Catalytic cracking process of petroleum hydrocarbons

Abstract

The present invention discloses a catalytic cracking process of petroleum hydrocarbons and a tube-in-tube riser reactor used therein. In the present invention, a catalyst is fed via an inlet conduit to an inner tube and an annular space between the inner and outer tubes of the tube-in-tube riser reactor to contact a hydrocarbon feedstock, and the hydrocarbon feedstock is cracked under FCC conditions, then a reaction stream thus produced flows into a separation apparatus via a confluence tube to separate a hydrocarbon product stream from a spent catalyst, the spent catalyst is stripped and regenerated, then a regenerated catalyst is recycled for reuse. The process of the present invention can improve both product distribution and product properties.

1 . A catalytic cracking process of petroleum hydrocarbons, comprising the following steps: 
 (1) feeding a catalyst from an inlet conduit to an inner tube and an annular space between inner and outer tubes of a tube-in-tube riser reactor, which flows upward under an action of pre-lifting media;    (2) feeding a hydrocarbon feedstock into the inner tube and the annular space between the inner and outer tubes of the reactor, which contacts the catalyst therein to form an oil-catalyst mixture, so that the reaction of the hydrocarbon feedstock is carried out under catalytic cracking reaction conditions to form a reaction stream which flows upward along vessel wall;    (3) the reaction streams both from the inner tube and from the annular space between the inner and outer tubes flow together at the inlet of a confluence tube, and then enter a separation apparatus via the confluence tube, where a hydrocarbon product stream is separated from a spent catalyst;    (4) further separating the hydrocarbon product stream into various products including gasoline, diesel oil and liquefied petroleum gas, stripping and regenerating the spent catalyst, and recycling a regenerated catalyst into the reactor for reuse.    
     
     
         2 . The process according to  claim 1 , wherein said hydrocarbon feedstocks fed into the inner tube and the annular space between the inner and outer tubes are selected from a group consisting of gaseous hydrocarbon, refinery gas, primary processing gasoline fraction, secondary processing Gasoline fraction, primary processing diesel oil fraction, secondary processing diesel oil fraction, straight run gas oil, coker gas oil, deasphalted oil, hydrofined oil, hydrocracking tail oil, vacuum gas oil, vacuum residuum, atmospheric residuum and a mixture thereof.  
     
     
         3 . The process according to  claim 2 , wherein said hydrocarbon feedstock fed into the inner tube is selected from a group consisting of straight run gas oil, coker gas oil, deasphalted oil, hydrofined oil, hydrocracking tail oil, vacuum gas oil, vacuum residuum, atmospheric residuum and a mixture thereof, and the hydrocarbon feedstock fed to the annular space between the inner and outer tubes is selected from a group consisting of gaseous hydrocarbon, refinery gas, primary processing gasoline fraction, secondary processing gasoline fraction, primary processing diesel oil fraction, secondary processing diesel oil fraction and a mixture thereof.  
     
     
         4 . The process according to  claim 1 , wherein said hydrocarbon feedstock is reacted in the inner tube under conditions as follows: a reaction temperature of 460-580° C., a reaction pressure of 0 1-0.6 MPa, a catalyst-oil ratio of 3-15, an oil-gas residence time of 1.0-10 seconds in the inner tube, a catalyst temperature of 620-720° C. before contacting the feedstock, and an atomization steam amount of 3-20% by weight.  
     
     
         5 . The process according to  claim 4 , wherein said hydrocarbon feedstock is reacted in the inner tube under conditions as follows: a reaction temperature of 480-550° C., a reaction pressure of 0.2-0.4 MPa, a catalyst-oil ratio of 4-10, an oil-gas residence time of 1.5-5.0 seconds in the inner tube, a catalyst temperature of 650-700° C. before contacting the feedstock, and an atomization steam amount of 2-15% by weight.  
     
     
         6 . The process according to  claim 1 , wherein said hydrocarbon feedstock is reacted in the annular space between the inner and outer tubes under conditions as follows: a reaction temperature of 300-680° C., a reaction pressure of 0.1-0.6 MPa, a catalyst-oil ratio of 2-30, an oil-gas residence time of 0.5-20 seconds, and an atomization steam amount of 1-20% by weight.  
     
     
         7 . The process according to  claim 6 , wherein said hydrocarbon feedstock is reacted in the annular space between the inner and outer tubes under conditions as follows: a reaction temperature of 400-600° C., a reaction pressure of 0.2-0.4 MPa, a catalyst-oil ratio of 4-20, an oil-gas residence time of l-15 seconds, and an atomization steam amount of 1-15% by weight.  
     
     
         8 . The process according to  claim 1 , wherein said catalyst fed to the inner tube and the annular space between the inner and outer tubes of the tube-in-tube riser reactor is selected from a group consisting of: a regenerated catalyst, a semi-regenerated catalyst, a spent catalyst and a mixture thereof, and the carbon content of the catalyst fed to the inner tube may be different from that of the catalyst fed to the annular space between the inner tube and outer tubes.  
     
     
         9  The process according to  claim 1 , wherein said tube-in-tube riser reactor is one having single conduit for feeding catalyst, which comprises mainly the following members: catalyst inlet conduit ( 1 ), inner tube ( 2 ), outer tube ( 3 ), confluence tube ( 4 ), pre-lifting distribution rings ( 5 ), ( 6 ) and ( 7 ) and feed nozzles ( 8 ) and ( 9 ); wherein inner tube ( 2 ) and outer tube ( 3 ) are coaxial, and the ratio of the cross-section area of the inner tube to the cross-section area of the annular space between the inner and outer tubes is 1:0.1-10; the lower end of the inner tube ( 2 ) is located at a place above the catalyst inlet, the inner tube has a length amounting to 10-70% of the total length of the reactor, one end of the confluence tube ( 4 ) is connected with the upper end of the outer tube ( 3 ), and the other end is connected with a gas/solid separation apparatus, the cross-section area ratio of the confluence tube ( 4 ) to the inner tube ( 2 ) is 1:0.2-0.8; the pre-lifting distribution rings ( 5 ), ( 6 ) and ( 7 ) are respectively located at the bottoms of the reactor, the inner tube and the outer tube.  
     
     
         10 . The process according to  claim 9 , wherein said ratio of the cross-section area of the inner tube to the cross-section area of the annular space between the inner and outer tubes in said tube-in-tube riser reactor is 1:0.2-2.  
     
     
         11 . The process according to  claim 9 , wherein said inner tube of the tube-in-tube riser reactor has a length amounting to 20-60% of the total length of the reactor.  
     
     
         12 . The process according to  claim 9 , wherein said tube-in-tube riser reactor has a distance of 1-30 meters from the outlet end of the inner tube to the outlet end of the confluence tube  
     
     
         13 . The process according to  claim 9 , characterized in that said tube-in-tube riser reactor is installed with 2-12 lines of shrouding wires or draw-bars between the inner tube and the outer tube.  
     
     
         14 . The process according to  claim 1 , wherein said tube-in-tube riser reactor is one having two conduits for feeding catalyst, and comprises mainly the following members: catalyst inlet conduits ( 21 ) and ( 22 ), inner tube ( 35 ), outer tube ( 36 ), confluence tube ( 38 ), pre-lifting distribution rings ( 31 ) and ( 33 ), and feed nozzles ( 32 ) and ( 34 ), wherein the inner tube ( 35 ) and outer tube ( 36 ) are coaxial; the ratio of the cross-section area of the inner tube to the cross-section area of the annular space between the inner and outer tubes is 1:0.1-10; the catalyst inlet conduit ( 21 ) is connected with the lower end of the inner tube ( 35 ), the length of the inner tube is 10-70% of the total length of the reactor; the distance from the lower end of the outer tube ( 36 ) to the lower end of the inner tube ( 35 ) is 2-20% of the total length of the reactor; the catalyst inlet conduit ( 22 ) is connected with the lower end of the outer tube ( 36 ); one end of the confluence tube ( 3 ) is connected with the upper end of the outer tube ( 36 ) and the other end is connected with a gas/solid separation apparatus, the cross-section area ratio of the confluence tube ( 38 ) to the inner tube ( 35 ) is 1:0.2-0.8, the pre-lifting distribution rings ( 31 ) and ( 33 ) are located at the bottom of the inner tube and the bottom of the annular space between the inner tube and outer tube respectively, and feed nozzles ( 32 ) and ( 34 ) are located at the lower parts of the inner tube and the outer tube respectively.  
     
     
         15 . The process according to  claim 14 , wherein said ratio of the cross-section area of the inner tube to the cross-section area of the annular space between the inner and outer tubes is 1.0.1-2 in said tube-in-tube riser reactor.  
     
     
         16 . The process according to  claim 14 , wherein said tube-in-tube riser reactor has an inner tube with a length amounting to 15-50% of the total length of the riser reactor.  
     
     
         17 . The process according to  claim 14 , wherein said distance from the lower end of the outer tube to the lower end of the inner tube in said tube-in-tube riser reactor is 5-15% of the total length of the riser reactor.  
     
     
         18 . The process according to  claim 14 , wherein said cross-section area ratio of the confluence tube to the inner tube is 1:0.3-0.7 in said tube-in-tube riser reactor.  
     
     
         19 . The process according to  claim 14 , wherein said tube-in-tube riser reactor is installed with 2-12 lines of shrouding wires or draw-bars between the inner tube and the outer tube.  
     
     
         20 . The process according to  claim 14 , wherein said tube-in-tube riser reactor has a distance of 0.5-20 meters from the outlet end of the inner tube to the outlet end of the confluence tube.  
     
     
         21  A catalytic cracking process of petroleum hydrocarbons, comprising mainly the following steps: 
 (1) sending a regenerated catalyst to the bottom of the tube-in-tube riser reactor via a catalyst conduit, which flows upwards under an action of a pre-lifting media, 20-80% by weight of the regenerated catalyst flowing into the inner tube, and the remaining part of the regenerated catalyst entering the annular space between the inner and outer tubes, which flows upward under an action of the pre-lifting media;  
 (2) feeding a hydrocarbon feedstock to the inner tube of the reactor to contact the catalyst therein and form a oil-catalyst mixture, so that the reaction of the hydrocarbon feedstock is carried out under catalytic cracking reaction conditions to form a reaction stream which flows upward along vessel wall;  
 (3) the reaction stream from the inner tube and the regenerated catalyst (stream) from the annular space flow together in the confluence tube, and making the reaction stream react continuously under catalytic cracking conditions; introducing the resulting reaction stream to a separation apparatus via the confluence tube, where a hydrocarbon product stream is separated from a spent catalyst;  
 (4) separating the hydrocarbon product stream further into various products including gasoline, diesel oil and liquefied petroleum gas; stripping and regenerating the spent catalyst, and recycling the regenerated catalyst into the reactor for reuse.  
 
     
     
         22 . The process according to  claim 21 , wherein said catalyst fed to the tube-in-tube riser reactor via the catalyst inlet conduit is a regenerated catalyst or a cooled regenerated catalyst.  
     
     
         23 . The process according to  claim 21  or  22 , wherein the active components of said catalyst are at least one kind of zeolite selected from a group consisting of Y-type or HY-type zeolite containing or not containing rare earth and/or phosphorous, ultra-stable Y-type zeolite containing or not containing rare earth and/or phosphorous, ZSM-5 family zeolite or high-silica zeolite having a pentasil structure, β-zeolite, ferrierite and a mixture thereof.  
     
     
         24 . The process according to  claim 21 , wherein said catalyst contains 0.5-60% by weight of ZSM-5 family zeolite or other high-silica zeolite having a pentasil structure.  
     
     
         25 . The process according to  claim 21 , wherein said hydrocarbon feedstock fed to the inner tube is selected from a group consisting of gaseous hydrocarbon, refinery gas, primary processing gasoline fraction, secondary processing gasoline fraction, primary processing diesel oil fraction, secondary processing diesel oil fraction, straight run gas oil, coker gas oil, deasphalted oil, hydrofined oil, hydrocracking tail oil, vacuum gas oil, vacuum residuum, atmospheric residuum and a mixture thereof.  
     
     
         26 . The process according to  claim 25 , wherein said hydrocarbon feedstock fed to the inner tube is selected from the group consisting of straight run gas oil, coker gas oil, deasphalted oil, hydrofined oil, hydrocracking tail oil, vacuum gas oil, vacuum residuum, atmospheric residuum and a mixture thereof.  
     
     
         27 . The process according to  claim 21 , wherein said hydrocarbon feedstock is reacted in the inner lube under conditions as follows, a reaction temperature of 480-700° C. a reaction pressure of 0.1-0.6 MPa, a catalyst-oil ratio of 3-30, an oil-gas residence time of 1.0-10 seconds in the inner tube, a catalyst temperature of 620-800° C. before contacting the feedstock, and an atomization steam amount of 1-45% by weight.  
     
     
         28 . The process according to  claim 27 , wherein said hydrocarbon feedstock is reacted in the inner tube under conditions as follows: a reaction temperature of 500-680° C., a reaction pressure of 0.2-0.4 MPa, a catalyst-oil ratio of 4-25, an oil-gas residence time of 1.5-5.0 seconds in the inner tube, a catalyst temperature of 640-750° C. before contacting the feedstock, and an atomization steam amount of 2-35% by weight.  
     
     
         29 . The process according to  claim 21 , wherein said reaction stream is reacted in the confluence tube under conditions as follows: a reaction temperature of 490-720° C., a reaction pressure of 0.1-0.6 MPa, a catalyst-oil ratio of 4-40, an oil-gas residence time of 0.5-10 seconds in the confluence tube, and a steam-oil ratio of 3-45% by weight.  
     
     
         30 . The process according to  claim 29 , wherein said reaction stream is reacted in the confluence tube under conditions as follows: a reaction temperature of 500-700° C., a reaction pressure of 0.2-0.4 MPa, a catalyst-oil ratio of 5-30, an oil-gas residence time of 1.0-5 seconds in the confluence tube, and a steam-oil ratio of 5-35% by weight.  
     
     
         31 . The process according to  claim 21 , wherein said tube-in-tube riser reactor is one having single conduit for feeding catalyst and comprises mainly the following members: catalyst inlet conduit ( 1 ), inner tube ( 2 ), outer tube ( 3 ), confluence tube ( 4 ), pre-lifting distribution rings ( 5 ), ( 6 ) and ( 7 ), and feed nozzles ( 8 ) and ( 9 ), wherein, the inner tube ( 2 ) and the outer tube ( 3 ) are coaxial, and the ratio of the cross-section area of the inner tube to the cross-section area of the annular space between the inner and outer tubes is in the range 1:0.1-10; the lower end of the inner tube ( 2 ) is located at a place above the catalyst inlet; the inner tube has a length amounting to 10-70% of the total length of the reactor; one end of the confluence tube ( 4 ) is connected with the upper end of the outer tube ( 3 ), and the other end is connected to the gas/solid separation apparatus, the cross-section area ratio of the confluence tube ( 4 ) to the inner tube ( 2 ) is 1:0.2-0.8; the pre-lifting distribution rings ( 5 ), ( 6 ) and ( 7 ) are located at the bottoms of the reactor, the inner tube and the outer tube respectively.  
     
     
         32 . The process according to  claim 31 , wherein said tube-in-tube riser reactor has a ratio of the cross-section area of the inner lube to the cross-section area of the annular space between the inner and outer tubes in a range of 1:0.2-2.  
     
     
         33 . The process according to  claim 31 , wherein said inner tube of the tube-in-tube riser reactor has a length amounting to 20-60% of the total length of the reactor.  
     
     
         34  The process according to  claim 31 , wherein said tube-in-tube riser reactor has a distance of 1-30 meters from the outlet end of the inner tube to the outlet end of the confluence tube.  
     
     
         35 . The process according to  claim 31 , characterized in that said tube-in-tube riser reactor is installed with 2-12 lines of shrouding wires or draw-bars between the inner tube and outer tube.  
     
     
         36 . The process according to  claim 21 , wherein said tube-in-tube riser reactor is one having two conduits for feeding catalyst and comprises mainly the following members: catalyst inlet conduits ( 21 ) and ( 22 ), inner tube ( 35 ), outer tube ( 36 ), confluence tube ( 38 ), pre-lifting distribution rings ( 31 ) and ( 33 ), and feed nozzles ( 32 ) and ( 34 ), wherein, the inner tube ( 35 ) and outer tube ( 36 ) are coaxial, the ratio of the cross-section area of the inner tube to the cross-section area of the annular space between the inner and outer tubes is 1:0.1-10; the catalyst inlet conduit ( 21 ) is connected with the lower end of the inner tube ( 35 ), the length of the inner tube is 10-70% of the total length of the reactor; the distance from the lower end of the outer tube ( 36 ) to the lower end of the inner tube ( 35 ) is 2-20% of the total length of the reactor, the catalyst inlet conduit ( 22 ) is connected with the lower end of the outer tube ( 36 ); one end of the confluence tube ( 38 ) is connected with the upper end of the outer tube ( 36 ), and the other end is connected with a gas/solid separation apparatus, the cross-section area ratio of the confluence tube ( 38 ) to the inner tube ( 35 ) is 1:0.2-0.8; the pre-lifting distribution rings ( 31 ) and ( 33 ) are located at the bottom of the inner tube and the bottom of the annular space between the inner and outer tubes respectively; feed nozzles ( 32 ) and ( 34 ) are located at the lower part of the inner tube and the lower part of the outer tube respectively.  
     
     
         37 . The process according to  claim 36 , wherein said tube-in-tube riser reactor has a ratio of the cross-section area of the inner tube to the cross-section area of the annular space between the inner and outer tubes in a range of 1.0.1-2  
     
     
         38 . The process according to  claim 36 , wherein said inner tube of said tube-in-tube riser reactor has a length amounting to 15-50% of the total length of the riser reactor.  
     
     
         39 . The process according to  claim 36 , wherein said tube-in-tube riser reactor has a distance of 5-15% of the total length of the riser reactor from a lower end of the outer tube to the lower end of the inner tube.  
     
     
         40 . The process according to  claim 36 , wherein said tube-in-tube riser reactor has an cross-section area ratio of the confluence tube to the inner tube in a range of 1:0.3-0.7.  
     
     
         41 . The process according to  claim 36 , wherein said tube-in-tube riser reactor is installed with 2-12 lines of shrouding wires or draw-bars between the inner tube and outer tube.  
     
     
         42 . The process according to  claim 36 , wherein said tube-in-tube riser reactor has a distance of 0.5-10 meters from the outlet end of the inner tube to the outlet end of the confluence tube.