Marek Tanczyk

Multicomponent pressure swing adsorption Part I. Modelling of large-scale PSA installations

Abstract A general model of multicomponent pressure swing adsorption (PSA) is presented which describes the operation of multi-column PSA installations. The individual columns can be packed with one or two layers of different adsorbents. All the basic steps of modern PSA cycles are taken into account. The operation of a large-scale PSA installation is analysed using a hydrogen purification plant as a test case

Multicomponent pressure swing adsorption. Part II. Experimental verification of the model

Abstract The mathematical model of nonisothermal multicomponent pressure swing adsorption, developed in Part I of this study (K. Warmuzinski, M. Tanczyk, Chem. Eng. Proc., 36 (1997) 89–99) is validated based on experimental data concerning the separation of CH 4 and H 2 on activated carbon and the production of hydrogen on zeolite 5A. For a wide range of the various operating parameters, the measured values of the purity and recovery of the products, together with the concentration and temperature profiles during a PSA cycle are compared with those predicted by the model. In all cases a satisfactory agreement is found between theory and experiment.

Facile and Scalable Synthesis of Nanoporous Materials Based on Poly(ionic liquid)s

A simple, fast, sustainable, and scalable strategy to prepare nanoporous materials based on poly(ionic liquid)s (PILs) is presented. The synthetic strategy relies on the radical polymerization of crosslinker-type ionic liquid (IL) monomers in the presence of an analogous IL, which acts as a porogenic solvent. This IL can be extracted easily after polymerization and recycled for further use. The great advantages of this synthetic approach are the atom-efficiency and lack of waste. The effects of different monomer/porogen ratios on the specific surface area, porosity, and pore size have been investigated. Finally, the potential of the materials as CO2 sorbents has been evaluated.

Cost analysis for the removal of volatile organic compounds from air using hybrid systems: membrane separation/condensation versus membrane separation/combustion

Air contaminated with volatile organic compounds (VOCs) is associated with a number of industrial processes. The purification of these air streams based on conventional techniques, such as combustion, condensation or adsorption is usually uneconomical. Environmental considerations require, however, that this problem should be dealt with as efficiently as possible. Therefore, the use of hybrid systems is analysed that include membrane separation and condensation or, alternatively, membrane separation followed by combustion.

Oscillatory Marangoni instability during absorption accompanied by chemical reaction

Abstract A model of cellular convection during absorption accompanied by chemical reaction has been extended to include non-zero time constants. Based on the model a numerical analysis has been carried out to test the validity of the principle of exchange of stabilities in the system considered. It has been found that, unlike in cases of pure mass transfer, oscillatory modes may appear in systems where absorption is coupled with chemical reaction.

Marangoni instability during the absorption of carbon dioxide into aqueous solutions of monoethanolamine

Abstract The paper presents a model of surface phenomena accompanying the absorption of carbon dioxide into aqueous solutions of monoethanolamine. The model is based on the assumption that the cellular convection is driven by surface tension gradients, induced in turn by infinitesimally small perturbations of concentration. The model derived makes it possible to study in detail certain characteristics of the process of chemical absorption. Thus, the probability of oscillatory modes occurring in the system is analysed, the dimensions of the convective cells are evaluated and the gas—liquid contact time necessary for the instability to appear is determined. The quantitative conclusions are compared with the relevant experimental data concerning the absorption of CO 2 into monoethanolamine in both wetted-wall and packed columns.

Poly(vinylbenzyl chloride)-based poly(ionic liquids) as membranes for CO2 capture from flue gas

Over the last decade, membrane-based CO2 capture using ionic liquids (ILs) has been demonstrated as a promising technology. However, elaborative synthesis of monomers and long-term instability of IL-based composite membranes have so far limited their industrial relevance. In this paper, novel membranes are introduced for CO2 separation using poly(ionic liquids) (PILs) based on polyvinylbenzyl chloride (PVBC). Three PIL-based membranes were prepared as thin-film composites (TFC) by solvent casting with subsequent sealing. They were tested for the CO2 removal from synthetic flue gas. An ammonium-derivatised PVBC-analogue was prepared as a first PIL-type by polymerisation of an IL monomer, whereas two other PILs, respectively with hydroxyethyl ammonium and pyrrolidinium cations, were obtained using a modification of commercial PVBC. Introduction of bis(trifluoromethylsulfonyl)imide (Tf2N) anions was accomplished by metathesis. A thorough characterisation of the material structure, composition, membrane morphology and gas separation properties demonstrates that the presence of hydroxyl groups in the polycation enhanced the interaction with CO2 molecules. The mixed-gas selectivity increases with the higher positive charge on the cation species (hydroxyethyl-dimethylammonium > trimethylammonium > pyrrolidinium). More importantly, experiments performed in humidified conditions particularly revealed a doubled CO2 permeance and a 20–30% increased selectivity in comparison to dry conditions. These developments are spurring the application of PIL-based TFC membranes for CO2 capture from flue gas streams.

On doubly diffusive Marangoni convection

The paper deals with the cellular convection resulting from the parallel mass transfer of two components. It is shown that the case analysed cannot be regarded as fully equivalent to that of the simultaneous mass and heat transport due to the effect of the phenomena occurring in the Gibbs dividing layer.

Analysis of the techniques for the utilisation of coal bed methane from Polish coal mines

Publisher Summary This chapter illustrates that a number of research organizations have focused their programs upon the abatement of greenhouse gases (GHG), including methane. Methane emissions, apart from the adverse environmental impact, lead to considerable losses of the valuable fuel. The utilization of methane becomes even more important in view of the ever-decreasing reserves of primary energy sources. The chapter deals with two techniques for the utilization of coal-related methane emissions in Poland. An analysis is carried out of the enrichment of coal bed methane via adsorptive separation to produce gas that can be used commercially in natural gas networks. It is found that a two-stage pressure swing adsorption system can yield the gas containing more than 90% of methane. Also, economic feasibility is studied for an alternative utilization option, namely, the combustion of ventilation air methane in existing boilers. Conditions are derived that determine the upper limit of the distance at which the transportation of ventilation air remains an economically viable solution.