Marathon Refining Transmix Processing

Transmix is a mixture of diesel fuel and gasoline that forms during the shipment of products through pipelines. Transmix is collected and returned to the refinery to be reprocessed. Historically, the refinery blended transmix with the crude oil in the crude oil tanks. This was unsatisfactory in that it reduced crude utilization and was difficult to control. The refinery asked that a system to independently charge the transmix to the crude unit be designed.


Process Engineering:

  • Conceptual design of the new transmix facility
  • Detailed design of the facility once the concept was approved
  • PFD preparation
  • Process simulation and heat and material balance preparation
  • P&ID preparation
  • Investigation of possible interferences with the crude tower operation
  • Participate in the project HAZOP as the process expert

Mechanical Engineering:

  • Heat integration of the new facilities with the existing crude unit facilities
  • Hydraulic design of the pumps and piping system
  • Specification of new process pumps flow and head
  • Thermal and hydraulic design of the transmix preheat exchanger
  • Specification of the new transmix preheat exchanger
  • Design and specification of a transmix wash system
  • Relief valve design
  • Review and approve vendor equipment drawings

Controls Design:

  • Overall design of the system controls