Boiler efficiencies

[dianad]

Hi,

I would like if anyone has a table with the common range of values for the boiler efficiencies for different fuels: Natural Gas, Propane, Butane, Biomass(wood chips), coal, fueloil.

thank you!

 

[Unotec]

I might be wrong, but the boiler efficiency I don't believe is due to the fuel itself, but more to the boiler. A natural gas boiler can be converted to an LP or diesel, but the efficiency will vary depending on the boiler's design.
Your best bet is to talk to the boiler manufacturers in your area

 

[macmet]

Biomass boiler "efficiencies" do depend on the fuel. Because of the variations in fuels there really is not an easy answer to this question (relating to biomass fuels).

 

[davefitz]

for a large boiler > 150 MWth LHV heat input, an efficiency of 88-92% based on LHV is normal for biomass firing . The key simplification is to calculate it based on LHV, since the high moisture content of biomass leads to a widely varying loss due to H2O if calculated based on HHV. The use of economizers, airheaters, water cooled furance enclosure, and steam cooled cyclone ( if provided) is assumed here.

If the boiler is downstream of a refractory incinerator, much higher radiation loss Lr would be expected , likewise if a refractory based CFB cyclone is used higher rad losses occur- for high efficiencies, aim toward steam cooled or water coolled furnaces and cyclones.

Smaller units have efficiencies all over the lot- can't generalize

 

[Feric]

Hi there:

In order to get started and get some numbers coming out, one can always do calculations for an ideal case -- no loss -- and start comparing different fuel types and find out what the mass flow rates are etc. ...

Once the ideal case is taken care of, then rules of thumb can be applied.

In the final run, experimental and operational values for given design conditions need to be taken into consideration and matched with the engineering calculations ...

Thanks,

Gordan

http://engware.i-dentity.com

 

[rmw]

I'd look in a publication like Steam by B&W. I'll let you search the site for information as to how to purchase.

rmw

 

[MJCronin]

dianad..

Overall boiler efficiency, as stated above, is a function both of the type of fuel and the mode of operation. Excess air has a significant affect on efficency.

Natural gas fired boilers can easily operate between 68-88% efficency. As I recall, boilers fired on #2 fuel oil can reach just above 90%

http://www1.eere.energy.gov/industry/bestpractices/pdfs/steam4_boiler_efficiency.pdf

Although efficency is important in a boiler firing a bio-fuel, operations and maintenance factors such as fouling and material degradation often become much more important in the overall economic evaluation of an installation.

My opinion only

-MJC