The differential form of the decay law for a solid acid catalyst in liquid-phase alkylation of isobutene with butanes was investigated. A pseudo-first order expression for the intrinsic rate of the main reaction and a pseudo-second order one for the poisoning reaction were assumed. The role of intraparticle diffusion on the apparent deactivation behavior was studied through the Shell Progressive Model (SPM). as the overall reaction is severely diffusion limited. The decay rate law was found to be fourth order in pellet activity and second order in external butane concentration. The effect of pore-mouth plugging was also studied. It was shown that this phenomenon causes an increased deviation from the SPM predictions and lowers the average order of deactivation. An empirical order of deactivation of 2.3 was obtained for zeolites. This value being considerably lower than four, implies appreciable pore-mouth plugging effects in the case of zeolite catalyzed alkylation.

The present study proposes modified solar-driven combined power and ejector refrigeration cycles (CPERCs) for low-temperature heat sources. The proposed cycles are constructed from a combination of simple organic Rankine cycle (ORC), ORC with an internal heat exchanger (IHE), a regenerative ORC, and a regenerative ORC with an IHE, with an ejector refrigeration cycle (ERC). The ejector is driven by the exhausts from the turbine to produce more power and refrigeration, simultaneously. The three modified ORCs are introduced to improve the performance of the energy systems. The first and second laws of thermodynamics have been applied to each cycle using R245fa and isobutene as working fluids. Also, solar energy is utilized as the main heat source of the energy system. Concerning each proposed cycle, the thermodynamic model has been validated by previous works. Using isobutene as a working fluid, the maximum thermal and exergetic efficiencies have been obtained at 50.46 and 58.08 %, respectively, which corresponded to regenerative combined power and ejector refrigeration cycle with an IHE. In general, the thermal efficiency of a system is improved by 7.54 and 5.76 % through this state-of-art modification using R245fa and isobutene as working fluids, respectively. This demonstrated that isobutene can be a good candidate for CPERCs based on the first and second laws of thermodynamics. Throughout these modifications, cooling capacity and net produced power of cycles are also increased, successively. In all proposed cycles, the generator has the highest exergy destruction ratio, falling into the range of (29.82-34.73) and (22.9-25.93) kW for R245fa and isobutene, respectively.

In this research different types of Al2O3 were used as supports to prepare catalysts for dehydrogenation of isobutane to isobutene. These supports were Al2O3 from Merck, Axen and gamma Al2O3 synthesized from Al (OH)3. Sn/Pt/Al2O3 catalysts were prepared by sequential impregnation, at first Pt and then Sn was deposited. Characterization of catalysts was performed by X-ray powder diffraction (XRD) and thermal analysis (TG/DTG) techniques. Elemental analysis of the catalysts was also carried out by wet chemical analysis using inductively coupled plasma (ICP) technique. Isobutane dehydrogenation was studied in a reactor under atmospheric pressure at 848 K. The conversion, selectivity and yield of the prepared catalysts were calculated.

In this research Na-Y was synthesized by hydrothermal method and used as support for preparation of Sn/Pt/Na-Y catalysts using two different tin precursors, Bu3Sn (Cl) and SnCl2.2H2O, by sequential impregnation, in which the Pt  was deposited first and in the next step Sn was deposited. The catalysts were characterized by H2 chemisorption, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray powder diffraction (XRD) and, thermogravimetrical analysis (TG) techniques. Elemental analysis of the catalysts was also carried out by X-ray fluorescence analysis (XRF). Dehydrogenation of isobutane was studied in a reactor under atmospheric pressure at 848 K. The conversion, selectivity and the yield of product and the efficiency of prepared catalysts were calculated. The aim of this work was to investigate effect of different Sn precursor and Pt dispersion on the performance of the prepared catalysts.