Abstract: In a process in which a fuel gas stream having a high BTU content is mixed with a fuel gas stream having a low BTU content to form a mixed fuel gas stream, the flow rate of the high BTU content fuel gas stream is manipulated to maintain a desired BTU content for the mixed fuel gas stream unless such control based on the desired BTU content for the mixed fuel gas stream would result in condensation in the mixed fuel gas stream. If condensation would occur, then the flow rate of the high BTU content fuel gas stream is manipulated so as to maintain the actual dew point temperature of the mixed fuel gas stream below the actual temperature of the mixed fuel gas stream to prevent condensation.

Abstract: In a fractional distillation column, a desired ratio between the flow rate of a side draw product stream and the internal reflux flow rate at the particular tray from which a side draw stream is withdrawn from the fractional distillation column is maintained by manipulating the flow rate of the center reflux stream so as to maintain the desired ratio between the internal reflux flow rate and a side draw product stream flow rate at the particular tray from which the side draw stream is withdrawn from the fractional distillation column. Control of the ratio between the flow rate of a side draw product stream and the internal reflux flow rate results in an improved side draw product stream purity.

Abstract: In a process in which a feedstock is provided through a desalting unit prior to introduction into a fractional distillation column, the feed stream flowing to the desalting unit is split and passed through multiple heat exchangers. Method and apparatus is provided for maintaining a desired effluent flow rate out of the desalting unit and for maintaining the temperatures of the split feed streams substantially equal. After passing through the desalting unit the feed stream may again be split and passed through multiple heat exchangers prior to introduction of the feed stream into the fractional distillation column. Method and apparatus is also provided for maintaining the temperature of the split feed streams provided from the desalting unit substantially equal.

Abstract: In a fractionation distillation process in which a pump around stream and an external reflux are utilized to control heat removal from an upper portion of the fractional distillation column and in which the pump around stream is utilized to preheat the feed stream flowing to the fractional distillation, the flow rate of the pump around stream is manipulated so as to substantially maximize the flow rate of the pump around stream while maintaining a desired heat removal from the fractional distillation column. Priority control of the pump around stream and external reflux result in a maximum preheating of the feed stream flowing to the fractional distillation column which improves the energy efficiency of the fractional distillation process.

Abstract: In a fractional distillation column, a desired ratio between the flow rate of a side draw product stream and the internal reflux flow rate at the particular tray from which a side draw stream is withdrawn from the fractional distillation column is maintained by manipulating the flow rate of the center reflux stream so as to maintain the desired ratio between the internal reflux flow rate and a side draw product stream flow rate at the particular tray from which the side draw stream is withdrawn from the fractional distillation column. Control of the ratio between the flow rate of a side draw product stream and the internal reflux flow rate results in an improved side draw product stream purity.

Abstract: In a fractionation distillation process in which a pump around stream and an external reflux are utilized to control heat removal from an upper portion of the fractional distillation column and in which the pump around stream is utilized to preheat the feed stream flowing to the fractional distillation, the flow rate of the pump around stream is manipulated so as to substantially maximize the flow rate of the pump around stream while maintaining a desired heat removal from the fractional distillation column. Priority control of the pump around stream and external reflux result in a maximum preheating of the feed stream flowing to the fractional distillation column which improves the energy efficiency of the fractional distillation process.