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Mitchell method

The catalysts with metals are previously impregnated with solutions of vanadyl and nickel naphtenates based on the Mitchell method [4], Before hydrothermal deactivation the samples were calcined in air at 600°C. The activity was performed in the conventional MAT test using 5 grams of catalyst, ratio cat/oil 5, stripping time 35 seconds, and reaction temperature 515°C. Elemental analyses to determine the total amount of carbon in the spent catalysts were done by the combustion method using a LECO analyzer. [Pg.145]

Properties Mitchell Method Cyclic Metals Impregnation Cyclic Propylene Steam... [Pg.139]

A simplified cyclic test (Mitchell method followed by cyclic propylene steaming) has been proposed which addresses the redox aging of the metal, but not the non-uniform laydown and age distribution of metals on the catalyst. Under actual FCC conditions, the penetration and age profile of the metals will influence the efficiency of the catalyst metal trapping function [23,39,40] and consequently catalyst activity and selectivity. [Pg.153]

An early attempt to simulate metals deactivation was the introduction of the Mitchell method steam deactivation procedure (2). This procedure involved impregnation of catalysts with Ni and V naphthenates, followed by steaming in the presence of air. While this method was easy to implement and did allow comparison of catalysts in the presence of metal contaminants, both the destruction of the zeolite and the metal dehydrogenation activity was greatly over-predicted (3, 4) in both MAT and riser testing. [Pg.172]

Metals in regnation was done according to the Mitchell Method (11). In this method the catalyst san )le is in )regnated with vanadium napthenate (ALFA) diluted with cyclohexane. After air drying for several hours the san )le is calcined at 600 F for 1 hour and then at 1100 F for 1 hour. The samples are subsequently steamed for 4 hours at 1450 F in an atmosphere of 90% steam and 10% air. [Pg.298]

Test Methods. Since its inception, the Mitchell Method (MM) or slight variations (often referred to as the Modified Mitchell Method) have been en )loyed by researchers evaluating FCC catalyst as a sin )le, inexpensive, and fast procedure by which to simulate the effect of contaminant metals on catalyst performance. As a fallout of more sophisticated catalytic testing in fixed fluid bed reactors, the method of cycUc metals deposition (CMD) has also emerged as a useful method for introducing metal contaminants. [Pg.299]

It would be desirous to have available a sinq)ler testing tool which could imitate many of the aspects of the cyclic deposition particularly the inq)ingement of the metals on the catalyst surface with the simplicity, efficiency, and cost of the Mitchell Method. One such test, at least so far developed for vanadium interaction, is what we termed above as the Engelhard Transfer Method (ETM) (7). [Pg.300]

Conclusions. It is necessary to test a catalyst s stabihty and performance under high vanadium conditions for materials which will be processing metals laden feedstocks. The Engelhard Transfer Method offers the benefits of both the Mitchell Method and... [Pg.308]

J.W. Koenst and E. Mitchell, Method of casting tubular polysulfone membranes in sand modufes, U.S. Patent 4,038,351, 26Julyl977. [Pg.398]

The crystal structure of NR is orthorhombic (space group Pbca) The (002) diffraction line, that is originated by lattice planes perpendicular to the c chain axis, is particularly informative. The corresponding average crystallite dimension, Z.002, assessed by the Scherrer equation, is often called in the literature the stem length and is used to describe the size of rubber crystallites. The (200) and (120) reflections correspond to lattice planes parallel to the chain direction. A very widespread procedure for measuring the crystallinity or rubber is based on the Mitchell method ... [Pg.526]


See other pages where Mitchell method is mentioned: [Pg.43]    [Pg.378]    [Pg.308]    [Pg.195]    [Pg.172]    [Pg.172]    [Pg.176]    [Pg.298]    [Pg.299]    [Pg.300]    [Pg.346]    [Pg.455]    [Pg.330]    [Pg.194]    [Pg.187]    [Pg.1321]    [Pg.408]   
See also in sourсe #XX -- [ Pg.299 ]




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