Comprehensive investigation of regeneration and performance of deactivated molecular sieves: Experimental characterization and molecular simulation analysis

Abstract

The objective of this work is focused on the regeneration of deactivated 3 A zeolite used for four years at the Ilam Gas Refining Company for natural gas drying. In particular, the impact of coke removal by thermal treatment on the final characteristics of the molecular sieve has been deeply investigated. XRD analyses indicated that the zeolite structure remained unchanged up to a thermal treatment of 550°C. Significant changes in the zeolite structure occurred at higher temperature values. A reduction in water adsorption capacity than the fresh sample of about 40 % was found for zeolite samples activated in the temperature range 400 °C-550°C. The regenerated molecular sieve samples preserved their mechanical stability and so confirming their reuse over time. Molecular simulation revealed that coke in the zeolite cavities reduced the interaction energy between water vapor molecules and zeolite, as well as the oxygen atoms within the zeolite structure.