Hydrocarbon conversion method and apparatus

Claim 1

In a process for the cyclic, continuous catalytic conversion of a hydrocarbon feedstock wherein the feedstock is subjected to conversion in contact with fluidized hydrocarbon conversion catalyst particles in a reaction zone comprising a transfer line reactor, catalyst particles which are deactivated by deposits formed thereon during hydrocarbon conversion in the reaction zone are separated from the reaction zone effluent and passed to a stripping zone wherein volatile deposits formed thereon during the hydrocarbon conversion in the reaction zone are removed from the catalyst particles by contact with a stripping gas, stripped catalyst particles are separated from the stripping zone effluent and passed to a catalyst regeneration zone wherein non-volatile deposits formed thereon during the hydrocarbon conversion in the reaction zone are removed from the catalyst particles to thereby regenerate the catalyst particles and the regenerated catalyst particles are separated from the regeneration zone effluent gas and recirculated to the reaction zone; the improvement comprising: providing a reaction vessel in the reaction zone and upstream of the transfer line reactor, and a plurality of feed inlets in the reaction zone to permit delivery of the hydrocarbon feed at one of a plurality of points spaced substantially upstream or downstream of one another in the reaction zone, at least one such point being in the reaction vessel; passing catalyst particles from the regeneration zone and into the reaction vessel, introducing a fluidizing gas into the reaction vessel and maintaining a dense fluidized bed of the catalyst particles in the reaction vessel so as to substantially completely fill the reaction vessel with the dense fluidized bed and so that the fluidized bed has a density within the range of from 12 to about 50 pounds per cubic foot; introducing the hydrocarbon feedstock into the reaction zone through a one of the plurality of feed inlets to thereby control the contact time of the hydrocarbon feedstock with the catalyst particles in the reaction zone and regulate the severity of the hydrocarbon conversion in the reaction zone; passing the entire effluent from the reaction vessel into the transfer line reactor; and separating the catalyst particles from the effluent from the transfer line reactor and passing the separated catalyst particles to the stripping zone.