In order to investigate the effects of oxygen addition amount and type of gasification medium on coal gasification efficiency as well as the optimization of integrated gasification combined cycle(IGCC) power system

a simulation analysis is carried out by baking two kinds of coals with significant differences in oxygen content as the examples. Firstly

based on the equilibrium reaction model

the influence of oxygen carbonation stoichiometric ratios(considering the oxygen content of different coal types) on gasification characteristics for different coal types is compared. Then

the gasification characteristics are analyzed and optimized when CO2 and steam are added as gasification media respectively. On this basis and considering CO2 capture

a novel IGCC power cycle system with CO2-assisted gasification

pure oxygen combustion and partial gas recirculation is proposed and analyzed

and the gas turbine model is simulated and optimized. The results show that

the coal gasification performance is the best when the total oxygen-carbonation stoichiometric ratio is around 0.47. Under this condition

adding CO2 as the gasification medium can increase the efficiency of cold gas by about 1.3%

compared with that of the conventional way that adding steam as the gasification medium. Compared with the conventional IGCC power system with pre-combustion decarbonization

the net power efficiency of the proposed system increases by about 1.5% and the exergy efficiency increases by 1.7%

which provides a new idea for designing a low-carbon and efficient IGCC power generation system.