METHOD FOR IMPROVING DURABILITY OF A STEAM TURBINE IN A THERMAL POWER PLANT

摘要

A method for improving the durability of a steam turbine in a thermal power plant according to the present invention forms a Cr_3C_2 coating part covering a bucket cover and a tenon part together since Cr3C2 powder supplied from a powder supply channel is melted by flames emitted from a nozzle and is sprayed by compressed air at high speed, using a coating apparatus comprising: the tenon part formed at an end of a number of buckets formed radially at a rotor wheel of the steam turbine for the thermal power plant; the powder supply channel supplying the Cr_3C_2 powder together with a nitrogen transfer gas at a center, to the bucket cover which is formed around the bucket and is combined to the tenon part of the bucket; a fuel oxygen supply channel supplied with a fuel mixed with oxygen outside the powder supply channel; a compressed air supply channel supplied with the compressed air outside the fuel oxygen supply channel; and a nozzle formed at a front part to melt and spray the Cr3C2 powder forward while the three channels meet.