A CFB unit for skeletal isomerization of linear c4-c6 olefins on ferrierite catalysts

Abstract Isoolefins can be used for production of environmentally preferred gasoline components. It is possible to increase the available C 4 -C 6 isoolefins by skeletal isomerization of the corresponding linear olefins. High activities and selectivities to isoolefins can be obtained with zeolites. The drawback of the zeolite catalyst is the limited catalyst life due to coke formation. Continuous reaction and catalyst regeneration can be performed in a CFB (Circulating Fluidized Bed) unit. Experiments were made in a pilot unit at 300°C with refinery FCC light naptha feed. Continuous regeneration was made at 400–600°C both with nitrogen and air. Stable conversion of about 40 wt-% and selectivity of 90 wt-% could be maintained during the test. The selectivity was dependent of the carbon content on the catalyst and an optimum yield was reached with about 5-wt% carbon on the catalyst. The CFB unit data was compared to fixed bed unit data.