Computer modeling of hydrocarbon pyrolysis

Ross, L. L., Shu, W. R., Computer Modeling of Hydrocarbon Pyrolysis for Olefins Production, in "Thermal Hydrocarbon Chemistry", Adv. Chem. Series,... 

Ross and Shu [38], discussing the computer modelling of hydrocarbon pyrolysis for olefin production, classify reaction models in four categories in order of increasing sophistication empirical, semi-kinetic, stoichiometric and mechanistic. Most concepts of this classification are included in Table 3 with, however, a more classical meaning of the word stoichiometry. 

Computer Modeling of Hydrocarbon Pyrolysis for Olefins Production... 

Computer modeling of hydrocarbon pyrolysis is discussed with respect to industrial applications. Pyrolysis models are classified into four groups mechanistic, stoichiometric, semi-kinetic, and empirical. Selection of modeling schemes to meet minimum development cost must be consistent with constraints imposed by factors such as data quality, kinetic knowledge, and time limitations. Stoichiometric and semi-kinetic modelings are further illustrated by two examples, one for light hydrocarbon feedstocks and the other for naphthas. The applicability of these modeling schemes to olefins production is evidenced by successful prediction of commercial plant data. 

For convenience, computer modeling of hydrocarbon pyrolysis may be categorized into four types. In order of decreasing degree of sophistication, these are mechanistic, stoichiometric, semikinetic, and empirical. A brief description of each follows. 

Dente and Ranzi (in Albright et al., eds., Pyrolysis Theory and Industrial Practice, Academic Press, 1983, pp. 133-175) Mathematical modeling of hydrocarbon pyrolysis reactions Shah and Sharma (in Carberry and Varma, eds., Chemical Reaction and Reaction Engineering Handbook, Dekker, 1987, pp. 713-721) Hydroxylamine phosphate manufacture in a slurry reactor Some aspects of a kinetic model of methanol synthesis are described in the first example, which is followed by a second example that describes coping with the multiplicity of reactants and reactions of some petroleum conversion processes. Then two somewhat simplified industrial examples are worked out in detail mild thermal cracking and production of styrene. Even these calculations are impractical without a computer. The basic data and mathematics and some of the results are presented. 

Chapters 7-9 deal with the process aspects of pyrolysis to produce epbba. The first discusses the use of aerospace technology to simulate an unconventional process. The second discusses the results of recent attempts to develop computer models for large scale pyrolysis of hydrocarbons and the third discusses recent process and furnace design advances. 

The use of computer generation systems in modelling the pyrolysis of large hydrocarbons is no longer considered simply an alternative to manual mechanism construction. It has become a necessity. The quantity of species and reactions becomes enormous, increasing molecular weight. This is particularly true if the focus is not merely on linear alkanes but also on other typical components of naphthas and gasoils, such as Bo-alkancs or cyc/o-alkanes, where the number of possible isomers increases exponentially with the number of carbon atoms in the molecule. 

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