Methods for reducing transmix production on petroleum pipelines

An automated method for reducing transmix production on a pipeline comprising:

• a) providing a flow of hydrocarbon in a transmission pipe comprising first and second hydrocarbon subtypes in sequence separated by transmix;
• b) providing a transmix pipe in fluid communication with the transmission pipe separated from the transmission pipe by a transmix valve under the control of a central processing unit;
• c) providing first and second cut-points for different physical properties of the first subtype;
• d) providing first and second cut-points for different physical properties of the second subtype;
• e) repeatedly analyzing the flow for physical property measurements;
• f) comparing, in the central processing unit, the physical property measurements to the first and second cut-points of the first subtype, and diverting the flow to a transmix pipe when the measurements reach the first or second cut-point of the first subtype;
• g) resuming the flow through the transmission pipe when the measurements reach the first and second cut-points for the second subtype.

An automated method for reducing transmix production on a pipeline comprising:

• a) providing a flow of hydrocarbon in a transmission pipe comprising first and second hydrocarbon subtypes in sequence separated by transmix;
• b) providing a transmix pipe in fluid communication with the transmission pipe separated from the transmission pipe by a transmix valve under the control of a central processing unit;
• c) receiving a subtype sequence identification signal at the central processing unit identifying the first and second subtypes and the location of the first and second subtypes in the transmission pipe;
• d) receiving physical property measurements of the flow passing through the valve at the central processing unit;
• e) executing programmed logic in the central processing unit to:
• i) determine the subtype flowing through the valve based on the subtype sequence identification signal;
• ii) when the first subtype is flowing through the valve, accessing a dataset comprising a first cut-point for the first subtype and comparing the physical property measurements to the first cut-point of the first subtype;
• iii) diverting the flow to the transmix pipe when a physical property measurement reaches the first cut-point of the first subtype;
• iv) accessing a dataset comprising the first cut-point of the second subtype, comparing the physical property measurements to the first cut-point of the second subtype;
• and
• v) resuming the flow through the transmission pipe when a physical property measurement reaches the first cut-point of the second subtype.

A system for reducing transmix production on a pipeline comprising:

• a) a transmission pipe comprising a flow of hydrocarbon subtypes in sequence comprising a first subtype and a second subtype separated by transmix;
• b) a transmix pipe in fluid communication with the transmission pipe, separated from the transmission pipe by an automated diversion valve;
• c) a first analytical unit in sensory communication with the transmission pipe, for generating measurements of a physical property of the flow;
• d) a central processing unit in sensory communication with the first analytical unit and the transmix valve, logically programmed to receive the measurements from the analytical unit, compare the measurements to first subtype and second subtype cut-points, signal the diversion valve to turn toward the transmix pipe when the measurements reach the first subtype cut-point, and signal the diversion valve to turn the flow toward the transmission pipe when the measurements reach the second subtype cut-point.