The Experts below are selected from a list of 465 Experts worldwide ranked by ideXlab platform
Lorenz T. Biegler - One of the best experts on this subject based on the ideXlab platform.
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Equation-Based Design, Integration, and Optimization of Oxycombustion Power Systems
Alternative Energy Sources and Technologies, 2016Co-Authors: Alexander W. Dowling, John P. Eason, David C. Miller, Lorenz T. BieglerAbstract:The application of “systems-based tools’’ including exergy/pinch analysis and process simulation has facilitated increases in the thermal efficiency of ambient pressure Oxycombustion coal-fired power systems with carbon capture from 36 to 39–40 %LHV, while also considering capital costs. This corresponds to a decrease in the energy penalty 10 %-points to 6–7 %-points (absolute), relative to reference air-fired coal power plants without CO2 capture (46 %LHV). These efficiency improvements are primarily due to tailored next-generation air separation systems and plant-wide heat integration. Furthermore, Oxycombustion power systems are an ideal candidate for numerical optimization, given the complex interactions between its five subsystems. This chapter extensively surveys the Oxycombustion literature and summarizes four key design questions. A new, fully equation-based, flowsheet optimization framework is then introduced and applied to three Oxycombustion-related case studies: design of a minimum energy air separation unit to produce an O2 enriched stream for the boiler, optimization of the CO2 polishing unit and compression train to minimize specific energy, and maximization of thermal efficiency in the oxy-fired steam cycle using a hybrid 1D/3D boiler model.
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a framework for efficient large scale equation oriented flowsheet optimization
Computers & Chemical Engineering, 2015Co-Authors: Alexander W. Dowling, Lorenz T. BieglerAbstract:Abstract Despite the economic benefits of flowsheet optimization, many commercial tools suffer from long computational times, limited problem formulation flexibility and numerical instabilities. In this study, we address these challenges and present a framework for efficient large scale flowsheet optimization. This framework couples advanced process optimization formulations with state-of-the-art algorithms, and includes several notable features such as (1) an optimization-friendly formulation of cubic equation of state thermodynamic models; (2) a new model for distillation column optimization based on rigorous mass, equilibrium, summation and heat (MESH) equations with a variable number of trays that avoids integer variables; (3) improvements on the Duran–Grossmann formulation for simultaneous heat integration and flowsheet optimization; and (4) a systematic initialization procedure based on model refinements and a tailored multi-start algorithm to improve feasibility and identify high quality local solutions. Capabilities of the framework are demonstrated on a cryogenic air separation unit synthesis study, including two thermally coupled distillation columns and accompanying multistream heat exchangers. A superstructure is formulated that includes several common ASU configurations in literature. As part of the optimization problem the solver selects the best topology in addition to operating conditions (temperatures, flowrates, etc.) for coal Oxycombustion applications. The optimization problem includes up to 16,000 variables and 500 degrees of freedom, and predicts specific energy requirement of 0.18 to 0.25 kWh/kg of O2 depending on design assumptions. These results are compared to literature and plans to extend the framework to an entire coal Oxycombustion power plant optimization study are discussed.
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Equation-oriented Optimization of Cryogenic Systems for Coal Oxycombustion Power Generation
Energy Procedia, 2014Co-Authors: Alexander W. Dowling, Cheshta Balwani, Lorenz T. BieglerAbstract:Abstract Efficient separation systems are essential to the development of economical CO 2 capture system for fossil flue power plants. Air Separation Units (ASU) and CO 2 Processing Units (CPU) are considering the best commercially available technologies for the O 2 /N 2 and CO 2 /N 2 , O 2 , Ar separations in coal Oxycombustion processes. Both of these systems operate at cryogenic temperatures and include self-integrated refrigeration cycles, making their design challenging. Several researchers have applied sensitivity tools available in the commercial flow sheet simulators to study and improve ASU and CPU systems for oxy-fired coal power plants. These studies are limited, however, as they neglect important interactions between design variables. In this paper, we apply an advanced equation-based flowsheet optimization framework to design these cryogenic separations systems. The key advantage of this approach is the ability to use state-of-the-art nonlinear optimization solvers that are capable of considering 100,000+ variables and constraints. This allows for multi-variable optimization of these cryogenic separations systems and their accompanying multi-stream heat exchangers. The effectiveness of this approach is demonstrated in two case studies. The optimized ASU designs requires 0.196 kWh/kg of O 2 , which are similar to a “low energy” design from American Air Liquide and outperforms other academic studies. Similarly, the optimized CPU requires 18% less specific separation energy than an academic reference case. Pareto (sensitivity) curves for the ASU and CPU systems are also presented. Finally, plans to apply the framework to simultaneously optimize an entire Oxycombustion process are discussed.
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Coal Oxycombustion Power Plant Optimization Using First Principles and Surrogate Boiler Models
Energy Procedia, 2014Co-Authors: Alexander W. Dowling, John P. Eason, David C. Miller, Lorenz T. BieglerAbstract:Abstract Numeric optimization has successfully been applied in the chemical industry to improve process performance, reduce emissions, create advanced control systems and intelligently explore process design alternatives. Regarding power plants, optimization methods provide a systematic approach to balance trade-offs when designing efficient and minimal cost carbon capture systems. Coal Oxycombustion power plants are an ideal candidate for optimization, given the complex trade-offs regarding flue gas recycle strategies, heat integration and design of cryogenic separation systems. Many Oxycombustion studies consider sensitivity analysis instead of multi-variable optimization, which neglect consequentially important interactions between subsystems. Furthermore, these studies rely on over- simplified boiler models available in commercial process simulators. In this paper we present a hybrid 1D/3D boiler model that balances accuracy and computational expense, making it well suited for optimization studies of an entire coal power plant. This model is then incorporated into an equation-based optimization framework for power plants. Trust region optimization methods are used to ensure convergence. Finally a proof-of-concept case study is presented, and future work is discussed.
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equation oriented optimization of cryogenic systems for coal Oxycombustion power plants
Computer-aided chemical engineering, 2014Co-Authors: Alexander W. Dowling, Qianwen Gao, Lorenz T. BieglerAbstract:Abstract In this paper we apply an equation-oriented (EO) optimization framework to design ASU and CPU systems for coal Oxycombustion power plants. Emphasis is placed formulating the sythesis problems as large-scale nonlinear programs (NLPs) and utilizing state-of-the-art optimization algorithms. Different modules in the framework are highlighted, including thermodynamics, distillation, heat integration and pressure-changing device models. Emphasis is placed on using complementarity constraints to model non-smooth switches without integer variables, including phase disappearance and utility temperature constraints in the heat integration subproblem. Optimization results for two case studies are presented, along with future directions.
Alexander W. Dowling - One of the best experts on this subject based on the ideXlab platform.
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Equation-Based Design, Integration, and Optimization of Oxycombustion Power Systems
Alternative Energy Sources and Technologies, 2016Co-Authors: Alexander W. Dowling, John P. Eason, David C. Miller, Lorenz T. BieglerAbstract:The application of “systems-based tools’’ including exergy/pinch analysis and process simulation has facilitated increases in the thermal efficiency of ambient pressure Oxycombustion coal-fired power systems with carbon capture from 36 to 39–40 %LHV, while also considering capital costs. This corresponds to a decrease in the energy penalty 10 %-points to 6–7 %-points (absolute), relative to reference air-fired coal power plants without CO2 capture (46 %LHV). These efficiency improvements are primarily due to tailored next-generation air separation systems and plant-wide heat integration. Furthermore, Oxycombustion power systems are an ideal candidate for numerical optimization, given the complex interactions between its five subsystems. This chapter extensively surveys the Oxycombustion literature and summarizes four key design questions. A new, fully equation-based, flowsheet optimization framework is then introduced and applied to three Oxycombustion-related case studies: design of a minimum energy air separation unit to produce an O2 enriched stream for the boiler, optimization of the CO2 polishing unit and compression train to minimize specific energy, and maximization of thermal efficiency in the oxy-fired steam cycle using a hybrid 1D/3D boiler model.
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a framework for efficient large scale equation oriented flowsheet optimization
Computers & Chemical Engineering, 2015Co-Authors: Alexander W. Dowling, Lorenz T. BieglerAbstract:Abstract Despite the economic benefits of flowsheet optimization, many commercial tools suffer from long computational times, limited problem formulation flexibility and numerical instabilities. In this study, we address these challenges and present a framework for efficient large scale flowsheet optimization. This framework couples advanced process optimization formulations with state-of-the-art algorithms, and includes several notable features such as (1) an optimization-friendly formulation of cubic equation of state thermodynamic models; (2) a new model for distillation column optimization based on rigorous mass, equilibrium, summation and heat (MESH) equations with a variable number of trays that avoids integer variables; (3) improvements on the Duran–Grossmann formulation for simultaneous heat integration and flowsheet optimization; and (4) a systematic initialization procedure based on model refinements and a tailored multi-start algorithm to improve feasibility and identify high quality local solutions. Capabilities of the framework are demonstrated on a cryogenic air separation unit synthesis study, including two thermally coupled distillation columns and accompanying multistream heat exchangers. A superstructure is formulated that includes several common ASU configurations in literature. As part of the optimization problem the solver selects the best topology in addition to operating conditions (temperatures, flowrates, etc.) for coal Oxycombustion applications. The optimization problem includes up to 16,000 variables and 500 degrees of freedom, and predicts specific energy requirement of 0.18 to 0.25 kWh/kg of O2 depending on design assumptions. These results are compared to literature and plans to extend the framework to an entire coal Oxycombustion power plant optimization study are discussed.
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An Equation-based Framework for Large-Scale Flowsheet Optimization and Applications for Oxycombustion Power System Design
2015Co-Authors: Alexander W. DowlingAbstract:Over the past thirty years, flowsheet optimization methods have evolved from “black box” approaches to sophisticated equation-oriented methods for simultaneous flowsheet convergence and optimization. This thesis explores the next generation of flowsheet optimization tools that leverage completely open models (with exact first and second derivatives) and utilizes start-of-theart nonlinear programming (optimization) solvers. A five part framework is proposed in this thesis: 1. Embedded cubic equation of state thermodynamic models with complementarity constraints to accommodate vanishing and reappearing phases 2. Simultaneous heat integration and process optimization using the pinch location method 3. Aggregate short-cut and rigorous tray-by-tray distillation models 4. Steam cycle equipment (e.g., turbine) and boiler models 5. Trust region optimization algorithm to incorporate models with expensive derivatives into the equations-based framework A systematic initialization routine based on model refinement and multistart procedure are also presented as practical alternatives to global optimization. Complementarity constraints are used throughout the framework to model switches, such as vanishing phases. Degeneracy Hunter, an algorithm that identifies irreducible sets of degenerate constraints (i.e., constraints with a rank deficient Jacobian) is proposed and used to refine the models. The framework is demonstrated in a series of case studies related to the design of Oxycombustion power systems with CO2 capture. Two case studies focus on the simultaneous optimization of gases separation systems and their accompanying multistream heat exchangers. In one of these case studies, the optimization procedure identifies common air separation unit configurations with comparable specific energy requirements to industrial designs. The framework is also used to optimize regenerate Rankine cycles, where steam flowrates from nine extraction points for boiler feedwater heating are considered as optimization variables. This allows for waste heat from compression to the completely integrated into the steam cycle. Steam table lookups (without derivatives) are incorporated using reduced models and a trust region optimization algorithm.
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Equation-oriented Optimization of Cryogenic Systems for Coal Oxycombustion Power Generation
Energy Procedia, 2014Co-Authors: Alexander W. Dowling, Cheshta Balwani, Lorenz T. BieglerAbstract:Abstract Efficient separation systems are essential to the development of economical CO 2 capture system for fossil flue power plants. Air Separation Units (ASU) and CO 2 Processing Units (CPU) are considering the best commercially available technologies for the O 2 /N 2 and CO 2 /N 2 , O 2 , Ar separations in coal Oxycombustion processes. Both of these systems operate at cryogenic temperatures and include self-integrated refrigeration cycles, making their design challenging. Several researchers have applied sensitivity tools available in the commercial flow sheet simulators to study and improve ASU and CPU systems for oxy-fired coal power plants. These studies are limited, however, as they neglect important interactions between design variables. In this paper, we apply an advanced equation-based flowsheet optimization framework to design these cryogenic separations systems. The key advantage of this approach is the ability to use state-of-the-art nonlinear optimization solvers that are capable of considering 100,000+ variables and constraints. This allows for multi-variable optimization of these cryogenic separations systems and their accompanying multi-stream heat exchangers. The effectiveness of this approach is demonstrated in two case studies. The optimized ASU designs requires 0.196 kWh/kg of O 2 , which are similar to a “low energy” design from American Air Liquide and outperforms other academic studies. Similarly, the optimized CPU requires 18% less specific separation energy than an academic reference case. Pareto (sensitivity) curves for the ASU and CPU systems are also presented. Finally, plans to apply the framework to simultaneously optimize an entire Oxycombustion process are discussed.
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Coal Oxycombustion Power Plant Optimization Using First Principles and Surrogate Boiler Models
Energy Procedia, 2014Co-Authors: Alexander W. Dowling, John P. Eason, David C. Miller, Lorenz T. BieglerAbstract:Abstract Numeric optimization has successfully been applied in the chemical industry to improve process performance, reduce emissions, create advanced control systems and intelligently explore process design alternatives. Regarding power plants, optimization methods provide a systematic approach to balance trade-offs when designing efficient and minimal cost carbon capture systems. Coal Oxycombustion power plants are an ideal candidate for optimization, given the complex trade-offs regarding flue gas recycle strategies, heat integration and design of cryogenic separation systems. Many Oxycombustion studies consider sensitivity analysis instead of multi-variable optimization, which neglect consequentially important interactions between subsystems. Furthermore, these studies rely on over- simplified boiler models available in commercial process simulators. In this paper we present a hybrid 1D/3D boiler model that balances accuracy and computational expense, making it well suited for optimization studies of an entire coal power plant. This model is then incorporated into an equation-based optimization framework for power plants. Trust region optimization methods are used to ensure convergence. Finally a proof-of-concept case study is presented, and future work is discussed.
Manuel Bailera - One of the best experts on this subject based on the ideXlab platform.
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lab scale experimental tests of power to gas Oxycombustion hybridization system design and preliminary results
Energy, 2021Co-Authors: Manuel Bailera, Pilar Lisbona, Begona Pena, J M Marin, Luis M RomeoAbstract:Abstract Power-to-Gas (PtG) represents one of the most promising energy storage technologies. PtG converts electricity surplus into synthetic natural gas by combining water electrolysis and CO2 methanation. This technology valorises captured CO2 to produce a ‘carbon neutral’ natural gas, while allowing temporal displacement of renewable energy. PtG-Oxycombustion hybridization is proposed to integrate mass and energy flows of the global system. Oxygen, comburent under oxy-fuel combustion, is commonly produced in an air separation unit. This unit can be replaced by an electrolyser which by-produces O2 reducing the electrical consumption and the energy penalty of the carbon separation process. The aim of this work is to present the design, construction and testing of a methanation reactor at laboratory scale to increase the knowledge of the key component of this system. Experimental data are used to validate the theoretical kinetic model at different operating temperatures implemented in Aspen Plus. CO2 conversions about 60–80% are found for catalyst temperature between 350 and 550 °C. These values agree well with expected theoretical conversions from the kinetic model.
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future applications of hydrogen production and co2 utilization for energy storage hybrid power to gas Oxycombustion power plants
International Journal of Hydrogen Energy, 2017Co-Authors: Manuel Bailera, Sergio Espatolero, Pilar Lisbona, Luis M Romeo, Nouaamane Kezibri, Chakib BouallouAbstract:Abstract Power to Gas (PtG) has appeared in the last years as a potential long-term energy storage solution, which converts hydrogen produced by renewable electricity surplus into synthetic methane. However, significant economic barriers slow down its massive deployment (e.g. operating hours, expensive investments). Within this framework, the PtG-Oxycombustion hybridization can palliate these issues by improving the use of resources and increasing the overall efficiency. In this study we assess the requirements for electrolysis, depending on the size of the Oxycombustion plant, the fuel physical and chemical properties and the final application of the hybrid system. Most suitable heat demanding options to implement this PtG-Oxycombustion hybridization are district heating, industrial processes and small combined cycled power plants. The latter case is modelled and simulated in detail and thermally integrated. The global efficiency of this hybrid system increases from 56% to 68%, thanks to avoiding the requirement of an air separation unit and integrating up to 88% of the available heat from methanation in a LP steam cycle.
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Power to Gas-biomass Oxycombustion hybrid system: Energy integration and potential applications
Applied Energy, 2016Co-Authors: Manuel Bailera, Pilar Lisbona, Luis M Romeo, Sergio EspatoleroAbstract:A promising hybridization which increases the chances of deployment of Power to Gas technology is found in the synergy with Oxycombustion of biomass. This study assesses the efficiency of an energy integrated system under different sizes and potential applications. District heating and industrial processes are revealed as the most suitable potential applications for this hybrid technology. Global efficiency of the combined system may be increased through thermal energy integration. The relative increment of efficiency achieved for those designs which avoid the requirement of an air separation unit and for those which completely consumed the generated CO2, are 24.5% and 29.7% respectively. A 2 MWthdistrict heating case study is also analysed, revealing that 81.2% of the total available heat from the PtG-oxy system could be integrated raising the global efficiency up to 78.7% at the adequate operational point. Further 'full-fuel-cycle' analysis will be required prior to decide the interest of the concept under a specific scenario in comparison to other available energy storage technologies.
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Power to gas-oxyfuel boiler hybrid systems
International Journal of Hydrogen Energy, 2015Co-Authors: Manuel Bailera, Pilar Lisbona, Luis M RomeoAbstract:One of the main future energy challenges is the management of electrical supply and demand, mainly motivated by the increase of share renewable energy in electricity mix. Thus, energy storage represents a crucial line of research and innovative solutions are currently being proposed. Power to Gas is a technology which stores excess of electrical energy in form of synthetic natural gas through the methanation of hydrogen produced by electrolysis. Methanation requires a source of CO2 which could be provided from the flue gas of an oxyfuel boiler. A further advantage of this hybridization comes from the supply of the oxygen generated by electrolysis to the oxyfuel combustion. In this study the concept is simulated using Aspen Plus® software and the performance of the combined system is analysed through the definition of a size ratio, ξoxy, that relates the flow of renewable hydrogen produced in electrolyser and the thermal output of the boiler. This variable has allowed defining different ranges of operation for a PtG-Oxycombustion hybridized plant. Thus, for ξoxy of 1.33, the air separation unit required as an auxiliary element for the oxyfuel boiler becomes unnecessary while if this ratio is increased up to 2.29, flue gas is completely consumed in the methanation plant and converted to synthetic natural gas.
Benito Navarrete - One of the best experts on this subject based on the ideXlab platform.
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ciuden ccs project status of the co2 capture technology development plant in power generation
Energy Procedia, 2011Co-Authors: Monica Lupion, Raidan Diego, L Loubeau, Benito NavarreteAbstract:Carbon Capture and Storage technology (CCS) has the potential to play a key role in reducing CO2 emissions as required by international commitments. CCS must be included in the portfolio of solutions in order to reach the target of world emissions reduction by 50% in 2050. One of the most relevant European initiatives for the deployment of CCS technologies is promoted by the Fundacion Ciudad de la Energia (CIUDEN). CIUDEN has a complete programme focused on the development of CCT and CCS, particularly Oxycombustion technology. This paper includes the description of CIUDEN’s Capture Technology Developing Plant, currently under construction in NW Spain. The installation includes a 20 MWth PC boiler, a 30 MWth CFB boiler, a fuel preparation unit, a biomass gasifier, a flue gas cleaning train, and a CO2 processing unit. The commissioning of the TDP is planned for November 2010. This is the only installation in the world with two large pilot oxy boilers capable of burning a wide range of coals, biomass and pet coke under conventional combustion or Oxycombustion conditions. Results are expected to significantly contribute to the development and deployment of Oxycombustion technologies, particularly valuable as technical support for the OXYCFB300 Compostilla Project which aims to validate this technology at demo scale. The Compostilla OXYCFB300 Project is based on a 300 MWe Circulating Fluidised Bed (CFB) supercritical Oxycombustion plant, with CO2 storage in a saline aquifer. The operation of this installation is planned to start in 2015.
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ciuden ccs project status of the co2 capture technology development plant in power generation
Energy Procedia, 2011Co-Authors: Monica Lupion, Raidan Diego, L Loubeau, Benito NavarreteAbstract:Carbon Capture and Storage technology (CCS) has the potential to play a key role in reducing CO2 emissions as required by international commitments. CCS must be included in the portfolio of solutions in order to reach the target of world emissions reduction by 50% in 2050. One of the most relevant European initiatives for the deployment of CCS technologies is promoted by the Fundacion Ciudad de la Energia (CIUDEN). CIUDEN has a complete programme focused on the development of CCT and CCS, particularly Oxycombustion technology. This paper includes the description of CIUDEN’s Capture Technology Developing Plant, currently under construction in NW Spain. The installation includes a 20 MWth PC boiler, a 30 MWth CFB boiler, a fuel preparation unit, a biomass gasifier, a flue gas cleaning train, and a CO2 processing unit. The commissioning of the TDP is planned for November 2010. This is the only installation in the world with two large pilot oxy boilers capable of burning a wide range of coals, biomass and pet coke under conventional combustion or Oxycombustion conditions. Results are expected to significantly contribute to the development and deployment of Oxycombustion technologies, particularly valuable as technical support for the OXYCFB300 Compostilla Project which aims to validate this technology at demo scale. The Compostilla OXYCFB300 Project is based on a 300 MWe Circulating Fluidised Bed (CFB) supercritical Oxycombustion plant, with CO2 storage in a saline aquifer. The operation of this installation is planned to start in 2015.
Luis M Romeo - One of the best experts on this subject based on the ideXlab platform.
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lab scale experimental tests of power to gas Oxycombustion hybridization system design and preliminary results
Energy, 2021Co-Authors: Manuel Bailera, Pilar Lisbona, Begona Pena, J M Marin, Luis M RomeoAbstract:Abstract Power-to-Gas (PtG) represents one of the most promising energy storage technologies. PtG converts electricity surplus into synthetic natural gas by combining water electrolysis and CO2 methanation. This technology valorises captured CO2 to produce a ‘carbon neutral’ natural gas, while allowing temporal displacement of renewable energy. PtG-Oxycombustion hybridization is proposed to integrate mass and energy flows of the global system. Oxygen, comburent under oxy-fuel combustion, is commonly produced in an air separation unit. This unit can be replaced by an electrolyser which by-produces O2 reducing the electrical consumption and the energy penalty of the carbon separation process. The aim of this work is to present the design, construction and testing of a methanation reactor at laboratory scale to increase the knowledge of the key component of this system. Experimental data are used to validate the theoretical kinetic model at different operating temperatures implemented in Aspen Plus. CO2 conversions about 60–80% are found for catalyst temperature between 350 and 550 °C. These values agree well with expected theoretical conversions from the kinetic model.
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future applications of hydrogen production and co2 utilization for energy storage hybrid power to gas Oxycombustion power plants
International Journal of Hydrogen Energy, 2017Co-Authors: Manuel Bailera, Sergio Espatolero, Pilar Lisbona, Luis M Romeo, Nouaamane Kezibri, Chakib BouallouAbstract:Abstract Power to Gas (PtG) has appeared in the last years as a potential long-term energy storage solution, which converts hydrogen produced by renewable electricity surplus into synthetic methane. However, significant economic barriers slow down its massive deployment (e.g. operating hours, expensive investments). Within this framework, the PtG-Oxycombustion hybridization can palliate these issues by improving the use of resources and increasing the overall efficiency. In this study we assess the requirements for electrolysis, depending on the size of the Oxycombustion plant, the fuel physical and chemical properties and the final application of the hybrid system. Most suitable heat demanding options to implement this PtG-Oxycombustion hybridization are district heating, industrial processes and small combined cycled power plants. The latter case is modelled and simulated in detail and thermally integrated. The global efficiency of this hybrid system increases from 56% to 68%, thanks to avoiding the requirement of an air separation unit and integrating up to 88% of the available heat from methanation in a LP steam cycle.
-
Power to Gas-biomass Oxycombustion hybrid system: Energy integration and potential applications
Applied Energy, 2016Co-Authors: Manuel Bailera, Pilar Lisbona, Luis M Romeo, Sergio EspatoleroAbstract:A promising hybridization which increases the chances of deployment of Power to Gas technology is found in the synergy with Oxycombustion of biomass. This study assesses the efficiency of an energy integrated system under different sizes and potential applications. District heating and industrial processes are revealed as the most suitable potential applications for this hybrid technology. Global efficiency of the combined system may be increased through thermal energy integration. The relative increment of efficiency achieved for those designs which avoid the requirement of an air separation unit and for those which completely consumed the generated CO2, are 24.5% and 29.7% respectively. A 2 MWthdistrict heating case study is also analysed, revealing that 81.2% of the total available heat from the PtG-oxy system could be integrated raising the global efficiency up to 78.7% at the adequate operational point. Further 'full-fuel-cycle' analysis will be required prior to decide the interest of the concept under a specific scenario in comparison to other available energy storage technologies.
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Power to gas-oxyfuel boiler hybrid systems
International Journal of Hydrogen Energy, 2015Co-Authors: Manuel Bailera, Pilar Lisbona, Luis M RomeoAbstract:One of the main future energy challenges is the management of electrical supply and demand, mainly motivated by the increase of share renewable energy in electricity mix. Thus, energy storage represents a crucial line of research and innovative solutions are currently being proposed. Power to Gas is a technology which stores excess of electrical energy in form of synthetic natural gas through the methanation of hydrogen produced by electrolysis. Methanation requires a source of CO2 which could be provided from the flue gas of an oxyfuel boiler. A further advantage of this hybridization comes from the supply of the oxygen generated by electrolysis to the oxyfuel combustion. In this study the concept is simulated using Aspen Plus® software and the performance of the combined system is analysed through the definition of a size ratio, ξoxy, that relates the flow of renewable hydrogen produced in electrolyser and the thermal output of the boiler. This variable has allowed defining different ranges of operation for a PtG-Oxycombustion hybridized plant. Thus, for ξoxy of 1.33, the air separation unit required as an auxiliary element for the oxyfuel boiler becomes unnecessary while if this ratio is increased up to 2.29, flue gas is completely consumed in the methanation plant and converted to synthetic natural gas.
