Boiler Load

[aquatica]

what are the practical means of verifying load on a boiler? I think there has to be more than one method. which one is most effective one and their accuracies? any literature?

cheers!

 

[davefitz]

ASME performance tests rely on the feedwater flow nozzle as the primary measurement of flow- all other flows are determined based on heat and mass balances that are pro-rated to the feedwater flow indication.

If you have the main steam P and T measurement and feedwater inlet T, you would calculate their enthalpy and the difference between these quantities yields the energy gained per pound of steam produced. There would them be added to this the energy lost in boiler drum blowdown ( typically 1% of main steam flow, at an enthalpy equal to saturated liquid at drum pressure). These simple calcs assume the spray water is taken off downstream of the feedwater flow nozzle.

Some major losses that can throw off this calc are: steam leakage thru drains , vents, bypasses and relief valve leaks, air entrained in the sensing lines to the flow measuring DP gauge.