Process to prepare paraffins and waxes

Abstract

A process for preparing paraffins and waxes includes providing a gas mixture comprising hydrogen and carbon monoxide to at least two conversion reactors for catalytically converting the gas mixture to obtain an initial Fischer-Tropsch product comprising paraffins having from 5 to 300 carbon atoms. The initial Fischer-Tropsch product streams from each of the reactors are combined before being subjected to a hydrogenation step. The hydrogenated product stream is separated into C5-C9, C10-C17 and C18-300 fractions. The C18-C300 fraction is separated to obtain one or more light waxes having a congealing point in the range of 30 to 75° C. and a heavy wax having a congealing point in the range of 75 to 120° C. The relative concentrations of the C5-C9 and the C10-C17 fractions, and the concentrations of the light and heavy waxes is changed by raising, lowering or maintaining the reaction temperature of at least one of the reactors.

1 . Process to prepare paraffins and waxes from a gas mixture comprising hydrogen and carbon monoxide in at least two conversion reactors, being a first and second reactor, said reactors comprising catalysts, which process at least comprises the following steps:
 (a) providing the gas mixture to the at least two conversion reactors;   (b) catalytically converting the gas mixture of step (a) at an initial reaction condition to obtain an initial Fischer-Tropsch product comprising paraffins having from 5 to 300 carbon atoms;   (c) combining the initial Fischer-Tropsch product streams from each of the at least two reactors of step (b) to obtain a combined Fischer-Tropsch product stream;   (d) subjecting the combined Fischer-Tropsch product stream of step (c) to a hydrogenation step to obtain a hydrogenated Fischer-Tropsch product stream;   (e) separating the hydrogenated Fischer-Tropsch product stream of step (d), thereby obtaining at least a fraction comprising 5 to 9 carbon atoms, a fraction comprising 10 to 17 carbon atoms and a fraction comprising 18 to 300 carbon atoms;   (f) separating the hydrogenated fraction comprising 18 to 300 carbon atoms of step (e), thereby obtaining one or more light waxes having a congealing point in the range of 30 to 75° C. and a heavy wax having a congealing point in the range of 75 to 120° C., wherein subsequently the relative concentration of the fraction comprising 5 to 9 carbon atoms, the fraction comprising 10 to 17 carbon atoms, the concentration of the light waxes and the concentration of the heavy waxes is changed by raising, lowering or maintaining the reaction temperature of at least one of the reactors.   
     
     
         2 . A process according to  claim 1 , wherein the Fischer-Tropsch reactors are operated at an initial reaction condition of step (b) comprising a temperature in the range of 200 to 250° C. and preferably from 205 to 230° C. 
     
     
         3 . Process according to  claim 1 , wherein the amount of the fraction comprising 5 to 9 carbon atoms of step (e) is in the range of from 3-14 wt. % based on the full Fischer-Tropsch hydrocarbonaceous comprising a C1 to C300 fraction. 
     
     
         4 . Process according to  claim 1 , wherein the amount of the fraction comprising 10 to 17 carbon atoms of step (e) is in the range of from 7-21 wt. % based on the full Fischer-Tropsch hydrocarbonaceous comprising a C1 to C300 fraction. 
     
     
         5 . Process according to  claim 1 , wherein one or more wax fractions having a congealing point in the range of 30 to 75° C. of step (f) are hydrofinished to obtain one or more hydrofinished wax fractions having a congealing point in the range of 30 to 75° C. 
     
     
         6 . Process according to  claim 1 , wherein the amount of hydrofinished wax fraction having a congealing point of 30° C. is in the range of from 3-7 wt. % based on the full Fischer-Tropsch hydrocarbonaceous comprising a C1 to C300 fraction. 
     
     
         7 . Process according to  claim 1 , wherein the amount of hydrofinished wax fraction having a congealing point of 50° C. is in the range of from 5-13 wt. % based on the full Fischer-Tropsch hydrocarbonaceous comprising a C1 to C300 fraction. 
     
     
         8 . Process according to  claim 1 , wherein the amount of hydrofinished wax fraction having a congealing point of 70° C. is in the range of from 7-16 wt. % based on the full Fischer-Tropsch hydrocarbonaceous comprising a C1 to C300 fraction-. 
     
     
         9 . Process according to  claim 1 , the heavy wax of step (f) is separated, thereby obtaining at least one distillate wax fraction having a congealing point in the range of between 75 to 85° C. and at least one residual wax fraction having a congealing point in the range of from 95 to 120° C. 
     
     
         10 . Process according to  claim 9 , the heavy distillate wax fraction having a congealing point in the range of between 75 to 85° C. is hydrofinished to obtain a hydrofinished heavy distillate wax fraction having a congealing point in the range of between 75 and 85° C. 
     
     
         11 . Process according to  claim 9 , wherein the heavy residual wax fraction having a congealing point in the range of 95 to 120° C. is hydrofinished to obtain a hydrofinished heavy residual wax fraction having a congealing point in the range of 95 to 120° C. 
     
     
         12 . Process according to  claim 1 , wherein the amount of hydrofinished wax fraction having a congealing point of 100 to 105° C. is in the range of from 15-70 wt. % based on the full Fischer-Tropsch hydrocarbonaceous comprising a C1 to C300 fraction. 
     
     
         13 . A process according to  claim 1 , wherein the reactor operating point is raised by:
 increasing the amount of synthesis gas provided to the reactor;   raising the temperature of the cooling water provided to the reactor; and/or   providing a nitrogen containing compound, to the reactor, preferably by adding the nitrogen containing compound to the gas mixture prior to step a) and b), preferably the nitrogen containing compound is selected from the group of ammonia, HCN, NO, an amine and combinations or two or more thereof.   
     
     
         14 . A process according to  claim 1 , wherein the reactor operating point is lowered by:
 decreasing the amount of synthesis gas provided to the reactor;   lowering the temperature of the cooling water provided to the reactor; and/or   providing a nitrogen containing compound, to the reactor, preferably by adding the nitrogen containing compound to the gas mixture prior to step a) and b), preferably the nitrogen containing compound is selected from the group of ammonia, HCN, NO, an amine and combinations or two or more thereof.