Crude Oil transporting rail cars need to be cleaned periodically to remove accumulated sludge, waxes etc. Diesel is widely used as the washing fluid for such applications. One such rail car washing facility in the south-west uses approximately 10,000 gallons of fresh diesel everyday. The spent diesel could not be reused due the water and sludge contamination and to be discarded.
The facility owner was familiar with Alfa Laval centrifuges being used for diesel purification from his navy days. The owner contacted Dolphin Centrifuge to consult about the possibility of using on of our industrial, three-phase centrifuges to purify the diesel and possibly reuse it.
The customer had previously sourced a chemical which would drop out some of the impurities into a heavy ‘black phase’ which would eventually drop out. This separated phase could then be decanted.
Dolphin Centrifuge recommended testing the chemical addition and separation process in our in-house testing facility. We mixed the desired ratio of the customer provided chemical into the black diesel. The mixed fluids were then processed through our pilot scale, disc-stack centrifuge. The purifier was able to efficiently separate the heavy phase from the diesel and produced a stream of clear diesel. The separated heavy phase was flowing out the heavy phase outlet.
The customer got the separated diesel analyzed for impurities and water. The analysis results showed diesel with less than 0.5% impurities. This was definitely re-usable to clean out rail cars!
Dolphin Centrifuge was awarded a contract to build a 40 GPM diesel fuel purifier system with a chemical injecting and mixing system included on the inlet feed line to the centrifuge. Dolphin integrated the dynamic mixer (sourced by the customer) into the centrifuge module both electrically and mechanically. Flow meters were integrated into the diesel and chemical line with a PID loop to control both pumps to monitor and assure a consistent diesel to chemical mix.
Dolphin Centrifuge’s engineering team did the site installation and commissioning . The system recovered the daily volume of used diesel during the night shift. The customer is reusing the diesel 2~3 times before refreshing the wash-diesel stock. This resulted in annual savings of over $2M! The diesel purifier module paid for itself within the first month!
The diesel fuel purification system module, designed and manufactured by Dolphin Centrifuge, is shown above. The specifications of this system are listed below.
Alfa Laval WHPX510 Centrifuge for Used Diesel Purifier System including:
- Alfa Laval WHPX510 Self-Cleaning Disc Centrifuge
- VFD Control PD Feed Pump & Chemical Mixer with Chemical Dosing Pump
- Fully Automatic PLC/Touch-Screen Control Panel
- Sludge Tank with Sludge Disposal System
Technical synopsis: A diesel fuel centrifuge purifies the fuel keeping the impurities to a minimum. A diesel purification system effectively removes water and sediment (down to 0.5µ) continually. The system processes up-to 40 GPM of #2 diesel to separate all free water and sediment.