A Dynamic Model for Glucose Fermentation in a Three-Phase Bioreactor

AbstractIn this study the performance of an special three-phase bioreactor for biological production of ethanol and hydrogen was modeled using computational fluid dynamics. The effect of different Hydraulic Retention Time (HRT) of 1, 2 and 4 hr and Glucose mass fraction in feed of 0.002, 0.004, 0.006, and 0.008 on Hydrogen and ethanol production rate was determined. The maximum value of H2 production rate at the HRT of equal to 2h and Glucose mass fraction of 0.008 is 0.033 kg/h. It was demonstrated that the model is capable of predicting the variation of the EGSB reactor performance for biohydrogen and bioethanol production at various substrate concentrations and HRT values

Experimental investigation on viscosity and density of MWCNT- Transformer oil nanofluid : Developed a new correlation

In the present study, the dynamic viscosity and density of multi-wall carbon nanotube (MWCNT) nanoparticles and transformer oil at 0.05 to 0.8 wt% and room temperature are investigated. The carbon nanotubes were functionalized by carboxyl groups (-COOH) and also sodium dodecyl sulfate (SDS) surfactant was used to stabilize the nanoparticles in the base fluid. The inner diameter and length of the nanoparticles are between 10-20 nm and 3-8 µm respectively and purity is 98%. A correlation for the dynamic viscosity and density relative to the weight fraction of nanoparticles at ambient temperature is proposed, which indicates that viscosity and density increase with increasing the weight fraction, and the highest enhancement of dynamic viscosity and density are 21% and 2%, respectively. Dynamic viscosity at various shear stress and speeds also are investigated and the results show that with increasing shear stress, the viscosity increases about an average of 40.9%. The results were compared with other existing models to evaluate the accuracy of the results and, a review of other research on the nanofluid viscosity and density is done and their results are mentioned

An Investigation of a Petrochemical Wastewater Treatment Utilizing GAC: A Study of Adsorption Kinetics

AbstractThe goal of the present research was to reduce the COD of the typical petrochemical wastewater via adsorption technique using a commercial granular activated carbon (GAC) as adsorbent. The parameters of kinetic models as well as; adsorption isotherms were determined through utilizing the Langmuir and Freundlich isotherms. The key parameters of kL = 0.0009 L/mg and qm = 33.33mg/g for the former and nf =0.5 L/mg and kf = 4e-6mg/g for the latter isotherms were resulted. Moreover, pseudo-first and -second order kinetics equations were implemented. These resulted in coefficients of k1=0.006min-1 and qe=2025mg/g as well as; k2=0.011mg/mg.min and qe=286mg/g; respectively for 5cm bed length. In addition, obtaining the correlation coefficients of 0.94 and 0.61 for these 1st and 2nd order kinetics; respectively indicated advantageous use of the former kinetic model. Ultimately; the current investigation paved down the road for predicting the system's behaviour on industrial scale