Kinetics of Chromium(III) Transport Through a Liquid Membrane Containing DNNSA as a Carrier

Kinetics of Cr(III) ions transport through a bulk liquid membrane containing dinonylnaphthalenesulfonic acid (DNNSA) as a carrier, flowing over aqueous phases, has been examined. Special attention has been paid to the effect of the membrane’s velocity flow on the chromium concentration decrease in a feed phase. For the description of relationships of chromium(III) concentration in particular phases with the time, a model based on the assumption of consecutive first-order reactions was proposed. Satisfactory compatibility of experiments and model results have been obtained both for the membrane flow velocities below 0.0034 m·s−1 when the interfaces begin to fluctuate slightly and for low initial Cr(III) concentration in the feed phase

Vapour-liquid equilibria in binary systems formed by methylocyclopentane with alcohols

583-592<span style="font-size:10.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-US">The modified Świętosławski ebulliometer was used for the accurate (uncertainty of measurements: 0.01 K, in the case of the temperature and 30 Pa, in the case of the pressure) determination of vapour-liquid equilibria in binary isothermal systems formed by methylcyclopentane with the following: 2-butanol, 2-pentanol K and 2-methyl-2-butanol from 313.25 K to 343 K. The vapour pressures of the pure substances are also given. The experimental data have been correlated by means of the Redlich-Kister, NRTL and Wilson equations.</span

Production and formation modelling of CaCO3 in multiphase reactions – A review

The paper presents different approaches to the proper and accurate production and modelling (multi- phase reaction) of CaCO3 formation in the most popular, different types of reactors, i.e. continuous reactor (STR – stirred tank reactors, MSMPR – mixed suspension, mixed product removal; tube reactor), a bubble column reactor and a thin film reactor. Many different methods of calcium carbonate production and their effect on the various characteristics of the product have been presented and discussed. One of the most important, from the point of view of practical applications, is the morphology and size of the produced particles as well as their agglomerates and size distribution. The size of the obtained CaCO3 particles and their agglomerates can vary from nanometers to micrometers. It depends on many factors but the most important are the conditions calcium carbonate precipitation and then stored. The experimental research was strongly aided by theoretical considerations on the correct description of the process of calcium carbonate precipitation. More than once, the correct modelling of a specific process contributed to the explanation of the phenomena observed during the experiment (i.e. formation of polyforms, intermediate products, etc.). Moreover, different methods and approaches to the accurate description of crystallization processes as well as main CFD problems has been widely reviewed. It can be used as a basic material to formulation and implementation of new, accurate models describing not only multiphase crystallization processes but also any processes taking place in different chemical reactors

Maximization of generated electric power in the TEG module at various heat exchange conditions

Thermoelectric generators using the Seebeck effect to generate electricity are increasingly used in various areas of human activity, especially in cases where a cheap high-temperature heat source is available. Despite many advantages, TEG generators have one major disadvantage: very low efficiency of heat conversion into electrical power which strongly depends on the applied load resistance. There is a maximum of generated power between the short and the open circuit in which it is zero. That is why optimization of TEG modules is particularly important. In this paper a method of maximization of generated power in a single TEG module is presented for two cases. The first case concerns a problem with fixed heat flux flow into the hot side of the module whereas the second one concerns a problem with fixed heat transfer parameters in hot heat exchanger i.e. supply gas temperature and heat transfer coefficient. A number of optimization results performed for various values of these parameters are presented and discussed

Calculation of the activity coefficients at infinite dilution in binary aqueous systems of pyridine and its derivatives

2281-2285The activity coefficients at infinite dilution of binary mixtures formed by water and pyridine and its derivatives (2-methylpyridine, 3-ethylpyridine, 2,4,6-trimethylpyridine) have been calculated using the NRTLmKW model. The calculation have been performed for experimental isothermal data measured at T=353.15K in a very narrow range of concentration using the ebulliometric method. The calculated activity coefficients have been compared with the activity coefficients at infinite dilution obtained directly from the measured vapour pressures. The obtained results have been fully discussed from the point of view of intermolecular interactions in the solutions and some recommendations have been made on the use of the NRTLmKW model for such calculation