Conversion of paraffins to gasoline
AssigneeMobil Oil Corporation
InventorMohsen N. Harandi
Life of this patent
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Abstract
An improved two-step process for the conversion of lower molecular weight paraffins, the process comprising contacting in a first step a C.sub.2 -C.sub.10 alkane-rich feedstock with a siliceous zeolite catalyst in a primary fluidized bed reaction zone under high temperature dehydrogenation conditions to obtain an intermediate product comprising oligomerizable olefinic hydrocarbons and aromatics; and then contacting in a second step the intermediate product with a siliceous zeolite catalyst in a secondary fluidized bed reaction zone under low temperature oligomerization conditions to obtain a final product comprising gasoline boiling range aliphatic and aromatic hydrocarbons.
Claims39
A continuous process for conversion of C.sub.2 -C.sub.4 alkanes to aromatic rich hydrocarbons boiling in the gasoline range comprising:
- maintaining a dual vertical column reactor comprising a lower transport riser reaction zone and an upper turbulent fluidized bed reaction zone, both zones containing fluidized catalyst comprising acid medium pore metallosilicate zeolite;
- contacting a feedstock comprising at least one C.sub.2 -C.sub.4 alkane with fluidized catalyst in the lower transport zone under high temperature dehydrogenation conditions to dehydrogenate the feedstock and substantially prevent cracking reacations to obtain an intermediate product comprising dehydrogenated hydrocarbons and aromatics;
- and
- contacting the intermediate hydrocarbon product with fluidized catalyst in the upper turbulent zone under lower temperature oligomerization conditions to obtain a final product comprising C.sub.5 + gasoline boiling range hydrocarbons.
In a process for dehydrocyclization of a paraffinic feedstock comprising C.sub.2 -C.sub.10 alkanes in a primary fluidized bed reaction zone over a catalyst comprising crystalline medium pore acid siliceous zeolite under high severity conversion conditions of temperature and pressure to obtain an aromatic product comprising benzene, toluene and/or xylenes, the improvement comprising:
- (a) optimizing the operating severity by adjusting the space velocity and temperature in the primary reaction zone to effect partial conversion of the paraffinic feedstock, thererby effectively dehydrogenating the C.sub.2 -C.sub.10 alkanes to obtain an intermediate product containing maximum lower olefins and aromatics.
- (b) adding a secondary fluidized bed reaction zone in series with the primary reaction zone, the secondary reaction zone containing a catalyst comprising crystalline medium pore acid siliceous zeolite;
- and
- (c) contacting the intermediate product in the secondary fluidized bed reaction zone over the siliceous catalyst under oligomerization conditions to obtain a final product comprising C.sub.5 + gasoline boiling range aliphatic and aromatic hydrocarbons and unconverted alkanes.
A process for the conversion of C.sub.2 -C.sub.10 alkanes to aromatic rich hydrocarbons boiling in the gasoline range comprising:
- contacting a feedstock comprising at least one C.sub.2 -C.sub.10 alkane with a catalyst comprising crystalline medium pore acid siliceous zeolite in a primary fluidized bed reaction zone under high temperature dehydrogenation conditions to substantially prevent cracking reactions to obtain an intermediate product comprising aromatic and olefinic hydrocarbons;
- and
- contacting the intermediate product with a catalyst comprising crystalline medium pore acid siliceous zeolite in a secondary fluidized bed reaction zone under lower temperature oligomeriztion conditions to obtain a final product comprising gasoline boiling range hydrocarbons and unreacted C.sub.2 -C.sub.10 alkane.
An apparatus for the continuous conversion of C.sub.2 -C.sub.4 alkanes to aromatic rich hydrocarbons boiling in the gasoline range comprising:
- a dual vertical column reactor comprising a lower transport riser reaction zone and an upper turbulent fluidized bed reaction zone, both zone containing fluidized catalyst comprising acid medium pore metallosiliate zeolite;
- means for contacting a feedstock comprising at least one C.sub.2 -C.sub.4 alkane with fluidized catalyst in the lower transport zone under high temperature dehydrogenation conditions to dehydrogenate the feedstock and substantially prevent cracking reactions to obtain an intermediate product comprising dehydrogenated hydrocarbons and aromatics;
- and
- means for contacting the intermediate hydrocarbon product with fluidized catalyst in the upper turbulent zone under lower temperature oligomerization conditions to obtain a final product comprising C.sub.5 + gasoline boiling range hydrocarbons.
An apparatus for the conversion of C.sub.2 -C.sub.10 alkanes to aromatic rich hydrocarbons boiling in the gasoline range comprising:
- means for contacting a feedstock comprising at least one C.sub.2 -C.sub.10 alkane with a catalyst comprising crystalline medium pore acid siliceous zeolite in a primary fluidized bed reaction zone under high temperature dehydrogenation conditions to substantially prevent cracking reactions to obtain an intermediate product comprising aromatic and olefinic hydrocarbons;
- and
- means for contacting the intermediate product with a catalyst comprising crystalline medium pore acid siliceous zeolite in a secondary fluidized bed reaction zone under lower temperature oligomerizatoin conditions to obtain a final product comprising gasoline boiling range hydrocarbons and unreacted C.sub.2 -C.sub.10 alkane.
Dependencies are inferred from the claim text.