Maximization of propylene in an industrial FCC unit

YesThe FCC riser cracks gas oil into useful fuels such as gasoline, diesel and some lighter products such as ethylene and propylene, which are major building blocks for the polyethylene and polypropylene production. The production objective of the riser is usually the maximization of gasoline and diesel, but it can also be to maximize propylene. The optimization and parameter estimation of a six-lumped catalytic cracking reaction of gas oil in FCC is carried out to maximize the yield of propylene using an optimisation framework developed in gPROMS software 5.0 by optimizing mass flow rates and temperatures of catalyst and gas oil. The optimal values of 290.8 kg/s mass flow rate of catalyst and 53.4 kg/s mass flow rate of gas oil were obtained as propylene yield is maximized to give 8.95 wt%. When compared with the base case simulation value of 4.59 wt% propylene yield, the maximized propylene yield is increased by 95%

TiO<SUB>2</SUB>-ZrO<SUB>2</SUB> mixed oxide as a support for hydrotreating catalyst

Pure TiO2, ZrO2 and TiO2-ZrO2 mixed oxides are prepared by urea hydrolysis. Hydrotreating catalysts containing 12 wt% molybdenum are prepared using these oxides and characterized by BET surface area, pore volume, XRD and oxygen chemisorption. It is observed that oxides produced by the method of urea hydrolysis have higher surface area as compared to those available commercially. With increasing zirconia content in the mixed oxide, the surface area increases and a maximum value is obtained for a mixed oxide having Ti and Zr molar ratio of 65/35. XRD results indicate that mixed oxides are poorly crystalline in nature. Thiophene hydrodesulfurization, cyclohexene hydrogenation and tetrahydrofuran hydrodeoxygenation are taken as model reactions for evaluating catalytic activities. It is found that both O2 uptake and catalytic activities increase with increasing zirconia content in mixed oxide and reach maximum values for the 12 wt% Mo/TiO2-ZrO2 (65/35) catalyst. With further increases in zirconia content, O2 uptake and catalytic activities decrease and the lowest values are observed for the pure ZrO2 supported catalyst

Studies on physico-chemical characterization and catalysis on high surface area titania supported molybdenum hydrotreating catalysts

A series of titania supported molybdenum catalysts were prepared by incipient wetness impregnation method and characterized by BET surface area, XRD, TPR, FTIR, ESCA, and low temperature oxygen chemisorption. Thiophene, cyclohexene and tetrahydrofuran were taken as model compounds for evaluating catalytic activities for hydrodesulfurization (HDS), hydrogenation (HYD), and hydrodeoxygenation (HDO) reactions, respectively. XRD results indicate that molybdenum oxide species are dispersed as a monolayer on the support up to 8 wt.% Mo and the formation of crystalline MoO<SUB>3</SUB> is observed above this loading. FTIR and TPR results showed that molybdenum oxide species were present predominantly in tetrahedral form at lower loading and polymeric octahedral forms are dominant at higher loading. Both oxygen chemisorption and rates of reaction were found to increase with increasing Mo loading up to 8 wt.% and then decrease with further increase in loading. HDS and HYD activities are more or less same but HDO activity is two times higher than HDS and HYD activities. The results are also interpreted with the help of other parameters, like dispersion, equivalent molybdenum surface area, surface coverage, crystalline size, quasi-turnover frequencies and intrinsic activities. ESCA results suggest that electron transfer is taking place from support to metal