Hartley Owen

Upgrading light olefin fuel gas in a fluidized bed catalyst reactor and regeneration of the catalyst

Process for the continuous conversion of light olefin gas feed containing ethene, propene and butene to produce heavier hydrocarbons by contacting the light olefin feed in a fluidized bed reaction zone with a medium pore molecular sieve zeolite catalyst under oligomerization conditions to convert the light olefin feed to heavier hydrocarbons. The catalytic reaction causes the conversion of the light olefins to heavier hydrocarbons, the deposition of coke by-product on the catalyst and the absorption of hydrocarbon product on the catalyst. The deposited coke causes the partial deactivation of the catalyst. A portion of the partially deactivated catalyst containing deposited coke and absorbed hydrocarbon product is continuously withdrawn from the reaction zone and transferred to a catalyst stripping zone in which the catalyst is contacted with an inert stripping gas to remove the absorbed hydrocarbons from the catalyst. The stripped catalyst containing deposited coke is withdrawn from the stripping zone and transferred to a catalyst regeneration zone in which the catalyst is maintained in a fluidized bed and contacted with an oxygen containing gas to effect combustion of the coke and removal of the coke from the catalyst and regeneration of the catalyst. The regenerated catalyst containing a minor amount of residual carbon is withdrawn from the regeneration zone and introduced to the reaction zone and contacted with fresh light olefin feed. The careful control of the operating conditions in the regeneration zone provides removal of substantially all of the coke deposits at relatively low temperatures and an effluent flue gas with a low carbon monoxide content and low water content.