Abstract:
CO
2 hydrogenation to light olefins is an exothermic reaction, while propane dehydrogenation to propylene is an endothermic reaction, and with generating of hydrogen. Coupling of the two reactions can break the equilibrium limit of thermodynamics and dynamics of the single reaction and improve yield of propylene. Therefore, the effects of different crystalline zeolites (HZSM-5, SAPO-34 and Al-SBA-16) on the reactivity of propane coupled with CO
2 to propylene were investigated. The properties of different zeolites were characterized by means of XRD, SEM, NH
3-TPD, N
2 desorption and TG, and the catalytic performance of the three different zeolites in the reaction of propane and carbon dioxide coupling to propylene was investigated in a fixed bed reactor. The experimental results showed that HZSM-5 zeolite had high content of weak acid, large specific surface area and excellent catalytic activity. Typically the propane conversion rate is 10.5%, the CO
2 conversion is 3.0%, the propylene selectivity is 38.4 and the yield is 4.0% when the volume ratio of propane to CO
2 is 1:4, the reaction pressure is 0.1 MPa, the reaction temperature is 580 ℃, the catalyst mass is 0.2 g and the space velocity is 6000 mL/(g
cat·h).