- Golden, Colorado, United States
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Water and energy are two inseparable and interdependent phenomena that play essential roles in economic productivity and sustainable development. This paper presents a novel, highly efficient, and modular hydrogen production unit that can... more
Water and energy are two inseparable and interdependent phenomena that play essential roles in economic productivity and sustainable development. This paper presents a novel, highly efficient, and modular hydrogen production unit that can be fully integrated with numerous power production units, including coal and natural gas-fired power plants. The system is designed to utilize various water sources as the process’s feedstock. All process components, including waste-water treatment system, flue gas cooling, separating unit, and high-temperature solid oxide electrolyzer cell (SOEC), are simulated and integrated using Aspen HYSYS. The SOEC model is first validated with experimental and available numerical data. The validation results show that the model can accurately predict SOEC performance at various operating conditions. Afterward, various system configurations are presented, and a comprehensive process analysis has been implemented to evaluate the effects of operating and design parameters on the system performance and efficiency of 97.4% for the SOEC. The overall thermal-to-hydrogen efficiency of the system is 56.3% without heat integration. Moreover, this novel process is integrated with renewable energy sources to ensure the system contribution to global energy decarbonization. Finally, a cradle-to-gate life cycle assessment (LCA) is performed to analyze the environmental impacts of the proposed system. The results indicate that the overall damage level is almost 50% higher using coal power plant as electricity source as to the solar PV and that water-energy nexus is eminent in energy sustainability, water preservation, and the prospect of this integrated system.
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ABSTRACT Design-point and part-load characteristics of a solid oxide fuel cell (SOFC) system, fuelled by methane and hydrogen, are investigated for its prospective use in the residential application. As a part of this activity, a detailed... more
ABSTRACT Design-point and part-load characteristics of a solid oxide fuel cell (SOFC) system, fuelled by methane and hydrogen, are investigated for its prospective use in the residential application. As a part of this activity, a detailed SOFC cell model is developed, evaluated and extended to a stack model. Models of all the required balance of plant components are also developed and are integrated to build a system model. Using this model, two system base cases for methane and hydrogen fuels are introduced. Cogeneration relevant performance figures are investigated for different system configurations and cell parameters i.e. fuel utilization, fuel flow rate, operation voltage and extent of internal fuel reforming. The results show high combined heat and power efficiencies for both cases, with higher thermal-to-electric ratio and lower electric efficiency for the hydrogen-fuelled cases. Performance improvements with radiation air pre-heaters and anode gas recycling are presented and the respective application limits discussed.
Research Interests: Engineering, Nuclear Engineering, Fuel Cells, Performance, Fuel Cell, and 15 moreProcess Engineering, Alternative Fuels, Hydrogen Fuel, Hydrogen Energy, Performance Improvement, Methane, Cogeneration, BOP, CHEMICAL SCIENCES, Model System, Flow Rate, Combined Heat and Power, CSTR, PEN, and Parametric analysis
Abstract The flexibility of membrane-based carbon capture systems (CCSs) has received considerable attention due to the increasing penetration of intermittent renewable sources. In this paper, a comprehensive techno-economic assessment of... more
Abstract The flexibility of membrane-based carbon capture systems (CCSs) has received considerable attention due to the increasing penetration of intermittent renewable sources. In this paper, a comprehensive techno-economic assessment of several membrane separation processes is performed to investigate the potential and viability of such systems as a flexible CCS technology for integrating into the future low carbon power plants. The technical model involves lumped parameter models for balance of plant and a mechanistic membrane model. The mechanistic membrane model can predict the spatial distributions of species along the membrane length in different flow patterns such as cross and counter-flow. The economic model comprises different cost factors for the capital cost, and operational cost of the system components. The aformentioned models are employed to evaluate four system designs with three membrane types. The impacts of several decision-making parameters such as feed pressure and membrane properties are thoroughly investigated. The results show that considering sweep gas and increasing the feed CO2 concentration lead to lowers required membrane area and energy consumption, respectively. Also, using a high CO2 selectivity membrane leads to lower specific energy, while membranes with a moderate selectivity and high permeability are economically preferable due to a lower required area. Finally, the economic comparison of designs shows that considering feed compression and a counter-current membrane module with sweep gas is the most cost-effective design with a CO2 capture cost of 22.76 $/tCO2. Also, using vacuum pumps is the most energy-efficient design for CO2 capturing, contributing to the flexible operation of the membrane-based CCS.
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Research Interests: Engineering, Materials Science, Fuel Cells, Medicine, Solid oxide fuel cell, and 15 moreSteady state, Lancet, CHEMICAL SCIENCES, Control Strategy, Dynamic behaviour of materials, Dynamic Model of WSN, Lumping Kinetic Model, Flow Rate, Power Sources, dynamic model, The Lancet, Dynamic Behaviour, Relaxation Time, Kinetic model, and Planar
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Methanol is expected to be a possible solution for reducing global greenhouse gas emissions and minimizing the dependency on fossil fuels. This paper presents a systematic approach of methanol (MeOH) production from industrial waste gases... more
Methanol is expected to be a possible solution for reducing global greenhouse gas emissions and minimizing the dependency on fossil fuels. This paper presents a systematic approach of methanol (MeOH) production from industrial waste gases including flue gas (FG) and coke oven gas (COG) that are considered an important threat to the environment. The impact of process parameters, including dimensional parameters (length, diameter, and number of tubes) and operational parameters (reactor temperature, pressure, and thermal fluid temperature) over the MeOH synthesis, are investigated by Aspen Plus. Firstly, the synthesis process is designed and optimized using syngas (SG) as a feed material. Secondly, by replacing the feed material with FG and COG, methanol production variability is investigated and demonstrated for the same optimized process. Afterward, an efficient heat exchange network system is developed for all three different processes using Aspen Energy Analyzer. The optimized dim...
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Fossil-fueled power plants are a major source of carbon dioxide (CO2) emission and the membrane process is a promising technology for CO2 removal and mitigation. This study aims to develop optimal membrane-based carbon capture systems to... more
Fossil-fueled power plants are a major source of carbon dioxide (CO2) emission and the membrane process is a promising technology for CO2 removal and mitigation. This study aims to develop optimal membrane-based carbon capture systems to enhance the sustainability of fossil-fuel power plants by reducing their energy consumption and operating costs. The multi-stage membrane process is numerically modeled using Aspen Custom Modeler based on the solution-diffusion mechanism and then the effects of important operating and design parameters are investigated. Multi-objective process optimization is then carried out by linking Aspen Plus with MATLAB and using an evolutionary technique to determine optimal operating and design conditions. The results show that, as the CO2 concentration in the feed gas increases, the CO2 capture cost significantly decreases and CO2 removal is enhanced, although the process energy demand slightly increases. The best possible trade-offs between objective funct...
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The membrane process is a promising technology for CO2 removal and mitigation. Since the energy consumption and economy of membrane-based carbon capture systems (CCSs) are critical for their large-scale deployments, optimal design and... more
The membrane process is a promising technology for CO2 removal and mitigation. Since the energy consumption and economy of membrane-based carbon capture systems (CCSs) are critical for their large-scale deployments, optimal design and operation of such systems are the primary aims of this study. To achieve these research goals, a numerical model based on the solution-diffusion mechanism for the multicomponent gas separation process with a hollow-fiber membrane module is developed using Aspen Custom Modeler. The model is employed to investigate the effects of important operating and design parameters. Multi-objective process optimization is then performed by linking Aspen Plus and MATLAB and using an evolutionary technique to determine the optimal operating and design conditions. Our results show that by increasing the CO2 concentration in the feed gas, the CO2 capture cost significantly decreases and CO2 removal improves, although the process energy requirement slightly increases. T...
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Water and energy are two inseparable and interdependent phenomena that play essential roles in economic productivity and sustainable development. This paper presents a novel, highly efficient, and modular hydrogen production unit that can... more
Water and energy are two inseparable and interdependent phenomena that play essential roles in economic productivity and sustainable development. This paper presents a novel, highly efficient, and modular hydrogen production unit that can be fully integrated with numerous power production units, including coal and natural gas-fired power plants. The system is designed to utilize various water sources as the process’s feedstock. All process components, including waste-water treatment system, flue gas cooling, separating unit, and high-temperature solid oxide electrolyzer cell (SOEC), are simulated and integrated using Aspen HYSYS. The SOEC model is first validated with experimental and available numerical data. The validation results show that the model can accurately predict SOEC performance at various operating conditions. Afterward, various system configurations are presented, and a comprehensive process analysis has been implemented to evaluate the effects of operating and design...
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Abstract Gas flaring is a significant cause of air contamination and a source of energy losses in the oil and gas industry. A liquid ring compressor is a cost-effective and appropriate technology, which can be used to recover flare gas... more
Abstract Gas flaring is a significant cause of air contamination and a source of energy losses in the oil and gas industry. A liquid ring compressor is a cost-effective and appropriate technology, which can be used to recover flare gas from various sources. In this paper, a novel flare gas recovery process based on liquid ring compressors is proposed, in which flare gases are compressed and treated simultaneously using methyl diethanolamine. This process is simulated here through some custom models in Aspen HYSYS and MATLAB software, and the effects of operating and design parameters on the performance of the proposed flare gas recovery system are examined. Results demonstrate that the H2S absorption efficiency can be improved by reducing amine temperature or raising the flow rate of the recycling amine. However, the energy consumption of the process increases in these conditions. It is also demonstrated that there is an optimum value for the lean amine solvent concentration to minimize the H2S concentration of the outlet gas. The process analysis shows that by integrating the proposed flare gas recovery system with a refinery plant generating 0.5 MMSCFD of flare gas, it is possible to recover 87% of the available heating value in the flare gas. Also, the environmental aspects of the plant is considerably improved by preventing the release of 28 mtCO2 equivalent per day to the atmosphere. Due to the overlapping effects of system operating parameters, a multi-objective optimization is conducted to optimize the process, and the Pareto solutions set consists of the best possible trade-offs between process energy consumption, H2S concentration of outlet gas, and lean amine solvent consumption are generated.
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Abstract The flexibility of membrane-based carbon capture systems (CCSs) has received considerable attention due to the increasing penetration of intermittent renewable sources. In this paper, a comprehensive techno-economic assessment of... more
Abstract The flexibility of membrane-based carbon capture systems (CCSs) has received considerable attention due to the increasing penetration of intermittent renewable sources. In this paper, a comprehensive techno-economic assessment of several membrane separation processes is performed to investigate the potential and viability of such systems as a flexible CCS technology for integrating into the future low carbon power plants. The technical model involves lumped parameter models for balance of plant and a mechanistic membrane model. The mechanistic membrane model can predict the spatial distributions of species along the membrane length in different flow patterns such as cross and counter-flow. The economic model comprises different cost factors for the capital cost, and operational cost of the system components. The aformentioned models are employed to evaluate four system designs with three membrane types. The impacts of several decision-making parameters such as feed pressure and membrane properties are thoroughly investigated. The results show that considering sweep gas and increasing the feed CO2 concentration lead to lowers required membrane area and energy consumption, respectively. Also, using a high CO2 selectivity membrane leads to lower specific energy, while membranes with a moderate selectivity and high permeability are economically preferable due to a lower required area. Finally, the economic comparison of designs shows that considering feed compression and a counter-current membrane module with sweep gas is the most cost-effective design with a CO2 capture cost of 22.76 $/tCO2. Also, using vacuum pumps is the most energy-efficient design for CO2 capturing, contributing to the flexible operation of the membrane-based CCS.
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The oil and gas industry operates by reciprocating natural gas engines which must comply with regulated emission standards for hazardous air pollutants, including NOx, CO, and volatile organic compounds (VOCs). These pollutants are... more
The oil and gas industry operates by reciprocating natural gas engines which must comply with regulated emission standards for hazardous air pollutants, including NOx, CO, and volatile organic compounds (VOCs). These pollutants are regulated by Environmental Protection Agency, and each engine is regularly tested for compliance with national emission standards. A general emissions control strategy in combustion engines is to control the air-to-fuel ratio. However, stationary reciprocating engines, especially two-stroke engines, rarely have any mechanisms to control air and fuel parameters at various operating conditions. This article discusses a novel air management system that is invented to control the air-to-fuel ratio for a large bore two-stroke naturally aspirated gas engine, that is, AJAX™ brand model number 2802. The method can also be used for other engines with the same working principle. This novel air management system has been developed through comprehensive computational...
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The unique and beneficial characteristics of SOFC technology, coupled with emerging energy production and supply paradigms related to distributed generation, hold much promise for their eventual widespread adoption in numerous residential... more
The unique and beneficial characteristics of SOFC technology, coupled with emerging energy production and supply paradigms related to distributed generation, hold much promise for their eventual widespread adoption in numerous residential and commercial building applications. This chapter focuses on the application of SOFC technology in both CHP and CCHP systems for residential and commercial buildings. In particular, modelling approaches, integration strategies, and benefits and challenges for SOFC‐based CHP/CCHP systems are presented. The chapter is organized such that a brief introduction to building application characteristics and integration considerations is first presented. An overview of SOFC‐based CCHP system configurations and operation is then discussed. Considering the lack of SOFC‐CCHP systems either commercially available or in demonstration, the presentation has a predominate focus on SOFC‐CHP systems at relatively small scales (< 10 kW). Basic modelling approaches and techniques for system design and simulation are given next, followed by a synthesis of results and observations concerning the expected effectiveness of SOFC‐CHP systems in residential and commercial building markets. The chapter concludes with an overview of SOFC commercialization efforts, technology and economic barriers, and market outlook.
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The high potential of reversible (or regenerative) solid oxide cell (rSOCs) systems for energy storage application motivates the present study which focuses on predicting rSOC performance through mathematical modeling. An intermediate... more
The high potential of reversible (or regenerative) solid oxide cell (rSOCs) systems for energy storage application motivates the present study which focuses on predicting rSOC performance through mathematical modeling. An intermediate fidelity model that can be used for identifying favorable electrochemical and thermal performance of rSOCs is developed and briefly reported here. The model is employed to investigate the rSOC performance particularly for pressurized operation. It has been observed that rSOCs can benefit from pressurized operation particularly in solid oxide fuel cell (SOFC) mode of operation. In the solid oxide electrolysis (SOEC) mode there are also advantages from pressurized operation, particularly above a certain current density. It has also been observed that the SOEC performance is more affected by changing the inlet feedstock condition (pressure and temperature) than the SOFC mode at pressurized operation.
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Models of fuel cell based combined heat and power systems, used in building energy performance simulation codes, are often based on simple black or grey box models. To model a specific device, input data from experiments are often... more
Models of fuel cell based combined heat and power systems, used in building energy performance simulation codes, are often based on simple black or grey box models. To model a specific device, input data from experiments are often required for calibration. This paper presents an approach for the theoretical derivation of such data. A generic solid oxide fuel cell (SOFC) system model is described that is specifically developed for the evaluation of building integrated co‐ or polygeneration. First, a detailed computational cell model is developed for a planar SOFC and validated with available numerical and experimental data for intermediate and high temperature SOFCs with internal reforming (IT‐DIR and HT‐DIR). Results of sensitivity analyses on fuel utilisation and air excess ratio are given. Second, the cell model is extended to the stack model, considering stack pressure losses and the radiative heat transfer effect from the stack to the air flow. Third, two system designs based on...
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The aim of this paper is to design and investigate the dynamic behavior of a PEM fuel cell system. Dynamic analysis of a PEM fuel cell system has been done in Matlab\Simulink software according to electrical current that has been applied... more
The aim of this paper is to design and investigate the dynamic behavior of a PEM fuel cell system. Dynamic analysis of a PEM fuel cell system has been done in Matlab\Simulink software according to electrical current that has been applied from hybrid system. In addition, dynamical fuel cell system has been explained according to oriented control that is started from air injection compressor model. Also hydrogen valve actuator has been controlled according to the compressor model. The results of the fuel cell dynamic model as well as the applied compressor model are fully validated based on the available results in the open literature. Finally, the effects of several operating parameters of the fuel cell system such as anode and cathode pressures, cell voltage, compressor voltage, compressor mass flow rate variation with respect to inlet pressure ratio, net and stack powers on the dynamic behavior of the hybrid system are investigated. The results show that the model can predict the d...
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This project centers on a novel device that stores energy electrochemically in tanks like a flow battery, while the materials and chemistry are more akin to those of a solidoxide fuel cell – hence the name “Solid Oxide Flow Battery”... more
This project centers on a novel device that stores energy electrochemically in tanks like a flow battery, while the materials and chemistry are more akin to those of a solidoxide fuel cell – hence the name “Solid Oxide Flow Battery” (SOFB). The SOFB is well suited for grid-scale energy storage because the energy storage capacity can be increased by increasing tank storage capacity. The objective of the project is to carry out the fundamental studies of the materials, cells, stacks, and system designs needed to validate the device concept and provide the information needed for further development. One set of challenges for SOFB technology includes the development of cells that yield the desired performance at the desired operating temperature and pressure, and that can work without significant degradation over thousands of electrolysis/fuelcell cycles. Other challenges are to develop viable stack and system designs that can yield the predicted ideal round-trip efficiencies of ~ 80%. ...
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This paper presents our progress in developing, testing, and implementing a Ubiquitous Sensing Network (USN) for real-time monitoring of methane emissions. This newsensor technology supports environmental management of industrial sites... more
This paper presents our progress in developing, testing, and implementing a Ubiquitous Sensing Network (USN) for real-time monitoring of methane emissions. This newsensor technology supports environmental management of industrial sites through a decision support system. Upon detection of specific inputs, data is processed before passing it on for appropriate actions (Data→Insight→Actions). The technology integrates wireless methane sensor nodes, weather sensors, edge-based devices and is powered by a self- contained solar-battery powered system. A cloud-based data analytics IoT solution is included for handling continuous sensor monitoring. A sample of results from an in-house simulated well site are presented within the body of this paper. Preliminary predictions seem to correlate well with the true emission rate as indicated by the proximity of the predictions to the forty-five-degree line. Running more tests should allow us to further estimate the error distribution as well as the prediction interval width and the overall emission rate prediction trend. The initial results demonstrate that the developed technology can quantify the emission rate (scfh) within 1% and 45% error, and a localization error within six feet to fifty feet given a test area of 10,000 square feet. This integrated solution is being ruggedized and the analytics are being optimized for continuous monitoring of methane emissions at customer sites for safety, product loss prevention, and regulatory compliance.