To tune the product selectivity by controlling the complicated reaction path is a big challenge in Fischer–Tropsch synthesis Here, we report an integrated catalytic process for the direct conversion of syngas (CO/H2) into different types of liquid fuels without subsequent hydrorefining post-treatments of Fischer–Tropsch waxes Outstanding selectivities for gasoline, jet fuel and diesel fuel as high as 74, 72 and 58% are achieved, respectively, by only using mesoporous Y-type zeolites in combination with cobalt nanoparticles The types of liquid fuels can be readily tuned by controlling the porosity and acid properties of the zeolites We further build a new product-distribution model for the bifunctional catalysts, which do not obey the traditional Anderson–Schulz–Flory (ASF) distribution The present work offers a simple and effective method for the direct synthesis of different types of liquid fuels

Integrated tuneable synthesis of liquid fuels via Fischer–Tropsch technology

Zeolites for adsorptive desulfurization from fuels: A review

Removal of sulfur from transportation fuels using zeolites as sorbents is an attractive desulfurization method, because of its low energy and cost requirements. However, diffusion limitations within the micropore structure of zeolites can reduce their adsorption capacity, especially when refractory sulfur compounds are present in fuels. Moreover, the selective adsorption of sulfur compounds from a mixture of hydrocarbons can be very challenging. The objective of this study was to address the aforementioned challenges of adsorptive desulfurization of fuels using metal-exchanged mesoporous Y zeolites. Mesoporosity was introduced in the Y zeolites by two top-down methods (desilication and surfactant-assisted). Metals, Ce and Cu, were introduced via ion-exchange. The prepared metal-exchanged mesoporous zeolites were characterized and tested in terms of their sulfur adsorption capacity using a fixed-bed column and model fuels. The strength of adsorption was determined using isosteric heat of adsorption calculations. Our results demonstrated that mesoporous Y reduced diffusion limitations and were very effective sorbents for removing sulfur compounds with high kinetic diameter, such as dibenzothiophene (DBT). Metals highly increased the selectivity toward sulfur compounds. According to experimental results, the tendency of thiophenic molecules to adsorb on the zeolites increase in the order of thiophene (TP)

Investigation of metal-exchanged mesoporous Y zeolites for the adsorptive desulfurization of liquid fuels

Nanoporous adsorbents are highly efficient in selectively capturing aromatic sulfur compounds such as thiophene, benzothiophene, dibenzothiophene, and 4,6-dimethyldibenzothiophene that are refractory to remove by traditional techniques from liquid hydrocarbon fuels. In the past decades, great progress has been made in design and fabrication of nanoporous adsorbents as well as the judicious strategies of promoting their performance for deep desulfurization. However to the best of our knowledge, a comprehensive review from this perspective has never been reported until now. Therefore, a review summarizing these nanoporous adsorbents and advanced strategies is highly anticipated. In this review, we provide an overview of the synthesis methods, improvement strategies, and prospective of the nanoporous adsorbents for applications with adsorptive desulfurization. The concerned materials cover most of the traditional and recently emerged nanoporous materials, and are introduced and basically grouped by material type. Each category is illustrated with some typical examples, and the fundamental principles on how to design and fabricate nanoporous adsorbents are highlighted. The adsorption mechanism is discussed in detail as well.

Design and fabrication of nanoporous adsorbents for the removal of aromatic sulfur compounds

We present an overview of the modern approaches to continuum nonequilibrium thermodynamics from the perspective of their connection with the problem of heatconductionwithfinitespeed.ThecelebratedCattaneoandGuyer–Krumhansl equations for the evolution of the heat flux are reinspected in the framework of the different thermodynamic theories which, in such a way, are reviewed and compared. 1. Preface

https://www.mb.uni-siegen.de/tts/personen/juk/jne_34-04(2009)umschlag.pdf

Different Thermodynamic Theories and Different Heat Conduction Laws

Adsorption, coadsorption, and reactions of sulfur compounds, olefins, and aromatics over Ce-exchanged Y zeolite (CeY) have been studied by N2 adsorption, intelligent gravimetric analyzers (IGA), X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FT-IR), frequency response (FR) techniques, and batch and fixed bed methods. The coadsorption of olefins can effectively contribute to the alkylation and oligomerization reactions of thiophene and further decrease the desulfurization performance of CeY. The influence of aromatics on the desulfurization performance of CeY can be related to the competitive adsorption/diffusion processes between sulfur compounds and aromatics. The diffusion process is the rate-controlling step for benzene, and the sorption process is the rate-controlling step for thiophene. Thiophene molecules can be preferentially ads...

Adsorption, Co-adsorption, and Reactions of Sulfur Compounds, Aromatics, Olefins over Ce-Exchanged Y Zeolite

Potassium titanates with a high crystallinity were successfully prepared by the sol-gel method and characterized by XRD, SEM, and BET surface area measurements. K6Ti4O11, K2Ti2O5, K2Ti4O9 were found to have better soot oxidation performance compared with Pt/TiO2 and CeO2 based catalysts. K2Ti2O5 may be an excellent candidate for soot oxidation due to its high oxidation activity, water-stability, resistance to sulfur poisoning and economical advantages. Certain amount of NOx can contribute to the catalytic combustion of diesel over potassium titanates, implying that K2TiO5 may be a kind of catalyst for simultaneous removal of NOx and soot.

Catalytic combustion of diesel soot over perovskite-type catalyst: Potassium titanates

Abstract Gravimetric equilibrium isotherms, thermodynamic parameters, and diffusion of p-xylene in silicalite-1 were investigated at several temperatures using an intelligent gravimetric analyzer (IGA). Both plateau and hysteresis loops appeared in the isotherms obtained at 323 and 343 K, respectively. Heat of sorption (Qst ), free energy change (ΔG), entropy change (ΔS), and entropy (Sa ) of the adsorbed phase at various sorption coverages were determined from the adsorption isotherms. The diffusion coefficients at different loadings were also calculated using Fick's equation. The calculated thermodynamic and kinetic parameters satisfactorily explain the adsorption process and isotherm features.

Thermodynamics and Kinetics Study of the Adsorption and Diffusion of p-Xylene in Silicalite-1

Adsorption and Diffusion of Benzene and Thiophene Over Y/MCM-41 Composite Zeolite

The sub-micron polystyrene (PS) microspheres with adjustable size were firstly synthesized using emulsion polymerization method by adding only a small amount of emulsifier. Then, three dimensionally ordered macroporous alumina with mesoporous walls and adjustable macropore size was facilely prepared by the colloidal template method. The alumina and PS spheres were characterized by nanoparticle size analyzer, SEM, XRD and N2 adsorption. The results show that the polystyrene microsphere has adjustable single-sized pore with diameter in the range of 100-350 nm and the yield is higher than that prepared by soap free emulsion polymerization. The alumina materials as prepared using the PS colloidal crystals as the template, had ordered meso-macroporous structures and adjustable apertures. The mesopores (about 3.6 nm) in γ-alumina were formed by controlling the heat treatment of alumina precursor. BET surface area and pore volume of the hierarchical alumina as obtained can reach to 241.3 m2/g and 0.33 cm3/g, respectively.

Xiuhong Meng

Papers

Adsorption, Co-adsorption, and Reactions of Sulfur Compounds, Aromatics, Olefins over Ce-Exchanged Y Zeolite

Catalytic combustion of diesel soot over perovskite-type catalyst: Potassium titanates

Thermodynamics and Kinetics Study of the Adsorption and Diffusion of p-Xylene in Silicalite-1

Adsorption and Diffusion of Benzene and Thiophene Over Y/MCM-41 Composite Zeolite

A novel synthesis and characterization of ordered meso/macroporous alumina with hierarchical and adjustable pore size.