International Journal of Chemical Reactor Engineering, 2008
Chlorine and hydrogen chloride are classified as potentially hazardous and toxic chemicals. Large... more Chlorine and hydrogen chloride are classified as potentially hazardous and toxic chemicals. Large-scale industrial processes worldwide use chlorine as primary raw material from which hydrogen chloride is obtained as a major byproduct. Hydrogen chloride is sold as aqueous HCl or used as a raw material for the production of chlorinated products, but the quantity of HCl produced by chlorine processes is much more than what the market can absorb, resulting in a toxic waste disposal problem. Recovery of material chlorine from this hydrogen chloride is very important and is of utmost industrial interest as it would cut down on the production of chlorine at the same time solve the waste disposal problem. It is theoretically possible to convert hydrogen chloride to chlorine for the recycling and reuse of chlorine. In this paper we have developed a process for recovery of chlorine from anhydrous hydrogen chloride obtained as a byproduct during low temperature vapor phase hydrolysis of titanium chloride to get TiO 2 . It is a twostage process where chlorination is carried out in a fixed bed reactor using copper oxide catalyst at a temperature in the range of 423-523 K followed by oxidation of copper chloride catalyst in a second fixed bed reactor operating at 573-653 K. This process operates under conditions in which the catalyst does not volatilize and in which the activity of the catalyst remains stable. Operation at relatively moderate temperature prevents corrosion and minimizes the extrinsic energy input required. The chlorine recovery process makes the new generation chloride process for synthesis of TiO 2 economical.
Hydrazine hydrate is now produced worldwide by an ecofriendly process using ammonia and hydrogen ... more Hydrazine hydrate is now produced worldwide by an ecofriendly process using ammonia and hydrogen peroxide as reactants, with methylethylketone (MEK) and acetamide being other active ingredients. Ketazine is an intermediate product during the formation of which, phase separation occurs between an upper organic layer enriched in ketazine and lower aqueous phase containing substantial amounts of acetamide (30 wt.%) and methylethylketone (5%) which have to be recycled in the form of a concentrated solution after partial removal of water (60%). The membrane based pervaporation (PV) technique has been successfully applied using the chemically compatible and highly hydrophilic chitosan membrane to dehydrate the highly alkaline aqueous layer. The effect of operating parameters such as feed composition and barrier thickness on membrane performance with respect to acetamide separation and water flux has been evaluated. High degree of acetamide separation was achieved along with reasonably good water flux and MEK separation.
The Chemical Engineering Journal and The Biochemical Engineering Journal, 1995
Based on the similarity in shape of the second virial coefficient and vapor pressure curves, and ... more Based on the similarity in shape of the second virial coefficient and vapor pressure curves, and the Antoine equation used for calculating the vapor pressure, a simple generalized equation for the reduced second virial coefficient Br = 0.125 -0.305/(Tr-0.345) was formulated and tested. Second virial coefficients of non-polar fluids can be estimated with an average absolute deviation of 8.4%, while the second virial coefficients of non-polar fluid mixtures can be estimated with an average absolute deviation of 10.1%.
Based on the similarity in shape of the second virial coefficient and vapor pressure curves, and ... more Based on the similarity in shape of the second virial coefficient and vapor pressure curves, and the Antoine equation used for calculating the vapor pressure, a simple generalized equation for the reduced second virial coefficient Br = 0.125 -0.305/(Tr-0.345) was formulated and tested. Second virial coefficients of non-polar fluids can be estimated with an average absolute deviation of 8.4%, while the second virial coefficients of non-polar fluid mixtures can be estimated with an average absolute deviation of 10.1%.
International Journal of Chemical Reactor Engineering, 2008
Chlorine and hydrogen chloride are classified as potentially hazardous and toxic chemicals. Large... more Chlorine and hydrogen chloride are classified as potentially hazardous and toxic chemicals. Large-scale industrial processes worldwide use chlorine as primary raw material from which hydrogen chloride is obtained as a major byproduct. Hydrogen chloride is sold as aqueous HCl or used as a raw material for the production of chlorinated products, but the quantity of HCl produced by chlorine processes is much more than what the market can absorb, resulting in a toxic waste disposal problem. Recovery of material chlorine from this hydrogen chloride is very important and is of utmost industrial interest as it would cut down on the production of chlorine at the same time solve the waste disposal problem. It is theoretically possible to convert hydrogen chloride to chlorine for the recycling and reuse of chlorine. In this paper we have developed a process for recovery of chlorine from anhydrous hydrogen chloride obtained as a byproduct during low temperature vapor phase hydrolysis of titanium chloride to get TiO 2 . It is a twostage process where chlorination is carried out in a fixed bed reactor using copper oxide catalyst at a temperature in the range of 423-523 K followed by oxidation of copper chloride catalyst in a second fixed bed reactor operating at 573-653 K. This process operates under conditions in which the catalyst does not volatilize and in which the activity of the catalyst remains stable. Operation at relatively moderate temperature prevents corrosion and minimizes the extrinsic energy input required. The chlorine recovery process makes the new generation chloride process for synthesis of TiO 2 economical.
Hydrazine hydrate is now produced worldwide by an ecofriendly process using ammonia and hydrogen ... more Hydrazine hydrate is now produced worldwide by an ecofriendly process using ammonia and hydrogen peroxide as reactants, with methylethylketone (MEK) and acetamide being other active ingredients. Ketazine is an intermediate product during the formation of which, phase separation occurs between an upper organic layer enriched in ketazine and lower aqueous phase containing substantial amounts of acetamide (30 wt.%) and methylethylketone (5%) which have to be recycled in the form of a concentrated solution after partial removal of water (60%). The membrane based pervaporation (PV) technique has been successfully applied using the chemically compatible and highly hydrophilic chitosan membrane to dehydrate the highly alkaline aqueous layer. The effect of operating parameters such as feed composition and barrier thickness on membrane performance with respect to acetamide separation and water flux has been evaluated. High degree of acetamide separation was achieved along with reasonably good water flux and MEK separation.
The Chemical Engineering Journal and The Biochemical Engineering Journal, 1995
Based on the similarity in shape of the second virial coefficient and vapor pressure curves, and ... more Based on the similarity in shape of the second virial coefficient and vapor pressure curves, and the Antoine equation used for calculating the vapor pressure, a simple generalized equation for the reduced second virial coefficient Br = 0.125 -0.305/(Tr-0.345) was formulated and tested. Second virial coefficients of non-polar fluids can be estimated with an average absolute deviation of 8.4%, while the second virial coefficients of non-polar fluid mixtures can be estimated with an average absolute deviation of 10.1%.
Based on the similarity in shape of the second virial coefficient and vapor pressure curves, and ... more Based on the similarity in shape of the second virial coefficient and vapor pressure curves, and the Antoine equation used for calculating the vapor pressure, a simple generalized equation for the reduced second virial coefficient Br = 0.125 -0.305/(Tr-0.345) was formulated and tested. Second virial coefficients of non-polar fluids can be estimated with an average absolute deviation of 8.4%, while the second virial coefficients of non-polar fluid mixtures can be estimated with an average absolute deviation of 10.1%.
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Papers by Usha Virendra