Field Charge Pumps Constrain Crude Feed Rate

At one of our Refinery clients in the Gulf Coast the Crude Unit continually dealt with constraints that limit the maximum throughput of their unit. At times the Crude Unit was limited by the feed system, which delivers crude from the South Tank Farm located over a mile from the unit.

Three problems were identified:

  1. The Crude Unit was constrained at times by its crude supply system when raw crude pumps cavitated at the unit due to low suction pressure. Because of this bottleneck, flow was reduced to control the problem.
  2. Lack of flexibility in moving adequate quantity of any of the crude.
  3. An intermediate Crude Unit Feed Tank had no spare and loss of this tank would cause the unit to shutdown. The only direct feed to the unit was through #4 pipeline which supplies approximately 60 TBD of crude. The Crude Unit needs a minimum of 150TBD.

The third problem, identified by Oil Movements was presented as an Action Team project at The Manufacturing Game. The goal was to develop an action plan to continue to run the unit in the event of failure of the intermediate Feed Tank.

Previous to this, work had been started and drawings generated to identify the existing flow system. Operations and Crude Unit personnel familiar with the problem were motivated and enthused to eliminate this defect. They selected the project above others feeling there would be significant rate increase and major savings if the defect were eliminated. The project team identified key activities, assigned responsibilities, and scheduled target dates for completing the project.

With an enthusiastic team, management support, and the addition of team members from Oil Movements, the project quickly moved forward. Field investigators of the crude supply piping system revealed the existence of jump-over (by-pass) pipe lines which would permit direct feed of crude to the unit. A pressure survey was performed which indicated additional crude could be fed directly to the unit. Diverting additional feed directly to the unit versus routing it through the intermediate Feed Tank and its pumps unloaded the feed system.

A contingency plan/procedure was developed by Oil Movements on what action steps need to be taken in the event of Feed Tank failure. A hydraulic study of the system revealed that lining up all 5 pipelines directly to the Crude Unit would allow the unit to operate at 170 TBD which is well above minimum.

The defect was eliminated without capital expenditure. Test runs revealed that crude supply pressure at raw crude pump suction increased from 40 to 65 psig at constant flow. The project utilized existing piping and reconfigured the flow to enable the unit to run a higher rate without a crude supply constraint. They eliminated pump cavitation, provided the flexibility to run heavier crude in desired quantities, and addressed a major reliability concern of the unit regarding loss of the Feed Tank.

The capacity increase that this project has created will be tested at a later date but is believed to be significant. Additionally, this project improved reliability by allowing the Crude Unit to continue to operate in the event of failure of the Feed Tank. This saves a potential penalty of $2 MM for a 5 day downtime.

The teams success is being shared across the organization. This project has led to the identification of other potential Action Team projects.