Special coke

The high temperatures applied to the bottom of the tower stills damaged them so that they had to be replaced frequently. This was relatively expensive. As a result, special coke stills were used. Similar to the tower stills but smaller, the bottoms of these stills were cheaper to replace. The crude oil was reduced in the tower still to about 20° to 25° API gravity and transferred to the atmospheric coke still. This still was then heated rapidly to effect the cracking and coking. The entire coking operation required about 40 hours (55). Twenty-five years ago, a major part of petroleum coke was made in such shell stills. 

The conversion of carbon-rich refining residues, which consist mainly of three-, four- and five-ring aromatics with partial alkyl substitution, into special cokes, graphite and carbon fibers occurs predominantly in the liquid phase. Carbon black, another important carbon product, on the other hand is obtained by pyrolysis in the gas phase. 

The vapor-phase conversion of aniline to DPA over a soHd catalyst has been extensively studied (18,22). In general, the catalyst used is pure aluminum oxide or titanium oxide, prepared under special conditions (18). Promoters, such as copper chromite, nickel chloride, phosphoric acid, and ammonium fluoride, have also been recommended. Reaction temperatures are usually from 400 to 500°C. Coke formed on the catalyst is removed occasionally by burning. In this way, conversions of about 35% and yields of 95% have been reported. Carba2ole is frequently a by-product. 

Where anodes are installed in special backfill, two series resistances are present — anode to backfill and backfill to soil. In practice, and with coke breeze backfill, a single calculation based upon the dimensions of the backfill column and soil resistivity is satisfactory. 

Backfill the soil replaced over the pipe in the trench (general connotation). In cathodic protection, special backfills are packed around the anodes. These backfills are selected to lower circuit resistance of the anode for sacrificial anodes a gypsum/bentonite mixture is used, and for impressed-current anodes, coke breeze. 

This interpretation of the experimental data is supported by the differences observed in the deactivation patterns and carbon contents after test, since one notorious effect of Hjp is the capacity to diminish the deactivation caused by coke deposition on the active sites [21,22]. This is supposed to be due to a reaction with the coke precursors, very likely a hydrogenolysis. In pure silica-aluminas, where no source of spillover is present, no special protection against deactivation should be observed. Indeed, the silica-aluminas lose most of their activity (about 80%) before reaching the steady-state and present the highest carbon contents after catalytic test. On the other hand, in the case of the mechanical mixtures, where spillover hydrogen is continuously produced by the CoMo/Si02 phase and can migrate to the silica-alumina surface, the predicted protection effect is noticed. The relative losses of activity are much lower... 

And at last it is the using of the special Automotive fuel on the base of liquid wastes of coke factories of Ukraine, containing a carcinogen and drug benzol in quantities that are exceeding in other countries of Europe and world in tens times. 

Mansfield A process for extracting copper from sulfide ores by roasting with anthracite or coke and a silicious flux in a special blast furnace. 

It should be noted here that since the original work done at Mobil was completed, there have been new developments published in the literature. Ishida and Wen (1968) analytically solved a special case for the transition region when the reaction rate does not depend on the local solids (coke) concentration. Wen (1968) has also numerically solved the more general problem for certain kinetic forms, and Amundson and co-workers have done much work on the diffusion and reaction in the boundry layer about a carbon particle (Caram and Amundson, 1977). We will not attempt to review the literature or compare the more accurate numerical solutions with our ad hoc approximation technique. However, we note that our technique was simple, fit the experimental and commercial data extremely well, and provided us with valuable insight and understanding... 

For either plant type, incineration, or fuel type, these factors must be empirically determined and controlled. Because dioxins as effluents are concerned, it is possible to reduce I-TE values from about 50 ng/m to about 1 ng/m. Additional secondary measures (filter techniques) are therefore necessary for obtaining the lower limit value of 0.1 ng/m. Secondary measures are special filter techniques for pollutants formed in nongreen processes, also called end-of-pipe technology. The main part of technical incineration plants consists of filter devices, mostly coke as adsorbent is used, which must be decontaminated later by itself by burning in hazardous-waste incinerators. The inhibition technology, discussed later, is related on principles of primary (green) measures for a clean incineration method. 

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