Heavy fuel oil pumps

Why heavy fuel oil is hard to pump

Heavy fuel oil is the residue left after lighter fractions have been distilled off. It is dense, very viscous when cold and, in the heaviest grades, almost solid at room temperature; high-sulphur and low-sulphur grades behave in the same way as far as pumping is concerned. In a boiler room or on board a ship the oil must be moved from storage to the settling tank, from the settling tank to the day tank and from there to the burner or the injectors, often with long suction lines and frequent starts.

A centrifugal pump cannot cope with this. A self-priming external gear pump can: the thick oil lubricates the gears and seals the internal clearances, the flow stays constant whatever the back pressure, and the pump draws oil even when the suction line is not completely full. For the whole family of thick products see our viscous fluid pumps.

Which series for HFO, bunker fuel and diesel

• NAV series — the industrial transfer pump for fuel oils: nine models from 54 to 2,770 l/min, flanged ports UNI from DN 40 to DN 125 PN 16, cast iron base, high discharge pressure together with high flow, continuous 24/7 duty in petrochemical plants.
• ZV series — compact pumps flanged to the motor for burner feeding, ring mains, diesel transfer and the dosing of fuel additives with an inverter: ten models from 0.47 to 102 l/min, threaded ports, no baseplate and no alignment.
• CR series — jacketed pump for the heaviest oils that must be kept warm to flow, with the jacket on thermal oil, steam or superheated water, or with electric cartridge heating where no thermal plant exists.

All three families can be supplied with ATEX documentation for installation in classified areas.

Applications for heavy fuel oil pumps

• Transfer of HFO from storage tanks to settling and day tanks in industrial boiler rooms and power plants.
• Bunker fuel handling at bunkering stations, depots and on board, including unloading of road tankers and barges.
• Burner feeding and ring main circulation, where the constant flow of a gear pump keeps the burner pressure stable.
• Diesel and gas oil transfer for generator sets and fuel farms, with the ZV series flanged directly to the motor.
• Refineries and petrochemical plants: dense naphtha, heavy lubricants, slops and tank bottoms, where the NAV series runs continuously.
• Circulation of thermal oil on the heating loops that keep the fuel oil tanks warm.

For pitch, bitumen and other products that need a heating jacket, the CR series uses the same principle with a fully jacketed pumping chamber.

Keeping thick oil flowing: heating and protection

Most heavy fuel oil installations keep the storage tank warm and trace the pipework. In that case a standard NAV in cast iron is the right choice. When the pump stands outdoors, when stops are frequent or when the grade is at the heavy end of the range, we recommend the CR with heating jacket: the jacket wraps the whole pumping chamber, so there is no cold spot where the oil can thicken and lock the gears at the next start.

Every pump is self-priming and gives a constant flow, whatever the pressure downstream. Stainless steel executions are available for aggressive products, and the flanged connections of the NAV series make it a direct replacement in existing fuel oil lines.

What we need to size your fuel oil pump

Send us the grade of fuel oil (HFO, bunker fuel, thick oil, diesel) and its viscosity at the working temperature, the temperature of the oil in the tank and at the pump, the flow in l/min or m³/h, the discharge pressure, the suction conditions and whether the installation is in an ATEX zone. If the pump must keep the oil warm, tell us which heating medium is available.

Write on WhatsApp or fill in the quote form. Our Bologna factory, building self-priming external gear pumps since 1955, replies with a technical proposal: model, speed, motor power and the options that make sense for your plant.