Search Results

You are looking at 1 - 10 of 1,167 items for :

  • Refine by Access: All Content x
Clear All

Abstract  

A number of catalysts were prepared for the desulphurization process of tail gases. Their carrier was alumina oxide while the active phase was manganese. The catalysts were being tested in an lab apparatus. The effect of calcination temperature and process temperature of model gas (1 vol% of SO2+99 vol% of N2) were studied. The increase in the desulphurization temperature up to about 500°C causes the efficiency of the desulphurizing yield to be increased, a further increase of the temperature process decreases the SO2 conversion. The DTA curves of catalysts after the desulphurizing process display the additional peak at a temperature of about 900°C being, perhaps, responsible for deactivation of the catalysts.

Restricted access

Abstract  

Microcalorimetric studies of oxygen and hydrogen chemisorption during the last decade improved the understanding of the structure and structural dynamics of supported bimetallic catalyst particles. For example, it was found that on graphitic supports two different reduced surface compositions/structures can be created for base metal/noble metal particles. Appropriate treatments “switch” the surface from almost pure reduced base metal to true alloy. Calorimetric studies also indicate support interactions play a major role in controlling bimetallic particle surface structure. In contrast to behaviour found on graphitic supports, iron/noble metal particles supported on refractory oxides apparently do not form alloy surfaces. The reduced surface is dominated by the noble metal. Several studies indicate the value of the models of surface composition/structure developed using microcalorimetry for predicting the activity/selectivity of bimetallic particles.

Restricted access

Abstract  

A catalytic action of the mechanochemical products of copper hydroxocarbonate with calcium carbonate was investigated in n-butyl alcohol oxidation tests. The solid products of high-energy milling were identified using thermogravimetry supplemented by X-ray diffraction method. It was shown that the mechanical activation induces more effective tested catalyst because it promotes the alcohol conversion at lower temperatures than that unmilled one.

Restricted access

A calorimetric method is proposed to evaluate the catalytic activity of a solid catalyst with respect to the exothermic oxidation of Volatile Organic Compounds (VOC).

Restricted access

Abstract  

A cracking catalyst designatedSRNY was manufactured from a commercialSRNY molecular sieve (M.S.). The support consisted of kaolin, clay and SiO2. The coking behaviour of theSRNY M.S., the support and the catalyst were examined with light diesel oil (LDO) as feedstock in a microreactor. The physico-chemical properties of both fresh and aged samples, subjected to or not subjected to the cracking reaction ofLDO, were sequentially characterized by means of pore structure determination and thermal analysis. The pore structure included the specific surface area and the pore volume or porosity. Thermal analysis methods used included TG and DSC. The results indicated that all coked samples exhibited obvious changes in surface pore structure and acidity in comparison with non-coked samples. Their specific surface area and acid amount decreased with increase in the coke content of the samples. The apparent activation energy data obtained from decoking samples in an air flow, using the temperature-programmed oxidation (TPO) method, showed that the kinetic parameters of theSRNY M.S. differed from those of theSRNY catalyst and its support.

Restricted access
Reaction Kinetics, Mechanisms and Catalysis
Authors: K. V. Novikova, M. O. Kompanets, O. V. Kushch, S. P. Kobzev, M. M. Khliestov, and I. O. Opeida

calculated from the slope of the linear plots of the volume of oxygen uptake vs. time. All kinetic measurements were carried out by using freshly prepared samples. The catalysts were characterized by comparison of their physical properties with those

Restricted access

32 Escardino A., Amoros J. L., Moreno A., Sanchez E. Utilizing the used catalyst from refinery fcc units as a substitute for kaolin in formulating ceramic frits, Waste Management and

Restricted access

vegetable oil at moderate temperatures (300–420 °C) with hydrogen at elevated pressures (20–100 bar). Conventional hydrodesulfurization (HDS) catalysts, such as sulfided CoMo, NiMo, or NiW supported on alumina have achieved the complete conversion of

Restricted access

Introduction Acid catalysis plays a vital role in many important reactions of the chemical and petroleum industries, and environmentally benign chemical processes [ 1 – 3 ]. The use of liquid phase acid catalysts suffers from

Restricted access
Reaction Kinetics, Mechanisms and Catalysis
Authors: Valeria Palermo, Ángel G. Sathicq, Patricia G. Vázquez, Horacio J. Thomas, and Gustavo P. Romanelli

variety of acid-catalyzed reactions such as esterification, etherification, olefin hydration, and dehydration of alcohols, and are also attractive as catalysts for oxidation processes [ 2 ]. Recently, we have used Keggin heteropolyacids in a range of

Restricted access