Iranian Journal of Chemical Engineering (IJChE)

Abstract The removal of hydrogen sulfide (H₂S) from airstreams was studied in a biotrickling filter packed with porous lava as a carrier of Thiobacillus thioparus (DSM5368) with counter current flows of the air and liquid streams. The effect of operating parameters on biotrickling filter performance was studied. Experiments were performed at different empty bed residence times (9-60 sec), and moderate H₂S concentrations (10-90 ppm) to assess the performance of biotrickling filter at different conditions of these parameters. The effect of superficial liquid velocity (0.98-1.95mh^-1) on the performance of biotrickling filter was evaluated. Increasing superficial liquid velocity decreased removal efficiency of the BTF. The gradual change in the concentration of H₂S in different heights of the BTF was investigated. Decreasing empty bed residence time lead to a slight increase in the homogeneity of the removal at different heights of the BTF; however the effect of change in the inlet concentration was insignificant. Complete removal was achieved in the first 85% of the bed. To gain a brief insight into the robustness of the biotrickling filter, its performance was investigated after several upsets in the system.
 
 

Abstract Lennard-Jones-Devonshire equation of state is an old but theoretical based EOS. The concept of the nearest neighboring molecules or coordination number is proposed to be a function of temperature and volume, whereas it is a constant in the original. The dilute gas and hard sphere limits of molecules are employed to determine this function. Improvement of this modification is demonstrated by property calculations for Lennard-Jones fluid. Results of the modified LJD equation of state offer senior accord with simulation data of Lennard-Jones fluid than those of the original version.    

Abstract Ternary phase diagrams for [polyethylene (Mw-420,000, Mw/Mn=2.6) / n-butane/ carbon dioxide], [polypropylene (Mw=290,000, Mw/Mn=1.32)/ n-pentane/carbon dioxide] and [polystyrene (Mw=187,000)/ cyclohexane/ carbon dioxide] have been generated using the Sanchez-Lacombe (SL) lattice-fluid model. The results show that at relatively low pressure, the ternary phase diagram has a L-L-V three-phase region bounded by two two-phase regions (L-V and L-L). At high pressure, L-L-V and L-V regions disappear and only the L-L region remains. With an increase of pressure this two-phase L-L region becomes smaller. This model can also predict transition LCST to UCST by increasing pressure. For polystyrene/ cyclohexane/ carbon dioxide mixture, the calculated results obtained using the SL-model are compared with the reported calculated results created by the perturbed hard-sphere chain model (PHSC) and the reported experimental data which indicate good agreement with both the calculated results by PHSC-model and experimental data.