In Situ Upgrading of Light Fluid Catalytic Cracking Naphtha for Minimum Loss

The key to reducing the olefin content in fluid catalytic cracking (FCC) gasoline is to upgrade the olefin-rich light FCC naphtha (LCN). To minimize the naphtha loss, several parameters were investigated in a pilot-scale riser FCC apparatus. The results indicate that, besides the reaction temperature, the catalyst-to-oil ratio, and the catalyst type, the boiling range and the olefin content of LCNs also have significant influence on the upgrading effect. Moreover, a relatively short residence time is beneficial for efficiently upgrading LCNs. In addition, the influence of the reactor structure should be brought to our attention. When a novel structurally changed reactor with a multinozzle feed system was used, significantly increased olefin conversion and decreased naphtha loss can be achieved. The calculation of hydrogen balance indicates that, because of the decrease of dry gas and coke yields, more hydrogen in the feed can be distributed into the desired products.