Model discrimination for multicomponent distillation

While rate-based models are available in commercial flowsheet simulation tools, packed distillation columns are still mostly designed based on the equilibrium stage model in combination with HETP values. In order to discriminate between both types of models in a simple way, this article proposes an algorithmic test, based on a geometric criterion for total reflux operation. Substantial differences are illustrated especially for wide-boiling mixtures, while component-specific mass transfer rates either increase or reduce the deviation. The derived results are validated by dedicated experiments

Lokalne drogi betonowe - trwałość na lata na przykładzie budowy drogi w Ratyczowie w 2000 roku

W artykule omówiono wyniki badań z realizacji lokalnej drogi w miejscowości Ratyczów oraz przedstawiono wnioski dotyczące funkcjonalności i trwałości zastosowanych rozwiązań po ponad 20 latach intensywnego użytkowania. Podczas inwestycji sprawdzono receptury na bazie różnych cementów, w tym także cementów o niższej zawartości klinkieru, a zatem i niższej emisyjności. Jak pokazały wyniki badań wykonywanych w trakcie realizacji osiągnięto wszystkie zakładane i projektowane właściwości betonu przeznaczonego do eksploatacji w tego typu elemencie. Swoistym certyfikatem użyteczności zastosowanych rozwiązań jest obecny stan drogi. Ocena wizualna i inwentaryzacja całości konstrukcji w ramach wykonanego przeglądu jednoznacznie wskazują, że wykorzystanie dobrze skomponowanego betonu jest gwarancją długowieczności. Oczywiście przy zachowaniu odpowiedniego reżimu technologicznego wykonania oraz odpowiednio wysokiego poziomu kontroli jakości.The article discusses the results of tests on the local road in Ratyczów and presents conclusions regarding the functionality and durability of the solutions applied after over 20 years of intensive use. During the investment, recipes based on various cements, including cements with a lower clinker content, and thus lower emissivity were checked. As shown by the results of tests carried out during, all the assumed and designed properties of concrete intended for use in this type of element have been achieved. The current condition of the road is a specific certificate of the usefulness of the solutions used. The visual assessment and inventory of the entire structure as part of the inspection carried out clearly indicate that the use of well-composed concrete is a guarantee of longevity. Of course, while maintaining the appropriate technological production regime and a sufficiently high level of quality control

Modification of Chitin Particles with Ionic Liquids Containing Ethyl Substituent in a Cation

Chitin cannot be dissolved in conventional solvents due to the strong inter- and intrasheet network of hydrogen bonds and the large number of crystalline regions. Some ionic liquids (ILs) have been suggested in the literature as possible solvents for chitin. Seven of them, all having an ethyl group as substituent in the cationic ring, have been tested in this work: [Emim][Cl], [Emim][Br], [Emim][I], [Emim][OAc], [Emim][Lact], [Epyr][I], and [EMS][BFSI]. Chitin was insoluble in [EMS][BFSI] while for all other ILs solubility was limited due to high viscosity of solutions and equilibria have not been reached. Changes in physical structure, particle size distribution, and crystallinity of recovered chitin depended on ionic liquid used. Increase in porosity was observed for chitin treated with [Emim][Cl], [Emim][I], [Emim][Br], and [Emim][Lact]; changes in particle size distribution were observed for [Emim][AcOH] and [EMS][BFSI]; increase in crystallinity was noticed for chitin treated with [Epyr][I] while decrease in crystallinity for [Emim][I] was noticed. All tested ionic liquids were reused four times and changes in FTIR spectra could be observed for each IL