Proceedings of the 2nd International Conference on Fluid Flow and Thermal Science (ICFFTS'21), 2021
A direct contact condenser with a packed bed is a highly efficient component of air/vapor mixture... more A direct contact condenser with a packed bed is a highly efficient component of air/vapor mixture condensation systems. A mathematical model is crucial to predict the performance of the condenser but existing models contain empirical correlations with limited or undefined range of validity. In this research, a comparison between several mass transfer coefficient correlations for air/vapor and liquid and the interfacial area is performed. An experimental setup has been built and tested for validation purposes. The boundary conditions and experimental data have been compared with the prediction from various listed models. It is concluded from the study that the Onda and Billet correlations are compatible with most of the results obtained from the experimental study.
An incremental thermodynamic equilibrium model has been developed for the chemical reactions driv... more An incremental thermodynamic equilibrium model has been developed for the chemical reactions driving a clean, hydrogen producing iron/iron oxide looping cycle. The model approximates a well-mixed reactor with continuous reactant gas flow through a stationary solid matrix, where the gas residence time is long compared to time constants associated with chemical kinetics and species transport. The model, which computes the theoretical limit for steam-to-hydrogen conversion, has been experimentally validated for the oxidation reaction using an externally heated, 21 mm inner diameter, tubular fluidized bed reactor. Experiments were carried out at 660 and 960 C with steam flow rates ranging from 0.9 to 3.5 g/min. For small flow rates, i.e., for long residence times, the experimentally observed cumulative steam-to-hydrogen conversion approaches the theoretically predicted conversion. At a 960 C operating temperature, the measured hydrogen yield approaches the theoretical limit (experimental yields are always within 50% of the theoretical limit), and the yield is insensitive to variations in the steam flow rate. In contrast, the measured hydrogen yield deviates significantly from the theoretical limit at a 660 C operating temperature, and strong variations in hydrogen yield are observed with variations in steam flow rate. This observation suggests that the reaction kinetics are significantly slower at lower temperature, and the model assumption is not satisfied.
Ea rly Di sc ou nt Pr ic in g No w Av ai la bl e! c o m p u t e r .o r g / c y b e r 2 0 1 5 CH R... more Ea rly Di sc ou nt Pr ic in g No w Av ai la bl e! c o m p u t e r .o r g / c y b e r 2 0 1 5 CH RIS CA LVE RT Gl ob al Di rec tor , HP En ter pr ise So lut ion s Pr od uc ts M AR CU S H. SA CH S Se nio r Vic e Pr es ide nt, Ch ief Se cu rit y Of fi ce r (N ER C) DR . SP EN CER SO OH OO CS O/ Di rec tor , Sc ien tifi c Co mp uti ng Ce da rs-Sin ai Me dic al Ce nte r
Proceedings of the 2nd International Conference on Fluid Flow and Thermal Science (ICFFTS'21), 2021
A direct contact condenser with a packed bed is a highly efficient component of air/vapor mixture... more A direct contact condenser with a packed bed is a highly efficient component of air/vapor mixture condensation systems. A mathematical model is crucial to predict the performance of the condenser but existing models contain empirical correlations with limited or undefined range of validity. In this research, a comparison between several mass transfer coefficient correlations for air/vapor and liquid and the interfacial area is performed. An experimental setup has been built and tested for validation purposes. The boundary conditions and experimental data have been compared with the prediction from various listed models. It is concluded from the study that the Onda and Billet correlations are compatible with most of the results obtained from the experimental study.
An incremental thermodynamic equilibrium model has been developed for the chemical reactions driv... more An incremental thermodynamic equilibrium model has been developed for the chemical reactions driving a clean, hydrogen producing iron/iron oxide looping cycle. The model approximates a well-mixed reactor with continuous reactant gas flow through a stationary solid matrix, where the gas residence time is long compared to time constants associated with chemical kinetics and species transport. The model, which computes the theoretical limit for steam-to-hydrogen conversion, has been experimentally validated for the oxidation reaction using an externally heated, 21 mm inner diameter, tubular fluidized bed reactor. Experiments were carried out at 660 and 960 C with steam flow rates ranging from 0.9 to 3.5 g/min. For small flow rates, i.e., for long residence times, the experimentally observed cumulative steam-to-hydrogen conversion approaches the theoretically predicted conversion. At a 960 C operating temperature, the measured hydrogen yield approaches the theoretical limit (experimental yields are always within 50% of the theoretical limit), and the yield is insensitive to variations in the steam flow rate. In contrast, the measured hydrogen yield deviates significantly from the theoretical limit at a 660 C operating temperature, and strong variations in hydrogen yield are observed with variations in steam flow rate. This observation suggests that the reaction kinetics are significantly slower at lower temperature, and the model assumption is not satisfied.
Ea rly Di sc ou nt Pr ic in g No w Av ai la bl e! c o m p u t e r .o r g / c y b e r 2 0 1 5 CH R... more Ea rly Di sc ou nt Pr ic in g No w Av ai la bl e! c o m p u t e r .o r g / c y b e r 2 0 1 5 CH RIS CA LVE RT Gl ob al Di rec tor , HP En ter pr ise So lut ion s Pr od uc ts M AR CU S H. SA CH S Se nio r Vic e Pr es ide nt, Ch ief Se cu rit y Of fi ce r (N ER C) DR . SP EN CER SO OH OO CS O/ Di rec tor , Sc ien tifi c Co mp uti ng Ce da rs-Sin ai Me dic al Ce nte r
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