Iranian Journal of Chemical Engineering (IJChE)

Abstract The removal of Acrylonitrile (AN) from waste gas streams using biological methods, due to their better performance, has recently gained more attraction. The purpose of this research is modeling the AN removal by a bio-filter. The validation of the model is done by using the experimental data of a bench-scale bio-filter bed column including yard waste compost and shredded hard plastics and thickened municipal activated sludge. In this work the kinetics of the biodegradation of Acrylonitrile is first investigated. Then equations of the biofilm and air are obtained at a steady state and constant temperature. The unknown parameters of the model are determined by the least square optimization method along with solving the model equations using MATLAB. For inlet concentrations less than 1 g/m³ the model results show reasonable similarities to the experimental data. The effect of various parameters on the bio-filter performance is evaluated. The Peclet number, biofilm thickness and biomass concentration are the most important parameters. The proposed model can be useful for design purposes.

Abstract In this study a developed model has been used to evaluate the paper drying process and examine the pocket dryer conditions of a multi-cylinder fluting paper machine. The model has been developed based on the mass and energy balance relationships in which the heat of sorption and its variations with paper temperature and humidity changes have been taken into account. The applied model can be used to compute the drying parameters and analyze the pocket drying conditions. Furthermore, the effects of web tension on the heat transfer have been investigated. In the available operating range of the web tension, the overall mean heat transfer coefficient will be within 300-550 W/m2.K. The pocket air temperature was between 50 and 90 oC. The dew point temperature wasn’t close to the pocket air temperature and dew drop never happened during the dryer section. Based on the modeling result and using a novel technique, the maximum level for the exhaust air in the studied machine can be estimated to be 0.2 kg H2O/kg dry air. Result shows that increasing the exhaust humidity to the optimal level will lead to 4% reduction in the required energy and 20% rise in the heat recovery potential. Accordingly the specific heat consumption per evaporated water for the studied drying section can be reduced from 3.96 to 3.81 GJ per ton water.

Abstract The separation of immiscible liquids plays an important role in the oil and petrochemical industries. In the outlet stream of a catalytic reactor of dehydrogenation of ethyl benzene to styrene monomer, water is present because it is used as high pressure steam to provide reaction heat. Therefore, aqueous and immiscible organic phases should be separated in a horizontal separator before fractionation. The objective of this work is to study the separation of ethyl benzene, styrene, and water in a horizontal pilot scale separator. Experiments showed that the performance of the separator is affected by feed flow rate and composition. Furthermore, the thickness of mesh installed in the inlet zone of the separator has an effect on the hydrodynamic behavior of the separator and its performance.

Abstract The separation of immiscible liquids is an important process in oil and petrochemical industries. In the outlet stream of a catalytic reactor of dehydrogenation of ethyl benzene to styrene monomer, water is present because it is used as a high pressure steam to provide reaction heat. Therefore, aqueous and immiscible organic phases should be separated in a horizontal separator before fractionation. The aim of this work is to study the batch separation of ethyl benzene and styrene from water. Different mixtures of water, styrene and ethyl benzene were prepared using different amounts of organic compounds and various mixing rates. The experiments show that the separation time of ethyl benzene and water mixtures are more than that for styrene and water mixtures. Furthermore, increasing the mixing rate increases the separation time because the dispersity of the system increases, but it has more effects on water/ethyl benzene mixtures.