Alkylation process with catalyst transfer

In an alkylation process including:

• introducing a hydrocarbon mixture comprising at least one olefin and at least one isoparaffin into a riser reactor via a first conduit for contact with an alkylation catalyst within said riser reactor to thereby produce a reactor effluent;
• passing said reactor effluent from said riser reactor to a settler vessel comprising a settler vessel top, a settler vessel bottom, wherein said settler vessel bottom is positioned at a first elevation, and wherein said reactor effluent is separated into a hydrocarbon phase and a catalyst phase;
• passing at least a portion of said catalyst phase from said settler vessel via a second conduit to a catalyst cooler comprising a catalyst cooler top and a catalyst cooler bottom, wherein said catalyst cooler top is positioned at a second elevation below said first elevation, for cooling, thereby forming a cooled catalyst;
• removing at least a portion of said hydrocarbon phase from said settler vessel via a third conduit to thereby form a settler effluent stream;
• passing said cooled catalyst from said catalyst cooler to said riser reactor for use as at least a portion of said alkylation catalyst, wherein the improvement comprises:
• a) providing a fourth conduit connected in fluid flow communication with said catalyst cooler and a catalyst receiving vessel comprising a catalyst receiving vessel top, a catalyst receiving vessel bottom, a pressure, an upper zone and a lower zone, wherein said catalyst receiving vessel top is positioned at a third elevation below said first elevation, said fourth conduit for transferring said catalyst phase to said catalyst receiving vessel with said fourth conduit having interposed therein a valve for blocking passage of fluid through said fourth conduit and, alternately, for allowing passage of fluid through said fourth conduit;
• b) providing a fifth conduit connected in fluid flow communication with said upper zone of said catalyst receiving vessel;
• c) providing a sixth conduit connected in fluid flow communication with said upper zone of said catalyst receiving vessel;
• d) introducing a condensible gas into said catalyst receiving vessel, through said sixth conduit, to inhibit air from entering said catalyst receiving vessel;
• e) opening said valve to thereby allow transfer of said catalyst phase from said settler vessel, through said catalyst cooler and said fourth conduit, to said catalyst receiving vessel by gravitational force and/or pressure differential means;
• and
• f) allowing adjustment of said pressure of said catalyst receiving vessel by allowing the removal of vapors from said catalyst receiving vessel through said fifth conduit.