To solve the problems that gas boilers need to upgrade the capacity and reduce NOxemission during combustion

all technical problems were systematically analyzed.A general design scheme was formed by reorganizing all the related calculations and design unit.Moreover

capacity upgrading and low NOxcombustion retrofitting of a gas boiler was taking as the example to verify the feasibility and operability of the general design scheme

by illustrating an engineering practice in detail including comprehensive evaluation

low NOxcombustion system design

thermodynamic checking calculation

hydrodynamic checking calculation

drum capacity upgrading and strength checking calculation

flue wind resistance checking calculations and economic evaluation.After the transformation

the steam generation increased by 20%

the boiler efficiency rose by 0.2%

the unit fuel consumption dropped

the NOxemission reduced by 140t

and the investment can be recovered within 3to 5years

according to the estimation.