Removal of Chlorine from Chlorine-Nitrogen Mixture in a Film of Liquid Water

In industry there are many examples of absorption of a gas with or without chemical reaction in the liquid phase. In physical absorption, a particular gaseous component is removed from a gas mixture due to its larger solubility in the liquid phase solvent. The removal of butane and pentane from a refinery gas mixture by a heavy oil in the liquid phase is an example of physical absorption. In absorption with chemical reaction, the gaseous component to be removed transfers across the gas-liquid interface due to a difference in the bulk chemical potentials or concentrations in the two phases. The transferred gas then reacts with a liquid-phase component while simultaneously diffusing in the liquid phase mixture. The gas purification processes, such as removal of chlorine from nitrogen or air by means of water, removal of carbon dioxide from synthesis gas by means of aqueous solutions of hot potassium carbonate or monoethanolamine, and removal of H2S and CO2 from hydrocarbon cracking gas by means of ethanolamine or sodium hydroxide, are some examples of absorption with chemical reaction

Removal of Chlorine from Chlorine-Nitrogen Mixture in a Film of Liquid Water

In industry there are many examples of absorption of a gas with or without chemical reaction in the liquid phase. In physical absorption, a particular gaseous component is removed from a gas mixture due to its larger solubility in the liquid phase solvent. The removal of butane and pentane from a refinery gas mixture by a heavy oil in the liquid phase is an example of physical absorption. In absorption with chemical reaction, the gaseous component to be removed transfers across the gas-liquid interface due to a difference in the bulk chemical potentials or concentrations in the two phases. The transferred gas then reacts with a liquid-phase component while simultaneously diffusing in the liquid phase mixture. The gas purification processes, such as removal of chlorine from nitrogen or air by means of water, removal of carbon dioxide from synthesis gas by means of aqueous solutions of hot potassium carbonate or monoethanolamine, and removal of H2S and CO2 from hydrocarbon cracking gas by means of ethanolamine or sodium hydroxide, are some examples of absorption with chemical reaction

Characterization of Iron Phthalocyanine as the Cathode Active Material for Lithium-Ion Batteries

The developed thermodynamic functions for the determination of Gibbs free energy, enthalpy, and entropy of formation of solid lithium-iron phthalocyanine (LixFePc) from solid lithium and iron phthalocyanine as a function of x, defined as g-moles of the intercalated lithium per g-mole of iron phthalocyanine, at a fixed set of temperature and pressure conditions are presented. In addition, a proposed expression for the evaluation of lithium diffusion coefficient in solid iron phthalocyanine as a function of both x and temperature, and the experimental results from the ongoing research/development work on the lithium/iron phthalocyanine cells are included

An Empirical Intrinsic Chemical Kinetic Model For The Carbon-Carbon Composite Pyrolysis Process

Lightweight, high mechanical strength matrix-carbon fibre reinforced composites are manufactured from phenol-formaldehyde matrix/carbon fibre composites by the pyrolysis process. Phenol-formaldehyde matrix/carbon fibre composites are heated in an inert gas environment to high temperatures, for example, up to 800°C in the so-called first carbonization process. Evolution of gaseous species in a relatively thick composite, during the transient heating period, leads to internal pressure build-up, resulting in the composite delamination. The composite delamination depends on the rate of thermal energy flux into the composite material, production of gaseous species via intrinsic chemical kinetics, and transport of the produced gases to the composite environment through its porous structure. A refined transient process model, incorporating the effects of intrinsic chemical kinetics and transport phenomena of heat and mass, still needs to be developed to predict/control the carbonization process to avoid delamination of a composite of thickness greater than 0.001 m. To this end, the overall intrinsic chemical kinetic model being presented here was developed using the experimental data, free of mass and heat transfer effects, on the pyrolysis of a phenol-formaldehyde resin [1]. Insight gained from the thermogravimetric data analyses [2-5] on thermal degradation of polymeric materials was helpful in the chemical kinetic model development

Performance/Design Formulation for a Solid Polymer Based Acid Electrolyte Hydrogen/Air Fuel Cell

Mathematical development of preliminary performance/design equations for a hydrogen/air, solid polymer acid electrolyte based fuel cell is presented. The development is based on the principles of transport phenomena, intrinsic electrochemical kinetics, and classical thermodynamics. The developed formulation is intended to quantitatively describe the mass fraction profiles of the chemical species, hydrogen and oxygen, in the cell anode and cathode diffusion and electrocatalytic reaction layers as a function of the distance in the proton transport direction at an axial distance parallel to the cell anode or cathode channel flow. Given the cell geometry, chemical species and charge transport, and intrinsic electrochemical kinetic parameters, the developed formulation can be employed to compute the species local mass fluxes and predict the cell anode and cathode cell overvoltages for a desired geometric current density. The presented single cell performance predictive formulation has also been linked to the formulation needed to predict the performance of a stack of a number of identical PEMFCs connected in series

Formulation of a Mathematical Process Model for the Foaming of a Mesophase Carbon Precursor

Mathematical equations have been formulated to guide an experimental effort to produce an open-celled mesophase pitch foam. The formulation provides an analytical description of homogeneous bubble nucleation and growth, diffusion of the blowing gas through the liquid to the bubble surface, and the average material thickness between bubbles. Implications of the formulation for the experimental production of mesophase pitch foam are discussed

Thermodynamic Equations for a Model Lithium-Ion Cell

Fundamentals of classical thermodynamics of electrochemical systems have been employed to formulate mathematical equations for a model lithium-ion and lithium electrode concentration cell. Equations have been formulated to determine the energetic lithium interaction coefficients in the solid lithium-ion electrode phases and the salt mean activity coefficient in the electrolytic solution used in the model cell from the measured experimental data. In addition, a mathematical equation to predict the open-circuit voltage of the model cell for the case of differing electrolyte compositions in its porous electrodes has been developed

Diffusion-Limited Self-Discharge Reaction in the Hubble Space Telescope Battery

The self-discharge rate of aerospace flight-quality nickel-hydrogen batteries is limited by hydrogen diffusion within the nickel electrode active material. A diffusion-limited reaction model is developed which accounts for the observed self-discharge behavior. Effective hydrogen diffusion coefficients were calculated from the open-circuit self-discharge data on Hubble space telescope flight-quantified nickel-hydrogen cells and ranged from 1.12×10−10 cm2/sec at 25°C to 7.45×10−12 cm2/sec at 0°C

Diffusion-Limited Model for a Lithium/Polymer Battery

A simple diffusion-limited model is presented to explain the capacity limitations of an actual 3 volt rechargeable lithium/polymer electrolyte/lithium manganese dioxide cell at low to moderate discharge rates. Chemical diffusion coefficients of lithium in lithium manganese dioxide on the order of 10−12–10−14 cm2/sec were determined for the temperature range of −10–40°C

Laser Interferometric Studies of the Control of Heat Transfer from Flame Gases by Electric Fields

The effects of dc electric fields on heat transfer between flame gases and solid bodies are studied under three conditions: (1) Sub-breakdown fields are used to displace hot combustion gases relative to calorimetric probes. The case of maintaining a solid body cool by deflecting flame gases away from it is shown to be the most promising practical application. (2) Additional ions generated by corona discharges are used to induct cold air flow from outside the flame. This is relevant, for example, to improving the cooling of perforated walls of combustion chambers. (3) Corona discharges are generated within the boundary layers of tubular calorimetric probes. The results are relevant to modifying heat transfer between pipes and un-ionized gases. In each case, the analysis is based on calorimetric measurements and on data produced by a large area, double-exposure, laser interferometer that was designed for this purpose on the plan of a schlieren system. Theoretical correlations developed to account for heat transfer under the influence of fields and corona discharges show good agreement with the experimental results