Feed stock chemical composition

In principle one can treat the thermodynamics of chemical reactions on a kinetic basis by recognizing that the equilibrium condition corresponds to the case where the rates of the forward and reverse reactions are identical. In this sense kinetics is the more fundamental science. Nonetheless, thermodynamics provides much vital information to the kineticist and to the reactor designer. In particular, the first step in determining the economic feasibility of producing a given material from a given reactant feed stock should be the determination of the product yield at equilibrium at the conditions of the reactor outlet. Since this composition represents the goal toward which the kinetic... 

Iran mix, Arab mix, and Dubai short residues (550°C+) obtained from Madras Refineries Ltd., Madras were used as the feed stocks. Their Physico-chemical characteristics, compositional analysis, elemental compositions and average molecular formulae as determined by standard ASTM/BIS/IP methods are given in Table 1. 

Base stock specifications, as defined by the producer or the purchaser, largely enumerate the physical properties required for the fluid—typically density, viscosity at two temperatures, viscosity index (VI), low temperature performance measures, flash and volatility properties, and solubility information from aniline point or viscosity-gravity constant (VGC)—the latter two are usually for naphthenic base stocks. While chemical composition is responsible for physical properties, it usually only surfaces as measurements of heteroatom content—sulfur and nitrogen—and aromatics content (or conversely that of saturates). Sulfur and aromatics levels in paraffinic base stocks are now criteria for American Petroleum Institute (API) classifications. However, detailed chemical compositional information is needed to understand the chemistry of the unit processes, the effects of changes in feeds, catalysts, and operating conditions, and behaviors of finished lubricant products. 

The steam-carbon dioxide-hydrocarbon conversion is conducted over a catalyst such as nickel (oxide) on alumina. This type of catalyst can be purchased in quite similar composition from a number of catalyst vendors. In the case in which the feed stock is processed over a catalyst as in steam-hydrocarbon reforming, it is essential that the gas be purified, at least to some extent, prior to its passage over the reforming catalyst, particularly if the catalyst is of the typical composition of supported and promoted nickel (oxide). In steam hydrocarbon reforming, the methane (natural gas) is usually detoxified using an adsorbent such as carbon on which is impregnated suitable chemical adsorbents such as elemental iron or copper. There are at least two of these metallized carbon desulfurizers in parallel with one on... 

As we shall see later, ultimately the continuous supply of fresh feed stock and the recycling of the unreacted part of the latter, lead to a steady state that is characterized by a constant flow of recycled material, a constant total feed to the reactor, and also by a constant chemical composition of these streams. In this case, in the steady state the quantity of reaction products produced in the system, will equal the amount of fresh feed stock supplied to the system. 

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