a. moghadassi

A molecular dynamic simulation study of n-heptane hydro conversion over bifunctional Pt/MSU catalyst have been accomplished. Investigating morphology and topology of catalyst structure, the performance of catalyst through diffusing feed as particles, passing through pores and connecting channels have been analyzed. Furthermore, product selectivity and other specific structural properties in the range of 573-723K and atmospheric pressure have been assessed from diffusion and kinetic point of view. The result of diffusion illustrates that the MSD of n-alkanes has incremental trend with temperature. Maximum MSD for monobranched (MB) and multibranched (MTB) isomers are 45000 and 25000A2 respectively. Diffusion coefficient for MB, MTB and methane are 91.8, 54.3 and 457m2/s. From kinetic simulation, the feed conversion, pairwise lateral interaction according to DFT calculation and Morse potential function are achieved and the source of cracked and isomer products have been specified.

This research presents the application of phytoremediation to remove ammonia from effluent possessing high ammonium content and alkalinity in one of the most complex refineries in Iran. The objective of this research was to find new methods to protect and preserve water resources. At first, the algae distribution was investigated. After purifying the samples, Chlorella Vulgaris was selected as resistant algae in the areas that experienced ammonia shocks. A 10-liter container and an airlift photobioreactor with similar laboratory conditions were developed to control biomass production. Experiments were conducted over 20 days and maximum biomass production occurred in the first 16-17 days. Cell density was expressed as dry cell weight in ammonia concentration from 10 mg/L to 500 mg/L. It was also observed that when the Nitrogen content of the culture medium was less than 50 mg/L, ammonia was completely removed in both methods. At a concentration of 10 mg/L, total ammonia in both methods was removed in the first week. At 50 mg/L to 100 mg/L concentrations, about 94% of ammonia was removed in the glass container and about 95% in the bioreactor. In these concentrations, with high ammonia content, the final cell density, and absorption power were significantly low and this was evident at 500 mg/L. Prevention of water evaporation and biomass settling, better control of some vital parameters including pH, temperature, light, and energy intensity, effective mass and heat transfer, and carbon dioxide concentration led to better efficiency of the airlift photobioreactor. A noteworthy point in this result was the extraordinary performance of Chlorella Vulgaris in removing toxic pollutants such as ammonia and possibly using it in the biological systems of sanitary, refineries, and petrochemicals.