Effect of cracking conditions

The results obtained in our search for optimal simulation conditions can also be interpreted in terms of the effect of reactor conditions on the cracking kinetics. 

ABSTRACT As a step in the application of the cracking of tar in fuel gas amelioration the characteristics of the endothermic reaction potential of tar was studied experimentally and theoretically. In this context, however, due to the structural complexity of tar and/or tany constituents in fuel gas well defined hydrocarbons as tar model compounds were applied with inexpensive and readily available materials (dolomites, dolomitic magnesium oxide [MgO], quicklime [CaO]). The effects of operation condition on extent of hydrocarbon conversion, gas product composition, and corresponding endotherai of the reaction potential have been explored. The results obtained in this work provide a basis for ture considerations of catalytic tar cracking. 

Isomerization of c-Ce, n-C(, and their mixtures has been investigated on Pt/H-MOR. The effects of reaction conditions and feed composition on the yield of isomers, as well as on the composition of cracked and other products were examined. Rate equations and parameters involved were determined for the isomerization of pure alkanes and their mixtures. Isomerization rate equation can be derived assuming rate determining skeletal rearrangement, while in mixtures and at higher pressures the transport in micropores seems to control the transformation. 

The mechanisms of fatigue crack closure have been identified for metals. These are illustrated by Anderson [16], who has also expanded upon the effects of crack closure on the fatigue properties of metals. The phenomenon can also manifest itself in polymer-based materials because of the plastic deformation, viscoelasticity, residual stresses, and environmental conditions. 

Dunn, M.L. (1994) The effects of crack face boundary conditions on the fracture mechanics of piezoelectric solids. Eng. Fract. Mech., 48, 25-39. 

A survey of much of the past work that has been done in this important area of study is given in Tsai. Other related topics of interest in the design of composites include the material response to impact on loading, fatigne nnder cyclic loading, fracture and crack propagation in composites, and the effects of environmental conditions on the material response. 

The ASME Codes recommend that hydrostatic tests be run at a temperature that is usually above the nil-ductility temperature of the material. This is, in effect, a pressure-temperature treatment of the vessel. When tested in the relatively ductile condition above the nil-ductihty temperature, the material will yield at the tips of cracks and flaws and at points of high residual weld stress. This procedure will... 

The effect of ozone is complicated in so far as its effect is largely at or near the surface and is of greatest consequence in lightly stressed rubbers. Cracks are formed with an axis perpendicular to the applied stress and the number of cracks increases with the extent of stress. The greatest effect occurs when there are only a few cracks which grow in size without the interference of neighbouring cracks and this may lead to catastrophic failure. Under static conditions of service the use of hydrocarbon waxes which bloom to the surface because of their crystalline nature give some protection but where dynamic conditions are encountered the saturated hydrocarbon waxes are usually used in conjunction with an antiozonant. To date the most effective of these are secondary alkyl-aryl-p-phenylenediamines such as /V-isopropyl-jV-phenyl-p-phenylenediamine (IPPD). 

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