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An Application of Microemulsion Method for Synthesis of Copper-Zinc Materials

100%

Pawlonka J. , Słowik G. , Gac W. , Borowiecki T.

nr 1-2

Microemulsion method was used for preparation of copperzinc mixed oxides. Samples were prepared from the solutions containing zinc and copper nitrates. Sodium carbonate was used as a precipitant and hydrazine as reducing agent. Water-in-oil (W/O) microemulsions were formed by the application of cyclohexane, isopropyl alcohol, and hexadecyltrimethylammonium bromide (CTAB) as surfactant. The aim of the studies was determination of the influence of the sequence of synthesis stages on the formation of materials, their surface and structural properties. Thermal decomposition studies of materials were carried out by infrared spectroscopy. The physicochemical properties were characterized by nitrogen adsorption-desorption method, X-ray diffraction (XRD) and temperature-programmed reduction (TPR).

Influence of Steam Reforming Catalyst Geometry on the Performance of Tubular Reformer – Simulation Calculations

88%

Franczyk E. , Gołębiowski A. , Borowiecki T. , Kowalik P. , Wróbel W.

Chemical and Process Engineering

2015

tom 36

nr 2

239-250

A proper selection of steam reforming catalyst geometry has a direct effect on the efficiency and economy of hydrogen production from natural gas and is a very important technological and engineering issue in terms of process optimisation. This paper determines the influence of widely used seven-hole grain diameter (ranging from 11 to 21 mm), h/d (height/diameter) ratio of catalyst grain and Sh/St (hole surface/total cylinder surface in cross-section) ratio (ranging from 0.13 to 0.37) on the gas load of catalyst bed, gas flow resistance, maximum wall temperature and the risk of catalyst coking. Calculations were based on the one-dimensional pseudo-homogeneous model of a steam reforming tubular reactor, with catalyst parameters derived from our investigations. The process analysis shows that it is advantageous, along the whole reformer tube length, to apply catalyst forms of h/d = 1 ratio, relatively large dimensions, possibly high bed porosity and Sh/St ≈ 0.30-0.37 ratio. It enables a considerable process intensification and the processing of more natural gas at the same flow resistance, despite lower bed activity, without catalyst coking risk. Alternatively, plant pressure drop can be reduced maintaining the same gas load, which translates directly into diminishing the operating costs as a result of lowering power consumption for gas compression.