Aiming to the performance analysis of boiler with supercritical carbon dioxide(S-CO_2) cycle

the boiler performance evaluation index system is built by taking the gas-fired boiler used in the 5 MW S-CO_2 Brayton cycle pilot unit at Xi'an Thermal Power Research Institute Co.

Ltd. as the research object. The core performance indexes of S-CO_2 boiler include the fuel efficiency of boiler

the ratio of heat absorption over the input heat for each heat exchanger

the performance of air preheater

the pressure drop of working fluid system

the NOx emission concentration

and others. The fuel consumption and excess air coefficient are calculated via the measurement of oxygen concentration. Meanwhile

the calculation method of heat loss due to exhaust gas is improved. The ratio of heat absorption over the input heat for each heat exchanger is introduced

which shows the contribution of each heat exchanger on heat absorption process. Finally

the calculation process is integrated becoming to an executable program

and it is applied in the running and monitoring procedures. An operating case showed that

for the research object

the actual condition is basically the same as that of the design parameters. The finally calculated boiler fuel efficiency is 92.05% without correction and 93.79% with correction

the later is similar as the designed value(93.53%).