In practical interest of Reynolds analogy for power and process industries, in a unified system approach an engineering prospective of thermo-fluid physics has been proposed by developing a theory of basic heat exchanger design and analysis. Needless to mention of excellent books on heat exchangers, this paper focuses on the novelty of heat exchanger, which in author’s view depends upon the possibility of energy exchange between two fluid streams at different temperatures. Since operation cannot be random, the principal act of design is to engineer a product such that it operates in specified manner to perform its desired function of de-energizing one stream by virtue of energizing the other. With law of the integral as the guiding principle of physics, it shall be made clear that energy exchange in the form of heat must be accompanied by energy transfer such that heat exchanger must operate due to simultaneous process of cooling and heating of the fluid streams with an intervening medium. To unlock the secret of steady operation a fundamental postulate concerning thermodynamic behavior of the system has been made by invoking zeroth law of thermodynamics. Remarkably, it lends itself a necessary and sufficient condition concerning proportionality between heat-flux and required temperature difference to yield fluids unique thermal response in relation to the heat transfer surface temperature. Consequently, far-reaching physical implications of the constant of proportionality on system design can be clearly exposed of with due consideration to Eulerian descriptions of conservation principles according to Newton’s mechanical theory. Consistently enough, because of thermal non-equilibrium, effectiveness of system design and off design performance warrants a fundamental theorem like one suggested by Reynolds concerning augmentation of thermal diffusion due to fluid motion. Accordingly, flow rates become critical operating parameters for thermal performance and pressure drop requirements. Furthermore, and most importantly, in support of the theorem an order magnitude analysis appears to be in order, to show the dependence of flow resistance and hence, system thermal response on fluid flow behavior in terms of non-dimensional parameters. As a result, it is made clear that development of design correlations for friction factor and non-dimensional heat transfer coefficient in terms of both Reynolds number and Prandtl number is an integral part of heat exchanger design process by gathering experimental data. Finally, generalized mathematical statement of Reynolds analogy has been obtained relating Stanton number with friction factor, which reduces to our familiar expression for Prandtl number of unity.
{"title":"Generalized Reynolds Analogy: An Engineering Prospective of Thermo-Fluid Physics for Heat Exchanger Design","authors":"A. Som","doi":"10.1115/power2021-65820","DOIUrl":"https://doi.org/10.1115/power2021-65820","url":null,"abstract":"\u0000 In practical interest of Reynolds analogy for power and process industries, in a unified system approach an engineering prospective of thermo-fluid physics has been proposed by developing a theory of basic heat exchanger design and analysis. Needless to mention of excellent books on heat exchangers, this paper focuses on the novelty of heat exchanger, which in author’s view depends upon the possibility of energy exchange between two fluid streams at different temperatures. Since operation cannot be random, the principal act of design is to engineer a product such that it operates in specified manner to perform its desired function of de-energizing one stream by virtue of energizing the other.\u0000 With law of the integral as the guiding principle of physics, it shall be made clear that energy exchange in the form of heat must be accompanied by energy transfer such that heat exchanger must operate due to simultaneous process of cooling and heating of the fluid streams with an intervening medium. To unlock the secret of steady operation a fundamental postulate concerning thermodynamic behavior of the system has been made by invoking zeroth law of thermodynamics. Remarkably, it lends itself a necessary and sufficient condition concerning proportionality between heat-flux and required temperature difference to yield fluids unique thermal response in relation to the heat transfer surface temperature. Consequently, far-reaching physical implications of the constant of proportionality on system design can be clearly exposed of with due consideration to Eulerian descriptions of conservation principles according to Newton’s mechanical theory. Consistently enough, because of thermal non-equilibrium, effectiveness of system design and off design performance warrants a fundamental theorem like one suggested by Reynolds concerning augmentation of thermal diffusion due to fluid motion. Accordingly, flow rates become critical operating parameters for thermal performance and pressure drop requirements.\u0000 Furthermore, and most importantly, in support of the theorem an order magnitude analysis appears to be in order, to show the dependence of flow resistance and hence, system thermal response on fluid flow behavior in terms of non-dimensional parameters. As a result, it is made clear that development of design correlations for friction factor and non-dimensional heat transfer coefficient in terms of both Reynolds number and Prandtl number is an integral part of heat exchanger design process by gathering experimental data. Finally, generalized mathematical statement of Reynolds analogy has been obtained relating Stanton number with friction factor, which reduces to our familiar expression for Prandtl number of unity.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82882891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present article highlights the implementation of differential evolution (DE)-assisted metaheuristic optimizer to provide the solution of an inverse multi-variable problem related to a flat absorber solar collector consisting of a single glass. For satisfying a given heating requirement from the solar collector, the necessary tilt angle and the thickness of the glass cover are simultaneously predicted using the proposed DE methodology. The existing study of inverse multi-variable optimization analysis has been done for dynamic values of solar energy radiation and different ambient conditions commonly encountered in various geographical locations of India. Formulation of the current research involves the minimization of a newly proposed cost function involving the required and the acquired heat transfer rates from the solar collector in Euclidean space. The solution approach then utilizes a dynamic exchange between evolutionary metaheuristic DE and a well-validated forward solver containing analytical expressions of heat energy balance within the solar collector. Variations of cost function and the estimated design variables are mainly studied to visualize the algorithm’s behavior for a single gazing-based solar thermal device. Multiple possible groupings of the unknown parameters of the solar collector are revealed, which always collectively result in a desired heating requirement from the solar collector. Sensitivity indices related to the design variables are evaluated for ascertaining the relative importance of parameter selection. Encouraging opportunity is found towards the system’s size reduction through sparing selection of inclination angle. The current study provides a convenient and cost-effective tool to select the necessary inclination and glass covers to obtain low to medium heating requirements from the available incident solar energy.
{"title":"An Inverse Method for Parameter Retrieval in Solar Thermal Collector With a Single Glass Cover","authors":"R. Das","doi":"10.1115/power2021-65601","DOIUrl":"https://doi.org/10.1115/power2021-65601","url":null,"abstract":"\u0000 The present article highlights the implementation of differential evolution (DE)-assisted metaheuristic optimizer to provide the solution of an inverse multi-variable problem related to a flat absorber solar collector consisting of a single glass. For satisfying a given heating requirement from the solar collector, the necessary tilt angle and the thickness of the glass cover are simultaneously predicted using the proposed DE methodology. The existing study of inverse multi-variable optimization analysis has been done for dynamic values of solar energy radiation and different ambient conditions commonly encountered in various geographical locations of India. Formulation of the current research involves the minimization of a newly proposed cost function involving the required and the acquired heat transfer rates from the solar collector in Euclidean space. The solution approach then utilizes a dynamic exchange between evolutionary metaheuristic DE and a well-validated forward solver containing analytical expressions of heat energy balance within the solar collector. Variations of cost function and the estimated design variables are mainly studied to visualize the algorithm’s behavior for a single gazing-based solar thermal device. Multiple possible groupings of the unknown parameters of the solar collector are revealed, which always collectively result in a desired heating requirement from the solar collector. Sensitivity indices related to the design variables are evaluated for ascertaining the relative importance of parameter selection. Encouraging opportunity is found towards the system’s size reduction through sparing selection of inclination angle. The current study provides a convenient and cost-effective tool to select the necessary inclination and glass covers to obtain low to medium heating requirements from the available incident solar energy.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72807100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In power plant engineering, gas turbine (GT) evaporative cooling is traditionally thought as one of the few power augmentation alternatives for existing plants. For most combined cycle plants operating at part load, the GT Inlet Guide Vanes (IGV) will throttle the air flow to the combustor to maintain the turbine exhaust temperature (TET) as high as possible, thus maximizing the overall combined cycle efficiency. The IGV air throttling results in a reduction of the turbine inlet air temperature (TIT) due to a reduction on the mass of fuel burned in the combustors as the available combustion air decreases due to IGV throttling to maintain an optimum air to fuel ratio, resulting on a lower TET compared with the same GT at base load. The compounded result of these effects limits the maximum steam production capacity on the heat recovery steam generator, particularly for the high-pressure section, hampering the efficiency of the steam turbine. The methodology developed in the subject study aims at counteracting the afore-mentioned effects by optimizing the evaporative cooler air/water ratio which results in the lower possible heat rate for full load and part load operation. By dynamically controlling the air/water ratio, a preheating effect can be achieved in the compressor inlet air, which results on higher exhaust gas temperature, thus augmenting the high-pressure steam production on the heat recovery steam generator and accordingly the steam turbine efficiency. For a newly built 907 MWe Combined Cycle Gas Turbine (CCGT) plant, application of the evaporative cooling part load optimization methodology presented in this study could lead to a potential reduction of up to 158kJ/kWh on heat rate and 9.318 g/kWh of CO2 emissions if compared with the same plant without dynamic control of the evaporative cooler air/water ratio.
{"title":"Gas Turbine Evaporative Cooling, A Novel Method for Combined Cycle Plant Part Load Optimization","authors":"Jose Carmona","doi":"10.1115/power2021-65289","DOIUrl":"https://doi.org/10.1115/power2021-65289","url":null,"abstract":"\u0000 In power plant engineering, gas turbine (GT) evaporative cooling is traditionally thought as one of the few power augmentation alternatives for existing plants.\u0000 For most combined cycle plants operating at part load, the GT Inlet Guide Vanes (IGV) will throttle the air flow to the combustor to maintain the turbine exhaust temperature (TET) as high as possible, thus maximizing the overall combined cycle efficiency. The IGV air throttling results in a reduction of the turbine inlet air temperature (TIT) due to a reduction on the mass of fuel burned in the combustors as the available combustion air decreases due to IGV throttling to maintain an optimum air to fuel ratio, resulting on a lower TET compared with the same GT at base load. The compounded result of these effects limits the maximum steam production capacity on the heat recovery steam generator, particularly for the high-pressure section, hampering the efficiency of the steam turbine.\u0000 The methodology developed in the subject study aims at counteracting the afore-mentioned effects by optimizing the evaporative cooler air/water ratio which results in the lower possible heat rate for full load and part load operation. By dynamically controlling the air/water ratio, a preheating effect can be achieved in the compressor inlet air, which results on higher exhaust gas temperature, thus augmenting the high-pressure steam production on the heat recovery steam generator and accordingly the steam turbine efficiency.\u0000 For a newly built 907 MWe Combined Cycle Gas Turbine (CCGT) plant, application of the evaporative cooling part load optimization methodology presented in this study could lead to a potential reduction of up to 158kJ/kWh on heat rate and 9.318 g/kWh of CO2 emissions if compared with the same plant without dynamic control of the evaporative cooler air/water ratio.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88094253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present work is focused on numerical investigation of melting of Phase change material (PCM) filled in a spherical capsule integrated with a metallic fin. n-octadecane having melting temperature of 28° C is selected as PCM and aluminum is considered as fin material. The effect of fin orientation on PCM melting in a spherical enclosure is analyzed considering constrained melting conditions. The orientation angle of the fin is varied from 0–30° in both clockwise and anticlockwise directions. The computational model is considered as two dimensional axisymmetric with laminar flow condition. To ascertain the validity of our numerical methodology present computational model is validated with the test results available in the literature and are found to be in good agreement. The numerical result reveals that employing fin at the center of the capsule (θ = 0°) decreases the melting time and increases the heat transfer performance of the system.
{"title":"Effect of Fin Orientation on PCM Melting in a Spherical Enclosure for Latent Heat Storage","authors":"A.K. Sharma, R. Kothari, Anuj Kumar, S. Sahu","doi":"10.1115/power2021-65622","DOIUrl":"https://doi.org/10.1115/power2021-65622","url":null,"abstract":"\u0000 The present work is focused on numerical investigation of melting of Phase change material (PCM) filled in a spherical capsule integrated with a metallic fin. n-octadecane having melting temperature of 28° C is selected as PCM and aluminum is considered as fin material. The effect of fin orientation on PCM melting in a spherical enclosure is analyzed considering constrained melting conditions. The orientation angle of the fin is varied from 0–30° in both clockwise and anticlockwise directions. The computational model is considered as two dimensional axisymmetric with laminar flow condition. To ascertain the validity of our numerical methodology present computational model is validated with the test results available in the literature and are found to be in good agreement. The numerical result reveals that employing fin at the center of the capsule (θ = 0°) decreases the melting time and increases the heat transfer performance of the system.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87964259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Worldwide energy consumption is accelerating at an unprecedented rate while humanity comes to understand the effects of climate change. Renewable resources such as wind and solar supply more energy every year, but the overwhelming majority of energy consumed is still from fossil fuels. The transition to zero carbon emission sources is important, but carbon negative energy could also become necessary in ensuring a sustainable global environment and economy. The most technically and commercially viable carbon negative solution is biomass-fueled power generation with carbon capture and sequestration. A conceptual design based on a biomass-fired circulating fluidized-bed boiler and developed using the Thermoflex software package (Thermoflow, Inc.) is presented that can be evaluated and pursued by the research, engineering, and business communities. Recommendations are proposed for siting and fuel supply in the Southeastern U.S., with an evaluation of some of the impacts from wood harvesting, processing, and transportation to the lifecycle carbon emissions. An economic analysis of this carbon negative concept indicates that certain policy proposals in the U.S. could make biomass power generation with carbon capture and sequestration an economically feasible resource. Results show that an owner and/or the public could realize a net benefit of up to $332/MWh above and beyond marginal energy or capacity values under aggressive carbon pricing.
{"title":"A Plan for Biomass Power Generation With Negative Carbon Emissions","authors":"M. Parker","doi":"10.1115/power2021-65822","DOIUrl":"https://doi.org/10.1115/power2021-65822","url":null,"abstract":"\u0000 Worldwide energy consumption is accelerating at an unprecedented rate while humanity comes to understand the effects of climate change. Renewable resources such as wind and solar supply more energy every year, but the overwhelming majority of energy consumed is still from fossil fuels. The transition to zero carbon emission sources is important, but carbon negative energy could also become necessary in ensuring a sustainable global environment and economy. The most technically and commercially viable carbon negative solution is biomass-fueled power generation with carbon capture and sequestration. A conceptual design based on a biomass-fired circulating fluidized-bed boiler and developed using the Thermoflex software package (Thermoflow, Inc.) is presented that can be evaluated and pursued by the research, engineering, and business communities. Recommendations are proposed for siting and fuel supply in the Southeastern U.S., with an evaluation of some of the impacts from wood harvesting, processing, and transportation to the lifecycle carbon emissions. An economic analysis of this carbon negative concept indicates that certain policy proposals in the U.S. could make biomass power generation with carbon capture and sequestration an economically feasible resource. Results show that an owner and/or the public could realize a net benefit of up to $332/MWh above and beyond marginal energy or capacity values under aggressive carbon pricing.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81172293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Paolo Pezzini, Harry Bonilla, Grant Johnson, Zachary T. Reinhart, K. Bryden
Real time models and digital twin environments represent a new frontier that allow the development of supplemental data analytics of measurable and unmeasurable parameters for a variety of power plant configurations. Performance prediction, monitoring of degradation effects, and a faster recognition of anomalous events during power plant load following operations and/or due to cyber-attacks can be easily detected with the support of digital twin environments. In the research work described in this article, a digital twin environment was developed to capture the dynamics of a micro compressor-turbine system modified for hybrid configuration at the Department of Energy’s National Energy Technology Laboratory (NETL). The innovative approach for the development of the digital twin environment was based on creating a compressor-turbine physics-based model using a stateless methodology generally utilized for microservices architectures. The advantage of using this approach was represented by modeling individual or a group of power plant components on distributed computational resources such as clouds in a lightweight and interchangeable manner. Supplemental data analytics were performed using an online system identification tool developed in previous work and applied to an unmeasurable parameter only available in the digital twin system. This work demonstrated the ability to train a recursive algorithm to predict a supplemental parameter for faster anomaly detection or for replacing the physics-based model during design or monitoring of operational systems. The thermodynamic compressor-turbine net power was the unmeasurable parameter only available in the digital twin model, which was predicted with the online system identification tool. Results showed that the online system identification algorithm predicted the dynamic response of the thermodynamic net power based on a set of experimental data points at nominal operating conditions with an absolute mean percentage error of ∼0.644%.
{"title":"A Digital Twin Environment Designed for the Implementation of Real Time Monitoring Tool","authors":"Paolo Pezzini, Harry Bonilla, Grant Johnson, Zachary T. Reinhart, K. Bryden","doi":"10.1115/power2021-65384","DOIUrl":"https://doi.org/10.1115/power2021-65384","url":null,"abstract":"\u0000 Real time models and digital twin environments represent a new frontier that allow the development of supplemental data analytics of measurable and unmeasurable parameters for a variety of power plant configurations. Performance prediction, monitoring of degradation effects, and a faster recognition of anomalous events during power plant load following operations and/or due to cyber-attacks can be easily detected with the support of digital twin environments. In the research work described in this article, a digital twin environment was developed to capture the dynamics of a micro compressor-turbine system modified for hybrid configuration at the Department of Energy’s National Energy Technology Laboratory (NETL). The innovative approach for the development of the digital twin environment was based on creating a compressor-turbine physics-based model using a stateless methodology generally utilized for microservices architectures. The advantage of using this approach was represented by modeling individual or a group of power plant components on distributed computational resources such as clouds in a lightweight and interchangeable manner.\u0000 Supplemental data analytics were performed using an online system identification tool developed in previous work and applied to an unmeasurable parameter only available in the digital twin system. This work demonstrated the ability to train a recursive algorithm to predict a supplemental parameter for faster anomaly detection or for replacing the physics-based model during design or monitoring of operational systems. The thermodynamic compressor-turbine net power was the unmeasurable parameter only available in the digital twin model, which was predicted with the online system identification tool. Results showed that the online system identification algorithm predicted the dynamic response of the thermodynamic net power based on a set of experimental data points at nominal operating conditions with an absolute mean percentage error of ∼0.644%.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78431344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Middleton, P. Brady, Jeffrey A. Brown, Serafina T. Lawles
Water management has become critical for thermoelectric power generation in the US. Increasing demand for scarce water resources for domestic, agricultural, and industrial use affects water availability for power plants. In particular, the population in the Southwestern part of the US is growing and water resources are over-stressed. The engineering and management teams at the Palo Verde Generating Station (PV) in the Sonoran Desert have long understood this problem and began a partnership with Sandia National Laboratories in 2017 to develop a long-term water strategy for PV. As part of this program, Sandia and Palo Verde staff have developed a comprehensive software tool that models all aspects of the PV (plant cooling) water cycle. The software tool — the Palo Verde Water Cycle Model (PVWCM) — tracks water operations from influent to the plant through evaporation in one of the nine cooling towers or one of the eight evaporation ponds. The PVWCM has been developed using a process called System Dynamics. The PVWCM is developed to allow scenario comparison for various plant operating strategies.
{"title":"The Palo Verde Water Cycle Model (PVWCM) – Development of an Integrated Multi-Physics and Economics Model for Effective Water Management","authors":"B. Middleton, P. Brady, Jeffrey A. Brown, Serafina T. Lawles","doi":"10.1115/power2021-65768","DOIUrl":"https://doi.org/10.1115/power2021-65768","url":null,"abstract":"\u0000 Water management has become critical for thermoelectric power generation in the US. Increasing demand for scarce water resources for domestic, agricultural, and industrial use affects water availability for power plants. In particular, the population in the Southwestern part of the US is growing and water resources are over-stressed.\u0000 The engineering and management teams at the Palo Verde Generating Station (PV) in the Sonoran Desert have long understood this problem and began a partnership with Sandia National Laboratories in 2017 to develop a long-term water strategy for PV. As part of this program, Sandia and Palo Verde staff have developed a comprehensive software tool that models all aspects of the PV (plant cooling) water cycle. The software tool — the Palo Verde Water Cycle Model (PVWCM) — tracks water operations from influent to the plant through evaporation in one of the nine cooling towers or one of the eight evaporation ponds.\u0000 The PVWCM has been developed using a process called System Dynamics. The PVWCM is developed to allow scenario comparison for various plant operating strategies.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87531298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Over the past decades there has been a dramatic increase in natural gas burning as the benign fossil fuel, offering far lower emissions than oil or coal. Its place had been established in a clean, or at least, cleaner energy future. Today, the national and international energy policy has been shifted to carbon neutrality — achieving net zero carbon emissions — and as result has moved natural gas from the “benign” to the “menace” category At present, there are chiefly two alternatives for fuel carbon neutrality under discussion: power-to-gas (PtG) producing methane (or synthetic natural gas, SNG, hydrogen etc.) and power-to-liquid, which stores electric power in the form of methanol. In opposite to other synthetic or fossil fuels, like synthetic methane, NG or hydrogen, methanol burning leads to significant reductions in emissions of nitrogen oxides without any substantial firing system design change. Burning of synthetic methane or hydrogen requires significant effort for NOx reduction. Hydrogen as a fuel offers many advantages in power production. It is a carbon-free fuel that can decarbonize power and heat generation, and transportation, to help meet long-term CO2 emission-reduction targets. However, things are different for NOx emissions are a different matter. The more hydrogen is added to a NG, the higher the NOx is anticipated. Dry Low NOx (DLN) combustor has traditionally mixed NG with sufficient air upstream the combustor, so burning can take place in a lean atmosphere to maintain a relatively cool flame and thus keep NOx down. That approach does not work so well when more hydrogen enters the picture due to auto ignition occurring in the premix zone. Some companies already have diffusion-type combustor technology where fuel and air are supplied separately. Combustion of hydrogen, specifically in diffusion mode, implies combustion with a hotter flame, leading to higher combustion temperatures and the formation of local hot spots. These, in turn, can cause NOx to increase. The generalized solution is to cool the flame using diluents, such as demineralized water, steam or nitrogen. However, reducing NOx, by dilution reduces efficiency compared to a DLN combustor. Another option of providing wide load range of GT operation, while maintaining low NOx emissions is fuel dilution with flue gas being recirculated from the exhaust (FGR - Flue gas recirculation). The present paper discusses the effect of burning renewable fuels produced from carbon dioxide and hydrogen which are being diluted with a flow of FGR on GT performance and emissions reduction in diffusion combustors. For the prediction of the combustion behavior a methodology that combines experimental work and computational simulations was used. Given the fact that due to the increase in renewable energy introduction into the grid, addition of renewable fuel-based energy produced from carbon dioxide becomes very significant. Hence, the development of enhanced firing systems burning synt
{"title":"Evaluation of Gas Turbine Combustors Running on Renewable Fuels Produced From Carbon Dioxide Aimed for Greenhouse Emission Reduction","authors":"B. Chudnovsky, I. Chatskiy, A. Lazebnikov","doi":"10.1115/power2021-60860","DOIUrl":"https://doi.org/10.1115/power2021-60860","url":null,"abstract":"\u0000 Over the past decades there has been a dramatic increase in natural gas burning as the benign fossil fuel, offering far lower emissions than oil or coal. Its place had been established in a clean, or at least, cleaner energy future. Today, the national and international energy policy has been shifted to carbon neutrality — achieving net zero carbon emissions — and as result has moved natural gas from the “benign” to the “menace” category At present, there are chiefly two alternatives for fuel carbon neutrality under discussion: power-to-gas (PtG) producing methane (or synthetic natural gas, SNG, hydrogen etc.) and power-to-liquid, which stores electric power in the form of methanol. In opposite to other synthetic or fossil fuels, like synthetic methane, NG or hydrogen, methanol burning leads to significant reductions in emissions of nitrogen oxides without any substantial firing system design change. Burning of synthetic methane or hydrogen requires significant effort for NOx reduction. Hydrogen as a fuel offers many advantages in power production. It is a carbon-free fuel that can decarbonize power and heat generation, and transportation, to help meet long-term CO2 emission-reduction targets. However, things are different for NOx emissions are a different matter. The more hydrogen is added to a NG, the higher the NOx is anticipated. Dry Low NOx (DLN) combustor has traditionally mixed NG with sufficient air upstream the combustor, so burning can take place in a lean atmosphere to maintain a relatively cool flame and thus keep NOx down. That approach does not work so well when more hydrogen enters the picture due to auto ignition occurring in the premix zone. Some companies already have diffusion-type combustor technology where fuel and air are supplied separately. Combustion of hydrogen, specifically in diffusion mode, implies combustion with a hotter flame, leading to higher combustion temperatures and the formation of local hot spots. These, in turn, can cause NOx to increase. The generalized solution is to cool the flame using diluents, such as demineralized water, steam or nitrogen. However, reducing NOx, by dilution reduces efficiency compared to a DLN combustor. Another option of providing wide load range of GT operation, while maintaining low NOx emissions is fuel dilution with flue gas being recirculated from the exhaust (FGR - Flue gas recirculation). The present paper discusses the effect of burning renewable fuels produced from carbon dioxide and hydrogen which are being diluted with a flow of FGR on GT performance and emissions reduction in diffusion combustors. For the prediction of the combustion behavior a methodology that combines experimental work and computational simulations was used. Given the fact that due to the increase in renewable energy introduction into the grid, addition of renewable fuel-based energy produced from carbon dioxide becomes very significant. Hence, the development of enhanced firing systems burning synt","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85523005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper is comprised of three sections and outlines the outcome achieved from instituting an effective preventative maintenance program; specifically, highlighting a steam surface condenser application that was originally equipped with a stainless-steel metal bellows type expansion joint system. In the first section of the paper, a general overview of steam inlet type expansion joint systems will be presented to provide an understanding of the specific application, typical design parameters and conditions, system components, varying expansion joint designs, configurations, and installation methodologies. The second section will outline types of inspections that typically support preventative maintenance programs within the power generation industry. Lastly, the case study will examine the account of an actual project and the practice of implementing a preventative maintenance program; outlining inspection types, how those measures supported a root cause analysis, and ultimately developing a unique solution to address the issues identified during subsequent inspections and analyses. The case study focuses on developing a retrofitted rubber ‘dog bone’ expansion joint system to replace the failed metal bellows expansion joint. Various points within the overall project life cycle will be reviewed; from the point of initial inspection that identified the root cause and defined loss in performance, evaluation and engineering to support the replacement design, onsite execution and installation methodology, and post-maintenance testing and operation.
{"title":"Steam Inlet Expansion Joint Design & Case Study: Surface Condenser Application","authors":"K. Squires","doi":"10.1115/power2021-64836","DOIUrl":"https://doi.org/10.1115/power2021-64836","url":null,"abstract":"\u0000 This paper is comprised of three sections and outlines the outcome achieved from instituting an effective preventative maintenance program; specifically, highlighting a steam surface condenser application that was originally equipped with a stainless-steel metal bellows type expansion joint system. In the first section of the paper, a general overview of steam inlet type expansion joint systems will be presented to provide an understanding of the specific application, typical design parameters and conditions, system components, varying expansion joint designs, configurations, and installation methodologies. The second section will outline types of inspections that typically support preventative maintenance programs within the power generation industry. Lastly, the case study will examine the account of an actual project and the practice of implementing a preventative maintenance program; outlining inspection types, how those measures supported a root cause analysis, and ultimately developing a unique solution to address the issues identified during subsequent inspections and analyses. The case study focuses on developing a retrofitted rubber ‘dog bone’ expansion joint system to replace the failed metal bellows expansion joint. Various points within the overall project life cycle will be reviewed; from the point of initial inspection that identified the root cause and defined loss in performance, evaluation and engineering to support the replacement design, onsite execution and installation methodology, and post-maintenance testing and operation.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89042227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seyed Navid Isfahani Roohani, Vinicius M. Sauer, I. Schoegl
Micro-combustion has shown significant potential to study and characterize the combustion behavior of hydrocarbon fuels. Among several experimental approaches based on this method, the most prominent one employs an externally heated micro-channel. Three distinct combustion regimes are reported for this device namely, weak flames, flames with repetitive extinction and ignition (FREI), and normal flames, which are formed at low, moderate, and high flow rate ranges, respectively. Within each flame regime, noticeable differences exist in both shape and luminosity where transition points can be used to obtain insights into fuel characteristics. In this study, flame images are obtained using a monochrome camera equipped with a 430 nm bandpass filter to capture the chemiluminescence signal emitted by the flame. Sequences of conventional flame photographs are taken during the experiment, which are computationally merged to generate high dynamic range (HDR) images. In a highly diluted fuel/oxidizer mixture, it is observed that FREI disappear and are replaced by a gradual and direct transition between weak and normal flames which makes it hard to identify different combustion regimes. To resolve the issue, a convolutional neural network (CNN) is introduced to classify the flame regime. The accuracy of the model is calculated to be 99.34, 99.66, and 99.83% for “training”, “validation”, and “testing” data-sets, respectively. This level of accuracy is achieved by conducting a grid search to acquire optimized parameters for CNN. Furthermore, a data augmentation technique based on different experimental scenarios is used to generate flame images to increase the size of the data-set.
{"title":"Classification of Microchannel Flame Regimes Based on Convolutional Neural Networks","authors":"Seyed Navid Isfahani Roohani, Vinicius M. Sauer, I. Schoegl","doi":"10.1115/power2021-64437","DOIUrl":"https://doi.org/10.1115/power2021-64437","url":null,"abstract":"\u0000 Micro-combustion has shown significant potential to study and characterize the combustion behavior of hydrocarbon fuels. Among several experimental approaches based on this method, the most prominent one employs an externally heated micro-channel. Three distinct combustion regimes are reported for this device namely, weak flames, flames with repetitive extinction and ignition (FREI), and normal flames, which are formed at low, moderate, and high flow rate ranges, respectively. Within each flame regime, noticeable differences exist in both shape and luminosity where transition points can be used to obtain insights into fuel characteristics. In this study, flame images are obtained using a monochrome camera equipped with a 430 nm bandpass filter to capture the chemiluminescence signal emitted by the flame. Sequences of conventional flame photographs are taken during the experiment, which are computationally merged to generate high dynamic range (HDR) images. In a highly diluted fuel/oxidizer mixture, it is observed that FREI disappear and are replaced by a gradual and direct transition between weak and normal flames which makes it hard to identify different combustion regimes. To resolve the issue, a convolutional neural network (CNN) is introduced to classify the flame regime. The accuracy of the model is calculated to be 99.34, 99.66, and 99.83% for “training”, “validation”, and “testing” data-sets, respectively. This level of accuracy is achieved by conducting a grid search to acquire optimized parameters for CNN. Furthermore, a data augmentation technique based on different experimental scenarios is used to generate flame images to increase the size of the data-set.","PeriodicalId":8567,"journal":{"name":"ASME 2021 Power Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91168718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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