Screening of different zeolites and silicoaluminophosphates for the retention of propene under cold start conditions

Abstract

Propene adsorption isotherms, breakthrough curves and temperature programme desorption profiles have been obtained for six different crystalline materials with distinctive framework structures (3D and 1D) and a variety of Si/Al ratios and cations (four zeolites: Silicalite-1, BETA, ZSM-5, Mordenite; and two silicoaluminophosphate molecular sieves: SAPO-41 and SAPO-5). Moreover, for a proper evaluation of the solids in a propene trap under cold start conditions, cold start tests have been performed, carrying out four cycles (adsorption/desorption) to analyze the ageing process of the materials. A detailed analysis of the experimental results points out that materials with high equilibrium propene adsorption capacity at 30 °C, where propene is mainly chemisorbed and, which presents some kinetics restrictions, seem to be the best for a propene trap under cold start conditions. BETA and ZSM-5 zeolites and SAPO-5 silicoaluminophosphate molecular sieve are promising materials as propene traps.