Control Impacts of Cold-Air Bypass on Pressurized Fuel Cell Turbine Hybrids

2015 ◽  
Vol 12 (1) ◽  
Author(s):  
Paolo Pezzini ◽  
Sue Celestin ◽  
David Tucker
Keyword(s):  
Fuel Cell ◽  
Risk Mitigation ◽  
Department Of Energy ◽  
Mitigation Strategies ◽  
Inlet Temperature ◽  
Unusual Behavior ◽  
Turbine Inlet Temperature ◽  
Cold Air ◽  
Turbine Efficiency ◽  
Turbine Inlet

A pressure drop analysis for a direct-fired fuel cell turbine hybrid power system was evaluated using a hardware-based simulation of an integrated gasifier/fuel cell/turbine hybrid cycle, implemented through the hybrid performance (Hyper) project at the National Energy Technology Laboratory, U.S. Department of Energy (NETL). The Hyper facility is designed to explore dynamic operation of hybrid systems and quantitatively characterize such transient behavior. It is possible to model, test, and evaluate the effects of different parameters on the design and operation of a gasifier/fuel cell/gas turbine hybrid system and provide means of evaluating risk mitigation strategies. The cold-air bypass in the Hyper facility directs compressor discharge flow to the turbine inlet duct, bypassing the fuel cell, and exhaust gas recuperators in the system. This valve reduces turbine inlet temperature while reducing cathode airflow, but significantly improves compressor surge margin. Regardless of the reduced turbine inlet temperature as the valve opens, a peak in turbine efficiency is observed during characterization of the valve at the middle of the operating range. A detailed experimental analysis shows the unusual behavior during steady state and transient operation, which is considered a key point for future control strategies in terms of turbine efficiency optimization and cathode airflow control.

Control Impacts of Cold-Air Bypass on Pressurized Fuel Cell Turbine Hybrids

2014 ◽  
Author(s):  
Paolo Pezzini ◽  
Sue Celestin ◽  
David Tucker
Keyword(s):  
Fuel Cell ◽  
Risk Mitigation ◽  
Department Of Energy ◽  
Mitigation Strategies ◽  
Inlet Temperature ◽  
Unusual Behavior ◽  
Turbine Inlet Temperature ◽  
Cold Air ◽  
Turbine Efficiency ◽  
Turbine Inlet

A pressure drop analysis for a direct-fired fuel cell turbine hybrid power system was evaluated using a hardware-based simulation of an integrated gasifier/fuel cell/turbine hybrid cycle (IGFC), implemented through the Hybrid Performance (Hyper) project at the National Energy Technology Laboratory, U.S. Department of Energy (NETL). The Hyper facility is designed to explore dynamic operation of hybrid systems and quantitatively characterize such transient behavior. It is possible to model, test and evaluate the effects of different parameters on the design and operation of a gasifier/fuel cell/gas turbine hybrid system and provide means of evaluating risk mitigation strategies. The cold air bypass in the Hyper facility directs compressor discharge flow to the turbine inlet duct, bypassing the fuel cell and exhaust gas recuperators in the system. This valve reduces turbine inlet temperature while reducing cathode airflow, but significantly improves compressor surge margin. Regardless of the reduced turbine inlet temperature as the valve opens, a peak in turbine efficiency is observed during characterization of the valve at the middle of the operating range. A detailed experimental analysis shows the unusual behavior during steady state and transient operation, which is considered a key point for future control strategies in terms of turbine efficiency optimization and cathode airflow control.

Avoiding Compressor Surge During Emergency Shutdown Hybrid Turbine Systems

2013 ◽  
Vol 135 (10) ◽  
Author(s):  
Paolo Pezzini ◽  
David Tucker ◽  
Alberto Traverso
Keyword(s):  
Fuel Cell ◽  
System Analysis ◽  
Risk Mitigation ◽  
Dynamic Effect ◽  
Transient Behavior ◽  
Open Loop ◽  
Department Of Energy ◽  
Mitigation Strategies ◽  
Emergency Shutdown ◽  
Compressor Surge

A new emergency shutdown procedure for a direct-fired fuel cell turbine hybrid power system was evaluated using a hardware-based simulation of an integrated gasifier/fuel cell/turbine hybrid cycle (IGFC), implemented through the Hybrid Performance (Hyper) project at the National Energy Technology Laboratory, U.S. Department of Energy (NETL). The Hyper facility is designed to explore dynamic operation of hybrid systems and quantitatively characterize such transient behavior. It is possible to model, test, and evaluate the effects of different parameters on the design and operation of a gasifier/fuel cell/gas turbine hybrid system and provide a means of quantifying risk mitigation strategies. An open-loop system analysis regarding the dynamic effect of bleed air, cold air bypass, and load bank is presented in order to evaluate the combination of these three main actuators during emergency shutdown. In the previous Hybrid control system architecture, catastrophic compressor failures were observed when the fuel and load bank were cut off during emergency shutdown strategy. Improvements were achieved using a nonlinear fuel valve ramp down when the load bank was not operating. Experiments in load bank operation show compressor surge and stall after emergency shutdown activation. The difficulties in finding an optimal compressor and cathode mass flow for mitigation of surge and stall using these actuators are illustrated.

Control Strategy for a Direct-Fired Fuel Cell Turbine Hybrid Power System

2014 ◽  
Author(s):  
Paolo Pezzini ◽  
David Tucker ◽  
Alberto Traverso
Keyword(s):  
Fuel Cell ◽  
Power System ◽  
Gas Turbine ◽  
Cell Model ◽  
Risk Mitigation ◽  
Department Of Energy ◽  
Mitigation Strategies ◽  
Hybrid Power System ◽  
Hardware Failure ◽  
Hybrid Power

A hardware-in-the-loop-simulation (HiLS) procedure for a direct-fired fuel cell turbine hybrid power system was evaluated for an integrated gasifier/fuel cell/turbine hybrid cycle (IGFC), implemented through the Hybrid Performance (Hyper) project at the National Energy Technology Laboratory, U.S. Department of Energy (NETL). The Hyper facility is designed to explore dynamic operation of hybrid systems and quantitatively characterize such transient behaviour. It is possible to model, test and evaluate the effects of different parameters on the design and operation of a gasifier/fuel cell/gas turbine hybrid system and quantify risk mitigation strategies. The previous implementation of emergency shut-down control strategies resulted in turbomachinery hardware failure. The primary linking event in these cases was compressor stall and surge resulting from the sudden loss of fuel during implementation of the standard double block and bleed strategy used during emergency failure. A new mitigation strategy involving automated ramps is proposed and described in detail to control the system from start-up to forced emergency shut-down. The control architecture shows how the virtual fuel cell model can be coupled to the real gas turbine safely, in all of stage of operations. The paper includes improvements to the emergency shutdown procedure, failure analyses, and the comparison of experimental data with previous results.

A Comparative Study on the Options in Combining Solid Oxide Fuel Cell With Gas Turbine

2015 ◽  
Author(s):  
Ji Hye Yi ◽  
Ju Hwan Choi ◽  
Tong Seop Kim
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
Solid Oxide ◽  
Inlet Temperature ◽  
Oxide Fuel ◽  
System Efficiency ◽  
Turbine Inlet Temperature ◽  
Turbine Inlet

Various options in combining a solid oxide fuel cell (SOFC) with a gas turbine (GT) were compared in this study. The combination of an SOFC with either a simple gas turbine or a gas/steam turbine combined cycle was investigated. For each combined system, the effect of using a recuperative heat exchanger was examined. The design parameters of a state-of-the-art gas turbine for central power stations were used. The GT modeling included modulation of turbine coolant flow depending on turbine working conditions. An SOFC temperature of 900°C was used. Given a currently available reference voltage, pressure-dependent SOFC cell voltage was used. The analysis was divided into two parts. In the first part, the turbine inlet temperature of the reference gas turbine was given and the influence of pressure ratio was analyzed. In the second part, the influence of varying turbine inlet temperature was analyzed to search for optimal design conditions. The results showed that the SOFC/GTCC systems would provide considerably higher efficiencies than the SOFC/GT systems. The optimal pressure ratio in terms of system efficiency is over 30 for non-recuperated systems but is around 10 for recuperated systems. Reducing the extra fuel to the gas turbine combustor improves system efficiency, especially in the SOFC/GT systems. With zero extra fuel, efficiencies of all of the four systems exceed 70%, the highest of which is obtained by the recuperated SOFC/GTCC layout.

Avoiding Compressor Surge During Emergency Shut-Down Hybrid Turbine Systems

2013 ◽  
Author(s):  
Paolo Pezzini ◽  
David Tucker ◽  
Alberto Traverso
Keyword(s):  
Fuel Cell ◽  
System Analysis ◽  
Hybrid Control ◽  
Risk Mitigation ◽  
Dynamic Effect ◽  
Transient Behavior ◽  
Open Loop ◽  
Department Of Energy ◽  
Mitigation Strategies ◽  
Compressor Surge

A new emergency shutdown procedure for a direct-fired fuel cell turbine hybrid power system was evaluated using a hardware-based simulation of an integrated gasifier/fuel cell/turbine hybrid cycle (IGFC), implemented through the Hybrid Performance (Hyper) project at the National Energy Technology Laboratory, U.S. Department of Energy (NETL). The Hyper facility is designed to explore dynamic operation of hybrid systems and quantitatively characterize such transient behavior. It is possible to model, test and evaluate the effects of different parameters on the design and operation of a gasifier/fuel cell/gas turbine hybrid system and provide means of quantifying risk mitigation strategies. An open-loop system analysis regarding the dynamic effect of bleed air, cold air by-pass and load bank is presented in order to evaluate the combination of these three main actuators during emergency shut-down. In the previous Hybrid control system architecture, catastrophic compressor failures were observed when the fuel and load bank were cut-off during emergency shut-down strategy. Improvements were achieved using a non-linear fuel valve ramp down when load bank was not operating. Experiments in load bank operation show compressor surge and stall after emergency shut-down activation. The difficulties in finding an optimal compressor and cathode mass flow for mitigation of surge and stall using these actuators are illustrated.

Performance Prediction of a Multi-Stage Ammonia-Water Turbine Under Variable Nozzle Operation via Machine Learning

2021 ◽  
Author(s):  
Yang Du ◽  
Tingting Liu ◽  
Yiping Dai ◽  
Gang Fan ◽  
Jiangfeng Wang ◽  
...  
Keyword(s):  
Machine Learning ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Nozzle Outlet ◽  
Turbine Inlet Temperature ◽  
Ammonia Water ◽  
Turbine Efficiency ◽  
Radial Turbine ◽  
Turbine Inlet ◽  
Multi Stage

Abstract This study proposes machine learning models to predict the performance of a multi-stage ammonia-water radial turbine using variable nozzle operation under different operating conditions. A 1.2 MW four-stage ammonia-water radial turbine is firstly designed. Then, the one-dimensional off-design simulation model is developed based on the geometric parameters to mainly evaluate the effects of different nozzle outlet angles and turbine inlet temperatures on the turbine performance. A set of data, which consists of 10,000 training points based on one-dimensional model, is used to train the proposed two high-dimensional model representation (HDMR) methods. The forward HDMR model predicts the mass flow rate, turbine outlet temperature, turbine power and turbine efficiency for any combination of turbine nozzle outlet angle and turbine inlet temperature, while the reverse HDMR model predicts the mass flow rate, turbine outlet temperature, turbine efficiency and turbine nozzle outlet angle for any combination of turbine power and turbine inlet temperature. The two HDMR models are validated using 238 sets of separated test data. The results show that the minimum coefficients of determination (R2) of forward HDMR model and reverse HDMR model are 0.9837 and 0.9953, respectively. The maximum relative errors of two HDMR models are below 1.6822%, so the quality of the proposed machine learning methods is high. The overall performance maps of multi-stage ammonia-water radial turbine under the variable nozzle operation method are constructed based on the reverse HDMR model. The reverse HDMR model is helpful in monitoring the healthy operation state of turbine.

Field and Laboratory Evaluations of Commercial and Next-Generation Alumina-Forming Austenitic Foil for Advanced Recuperators

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Bruce A. Pint ◽  
Sebastien Dryepondt ◽  
Michael P. Brady ◽  
Yukinori Yamamoto ◽  
Bo Ruan ◽  
...  
Keyword(s):  
Field Trials ◽  
Austenitic Steels ◽  
Inlet Temperature ◽  
Next Generation ◽  
Turbine Inlet Temperature ◽  
New Class ◽  
Turbine Inlet ◽  
Higher Temperature ◽  
Oxidation Testing

Alumina-forming austenitic (AFA) steels represent a new class of corrosion- and creep-resistant austenitic steels designed to enable higher temperature recuperators. Field trials are in progress for commercially rolled foil with widths over 39 cm. The first trial completed 3000 hrs in a microturbine recuperator with an elevated turbine inlet temperature and showed limited degradation. A longer microturbine trial is in progress. A third exposure in a larger turbine has passed 16,000 hrs. To reduce alloy cost and address foil fabrication issues with the initial AFA composition, several new AFA compositions are being evaluated in creep and laboratory oxidation testing at 650–800 °C and the results compared to commercially fabricated AFA foil and conventional recuperator foil performance.

Long-Life Base Load Service at 1600 F Turbine Inlet Temperature

1967 ◽  
Vol 89 (1) ◽  
pp. 41-46 ◽  
Author(s):  
N. E. Starkey
Keyword(s):  
Inlet Temperature ◽  
Air Cooling ◽  
Turbine Inlet Temperature ◽  
Fuel Distribution ◽  
Design Considerations ◽  
Turbine Inlet ◽  
Accurate Temperature ◽  
Long Life ◽  
Accurate Temperature Control ◽  
Base Load

Design considerations required for base load long-life service at turbine inlet temperature above 1600 F are discussed. These include control of combustion profile, air cooling of the first-stage nozzle, long-shank turbine buckets, accurate air and fuel distribution, and accurate temperature control.

Influence of Turbine Inlet Temperature on the Efficiency of Externally Fired Gas Turbines

2014 ◽  
pp. 79-95 ◽  
Author(s):  
Paulo Eduardo Batista de Mello ◽  
Sérgio Scuotto ◽  
Fernando dos Santos Ortega ◽  
Gustavo Henrique Bolognesi Donato
Keyword(s):  
Gas Turbines ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Turbine Inlet
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