On the basis of steam-driven induced draft fan(ID fan)renovation in large scale coalfired power plants

a new fast economic decision-making algorithm was proposed.Compared with the conventional heat balance method

this algorithm can obtain the calculation parameters more easily

and directly calculate the difference of power generation standard coal consumption between steam-driven ID fan scheme and electric-driven ID fan scheme

so as to obtain the economic benefits of the above two schemes before and after the transformation.Calculation for an ultra supercritical 1 036MW unit showed that

under 100%THA

75% THA and 50% THA load conditions

the steam-driven scheme consumed 3.143g/(kW·h)

3.351g/(kW·h)and 3.094g/(kW·h)standard coal more than the electric-driven scheme

respectively.However

in the steam-driven scheme

the auxiliary power ratio was decreased significantly

which resulted in roughly 7.439×106 yuan excess profit

so the investment const can be recovered after about2.8years.