Abstract: Apparatus and methods for determining the Reid Vapor Pressure of either an overhead, side draw or bottoms product stream of a fractionating column used for fractionating a multi-component hydrocarbon feed stream into an overhead product stream, a side draw product stream and a bottoms product stream are provided. The Reid Vapor Pressure of the particular product stream is determined in response to the temperature of the product stream, the vapor pressure of the product stream, the rate of flow of the bottoms product stream, the rate of flow of the overhead product stream, and/or the rate of flow of the side draw product stream without further analyses thereof. The Reid Vapor Pressure indication is used to maintain the actual Reid Vapor Pressure of the particular product stream substantially equal to the desired Reid Vapor Pressure of the particular product stream and to thereby control the quality of the desired product stream.

Abstract: Apparatus and methods for determining the Reid Vapor Pressure of a bottoms product stream of a fractionating column used for fractionating a multi-component hydrocarbon feed stream into an overhead product stream and a bottoms product stream are provided. The Reid Vapor Pressure of the bottoms product stream is determined in response to the temperature of the bottoms product stream, the vapor pressure of the bottoms product stream, the rate of flow of the bottoms product stream and the rate of flow of the overhead product stream, without an analysis of the particular product stream. The Reid Vapor Pressure indication is used to maintain the actual Reid Vapor Pressure of the bottoms product system substantially equal to the desired Reid Vapor Pressure of the bottoms product stream and to thereby control the quality of the bottoms and other product streams.