Recovery and separation of n-paraffins by continuous adsorption with molecular sieves

Abstract

1. A flow plan has been developed for the recovery and separation of n-paraffins by continuous adsorption with CaA zeolite. 2. The adsorption-desorption capabilities of granulated CaA zeolite have been studied with reference to C5-C8 n-paraffins, at various temperatures. 3. It has been established that the adsorptive capacity of CaA zeolite for n-paraffins (in wt. %) at 100°C is as follows: pentane 6.8%, hexane 8%, heptane 10.2%, octane 12%. The degree of desorption from CaA zeolite at 400° C is as follows: pentane 95%, hexane 85%, heptane 80%, and up to 90% for a mixture of these three hydrocarbons. 4. A study has been made of breakdown and losses of microbead CaA zeolite due to abrasion during continuous circulation in a closed system under nonisothermal conditions. It was established that severe attrition of the zeolite takes place in the initial operating period, but after 800 cycles, the particle breakdown has stabilized. The zeolite losses due to abrasion after 800 cycles of continuous operation in the unit are at most 2% by weight.