In order to meet the requirement of lay-up corrosion protection for thermal system of gas-steam combined cycle units

a dry-air protection system covering all the thermal equipment of the unit was designed

according to the characteristics of the thermal system of the test unit. Moreover

a volatile corrosion inhibition suitable for dryair combined protection process was compounded

and the corrosion coupon test was carried out for 39 days in the test unit

to study the protective effect of the dry-air combined protection process and the compound gas-phase corrosion inhibitor. The test results show that

by the dry-air combined protection

only the carbon steel piece at the bottom of condense was slightly corroded

the steel pieces at other positions were basically non-corrosive. Compared with the waste heat drying method

the water consumption during cold start flushing decreased by about 50%

the average iron ion mass concentration of condensate water and feed water decreased by 63.5% and 23.7% respectively during the turbine start-up stage

and they decreased by 80.5% and 79.0% respectively after running for 8 hours.