garyb
25-06-2009, 11:06 AM
We are considering converting an existing flooded R22 glycol chiller to ammonia. System has two VMY336 screws with liquid injection cooling, secondary oil separation vessel, evap condenser, receiver, thermosiphon PHE and surge drum. System is 95% steel so only a little bit of pipe work to replace, shaft seal will need replacement and surge drum oil recovery will need to be reconfigured - all pretty straight forward. System charge is around 600kg with mineral oil.
The big question is how clean do we need to get the system so that we are not going to have R22/NH3 contamination issues? We are well aware of the toxic and corrosive compounds that this can create. No matter what we do we will never get all the old oil out of the lines and I imagine that the R22 has been absorbed into the pores of the inside of the steel pipe work. Will multiple evacuations and dry nitrogen breaks sufficiently remove the residual R22? I don't believe that flushing is an option as getting all of the flushing agent out will as much of a problem in itself.
Has anyone done an R22 to NH3 conversion successfully?
Will multiple evacuations and multiple oil changes after restarting be adequate?
The big question is how clean do we need to get the system so that we are not going to have R22/NH3 contamination issues? We are well aware of the toxic and corrosive compounds that this can create. No matter what we do we will never get all the old oil out of the lines and I imagine that the R22 has been absorbed into the pores of the inside of the steel pipe work. Will multiple evacuations and dry nitrogen breaks sufficiently remove the residual R22? I don't believe that flushing is an option as getting all of the flushing agent out will as much of a problem in itself.
Has anyone done an R22 to NH3 conversion successfully?
Will multiple evacuations and multiple oil changes after restarting be adequate?