Catalytic Reformer Recycle Gas Compressor Efficiency

Abstract

Methods for improving the efficiency of a catalytic reforming recycle gas compressor by combining a high molecular weight light hydrocarbon process stream from a unit operation associated with the catalytic reforming process with a lower molecular weight reactor off gas recycle stream to form a combined recycle gas stream.

1 . A method for increasing hydrogen flow through a recycle gas compressor associated with a catalytic reforming process comprising the steps of:
 a. operating the recycle gas compressor having an inlet and an outlet in a catalytic reforming process including at least one catalytic reforming reactor to increase the pressure of a combined recycle gas stream directed to an inlet of the at least one catalytic reforming reactor;   b. directing a recycle gas stream including hydrogen from an outlet of the catalytic reforming reactor to the compressor inlet;   c. combining a gaseous product stream from a unit operation associated with the catalytic reforming process with the recycle gas stream to form a combined recycle stream wherein the combined recycle stream molecular weight is greater than the recycle gas stream molecular weight; and   d. directing the combined recycle stream into the inlet of the at least one catalytic reforming reactor.   
   
   
       2 . The method of  claim 1  wherein the gaseous product stream is combined with the recycle gas stream including hydrogen to form a combined recycle stream at a point before the compressor inlet. 
   
   
       3 . The method of  claim 1  wherein the gaseous product stream is combined with the recycle gas stream including hydrogen to form a combined recycle stream at a point following the compressor outlet. 
   
   
       4 . The method of  claim 1  wherein the gaseous product stream is the product of a unit operation associated with the catalytic reforming process selected from a depropanizer, a debutanizer, a depentanizer, or any of a depropanizer, debutanizer, and depentanizer followed by a deethanizer. 
   
   
       5 . The method of  claim 4  wherein the unit operation is a debutanizer and wherein the product stream is a debutanizer overhead liquid stream. 
   
   
       6 . The method of  claim 1  wherein the gaseous product stream from a unit operation associated with the catalytic reforming process is an LPG stream that has a molecular weight that is greater than the molecular weight of the recycle gas stream including hydrogen. 
   
   
       7 . The method of  claim 5  wherein the debutanizer overhead liquid stream is flashed to form a gaseous product stream before the gaseous product stream is combined with the recycle gas stream. 
   
   
       8 . The method of  claim 1  wherein a catalytic reforming reactor product stream is directed into a separator to form a separator gas stream and a separator liquid stream where the separator gas stream is divided into a net gas stream and the recycle gas stream including hydrogen wherein at least a potion of the net gas stream is combined with at least a portion of the separator liquid stream to form a recontacted product steam. 
   
   
       9 . The method of  claim 8  wherein the recontacted product stream is directed to a unit operation selected from the group consisting of a depropanizer, a debutanizer, a depentanizer, or any of a depropanizer, debutanizer, and depentanizer followed by a deethanizer. 
   
   
       10 . The method of  claim 1  wherein the combined compressor recycle stream has a molecular weight of from about 5 to about 20. 
   
   
       11 . The method of  claim 1  wherein the combined compressor recycle stream has a molecular weight that is about 25-50% greater than the molecular weight of the recycle gas stream including hydrogen. 
   
   
       12 . The method of  claim 1  wherein the combined compressor gas recycle stream includes at least about 70-85 mole % hydrogen.