Coke deposits blend

The effects noted when cracking gas oils of different types agree in general with those observed in work with pure hydrocarbons as feeds. Quantitative comparisons are difficult, however. One of the complicating factors, particularly in fixed-bed comparisons, arises from the fact that, when dissimilar feeds are cracked in admixture, each component is cracked to a different extent than when cracked separately under the same nominal conditions. For example, a hydrocarbon with a low coke-producing tendency cracks to a smaller extent in blends because the other component or components deposit more coke on the catalyst and lower its activity. Although this difficulty can be overcome by specially designed experiments, such data are usually not obtained. 

Table III presents data on coking tendencies of by-product liquids from gas oil pyrolysis. The data show that the pyrolysis gasoline is the most reactive of the components with significant formation of deposits at a temperature of 177 C. The gas oil, which contains fewer diolefins and alkenyl aromatics than the gasoline, is more stable and may be viewed as a diluent for the gasoline i.e., the blend of pyrolysis gasoline and gas oil can be processed at a higher temperature than the gasoline alone.

The development of chemical industry in each of the three segments of the partitioned Poland was to some extent determined by the availability of raw-materials in those regions. The richest part was Upper Silesia, where coal, notably the largest deposits in Europe of coking coal, occurred beside the iron ores and large quantities of the zinc ores calamine and blende. In the neighbouring... 

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