Increase Isoalkanes In The Gasoline Catalyst Features

About 80% of the gasoline pooi as a whole in China for supplying the domestic market at current stage directly originates from FCC units. Atmosphere is polluted by high olefin component of gasoline which combusts in the engine of car. One way of solving the problem is to convert olefin of gasoline into iso-paralfm, the environment friendly component.The isomerization reaction of n-hexene has been studied in FCC process. The isomerization process of carbonium ions has been studied using molecular simulation approach. The isomerization of earbonium ion proceeds through transition state of a carbonium ion of cyelopropyl structure to form a primary carbonium ion, which in turn transforms into a secondary or a tertiary earbonium ion by hydrogen transfer.Zeolites with different structure and pore diameters were evaluated by pure hydrocarbon pulse microreactor. The results showed that using n-CJ and n-C.> as feedstock the order of the selectivity of iso-paraffin of zeolite is as follows: Y> ~3 >ZRP>Mordenite>ferrierite. Zeolite Y modified by SiC14 with different Si1'Al ratio was characterized by MASNMR, XRD, BET and ~. The modified zeolites Y by SiC14 show better crystalinity, higher thermal and steam thermal stability than that of USY by hydrothermal method.The high silica Y zeolites with different Si/Ad ratio were evaluated by the pure hydrocarbon pulse microreactor. The results indicate that the selectivity of ~so-paraffln of zeolite increase first and then decrease with their cell dimension decreasing, and the maximum value of selectivity appears at the cell dimension of about 2.42~ nm. Acid site density of zeolite plays an important role in the isomerization of n-hexene.Rare earth was exchanged into the zeolites with different Si/Al ratio to obtain three REY zeolite samples. Four catalyst samples were made by selecting any two kinds of REY zeolite in different proportion. These samples were evaluated by the heavy oil microreactor. The results show that the catalyst sample made of two kinds of zeolites with different Si/Al ratio and different rare earth content has better cracking activity and isomerization activity than the catalyst sample with only one type zeolite component.