficiency and ultra-low to zero criteria pollutant emissions and environmental impact. This paper performs the technical feasibility analysis for replacing the conventional diesel engine powertrain on board a commercial vessel with an innovative system consisting of ammonia-fuel-based Solid Oxide Fuel Cell (SOFC) technology. Taking into account the size of the diesel engines installed on board and the typical cruise performed by the commercial vessel, the ammonia consumption, as well as the optimal size of the innovative propulsion system have been assessed. In particular, the SOFC powertrain is sized at the same maximum power output as the main reference diesel engine. The mass and energy balances of the ammonia-based SOFC system have been performed in Aspen PlusTM environment. The gravimetric (kWh kg−1) and volumetric (kWh m−3) energy density features of the ammonia storage technology as well as the weight and volume of the proposed propulsion system are evaluated for verifying the compliance with the ship’s weight and space requirements. Results highlight that the proposed propulsion system involves an increase in weight both in the engine room and in the fuel room compared to the diesel engine and fuel. In particular, a cargo reduction of about 2.88% is necessary to fit the ammonia-based SOFC system compared to the space available in the reference diesel-fueled ship.

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