wayuu1981
Mechanical
- Sep 15, 2006
- 47
We are changing the reheater tubes, 75 panels of 4 tubes each, so we are performing 600 site weld plus more than 1000 panel fabrication welds, all 2" diameter, 0.150" thick, using GTAW. We decided to blow-out these tubes prior to admitting steam to turbine, so we are going to disassemble the RSV's (reheater stop valve's) cover at the I.P. turbine inlet, and install a temporary blow-out pipe to atmosphere bolted to the RSV covers.
That was the original blow-out procedure used during plant erection.
Because we didn't work on the superheaters and main steam pipe, we won't blow-out these lines, so we will blow out the reheater tubes and pipes using steam generated by boiler through the HP turbine Bypass valve (installed before the boiler stop valve). Here is where we differ form the original procedure, because during erection the whole boiler was blown, then the reheater was blown through the boiler stop valve and the HP turbine was bypassed using another temporary pipe connected to the main steam stop valve.
Is there any problem in using the HP turbine bypass valve instead the boiler stop valve with another temporary pipe to Blow-out the reheater? Is there any risk the superheaters and main steam pipe, (that must be clean inside because they're have been operating for several years) because of the blow-out temperature and pressure change, and high steam velocities, will carry-over any solid particle to boiler stop valve ans later to HP turbine?
Javier Guevara E.
Projects, Mechanical Engineer
TERMOGUAJIRA - GECELCA S.A. E.S.P.
That was the original blow-out procedure used during plant erection.
Because we didn't work on the superheaters and main steam pipe, we won't blow-out these lines, so we will blow out the reheater tubes and pipes using steam generated by boiler through the HP turbine Bypass valve (installed before the boiler stop valve). Here is where we differ form the original procedure, because during erection the whole boiler was blown, then the reheater was blown through the boiler stop valve and the HP turbine was bypassed using another temporary pipe connected to the main steam stop valve.
Is there any problem in using the HP turbine bypass valve instead the boiler stop valve with another temporary pipe to Blow-out the reheater? Is there any risk the superheaters and main steam pipe, (that must be clean inside because they're have been operating for several years) because of the blow-out temperature and pressure change, and high steam velocities, will carry-over any solid particle to boiler stop valve ans later to HP turbine?
Javier Guevara E.
Projects, Mechanical Engineer
TERMOGUAJIRA - GECELCA S.A. E.S.P.
