Selection of appropriate pump


Thread Starter


In power Plants, positive displacement pumps (screw type) are used for pumping heavy oil (furnace oil) because of their high viscosity while for pumping HSD centrifugal pumps are used. Is it possible to use centrifugal pumps for pumping furnace oil?
I believe if you look at the High-pressure Liquid Fuel Pump on your GE-design heavy duty gas turbines, you will see they use positive-displacement pumps.

You probably can move heavy fuel oil with a centrifugal pump, but it's probably going to have to be very powerful to move it at ambient temperature.

Have you ever smelled or been in contact with heavy fuel oil such as is used in the large low-speed engines or boilers of ships? I've never heard of it referred to as "marine fuel oil" until a couple of weeks ago in this forum! It's not really oil, like distillate (diesel oil) or even motor oil, or even gear oil. It's usually extremely thick (high viscosity) at ambient temperatures; that's why it needs to be heated to make it easier to pump, in addition to being easier to atomize, and it's very "aromatic". Nothing like the smell of concentrated hydrocarbons in the morning!

Some of the heavy fuel oils can even be corrosive; the leather toes of my safety shoes had large holes in them after just a few hours of heavy fuel oil spilling on them. One doesn't want to have it come in contact with their skin, and not just because it's usually very hot.

I must not be understanding the question or the context of the question. I need to ask are you considering moving the heavy fuel oil from the storage tank and fuel treatment skids to the High-pressure Liquid Fuel Pump with centrifugal pumps? Because most gas turbines with distillate/heavy fuel oil capability use the same High-pressure Liquid Fuel Pump to supply the fuel to the fuel nozzles. There's just a transfer valve upstream of the High-pressure Liquid Fuel Pump which reduces the distillate fuel flow as it increases the heavy fuel oil flow when switching from distillate to heavy fuel. The same Liquid Fuel Bypass Valve and High-pressure Liquid Fuel Pump are used for both distillate and heavy fuel oils, at least on all the systems I have seen or worked on.

Heavy fuel oil can be pumped with either type of pump. Using a positive displacement pump probably lets the pump move heavy fuel oil at lower temperatures than a comparably rated (HP) centrifugal pump. So, the PD pump can be used over a larger temperature range than a comparably rated centrifugal pump. It's probably easier to get the oil flowing, even if it's heated, with a PD pump (there will always be some piping between a heated storage tank, the suction strainers, and the PD pump, as well as downstream of the pump that isn't necessarily as warm as the heavy fuel oil in the tank, not to mention the volume of oil is the PD pump. Heat tracing would help, and would probably be mandatory for most heavy fuel oils.

But, other than that, I don't know what wasn't to understand in my previous reply. I think (I have been wrong before, though) that to move heavy fuel oil with a centrifugal pump it's going to take a larger pump and motor (more HP) to move the heavy fuel oil over the same possible temperature range as a smaller or even a comparable positive displacement pump. But I don't think it's an either/or proposition. And I don't understand the context of the question.
Centrifugal pumps work on only low viscosity (typically less than 25 cP). So unless the oil is very hot you will need to stay with PD type pumps. Check out for references on using pumps.

John Catch