Conversion of C1-C3 alkanes and Fischer-Tropsch products to normal alpha olefins and other liquid hydrocarbons

Abstract

Processes for converting C 1 to C 3 alkanes into high purity C 6 to C 24 normal alpha olefins and internal combustion engine grade fuels and/or lubricating oils comprising a sequence of fractionation and thermal cracking and/or hydrocracking operations. The C 6 to C 24 normal alpha olefin fractions generally have a purity of at least about 90 wt. %.

What is claimed is:  
     
         1 . A process for converting a Fischer-Tropsch type reaction product fraction comprising at least about 90 wt. % C 16 -C 50  linear paraffins into high purity C 6 -C 24  normal alpha olefins which comprises the steps of: 
 a) thermal cracking said reaction product in the presence of at least 5 moles of steam per mole of said reaction product at a conversion based on said reaction product no greater than 30 wt. % thereby producing a product mixture comprising a fraction boiling in the C 6 -C 24  normal alpha olefin range containing at least about 90 wt. % C 6 -C 24  normal alpha olefins; and    b) separating the product mixture of step a) to recover one or more fractions boiling within the boiling range of C 6 -C 24  normal alpha olefins having a normal alpha olefin purity of at least about 90 wt. %.    
     
     
         2 . The process according to  claim 1  wherein said separation in step b) is conducted by fractional distillation.  
     
     
         3 . The process according to  claim 1  wherein said product mixture is fractionated in said step b) by extractive fractional distillation to produce one or more normal alpha olefin fractions within the range of C 6 -C 24  and wherein said fractions have a normal alpha olefin purity of at least about 95 wt. %.  
     
     
         4 . The process of according to  claim 1  wherein said reaction product is thermal cracked to a conversion between about from 15 to 25 wt. %.  
     
     
         5 . The process according to  claim 1  wherein said product mixture is fractionated in step b) by adsorption to produce one or more normal alpha olefin fractions within the range of C 6 -C 24  and wherein said fractions have a normal alpha olefin purity of at least 95 wt. %.  
     
     
         6 . The process according to  claim 1  wherein said Fischer-Tropsch type reaction product is a Fischer-Tropsch reaction product.  
     
     
         7 . A process for upgrading Fischer-Tropsch type reaction products comprising a first hydrocarbon reaction product boiling above about 540° F. (282° C.) comprising C 16 -C 50  paraffins liquid fuel hydrocarbons and oxygenates and a second reaction product boiling below about 540° F. (282° C.) comprising tail gases, paraffins, olefins and oxygenates which process comprises the steps of: 
 a) fractionating said first hydrocarbon reaction product into separate fractions comprising a fraction boiling in the liquid fuel boiling range, a wax fraction boiling in about the range of about 540° F.-1100° F. comprising at least about 90 wt. % C 16 -C 50  linear paraffins, and a fraction boiling above about 1100° F.;  
 b) thermal cracking the wax fraction of step a) in the presence of steam at a mole ratio of steam to said wax fraction of about from 3:1 to 5:1, under reactive conditions adjusted to provide a conversion no greater than about 30 wt. % of said wax fraction thereby yielding a reaction product mixture containing substantial amounts of normal alpha olefins of varying chain length within the range of C 6 -C 24 , without the production of significant amounts of C 6 -C 24  dienes and wherein the fraction of said reaction product mixture boiling within the C 6  to C 24  normal alpha olefin boiling range contains at least 90 wt. % C 6  to C 24  normal alpha olefins;  
 c) fractionating the reaction product of step b) into separate fractions comprising at least one normal alpha olefin product fraction comprising normal alpha olefins selected within the range of 6 to 24 carbon atoms and a higher boiling fraction boiling above about 730° F. (388° C.) comprising higher boiling olefins and paraffins;  
 d) separating said second Fischer-Tropsch reaction product into a tail gas fraction and a condensate fraction boiling below about 540° F. comprising C 5  and higher carbon atom hydrocarbons,  
 e) hydrocracking said condensate fraction of step d), the higher boiling fraction of step c) and the liquid fuel fraction of step a) with hydrogen under hydrocracking conditions in the presence of a catalyst comprising a hydrogenation component and an acid catalyst cracking component in a hydrocracker under hydrocracking conditions to produce a liquid reaction product mixture comprising a liquid fuel boiling fraction and a higher boiling fraction; and  
 f) fractionating the liquid reaction product mixture of step e) into separate fractions comprising at least one liquid fuel boiling range fraction and at least one higher boiling fraction and recycling at least one higher boiling fraction back to said hydrocracker.  
 
     
     
         8 . The process of  claim 7  wherein said step b) is conducted at a temperature of about from 1000° F. (538° C.) to 1600° F. (871° C.) in the presence of about from 0.2 to 1 part by wt. of steam per part by wt. of said wax fraction.  
     
     
         9 . The process of  claim 7  wherein said catalyst of step e) contains at least one non-noble Group VIII metal and at least one Group VIB metal and an acid catalyst component.  
     
     
         10 . The process according to  claim 7  wherein said first hydrocarbon reaction product is contacted with hydrogen under hydrotreating reactive conditions in the presence of a hydrotreating catalyst thereby converting oxygenates and olefins into paraffins.  
     
     
         11 . The process according to  claim 7  wherein said wax fraction is contacted with hydrogen under hydrotreating reactive conditions in the presence of a hydrotreating catalyst thereby converting oxygenates and olefins into paraffins.  
     
     
         12 . A process for converting C 1 -C 3  alkanes into liquid hydrocarbon products comprising C 6 -C 24  normal alpha olefins and fuels which comprises the steps of: 
 a) reforming said C 1 -C 3  alkanes into a syngas having a mole ratio of hydrogen to carbon monoxide of about from 1 to 3 moles of hydrogen per mole of carbon monoxide;    b) contacting the syngas product of step a) with a Fischer-Tropsch catalyst under Fischer-Tropsch reaction conditions to yield a first hydrocarbon reaction product boiling above about 540° F. comprising a major amount of C 16 -C 50  linear paraffins and lesser amounts of oxygenates and higher boiling hydrocarbons and a second reaction product boiling below about 540° F. comprising tail gases, oxygenates and liquid fuel paraffins and oxygenates;    c) fractionating said first reaction product of step b) into separate fractions comprising a fraction boiling in the liquid fuel boiling range, a wax fraction boiling in the range of about 540° F.-1100° F. comprising at least about 90 wt. % C 16 -C 50  linear paraffins and a high boiling fraction boiling above about 1100° F.;    d) thermal cracking the wax fraction of step e) in the presence of steam at a mole ratio of steam to said wax fraction of about from 3:1 to 5:1, under reactive conditions adjusted to provide a conversion no greater than about 30 wt. % of said wax fraction thereby yielding a reaction product mixture containing substantial amounts of C 6 -C 24 , alpha olefins of varying chain length without the production of significant amounts of C 6 -C 24  dienes and wherein the fraction of said reaction product boiling within the C 6 to C 24  normal alpha olefin boiling range contains at least 90 wt. % C 6  to C 24  normal alpha olefins;    e) fractionating the reaction product of step d) into separate fractions comprising at least one normal alpha olefin product fraction comprising a normal alpha olefin fraction selected within the range of 6 to 24 carbon atoms and having a normal alpha olefin purity of at least 90 wt. % and a higher boiling fraction comprising higher boiling olefins and paraffins;    f) hydrocracking said higher boiling fraction of step e) the liquid fuel fraction and the high boiling fraction of step c) and with hydrogen in the presence of a catalyst comprising a hydrogenation component and an acid catalyst cracking component under hydrocracking conditions to produce a liquid reaction product mixture comprising a liquid fuel boiling fraction and a higher boiling fraction; and    g) fractionating the liquid reaction product mixture of step f) into separate fractions comprising at least one liquid fuel fraction and at least one higher boiling fraction and recycling at least one said higher boiling fraction back to said hydrocracker.    
     
     
         13 . The process of  claim 12  wherein said second reaction product of step b) is separated into a tail gas fraction and a C 5  and higher carbon atom hydrocarbon fraction boiling below about 540° F. and hydrocracking said C 5  and higher carbon atom hydrocarbon fraction with hydrogen in the presence of a hydrocracking catalyst comprising a hydrogenation component and an acid cracking component under hydrocracking conditions.  
     
     
         14 . The process of  claim 12  wherein said step b) in conducted in a bubble slurry reactor.  
     
     
         15 . The process of  claim 12  wherein said step d) is conducted at a temperature of about from 650 to 1900° F. in the presence of about 0.2 to 1 part per weight of steam per part by weight of said wax fraction.  
     
     
         16 . The process of  claim 12  wherein said catalyst of step f) contains at least one non-noble Group VIII metal and at least one Group VIB metal and an acid catalyst component.  
     
     
         17 . The process according to  claim 12  wherein said first hydrocarbon reaction product is contacted with hydrogen under hydrotreating reactive conditions in the presence of a hydrotreating catalyst thereby converting oxygenates and olefins into paraffins.  
     
     
         18 . The process according to  claim 12  wherein said wax fraction is contacted with hydrogen under hydrotreating reactive conditions in the presence of a hydrotreating catalyst thereby converting oxygenates and olefins into paraffins.  
     
     
         19 . A process for upgrading a Fischer-Tropsch reaction product boiling above about 540° F. containing C 16  to C 50  linear paraffins, oxygenates, hydrocarbons boiling in the liquid fuel ranges and linear boiling hydrocarbons and wherein said reaction product contains at least 20 wt. % of C 16  to C 50  linear paraffins and less than 5 wt. % of said oxygenates, which process comprises the steps of: 
 a) fractionating said Fischer-Tropsch reaction product into separate fractions comprising a fraction boiling in the liquid fuel boiling range, a wax fraction boiling in about the range of 540° F. to 1100° F. comprising at least about 90 wt. % C 16  to C 50  linear paraffins and a high boiling fraction boiling above about 1100° F.  
 b) thermal cracking the wax fraction of step a) in the presence of steam at a mole ratio of steam to said wax fraction of at least 5:1, under reactive conditions adjusted to provide a conversion no greater than about 30 wt. % of said wax fraction thereby yielding a reaction product mixture containing normal alpha olefins of varying chain length within the range of C 6  to C 24 , without the production of significant amounts of C 6  to C 24  dienes and wherein the fraction of said reaction product boiling within the C 6  to C 24  normal alpha olefin boiling range contains at least 90 wt. % C 6  to C 24  normal alpha olefins;  
 c) fractionating the reaction product of step b) into separate fractions comprising at least one normal alpha olefin product fraction comprising normal alpha olefins selected within the range of 6 to 24 carbon atoms having purity of said normal alpha olefins of at least 90 wt. % and a higher boiling fraction comprising higher boiling olefins and paraffins;  
 d) hydrocracking said higher boiling fraction of step c), and the liquid fuel fraction of step a) with hydrogen in a hydrocracker in the presence of a catalyst comprising a hydrogenation component and an acid catalyst cracking component, under hydrocracking conditions to produce a liquid reaction product mixture comprising a liquid fuel boiling fraction; and  
 e) fractionating the liquid reaction product mixture of step d) into separate fractions comprising a liquid fuel fraction, and at least one higher boiling hydrocarbon fraction and recycling at least one of said higher boiling fraction back to said hydrocracker.  
 
     
     
         20 . The process of  claim 19  wherein said step b) is conducted at a temperature of about from 1000° F. (538° C.) to 1600° F. (871° C.) in the presence of about from 0.2 to 1 part by wt. of steam per part by wt. of said wax fraction.  
     
     
         21 . The process of  claim 19  wherein said catalyst of step d) contains at least one non-noble Group VIII metal and at least one Group VIB metal and an acid catalyst component.  
     
     
         22 . The process according to  claim 19  wherein said Fischer-Tropsch reaction product is contacted with hydrogen under hydrotreating reactive conditions in the presence of a hydrotreating catalyst thereby converting oxygenates and olefins into paraffins.  
     
     
         23 . The process according to  claim 19  wherein after fractionation said wax fraction is contacted with hydrogen under hydrotreating reactive conditions in the presence of a hydrotreating catalyst thereby converting oxygenates and olefins into paraffins.  
     
     
         24 . A process for converting C 1 -C 3  alkanes into liquid hydrocarbon products comprising normal alpha olefins and fuels which comprises the steps of: 
 a) reforming said C 1 -C 3  alkanes into a syngas having a mole ratio of hydrogen to carbon monoxide of about from 1 to 3 moles of hydrogen per mole of carbon monoxide;    b) contacting the syngas product of step a) with a Fischer-Tropsch catalyst under Fischer-Tropsch reaction conditions to yield a liquid hydrocarbon reaction product boiling in about the range of 68° F. to 1300° F. comprising at least about 20 wt. % C 16  to C 50  linear paraffins, and lesser amounts of oxygenates;    c) fractionating the reaction product of step b) into separate fractions comprising a fraction boiling in the liquid hydrocarbon fuel range; a wax fraction boiling in about the range of 540° F. to 1100° F. comprising at least 90 wt. % C 16  to C 50  linear paraffins; and a high boiling hydrocarbon fraction boiling above 1100° F.; and    d) thermal cracking the wax fraction of step c) in the presence of at least five moles of steam per mole of said wax fraction under reactive conditions adjusted to provide a conversion, based on said wax fraction no greater than 30 wt. % thereby yielding a reaction product mixture containing normal alpha olefins of varying chain length within the range of C 6  to C 24 , uncracked linear paraffins without the production of significant amounts of C 6  to C 24  dienes and wherein the fraction boiling within the boiling range of C 6  to C 24  normal alpha olefins contains at least 90 wt. % C 6  to C 24  normal alpha olefins;    e) fractionating the reaction product of step d) into separate fractions comprising at least one normal alpha olefin product fraction comprising normal alpha olefins selected within the range of 6 to 24 carbon atoms and a higher boiling fraction comprising higher boiling olefins and paraffins and wherein said normal alpha olefin fractions have a purity of at least about 90 wt. %;    f) hydrocracking the fuel fraction and higher boiling fraction of step c) and the higher boiling fraction of step e) by contacting said fraction with hydrogen in the presence of a catalyst comprising a hydrogenation component and an acid catalyst cracking component, under hydrocracking conditions to produce a liquid reaction product mixture comprising a fuel boiling fraction;    g) fractionating the liquid reaction product mixture of step f) into separate fractions comprising a liquid fuel boiling range fraction, and at least one higher boiling hydrocarbon fraction and recycling at least one of said higher boiling fraction back to said hydrocracker.    
     
     
         25 . The process of  claim 24  wherein said step b) in conducted in a bubble slurry reactor.  
     
     
         26 . The process of  claim 24  wherein said step d) is conducted at a temperature of about from 650 to 1900° F. in the presence of about 0.2 to 1 part per weight of steam per part by weight of said wax fraction.  
     
     
         27 . The process of  claim 24  wherein said catalyst of step f) contains at least one non-noble Group VIII metal and at least one Group VIB metal and an acid catalyst component.  
     
     
         28 . The process according to  claim 24  wherein said liquid hydrocarbon reaction product of step (b) is contacted with hydrogen under hydrotreating reactive conditions in the presence of a hydrotreating catalyst thereby converting oxygenates and olefins into paraffins.  
     
     
         29 . The process according to  claim 24  wherein said wax fraction is contacted with hydrogen under hydrotreating reactive conditions in the presence of a hydrotreating catalyst thereby converting oxygenates and olefins into paraffins.