Renewable diesel interface recombination

A method to transport renewable diesel through a pipeline, the method comprising:

• supplying a first diesel fuel and a second diesel fuel each compatible with the renewable diesel, the first diesel fuel having a first predetermined composition and the second diesel fuel having a second predetermined composition, the first predetermined composition and the second predetermined composition comprising a selected amount of the renewable diesel, the selected amount being less than the selected amount allowed in a second target composition for the first diesel fuel and the second diesel;
• transporting, through a pipeline, a first movement of the first diesel fuel having the first predetermined composition;
• transporting, through the pipeline, a first movement of the renewable diesel immediately sequentially following the first movement of the first diesel fuel having the first predetermined composition, such that a head of the first movement of the renewable diesel is wrapped by a tail of the first movement of the first diesel fuel having the first predetermined composition;
• transporting, through the pipeline, a second movement of the second diesel fuel having the second predetermined composition sequentially following the first movement of the renewable diesel, such that the tail of the first movement of the renewable diesel is wrapped by the head of the second movement of the second diesel fuel having the second predetermined composition;
• separating a renewable diesel fraction stream, a first diesel fuel having a first predetermined composition fraction stream, a second diesel fuel having a second predetermined composition fraction stream, and a mixed interface fraction stream, the mixed interface fraction stream comprising a mixture of the renewable diesel and the diesel fuel having the first predetermined composition so that when transporting the renewable diesel, the first diesel fuel and the second diesel fuel from the first pipeline terminal to the second pipeline terminal, interfacial mixing occurs, thereby to define the mixed interface fraction stream;
• and
• combining at least a portion of the mixed interface fraction stream with at least a portion of one or more of (a) the first diesel fuel having the first predetermined composition fraction stream or (b) the second diesel fuel having the second predetermined composition fraction, thereby to produce a diesel fuel stream having the second target composition.

A system to transport fuels through a pipeline, the system comprising:

• a midstream pipeline terminal configured to receive an inlet stream from one or more upstream pipeline terminals, the inlet stream comprising a first fuel wrapped head and tail with one or more second fuels, the one or more second fuels compatible with the first fuel and having a first predetermined composition comprising a selected amount of the first fuel, the selected amount of the first fuel less than the selected amount allowed in a second target composition for the second fuel;
• a separator to separate a first fuel fraction stream, a second fuel fraction stream, and an interface fraction stream from the inlet stream, the interface fraction stream comprising a mixture of the first fuel and second fuel;
• a first storage tank configured to receive and store the first fuel fraction stream;
• a second storage tank configured to receive and store the interface fraction stream;
• a third storage tank configured to receive and store the second fuel fraction stream;
• and
• a midstream pipeline terminal outlet stream in fluid communication with one or more downstream pipeline terminals, the third storage tank in fluid communication with the midstream pipeline terminal outlet stream by a first flow line positioned to flow the second fuel fraction stream stored in the third storage tank to the midstream pipeline terminal outlet stream, the first flow line in fluid communication with an injection flow line in fluid communication with the second storage tank and operable to flow at least a portion of the interface fraction stream stored in the second storage tank into the first flow line such that a second fuel stream meeting a second target specification is generated by the mixing of the second fuel fraction stream and a stream of the stored interface fraction stream.