Comparison of performance of Ni-Mo/γ-alumina catalyst in HDS and HDN reactions of main distillate fractions

A bimetallic nickel-molybdenum catalyst supported on γ-alumina was synthesized by the two-step incipient wetness impregnation technique.The activity of the prepared Ni-Mo/γ-alumina catalyst was evaluated in a down flow fixed-bed microreactor.In this way,hydrodesulfurization(HDS)and hydrodenitrogenation(HDN)reactions of the main distillate fractions of crude oil were assessed.XRD,SEM,TPR,ICP-OES,BET-BJH and nitrogen adsorption/desorption methods were used for characterizing the synthesized Ni-Mo/γ-alumina catalyst.The active metals with Ni/Mo mass ratio of 0.23 and total metal of 13.7 wt% were loaded on the support,similar to the commercial industrial catalyst.The performance tests were conducted at 3.0 MPa(for light naphtha and heavy naphtha)and at 4.5 MPa(for kerosene and gas oil).The results revealed that the total sulfur conversion of the light naphtha,heavy naphtha,kerosene and gas oil fractions was 98.3%,95%,91.7% and 90.1%(after 24 h),respectively.

Effect of graphene functionalizing on the performance of NiMo/graphene in HDS and HDN reactions

In this research,to remove sulfur and nitrogen compounds from heavy naphtha,various nanocatalysts were prepared through supporting NiMo over nanoporous graphene and evaluated in hydrodesulfurization and hydrodenitrogenation reactions.The nanoporous graphene was initially functionalized in order to facilitate the metal being loaded on it.Three different methods were used to functionalize the nanoporous graphene.The NiMo/nanoporous graphene nanocatalysts were characterized by field emission scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray diffraction,inductively coupled plasma optical emission spectrometry,temperature-programmed reduction,nitrogen adsorption-desorption isotherms and transmission electron microscopy techniques.Catalyst performance was evaluated in terms of conversions of sulfur,mercaptans(R-SH)and nitrogen compounds.It was found that the functionalized nanoporous graphene support could significantly enhance the catalytic performance in comparison with the industrial NiMo/alumina catalyst.Among the functionalized graphene supports,amine-functionalized graphene exhibited the best results.By using NiMo supported over amine-functionalized graphene,the conversions of total sulfur and R-SH reached 97.8%and 98.1%,respectively.

Process design for gas condensate desulfurization and synthesis of nano-13X zeolite adsorbent: equilibrium and dynamic studies

This paper summarizes the results of a study of adsorption of sulfur compounds from a high-sulfur feed on improved spherical-shaped nano-AgX zeolite. For this purpose, the nano-AgX zeolite was initially synthesized and improved with silver compounds such as silver nitrate, and then it was utilized in the adsorption process. In order to investigate the equilibrium and dynamics of the adsorption process, adsorptive desulfurization of real feed(i.e., sour gas condensate from the South Pars gas field) was carried out in batch and continuous processes under several operating conditions; a temperature-dependent Langmuir isotherm model was used to fit the equilibrium data. The value of monolayer adsorption capacity(q_m) and adsorption enthalpy(ΔH) were calculated to be 1.044 mmol/g and 16.8 kJ/mol, respectively. Furthermore, a detailed theoretical model was employed in order to model the breakthrough experiments. The results revealed that an increase in the feed flow rate and 1/T values will cause linear and exponential increase in the total mass transfer coefficient(ks). Isotherm and dynamic breakthrough models were found to be in agreement with the experimental data.