An integrated system comprising: a. an additive delivery system comprising a transfer drum that feeds an immiscible liquid stream towards one or more injection quills; b. a solvent flushing system, comprising one or more additive addition lines that transfer the immiscible liquid stream from the additive delivery system; and c. an additive injection and mixing system comprising the one or more injection quills, wherein the immiscible liquid stream is injected into a larger liquid stream. Also, a process comprising: a. feeding the immiscible liquid stream to a transfer drum; b. transferring the immiscible liquid stream from the transfer drum to injection quills in a solvent flushing system, wherein the solvent flushing system injects a solvent into one or more additive addition lines in the solvent flushing system; and c. injecting the immiscible liquid stream into the larger liquid stream in an additive injection and mixing system comprising injection quills.