Page 1. Adsorption from Liquid Mixtures on Solids: Thermodynamics of Excess Properties and Their ... more Page 1. Adsorption from Liquid Mixtures on Solids: Thermodynamics of Excess Properties and Their Temperature Coefficients Shivaji Sircar, Jaromir Novosad, and Alan 1. Myers* School oj Chemical Engineering, Cniversity oj Pennsylvania, Philadelphia. Pa. 19104 ...
ABSTRACT Decentralized residential power generation employing a H2 PEM fuel cell requires that es... more ABSTRACT Decentralized residential power generation employing a H2 PEM fuel cell requires that essentially COx free H2 be produced on site by catalytic steam reforming of piped natural gas and then purifying the product H2 (removal of bulk CO2 and dilute CO impurities). Currently, it may be achieved by subjecting the reformed gas to water gas shift reaction followed by (a) removal of all impurities by a PSA process or (b) selective oxidation in a catalytic PROX reactor to reduce only the CO impurity below ~ 10 ppm for use in the fuel cell. The latter approach assumes that the detrimental effect of CO2 on the performance of the fuel cell is minimum. This assumption may not be valid. A recently developed thermal swing sorption enhanced reaction (TSSER) process scheme can be used to combine reformation, shifting, and purification in a compact, single unit operation for this application. The process permits circumvention of the thermodynamic limits of the SMR reaction and permits direct production of fuel cell grade H2 with high recovery and purity, yet operating the SMR reaction at a lower temperature. Simulated performance of the process, preliminary process design for supplying H2 to a 250 KW fuel cell, and first pass costs are described.
Stress induced martensitic transformation in a polycrystalline near equiatomic Ti-Ni alloy has be... more Stress induced martensitic transformation in a polycrystalline near equiatomic Ti-Ni alloy has been investigated by following instantaneous temperature rise during such a transformation. Stress free M{sub s} temperature of the alloy on cooling, was 263 K stress induced transformation studies were conducted at â¼300 K. A two stage temperature rise during stressing was observed which has been interpreted as a
Enthalpic effects accompanying adsorption are needed for energy balances in the design of adsorbe... more Enthalpic effects accompanying adsorption are needed for energy balances in the design of adsorbers. Heats of adsorption are also useful for predicting (1) the selectivity of the adsorbent for different substances and (2) the temperature coefficient of adsorption. The heat of immersion of an adsorbent in a liquid mixture (AH) is connected by thermodynamics to the isosteric heat of adsorption (q,J of its vapor.
Http Dx Doi Org 10 1080 01496395 2014 976876, Jan 20, 2015
ABSTRACT The performances of a novel rapid pressure swing adsorption system for continuous produc... more ABSTRACT The performances of a novel rapid pressure swing adsorption system for continuous production of ~ 90% O2 from a compressed air feed were experimentally studied using two different samples of pelletized LiLSX zeolite. Bed size factor (BSF) and O2 recovery (R) were compared as functions of total process cycle times. The optimum performance by the samples differed substantially - one exhibiting ~ 30 % smaller BSF and ~ 6 % higher R than the other, even though the adsorption isotherms and column dynamics for the pure gases were nearly identical. Column pressure drop during the desorption step was the cause.
A cyclic process for operating an equilibrium controlled reaction in a plurality of reactors cont... more A cyclic process for operating an equilibrium controlled reaction in a plurality of reactors containing an admixture of an adsorbent and a reaction catalyst suitable for performing the desired reaction which is operated in a predetermined timed sequence wherein the heating and cooling ...
The performance of a novel nanoporous carbon membrane for separation of hydrogen-hydrocarbon gas ... more The performance of a novel nanoporous carbon membrane for separation of hydrogen-hydrocarbon gas mixtures is described. The membrane selectively adsorbs hydrocarbons from hydrogen at the high pressure side and the adsorbed molecules then diffuse along the pore walls to the low pressure side. Pressure levels at the high and low pressure sides of the membrane and the type and flow rate of the sweep gas at the low pressure side of the membrane were varied. The effects of these variables on the hydrogen recovery and hydrocarbon rejection by the membrane were investigated.
The kinetics of Agl film growth on silver under the action of applied static charge of both the p... more The kinetics of Agl film growth on silver under the action of applied static charge of both the polarities, as well as under normal iodination conditions in the temperature range of 294 to 338 K and in the iodine partial pressure range of 0.03 to 0.22kPa, conform to parabolic rate law. Compared to normal iodination, an enhancement in rate under both positive and negative surface charge conditions at the Ag/Agl interface and a decrease in rate under either surface charge condition at the Agl/12 interface have been observed. The increased rate with negative charge at the Ag/Agl interface and the decreased rate with same kind of charge at the Agl/I 2 interface, compared to normal iodination, can be explained on the basis of positive hole transport, while the observed effects with positive charge at either of the interfaces receive reasonable support from cation migration as the ,rate limiting factor during the film growth process.
Page 1. Adsorption from Liquid Mixtures on Solids: Thermodynamics of Excess Properties and Their ... more Page 1. Adsorption from Liquid Mixtures on Solids: Thermodynamics of Excess Properties and Their Temperature Coefficients Shivaji Sircar, Jaromir Novosad, and Alan 1. Myers* School oj Chemical Engineering, Cniversity oj Pennsylvania, Philadelphia. Pa. 19104 ...
ABSTRACT Decentralized residential power generation employing a H2 PEM fuel cell requires that es... more ABSTRACT Decentralized residential power generation employing a H2 PEM fuel cell requires that essentially COx free H2 be produced on site by catalytic steam reforming of piped natural gas and then purifying the product H2 (removal of bulk CO2 and dilute CO impurities). Currently, it may be achieved by subjecting the reformed gas to water gas shift reaction followed by (a) removal of all impurities by a PSA process or (b) selective oxidation in a catalytic PROX reactor to reduce only the CO impurity below ~ 10 ppm for use in the fuel cell. The latter approach assumes that the detrimental effect of CO2 on the performance of the fuel cell is minimum. This assumption may not be valid. A recently developed thermal swing sorption enhanced reaction (TSSER) process scheme can be used to combine reformation, shifting, and purification in a compact, single unit operation for this application. The process permits circumvention of the thermodynamic limits of the SMR reaction and permits direct production of fuel cell grade H2 with high recovery and purity, yet operating the SMR reaction at a lower temperature. Simulated performance of the process, preliminary process design for supplying H2 to a 250 KW fuel cell, and first pass costs are described.
Stress induced martensitic transformation in a polycrystalline near equiatomic Ti-Ni alloy has be... more Stress induced martensitic transformation in a polycrystalline near equiatomic Ti-Ni alloy has been investigated by following instantaneous temperature rise during such a transformation. Stress free M{sub s} temperature of the alloy on cooling, was 263 K stress induced transformation studies were conducted at â¼300 K. A two stage temperature rise during stressing was observed which has been interpreted as a
Enthalpic effects accompanying adsorption are needed for energy balances in the design of adsorbe... more Enthalpic effects accompanying adsorption are needed for energy balances in the design of adsorbers. Heats of adsorption are also useful for predicting (1) the selectivity of the adsorbent for different substances and (2) the temperature coefficient of adsorption. The heat of immersion of an adsorbent in a liquid mixture (AH) is connected by thermodynamics to the isosteric heat of adsorption (q,J of its vapor.
Http Dx Doi Org 10 1080 01496395 2014 976876, Jan 20, 2015
ABSTRACT The performances of a novel rapid pressure swing adsorption system for continuous produc... more ABSTRACT The performances of a novel rapid pressure swing adsorption system for continuous production of ~ 90% O2 from a compressed air feed were experimentally studied using two different samples of pelletized LiLSX zeolite. Bed size factor (BSF) and O2 recovery (R) were compared as functions of total process cycle times. The optimum performance by the samples differed substantially - one exhibiting ~ 30 % smaller BSF and ~ 6 % higher R than the other, even though the adsorption isotherms and column dynamics for the pure gases were nearly identical. Column pressure drop during the desorption step was the cause.
A cyclic process for operating an equilibrium controlled reaction in a plurality of reactors cont... more A cyclic process for operating an equilibrium controlled reaction in a plurality of reactors containing an admixture of an adsorbent and a reaction catalyst suitable for performing the desired reaction which is operated in a predetermined timed sequence wherein the heating and cooling ...
The performance of a novel nanoporous carbon membrane for separation of hydrogen-hydrocarbon gas ... more The performance of a novel nanoporous carbon membrane for separation of hydrogen-hydrocarbon gas mixtures is described. The membrane selectively adsorbs hydrocarbons from hydrogen at the high pressure side and the adsorbed molecules then diffuse along the pore walls to the low pressure side. Pressure levels at the high and low pressure sides of the membrane and the type and flow rate of the sweep gas at the low pressure side of the membrane were varied. The effects of these variables on the hydrogen recovery and hydrocarbon rejection by the membrane were investigated.
The kinetics of Agl film growth on silver under the action of applied static charge of both the p... more The kinetics of Agl film growth on silver under the action of applied static charge of both the polarities, as well as under normal iodination conditions in the temperature range of 294 to 338 K and in the iodine partial pressure range of 0.03 to 0.22kPa, conform to parabolic rate law. Compared to normal iodination, an enhancement in rate under both positive and negative surface charge conditions at the Ag/Agl interface and a decrease in rate under either surface charge condition at the Agl/12 interface have been observed. The increased rate with negative charge at the Ag/Agl interface and the decreased rate with same kind of charge at the Agl/I 2 interface, compared to normal iodination, can be explained on the basis of positive hole transport, while the observed effects with positive charge at either of the interfaces receive reasonable support from cation migration as the ,rate limiting factor during the film growth process.
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