The invention relates to C.sub.5+ hydrocarbon conversion. More particularly, the invention relates to separating a vapor phase product and a liquid phase product from a heated mixture that includes steam and C.sub.5+ hydrocarbons, catalytically cracking the liquid phase product and steam cracking the vapor phase product.

Embodiments of methods for converting gas condensate into a product stream comprising propylene comprise feeding gas condensate at a top region of a downflow high severity fluidized catalytic cracking reactor (HSFCC), where the gas condensate comprises: at least 50% by weight paraffins, and less than 0.1% by weight olefins. The method further comprises feeding catalyst to the top region of the downflow HSFCC reactor in an amount characterized by a catalyst to gas condensate weight ratio of about 5:1 to about 40:1, where the catalyst comprises nano-ZSM-5 zeolite catalyst having an average particle diameter from 0.01 to 0.2 μm, a Si/Al molar ratio from 20 to 40, and a surface area of at least 20 cm.sup.2/g. The method further comprises cracking the gas condensate in the presence of the catalyst at a reaction temperature of about 500° C. to about 700° C. to produce the product stream comprising propylene.

A start-up method for contacting a feed stream with fluidized catalyst is disclosed. The start-up method comprises reacting a feed stream over a catalyst to produce a gas stream and spent catalyst. The gas stream is separated from the spent catalyst. The separated gas stream is passed to a compressor. The operating condition associated with the compressor is measured. Based on the measured operating condition associated with the compressor, one or both of a supplemental hydrocarbon stream and a supplemental hydrogen gas stream is provided to the compressor to meet a predetermined operating condition associated with the compressor.

A method of predicting the tendency of a heavy oil feed to generate coke deposits in the FCC riser under a given set of operating parameters in the unit; thus, by utilizing operating parameters appropriate to the feed, the formation of coke deposits in the riser may be minimized. The margin between the theoretical dew point of the hydrocarbon feed established from unit operating parameters and the theoretical mix zone temperature in the feed injection zone of the unit is developed by applying a regression-derived linear model from multiple rigorous model runs. The mix zone of the unit is then operated at a temperature which reduces the level of riser coking predicted from this ascertainable margin or, at least, maintains it within levels which are predictable and acceptable.

A method of predicting the tendency of a heavy oil feed to generate coke deposits in the FCC riser under a given set of operating parameters in the unit; thus, by utilizing operating parameters appropriate to the feed, the formation of coke deposits in the riser may be minimized. The margin between the theoretical dew point of the hydrocarbon feed established from unit operating parameters and the theoretical mix zone temperature in the feed injection zone of the unit is developed by applying a regression-derived linear model from multiple rigorous model runs. The mix zone of the unit is then operated at a temperature which reduces the level of riser coking predicted from this ascertainable margin or, at least, maintains it within levels which are predictable and acceptable.

Disclosed is a method for producing low carbon olefins and/or aromatics from feedstock comprising naphtha. The method can include the following steps: a) feeding feedstock comprising naphtha into a fast fluidized bed reactor; b) contacting the feedstock with a catalyst under conditions to produce a gas product and spent catalyst; c) separating the gas product to produce a stream comprising primarily one or more low carbon olefins and/or one or more aromatics; d) transporting the spent catalyst to a regenerator; e) regenerating the spent catalyst in the regenerator to form regenerated catalyst; and f) returning the regenerated catalyst to the fast fluidized bed reactor.

Disclosed is a method for producing low carbon olefins and/or aromatics from feedstock comprising naphtha. The method can include the following steps: a) feeding feedstock comprising naphtha into a fast fluidized bed reactor; b) contacting the feedstock with a catalyst under conditions to produce a gas product and spent catalyst; c) separating the gas product to produce a stream comprising primarily one or more low carbon olefins and/or one or more aromatics; d) transporting the spent catalyst to a regenerator; e) regenerating the spent catalyst in the regenerator to form regenerated catalyst; and f) returning the regenerated catalyst to the fast fluidized bed reactor.

A zeolite fluid catalytic cracking catalyst is provided that passivates nickel and vanadium during catalytic cracking. The zeolite fluid catalytic cracking catalyst includes Y-faujasite crystallized in-situ from a metakaolin-containing calcined microsphere. The zeolite fluid catalytic cracking catalyst further includes an alumina-containing matrix obtained by calcination of a dispersible crystalline boehmite and a kaolin contained in the metakaolin-containing calcined microsphere, where the dispersible crystalline boehmite has a crystallite size of less than 500 Å. Also provided are a method of reducing contaminant coke and hydrogen yields and a method of catalytic cracking of heavy hydrocarbon feed stocks.

A zeolite fluid catalytic cracking catalyst is provided that passivates nickel and vanadium during catalytic cracking. The zeolite fluid catalytic cracking catalyst includes Y-faujasite crystallized in-situ from a metakaolin-containing calcined microsphere. The zeolite fluid catalytic cracking catalyst further includes an alumina-containing matrix obtained by calcination of a dispersible crystalline boehmite and a kaolin contained in the metakaolin-containing calcined microsphere, where the dispersible crystalline boehmite has a crystallite size of less than 500 Å. Also provided are a method of reducing contaminant coke and hydrogen yields and a method of catalytic cracking of heavy hydrocarbon feed stocks.

Disclosed herein is a fluid catalyst cracking (FCC) catalyst composition that includes a first component and a second component. The first component and second component may be separate microspheroidal FCC catalysts or may be incorporated in a common microspheroidal FCC catalyst. The first component includes zeolite Y and a first matrix that includes gamma-alumina. The second component includes beta zeolite and a second matrix. Also disclosed herein are methods of preparing the FCC catalyst composition and method of using the FCC catalyst composition.