ADDITIVITY OF CHEMICAL-ENERGIES OF ALKANES

A standard thermochemical model is proposed for the reference environm ent. Chemical exergies of liquid and gaseous alkanes were calculated o ver a wide temperature range using the proposed model. The exergies of alkanes may be calculated using additive methods. Two additive scheme s were studied: a scheme with effective bonds and a replacement scheme . The thermal dependence of the additive constants was investigated. E ach compound in the liquid state has a different temperature range for the initial thermodynamic data. This fact limits exergy calculations for a wide temperature range. A new method for calculation of the addi tive constants over a wide temperature range using polynomials is prop osed. This method allows the calculation of chemical exergies of gaseo us and liquid alkanes from 200 to 1500 K and 150 to 370 K, respectivel y. (C) 1998 Elsevier Science Ltd. All rights reserved.