The Experts below are selected from a list of 8682 Experts worldwide ranked by ideXlab platform
Marc Clausse - One of the best experts on this subject based on the ideXlab platform.
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a theoretical analysis of the energy consumption of post combustion co2 capture processes by temperature swing adsorption using solid sorbents
International Journal of Greenhouse Gas Control, 2013Co-Authors: Gerhard D Pirngruber, Florent Guillou, Adrien Gomez, Marc ClausseAbstract:Abstract CO2 capture processes based on dry solid sorbents have been praised as a very attractive alternative to absorption by amine solvents (in particular monoethanolamine) in terms of energy consumption. The present paper critically analyzes these very optimistic predictions. It presents a theoretical analysis of three different temperature swing adsorption (TSA) processes: (i) a fixed bed, (ii) an isothermal fluidized bed and (iii) an adiabatic fluidized bed. The solid sorbent is supposed to be an amine immobilized on a support material. A high-level estimation of the energy consumption of the three processes shows that the fixed bed process would be by far the most interesting option, because the thermodynamic driving force for adsorption is higher in the fixed bed. The performances of both the fixed and fluidized bed process dramatically improve if the adsorption step is operated under close to isothermal conditions. Heat transfer in a fixed bed is much slower than in a fluidized bed. Providing the Heat Exchange Area required for isothermal operation is challenging in the fixed bed, but not impossible according to our rough estimations. The paper also defines the adsorption properties (adsorption constant, adsorption capacity, Heat of adsorption) of the optimal solid sorbent.
Gilles Flamant - One of the best experts on this subject based on the ideXlab platform.
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solar hydrogen production from the thermal splitting of methane in a high temperature solar chemical reactor
Solar Energy, 2006Co-Authors: Stephane Abanades, Gilles FlamantAbstract:Abstract This study addresses the single-step thermal decomposition (pyrolysis) of methane without catalysts. The process co-produces hydrogen-rich gas and high-grade carbon black (CB) from concentrated solar energy and methane. It is an unconventional route for potentially cost effective hydrogen production from solar energy without emitting carbon dioxide since solid carbon is sequestered. A high temperature solar chemical reactor has been designed to study the thermal splitting of methane for hydrogen generation. It features a nozzle-type graphite receiver which absorbs the solar power and transfers the Heat to the flow of reactant at a temperature that allows dissociation. Theoretical and experimental investigations have been performed to study the performances of the solar reactor. The experimental set-up and effect of operating conditions are described in this paper. In addition, simulation results are presented to interpret the experimental results and to improve the solar reactor concept. The temperature, geometry of the graphite nozzle, gas flow rates, and CH4 mole fraction have a strong effect on the final chemical conversion of methane. Numerical simulations have shown that a simple tubular receiver is not enough efficient to Heat the bulk gas in the central zone, thus limiting the chemical conversion. In that case, the reaction takes place only within a thin region located near the hot graphite wall. The maximum CH4 conversion (98%) was obtained with an improved nozzle, which allows a more efficient gas Heating due to its higher Heat Exchange Area.
Sh Pourhoseini - One of the best experts on this subject based on the ideXlab platform.
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Numerical study of inlet air swirl intensity effect of a Methane-Air Diffusion Flame on its combustion characteristics
'Elsevier BV', 2020Co-Authors: Aa Hosseini, Ghodrat M, Moghiman M, Sh PourhoseiniAbstract:© 2020 The Authors. In this paper, the effect of inlet air swirl number of a Methane-Air Diffusion Flame on dynamic flow behavior, temperature, and radiation Heat flux distribution was investigated using ANSYS-Fluent CFD code. Based on the swirling effect on dynamic flow behavior, a specific equation in terms of axial and tangential velocity components was used to reach the swirl number. The modeling of the chemical reaction was carried out by applying the Eddy Dissipation Model (EDM). Furthermore, radiation Heat flux and turbulent flow characteristics were performed by using P-1 and standard k-ϵ models. The results showed that the elevating swirl number of the inlet air from 0.0 to 0.6 develops the furnace internal recirculation zone which leads to producing the combustion products in the internal recirculation zone. Consequently, fuel and air are mixed more efficiently, which results in the enhancement of combustion efficiency by removing the high-temperature zones as the leading cause of producing nitrogen oxides (NOx). Moreover, as the swirl number increases, the radial flow distribution improves, and the flame Heat Exchange Area enhances regardless of the maximum flame temperature reduction, which will increase the flux radiation efficiency by 36.5% and reduces the pollutant NOx by 58.6%
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Numerical study of inlet air swirl intensity effect of a Methane-Air Diffusion Flame on its combustion characteristics
'Elsevier BV', 2020Co-Authors: Aa Hosseini, Ghodrat M, Moghiman M, Sh PourhoseiniAbstract:In this paper, the effect of inlet air swirl number of a Methane-Air Diffusion Flame on dynamic flow behavior, temperature, and radiation Heat flux distribution was investigated using ANSYS-Fluent CFD code. Based on the swirling effect on dynamic flow behavior, a specific equation in terms of axial and tangential velocity components was used to reach the swirl number. The modeling of the chemical reaction was carried out by applying the Eddy Dissipation Model (EDM). Furthermore, radiation Heat flux and turbulent flow characteristics were performed by using P-1 and standard k-ϵ models. The results showed that the elevating swirl number of the inlet air from 0.0 to 0.6 develops the furnace internal recirculation zone which leads to producing the combustion products in the internal recirculation zone. Consequently, fuel and air are mixed more efficiently, which results in the enhancement of combustion efficiency by removing the high-temperature zones as the leading cause of producing nitrogen oxides (NOx). Moreover, as the swirl number increases, the radial flow distribution improves, and the flame Heat Exchange Area enhances regardless of the maximum flame temperature reduction, which will increase the flux radiation efficiency by 36.5% and reduces the pollutant NOx by 58.6%
Ning Mei - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation on binary ammonia water and ternary ammonia water lithium bromide mixture based absorption refrigeration systems for fishing ships
Energy Conversion and Management, 2018Co-Authors: Han Yuan, Ji Zhang, Xiankun Huang, Ning MeiAbstract:Abstract Heat recovery of marine engine exhaust gas is an effective way of improving the onboard fuel economy and environmental compliance of fishing ships. Among such Heat recovery techniques, the absorption refrigeration cycle shows potential as it can convert the exhaust thermal energy into refrigeration output and meet the onboard refrigeration requirement. However, the severe operating conditions on the shipboard poses a great challenge for its application. This paper presents an experimental investigation of an absorption refrigeration system for the Heat recovery of marine engine exhaust gas. To overcome the adverse effect of the severe onboard condition on the rectification process of the absorption refrigeration system, a ternary ammonia–water–lithium bromide mixture is selected as the working fluid. A prototype of the absorption system is designed and an experimental investigation is conducted. Then, the performances of both the ternary ammonia–water–lithium bromide-based system and binary ammonia–water-based system are compared. The results show that the rectifier Heat Exchange Area can be reduced by approximately 16% under the experimental working condition. Furthermore, the ternary system operates at a relatively lower pressure, with a refrigeration temperature of less than −15.0 °C, which is higher compared to the temperature of less than −23.6 °C associated with the binary system. Nevertheless, the ternary system achieves a remarkably higher cooling capacity. Moreover, by using the ternary ammonia–water–lithium bromide mixture, the Heat loss of the prototype is reduced while the coefficient of performance and electric coefficient of performance are increased, indicating that the ternary system has a higher energy conversion efficiency.
Xiaosong Zhang - One of the best experts on this subject based on the ideXlab platform.
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study on performance of a novel energy efficient Heat pump system using liquid desiccant
Applied Energy, 2018Co-Authors: Nannan Shan, Yonggao Yin, Xiaosong ZhangAbstract:Abstract In this paper, a novel Heat pump system is proposed, which operates as a Heat-source-tower Heat pump with no frosting in winter, and as a hybrid refrigerant system consisting of a conventional chiller combined with a liquid desiccant dehumidification and evaporative cooling subsystem in summer. A validated mathematical model of the proposed system operating in summer is established to investigate the effects of key parameters, including solution to refrigerant flow ratio (FR), condensation Heat recovery ratio (Rcond) and ambient parameters, on the cooling performance. Besides, this paper analyzes key factors that should be considered in designing the Heat Exchange Area of the solution-cooled condenser (SCC). The results show that the maximum COP and ECOP of the Heat pump system are 13.4% and 10.3% higher than those of conventional vapor compression refrigerant systems under the typical summer condition of Nanjing, respectively. The recommended range of FR is from 1.2 to 6 and that for Rcond is from 16% to 40%. Moreover, the proposed system is more superior to conventional ones when applied in hot and humid regions.
