heating fuel oil

[philkasza]

We have a oil fired evap. with 2-601 carlin burners. We were wondering how we could heat the fuel oil going to the burners for improved efficentcy. We don't have a steam away so we can not use that hot water. Our thought was to 1(build an insulated building around the 1000 gal. fuel tank and heat it or 2(run the lines through hot water or under the steam hood. Any thoughts or ideas?:confused:

Sam

[maplecrest]

You do not want to run any where near steam or hood. Mine runs thru the length of the arch. Between the insulation and outer shell of arch. If you have any leaks at the fittings the hot oil will find them. Even if you ran the line along the base of arch. There is heat loss there that would warm the oil.

[Mark]

If you heat the oil a lot you may have to adjust your burner air. If I remember right when the oil warms up it will lean out. I think you get less oil through the nozzel because the thin oil has a higher rotational speed in the nozzel and a larger cone developes inside the nozzel which can slow the flow.

[Beweller]

One pound of fuel oil yields something like 20,000 Btu when combusted. Heating that pound of fuel oil to say 300 F gives you an additional 150 Btu of heat.

You will never see the difference in efficiency. Very heavy fuel oils--No. 5 or No. 6--may be preheated to improve atomization, but not to gain thermal efficiency.

[Teuchtar]

I agree, there's a trivial gain in efficiency.
Another issue is that hot fuel takes up more volume for the same mass flow. So that when your oil pump is pumping a fixed gpm of hot fuel you are actually delivering less lb/hr of fuel to the burner. So you will see your burner heat go down a small amount.
These effects are small, but definitely measurable with instrumentation.
Often we heat fuel for engines in winter, to bring it up to a minimum temperature for pumpability, and not wax the filters.
But when the fuel gets too hot (fuel heaters inadvertently operated in summer) , the injectors don't atomize properly (viscosity too low) and you get much smoke and power loss from incomplete combustion.
I believe ISO 3046 still has an engine derate formula for hot fuel. Not sure about boiler burners.
Overall, I would not advise to heat the fuel.