In order to explore the steam blowing process suitable for supercritical carbon dioxide(S-CO_2) boiler

four technical schemes such as open CO_2 purging

closed CO_2 purging

open air and open water steam purging are proposed based on the 5 MW S-CO_2 cycle power generation test unit designed and built by Xi'an Thermal Power Research Institute Co.

Ltd.

combining with the characteristics of main and auxiliary equipment. Moreover

the above four schemes are compared from the aspects of economy

environmental protection

safety and efficiency. The results show that

the open CO_2 purging scheme has high cost and is not environmental frendly

and the gas momentum of open air purging scheme is far from meeting the quality requirements of blowing pipe. Neither of the above two schemes is feasible. The closed CO_2 purging scheme has simple system and convenient operation

but the filter screen needs to be cleaned and replaced repeatedly

which takes time and labor

and causes a lot of carbon emission. If it can be combined with efficient chemical cleaning

the purging time will be greatly shortened. The open steam purging process is mature and reliable in quality

but the investment of installing temporary purging system after using water as the fluid is large. Considering that some water inlet and drainage devices should be designed for S-CO_2 boilers in the future

which makes some transformation items become standard items

the cost of the scheme is expected to be significantly reduced. Therefore

in a comprehensive way

both the closed S-CO_2 purging and open steam purging schemes have higher practical feasibility. The closed S-CO_2 purging scheme combining with high efficient chemical cleaning can reduce the replacement times of filter screen and has a better comprehensive application prospect.