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Full-Text Articles in Engineering
A Multi-Physics Model For Solid Oxide Iron-Air Redox Flow Battery: Simulation Of Discharge Behavior At High Current Density, Meng Guo, Xuan Zhao, Ralph E. White, Kevin Huang
A Multi-Physics Model For Solid Oxide Iron-Air Redox Flow Battery: Simulation Of Discharge Behavior At High Current Density, Meng Guo, Xuan Zhao, Ralph E. White, Kevin Huang
Faculty Publications
A rigorous physics-based mathematical model for a solid oxide iron-air redox flow battery system is presented in this paper. The modeled flow battery system combines a Fe-FeO redox couple as the energy storage unit and a regenerative solid oxide fuel cell as the electrical functioning unit in a 2D axial symmetric geometry. This model was developed from fundamental theories of reaction engineering in which basic transport phenomena and chemical/electrochemical kinetics are included. The model shows good agreement with the experimental data. Simulation results for the chemical, electrochemical and transport behavior of the battery are discussed.
A Model On An Entrained Bed-Bubbling Bed Process For Co2 Capture From Flue Gas, Jeong-Hoo Choi, Chang-Keun Yi, Sung-Ho Jo
A Model On An Entrained Bed-Bubbling Bed Process For Co2 Capture From Flue Gas, Jeong-Hoo Choi, Chang-Keun Yi, Sung-Ho Jo
The 13th International Conference on Fluidization - New Paradigm in Fluidization Engineering
A simplified model has been developed to investigate effects of important operating parameters on performance of an entrained-bed absorber and bubbling-bed regenerator system collecting CO2 from flue gas. The particle population balance was considered together with chemical reaction to determine the extent of conversion in both absorber and regenerator. Effects of several absorber parameters was tested in a laboratory scale process. The CO2 capture efficiency decreased as temperature or gas velocity increased. However, it increased with static bed height or moisture concentration. The CO2 capture efficiency was exponentially proportional to each parameter. Based on the absolute value of exponent of …
Fast Pyrolysis Of Biomass In A Circulating Fluidised Bed, Manon Van De Velden, Xianfeng Fan, Andy Ingram, Jan Baeyens
Fast Pyrolysis Of Biomass In A Circulating Fluidised Bed, Manon Van De Velden, Xianfeng Fan, Andy Ingram, Jan Baeyens
The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering
CFB biomass pyrolysis produces mostly bio-oil. Reaction rates are fast (k > 0.5 s-1). Yields exceed 60 wt% of bio-oil at 500 °C and at a residence time for oil and char t < 2.5 s. as achieved in plug flow CFB-mode, shown by PEPT to occur at U > (Utr + 1) m/s and G > 200 kg/m² s.
Optimization Of Cell Density And Dilution Rate In Pichia Pastoris Continuous Fermentations For Production Of Recombinant Proteins, Mehmet Inan, Michael M. Meagher, Wenhui Zhang, Chih Ping Liu
Optimization Of Cell Density And Dilution Rate In Pichia Pastoris Continuous Fermentations For Production Of Recombinant Proteins, Mehmet Inan, Michael M. Meagher, Wenhui Zhang, Chih Ping Liu
Papers in Biomolecular Engineering
This paper provides an approach for optimizing the cell density (Xc) and dilution rate (D) in a chemostat for a Pichia pastoris continuous fermentation for the extracellular production of a recombinant protein, interferon τ (INF-τ). The objective was to maximize the volumetric productivity (Q, mg INF-τ I-1 h-1), which was accomplished using response surface methodology (RSM) to model the response of Q as a function of Xc and D within the ranges 150 ≤ Xc ≤ 450 g cells (wet weight) l-1 and 0.1 μm ≤D ≤ 0.9 μm (μm =0.0678 h-1, the maximum specific growth rate obtained from a …
Modeling Nitrogen Evolution During Coal Pyrolysis Based On A Global Free-Radical Mechanism, Steven T. Perry, Thomas H. Fletcher
Modeling Nitrogen Evolution During Coal Pyrolysis Based On A Global Free-Radical Mechanism, Steven T. Perry, Thomas H. Fletcher
Faculty Publications
A global free-radical mechanism and an associated rate equation for the evolution of light gas nitrogen during coal devolatilization are presented. The light gas nitrogen rate equation was used to modify an existing nitrogen model so that only a network devolatilization model and coal-specific chemical structural input data are required to adequately predict light gas nitrogen release at a variety of pyrolysis conditions. Model predictions show good agreement with nitrogen release data from pyrolysis of coals of rank from lignite to low volatile bituminous at heating rates from 0.5 to 105 K/s, temperatures as high as 2300 K, and …
Modeling Nitrogen Release During Devolatilization On The Basis Of Chemical Structure Of Coal, Dominic Genetti, Thomas H. Fletcher
Modeling Nitrogen Release During Devolatilization On The Basis Of Chemical Structure Of Coal, Dominic Genetti, Thomas H. Fletcher
Faculty Publications
A model that predicts the amount and distribution between tar and light gas of nitrogen released during devolatilization has been developed and incorporated into the chemical percolation devolatilization (CPD) model. This work represents the first volatile nitrogen release model developed on the basis of 13C NMR measurements of coal structure. This work also represents the first volatile nitrogen release model evaluated by comparing model predictions with chemical structural features of the char (determined by 13C NMR spectral analyses). The model is limited to nitrogen release during primary pyrolysis, and assumes that all light-gas nitrogen is HCN. Model predictions …
Modeling Soot Derived From Pulverized Coal, Alexander L. Brown, Thomas H. Fletcher
Modeling Soot Derived From Pulverized Coal, Alexander L. Brown, Thomas H. Fletcher
Faculty Publications
A semiempirical model has been developed for predicting coal-derived soot. The main feature of the model is a transport equation for soot mass fraction. Tar prediction options include either an empirical or a transport equation approach, which directly impacts the source term for soot formation. Also, the number of soot particles per unit mass of gas may be calculated using either a transport equation or an assumed average. Kinetics are based on Arrhenius rates taken from published measurements. Radiative properties are calculated as a function of averaged optical constants, predicted gas temperatures, predicted gas densities, and the soot mass fractions. …
Chen, W., L. D. Smoot, S. C. Hill, And T. H. Fletcher, “Global Rate Expression For Nitric Oxide Reburning. Part 2,” Energy And Fuels, 10, 1046-1052 (1996)., Wei Chen, L Douglas Smoot, Scott C. Hill, Thomas H. Fletcher
Chen, W., L. D. Smoot, S. C. Hill, And T. H. Fletcher, “Global Rate Expression For Nitric Oxide Reburning. Part 2,” Energy And Fuels, 10, 1046-1052 (1996)., Wei Chen, L Douglas Smoot, Scott C. Hill, Thomas H. Fletcher
Faculty Publications
An investigation of a global reburning-NO reaction, sum(CiHj) + NO => HCN + . . ., which is a reduction pathway of nitric oxide (NO) by reaction with gaseous hydrocarbons, was conducted. The global reburning-NO rate expression was deduced from a combination of elemental reactions. The global rate expression and its rate constants were then determined by correlating predicted species profiles from simple hydrocarbon flames. This global reburning-NO rate constant can be expressed as 2.7x106 exp(-18,800/RT) (gmol/cm3 s). This expression and constants are applicable to atmospheric pressure with an equivalence ratio range of 1.0-2.08 …
A Computational Method For Determining Global Fuel-No Rate Expressions. Part 1, Wei Chen, L Douglas Smoot, Thomas H. Fletcher, Richard D. Boardman
A Computational Method For Determining Global Fuel-No Rate Expressions. Part 1, Wei Chen, L Douglas Smoot, Thomas H. Fletcher, Richard D. Boardman
Faculty Publications
Global chemical reaction rates used in the modeling of NOx formation in comprehensive combustion codes have traditionally been obtained through correlation of experimental data. In this paper, a computational approach for obtaining global rates is presented. Several premixed flames were simulated, and sensitivity analysis of species concentration profiles was used to suggest global pathways in fuel-nitrogen conversion to NO. Based on these analyses, the global reaction rates were formulated. The predicted species concentration profiles and their derivatives were then used in the determination of the global rate constants. The correlation of rate constants for the two fuel-NO global rates …