ADSORPTION OF N-BUTANE AND N-HEPTANE ON 5A ZEOLITE

Adsorption thermodynamics of n-butane and n-heptane on 5A zeolite was studied by the flow gravimetric-chromatograph technique at temperature s ranging from 533 K to 653 K and over a range of hydrocarbon partial pressures. It is shown that the equilibrium amount of n-heptane adsorb ed is much larger than that of n-butane. Adsorption isotherms are mode led satisfactorily by using a modified virial equation and the Dubinin -Astakhov (D-A) equation. It is concluded that the influence of n-buta ne is very small while the influence of n-heptane is significant in th e separation stage of the total isomerization process. Modified virial equation: P = a(n) exp(C-1 + C(2)a + C(3)a(2)) D-A equation: a = a(m) exp{B [ln[(T/T-c)P-2(c)/P]](n)} The adsorption isosteric heat and ent ropy were calculated, and the results show that the adsorption isoster ic heat of n-heptane is larger than that of butane at low loadings.