Abstract: The scaling up in the degree of oil refining and the transition to heavier oil feedstock is inevitably accompanied by an increase in the formation of waste hydrocarbon refinery gases, while light alkanes, in particular the n-butane fractions, do not meet an equivalent market and are used mostly as fuel gases. Earlier in [1], we have considered the possibility of utilizing n-butane fractions by isomerization, followed by oxidative processing of isobutane into tertiary-butyl alcohol based high-octane oxygen-containing components of motor fuels [2]. In this work, we determined the equilibrium yields of isobutane under the conditions of processing the n-butane fractions of refinery gases. Thermodynamic calculations consisted in the determining the composition of the reacting gases in the state of chemical equilibrium; the method used was minimization the free Gibbs energy of the initial reactants and the intended products in the pressure range of 0.1-2.5 MPa, temperatures of 20-300°C. Compositions of refinery gases differed in the initial content of isobutane and hydrogen. In the analysis, we assumed the nomenclature of the reaction products, which is typical for isomerization of n-butane on a palladium-promoted sulfated zirconia catalyst PdSZ [3]: methane, ethane, propane, isobutane, butenes, pentane, and hexane. For maintaining the stability of the catalyst in the n-butane isomerization reaction, a small quantity of hydrogen in the feed is required. Therefore, in these calculations, the equilibrium composition of the products was determined at the ratios [H2] / [nC4] = 0; 0.1; 0.5; 1.0

Cite: Ovchinnikova E.V. , Ivanov E.A. , Chumachenko V.A.
Thermodynamic Analysis of Equilibrium Isobutane Yields in the Isomerization of n-Butane Fractions of Refinery Gases
XI International Conference Mechanisms of Catalytic Reactions 07-11 Oct 2019