In order to investigate the effects of different types of biomass on the combustion process of boiler

numerical simulation was carried out for re-burning process of an ultra-supercritical 660 MW coal-fired coupled biomass（gas） boiler

on the basis of establishing a model for the boiler using Fluent software. The boiler was reformed by adding a biomass（gas）re-burning nozzle between the top secondary air nozzle and the burn-out air. The combustion characteristics of solid biomass re-burning and biomass gas re-burning conditions were numerically

simulated to research the law of change on temperature field in combustion zone

component distribution and concentration distribution of CO

2

and NO

x

in flue gas at the outlet of furnace. The results show that the biomass re-burning reduces the pulverized coal consumption and the combustion temperature in the primary combustion zone

and it will increase the volume fraction of CO in the furnace. But at the same time

the center of the combustion flame in the furnace moves up

increasing the exhaust heat loss. Compared with pure coal conditions

both solid biomass and biomass gas re-burning can reduce the volume fraction of CO

2

and NO

x

at the outlet of the furnace

but the effect of biomass gas is significantly higher than that of solids biomass.Among them

food waste gas re-burning has the best effect on reducing carbon emission and nitrogen emission

with carbon emission reduction rate reaching 13.87% and nitrogen reduction rate reaching 24.13%.