Model-Based Thermodynamic Analysis of a Hydrogen-Fired Gas Turbine with External Exhaust Gas Recirculation

2021 ◽  
Author(s):  
Thomas Bexten ◽  
Sophia Jörg ◽  
Nils Petersen ◽  
Manfred Wirsum ◽  
Pei Liu ◽  
...  
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Carbon Capture ◽  
Exhaust Gas ◽  
Model Based ◽  
Renewable Power ◽  
Renewable Power Generation

Abstract Climate science shows that the limitation of global warming requires a rapid transition towards net-zero emissions of greenhouse gases (GHG) on a global scale. Expanding renewable power generation is seen as an imperative measure within this transition. To compensate for the inherent volatility of renewable power generation, flexible and dispatchable power generation technologies such as gas turbines are required. If operated with CO2-neutral hydrogen or in combination with carbon capture plants, a GHG-neutral gas turbine operation could be achieved. An effective leverage to enhance carbon capture efficiency and a possible measure to safely burn hydrogen in gas turbines is the partial external recirculation of exhaust gas. By means of a model-based analysis of a gas turbine, the present study initially assesses the thermodynamic impact caused by a fuel switch from natural gas to hydrogen. Although positive trends such as increasing net electrical power output and thermal efficiency can be observed, the overall effect on the gas turbine process is only minor. In a following step, the partial external recirculation of exhaust gas is evaluated and compared both for the combustion of natural gas and hydrogen, regardless of potential combustor design challenges. The influence of altering working fluid properties throughout the whole gas turbine process is thermodynamically evaluated for ambient temperature recirculation and recirculation at an elevated temperature. A reduction in thermal efficiency can be observed as well as non-negligible changes of relevant process variables. These changes are more distinctive at a higher recirculation temperature

Model-Based Thermodynamic Analysis of a Hydrogen-Fired Gas Turbine With External Exhaust Gas Recirculation

2020 ◽  
Author(s):  
Thomas Bexten ◽  
Sophia Jörg ◽  
Nils Petersen ◽  
Manfred Wirsum ◽  
Pei Liu ◽  
...  
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Carbon Capture ◽  
Electrical Power ◽  
Working Fluid ◽  
Exhaust Gas ◽  
Model Based

Abstract Climate science shows that the limitation of global warming requires a rapid transition towards net-zero emissions of green house gases (GHG) on a global scale. Expanding renewable power generation in a significant way is seen as an imperative measure within this transition. To compensate for the inherent volatility of wind- and solar-based power generation, flexible and dispatchable power generation technologies such as gas turbines are required. If operated with CO2-neutral fuels such as hydrogen or in combination with carbon capture plants, a GHG-neutral gas turbine operation could be achieved. An effective leverage to enhance carbon capture efficiency and a possible measure to safely burn hydrogen in gas turbines is the partial external recirculation of exhaust gas. By means of a model-based analysis of an industrial gas turbine, the present study initially assesses the thermodynamic impact caused by a fuel switch from natural gas to hydrogen. Although positive trends such as increasing net electrical power output and thermal efficiency can be observed, the overall effect on the gas turbine process is only minor. In a following step, the partial external recirculation of exhaust gas is evaluated and compared both for the combustion of natural gas and hydrogen, regardless of potential combustor design challenges. The influence of altering working fluid properties throughout the whole gas turbine process is thermodynamically evaluated for ambient temperature recirculation and recirculation at an elevated temperature. A reduction in thermal efficiency can be observed as well as non-negligible changes of relevant process variables. These changes are are more distinctive at a higher recirculation temperature.

Model-Based Analysis of a Liquid Organic Hydrogen Carrier (LOHC) System for the Operation of a Hydrogen-Fired Gas Turbine

2020 ◽  
Author(s):  
Jason John Dennis ◽  
Thomas Bexten ◽  
Nils Petersen ◽  
Manfred Wirsum ◽  
Patrick Preuster
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Waste Heat ◽  
Renewable Power ◽  
Steady State Model ◽  
Renewable Power Generation ◽  
Hydrogen Carrier ◽  
Viable Method ◽  
Model Based Analysis

Abstract One of the main challenges currently hindering the transition to energy systems based on renewable power generation is grid stability. To compensate for the volatility of wind- and solar-based power generation, storage facilities able to adapt to seasonal and short term differences in energy production and demand are required. Liquid Organic Hydrogen Carriers (LOHCs) represent a viable method of chemically binding elemental hydrogen, offering opportunities for largescale and safe energy storage. In times of energy shortage, flexible and dispatchable power generation technologies such as gas turbines can be fueled by hydrogen stored in this manner. Hydrogen can be released from its liquid carrier via an endothermic dehydrogenation reaction using waste heat provided by the gas turbine. This gaseous hydrogen can be supplied to the gas turbine combustion chamber using a hydrogen compressor. In the present study a steady state model is developed in order to analyse the heat-integrated combination of a 7.7 MW hydrogen-fired gas turbine and a H18-DBT/H0-DBT LOHC system. For the best-performing parameter set the effective storage density of the LOHC oil comes to 1.5 kWh/L. This value is situated in-between that of compressed hydrogen at 350 bar (1.01 kWh/L) and liquid hydrogen (2.33 kWh/L). Concurrently, the corresponding energy required for hydrogen compression reduces the overall system efficiency to 22.00 % (ηGT = 30.15%). The resulting optimal electricity yield, being a product of these two values, amounts to 0.33 kWhel/L.

Analysis of the Emission Reduction Potential and Combustion Stability Limits of a Hydrogen-Fired Gas Turbine With External Exhaust Gas Recirculation

2021 ◽  
Author(s):  
Nils Hendrik Petersen ◽  
Thomas Bexten ◽  
Christian Goßrau ◽  
Manfred Wirsum
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Nox Emissions ◽  
Diffusion Type ◽  
Renewable Power ◽  
Net Zero ◽  
Renewable Power Generation ◽  
Stability Limits ◽  
Flame Behaviour

Abstract To mitigate its impact on global climate, the power generation sector must strive towards a transition to net-zero emissions of greenhouse gases. This can be achieved by a massive penetration of renewable power generation. However, a high share of renewable power generation requires dispatchable and flexible power generation technologies such as gas turbines to maintain the stability of power grids. To achieve net-zero green house gas emissions, gas turbines have to be operated exclusively with carbon-neutral fuels. Hydrogen is a promising carbon-neutral fuel, although it comes along with several challenges regarding stable combustion. A possible measure to stabilize hydrogen combustion is the partial external recirculation of exhaust gases (EGR). In a previous study, the authors presented a model-based thermodynamic analysis of an industrial gas turbine featuring EGR. The next step was to answer the question of whether the thermodynamically negative impact of EGR (i.e. lower thermal efficiency) is justified by positive effects, such as reduced NOx emissions or a more controllable combustion of hydrogen. By means of a simple 1-D flame approach, the present study provides further insight into the flame behaviour and stability limits during a fuel switch from natural gas to hydrogen. In a following step, the same approach is used to investigate the flame behaviour in an EGR environment at two recirculation temperatures. The results show that if a hydrogen-fired, diffusion-type combustor is combined with sufficiently high EGR ratios, NOx emissions are potentially in the order of a state-of-the-art diffusion-type combustor fired with natural gas. In addition, based on the calculated laminar flame speeds and extinction strain rates, the higher reactivity of hydrogen could potentially be controlled by employing EGR. However, relevant literature suggests that stronger dilution might be required to compensate for the additional impact of turbulence-chemistry interaction in real application which could lead to flame stabilization issues and higher NOx emissions. Moreover, considering the industry efforts to develop hydrogen-capable premixed-type combustors, the results show that EGR has no significantly positive influence on the reactivity of a premixed pure hydrogen flame. The question regarding the preferred EGR temperature is addressed but cannot be answered conclusively.

Predicting Flameholding for Hydrogen and Natural Gas Flames at Gas Turbine Premixer Conditions

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Elliot Sullivan-Lewis ◽  
Vincent McDonell
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Experimental Studies ◽  
Temperature Variations ◽  
Auto Ignition ◽  
Chamber Temperature ◽  
Transient Events ◽  
Significant Effort

Lean-premixed gas turbines are now common devices for low emissions stationary power generation. By creating a homogeneous mixture of fuel and air upstream of the combustion chamber, temperature variations are reduced within the combustor, which reduces emissions of nitrogen oxides. However, by premixing fuel and air, a potentially flammable mixture is established in a part of the engine not designed to contain a flame. If the flame propagates upstream from the combustor (flashback), significant engine damage can result. While significant effort has been put into developing flashback resistant combustors, these combustors are only capable of preventing flashback during steady operation of the engine. Transient events (e.g., auto-ignition within the premixer and pressure spikes during ignition) can trigger flashback that cannot be prevented with even the best combustor design. In these cases, preventing engine damage requires designing premixers that will not allow a flame to be sustained. Experimental studies were conducted to determine under what conditions premixed flames of hydrogen and natural gas can be anchored in a simulated gas turbine premixer. Tests have been conducted at pressures up to 9 atm, temperatures up to 750 K, and freestream velocities between 20 and 100 m/s. Flames were anchored in the wakes of features typical of premixer passageways, including cylinders, steps, and airfoils. The results of this study have been used to develop an engineering tool that predicts under what conditions a flame will anchor, and can be used for development of flame anchoring resistant gas turbine premixers.

Advanced Gas Turbine and High Performance Gas-Steam Combined Cycle Plant With Blade Cooling Air Controlling

2006 ◽  
Author(s):  
Tadashi Tsuji
Keyword(s):  
Power Generation ◽  
Heat Exchanger ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Hot Water ◽  
Blade Cooling ◽  
Combined Cycle Plant ◽  
Cooling Air

Air cooling blades are usually applied to gas turbines as a basic specification. This blade cooling air is almost 20% of compressor suction air and it means that a great deal of compression load is not converted effectively to turbine power generation. This paper proposes the CCM (Cascade Cooling Module) system of turbine blade air line and the consequent improvement of power generation, which is achieved by the reduction of cooling air consumption with effective use of recovered heat. With this technology, current gas turbines (TIT: turbine inlet temperature: 1350°C) can be up-rated to have a relative high efficiency increase. The increase ratio has a potential to be equivalent to that of 1500°C Class GT/CC against 1350°C Class. The CCM system is designed to enable the reduction of blade cooling air consumption by the low air temperature of 15°C instead of the usual 200–400°C. It causes the turbine operating air to increase at the constant suction air condition, which results in the enhancement of power and thermal efficiency. The CCM is installed in the cooling air line and is composed of three stage coolers: steam generator/fuel preheater stage, heat exchanger stage for hot water supplying and cooler stage with chilled water. The coolant (chilled water) for downstream cooler is produced by an absorption refrigerator operated by the hot water of the upstream heat exchanger. The proposed CCM system requires the modification of cooling air flow network in the gas turbine but produces the direct effect on performance enhancement. When the CCM system is applied to a 700MW Class CC (Combined Cycle) plant (GT TIT: 135°C Class), it is expected that there will be a 40–80MW increase in power and +2–5% relative increase in thermal efficiency.

Economic and Technical Challenges Facing Large-Scale Gas Turbine Projects due to Environmental Requirements for Extremely Low Emissions

2001 ◽  
Author(s):  
Justin Zachary
Keyword(s):  
United States ◽  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Large Scale ◽  
The United States ◽  
Fuel Gas ◽  
Environmental Requirements ◽  
Low Sulfur

Since 1998, the United States has experienced a tremendous increase in power generation projects using gas turbine technology. By burning natural gas as the primary fuel and low sulfur oil as a back-up fuel, gas turbines are the cleanest form of fossil power generation.

Study of Using Exhaust Gas Recirculation on a Gas Turbine for Carbon Capture

2020 ◽  
Author(s):  
Dan Burnes ◽  
Priyank Saxena ◽  
Paul Dunn
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Carbon Capture ◽  
Hydrocarbon Fuel ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Hybrid Solutions ◽  
Industrial Gas Turbines ◽  
Industrial Gas Turbine ◽  
Gas Recirculation

Abstract The growing call of minimizing carbon dioxide and other greenhouse gases emitting from energy and transportation products will spur innovation to meet new stringent requirements while striving to preserve significant investments in the current infrastructure. This paper presents quantitative analysis of exhaust gas recirculation (EGR) on industrial gas turbines to enable carbon sequestration venturing towards emission free operation. This study will show the effect of using EGR on gas turbine performance and operation, combustion characteristics, and demonstrate potential hybrid solutions with detailed constituent accounting. Both single shaft and two shaft gas turbines for power generation and mechanically driven equipment are considered for application of this technology. One key element is assessing the combustion system operating at reduced O2 levels within the industrial gas turbine. With the gas turbine behavior operating with EGR defined at a reasonable operating state, a parametric study shows rates of CO2 sequestration along with quantifying supplemental O2 required at the inlet, if needed, to sustain combustion. With rates of capture known, a further exploration is examined reviewing potential utilities, monetizing these sequestered constituents. Ultimately, the objective is to preview a potential future of operating industrial gas turbines in a non-emissive and in some cases carbon negative manner while still using hydrocarbon fuel.

Optimal Operation of a Gas Turbine Cogeneration Unit With Energy Storage for Wind Power System Integration

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Thomas Bexten ◽  
Manfred Wirsum ◽  
Björn Roscher ◽  
Ralf Schelenz ◽  
Georg Jacobs ◽  
...  
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Wind Power ◽  
System Integration ◽  
Design Parameters ◽  
System Configuration ◽  
Local Wind ◽  
Wind Power Integration ◽  
Renewable Power ◽  
Renewable Power Generation

Many energy supply systems around the world are currently undergoing a phase of transition characterized by a continuing increase in installed renewable power generation capacities. The inherent volatility and limited predictability of renewable power generation pose various challenges for an efficient system integration of these capacities. One approach to manage these challenges is the deployment of small-scale dispatchable power generation and storage units on a local level. In this context, gas turbine cogeneration units, which are primarily tasked with the provision of power and heat for industrial consumers, can play a significant role, if they are equipped with a sufficient energy storage capacity allowing for a more flexible operation. The present study investigates a system configuration, which incorporates a heat-driven industrial gas turbine interacting with a wind farm providing volatile renewable power generation. The required energy storage capacity is represented by an electrolyzer and a pressure vessel for intermediate hydrogen storage. The generated hydrogen can be reconverted to electricity and process heat by the gas turbine. The corresponding operational strategy for the overall system aims at an optimal integration of the volatile wind farm power generation on a local level. The study quantifies the impact of selected system design parameters on the quality of local wind power system integration, that can be achieved with a specific set of parameters. In addition, the impact of these parameters on the reduction of CO2 emissions due to the use of hydrogen as gas turbine fuel is quantified. In order to conduct these investigations, detailed steady-state models of all required system components were developed. These models enable accurate simulations of the operation of each component in the complete load range. The calculation of the optimal operational strategy is based on an application of the dynamic programming algorithm. Based on this model setup, the operation of the overall system configuration is simulated for each investigated set of design parameters for a one-year period. The simulation results show that the investigated system configuration has the ability to significantly increase the level of local wind power integration. The parameter variation reveals distinct correlations between the main design parameters of the storage system and the achievable level of local wind power integration. Regarding the installed electrolyzer power consumption capacity, smaller additional benefits of capacity increases can be identified at higher levels of power consumption capacity. Regarding the geometrical volume of the hydrogen storage, it can be determined that the storage volume loses its limiting character on the operation of the electrolyzer at a characteristic level. The additional investigation of the CO2 emission reduction reveals a direct correlation between the level of local wind power integration and the achievable level of CO2 emission reduction.

Flexible Natural Gas/Intermittent Renewable Hybrid Power Plants

2017 ◽  
Author(s):  
Michael Welch ◽  
Andrew Pym
Keyword(s):  
Power Generation ◽  
Energy Storage ◽  
Power Plant ◽  
Natural Gas ◽  
Gas Turbines ◽  
Fossil Fuel ◽  
Power Transmission ◽  
Hybrid Power ◽  
Renewable Power ◽  
Storage Technologies

Increasing grid penetration of intermittent renewable power from wind and solar is creating challenges for the power industry. There are times when generation from these intermittent sources needs to be constrained due to power transmission capacity limits, and times when fossil fuel power plant are required to rapidly compensate for large power fluctuations, for example clouds pass over a solar field or the wind stops blowing. There have been many proposals, and some actual projects, to store surplus power from intermittent renewable power in some form or other for later use: Batteries, Compressed Air Energy Storage (CAES), Liquid Air Energy Storage (LAES), heat storage and Hydrogen being the main alternatives considered. These technologies will allow power generation during low periods of wind and solar power, using separate discrete power generation plant with specifically designed generator sets. But these systems are time-limited so at some point, if intermittent renewable power generation does not return to its previous high levels, fossil fuel power generation, usually from a large centralized power plant, will be required to ensure security of supplies. The overall complexity of such a solution to ensure secure power supplies leads to high capital costs, power transmission issues and potentially increased carbon emissions to atmosphere from the need to keep fossil fuel plant operating at low loads to ensure rapid response. One possible solution is to combine intermittent renewables and energy storage technologies with fast responding, flexible natural gas-fired gas turbines to create a reliable, secure, low carbon, decentralized power plant. This paper considers some hybrid power plant designs that could combine storage technologies and gas turbines in a single location to maximize clean energy production and reduce CO2 emissions while still providing secure supplies, but with the flexibility that today’s grid operators require.

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