Screw Compressor Problems

Are you sure that no liquid propylene is entering the compressor?

we replace male rotor active side thrust pads at shop and then install compressor at sit after purge and calibrate of slid valve posation by oil pump pressure .we start turbine and change load from the same compressor motor drive and compressor work for 8 miniuts we see leakage from mechanical seal . how sure that no liquid propylene isnt entering the compressor? Thanks

a level transmitter examines the amount of liquid in the refrigerant/chilled water exchanger . A Controller maintains a specified set point using the one valve ,which controls the amount of liquid entering exchanger . We know that the liquid level is not approaches an unreasonable level.

yes there is a pressure lubrication system with a separate motor-pump that keeps the bearings and screw lubricated. the compressor before oil pressure is up. ,this compressor is driven from a steam turbine And compressor driven with a gear box from the turbine. the thrust bearing on the same side as the turbine, the oil pressure kept off during shutdown.

Divide the load between the two compressors.

Compressors need continual lubricants to function. Otherwise, the internal working parts will create friction, which will cause damage to the compressor over time. The compressor can often operate with a low percentage of lubrication within it. However, the condenser eventually will develop a problem with the compressor lubricant, which will manifest first as a problem with the coalescers. If the coalescer has a good rating, the coalescer was likely not installed properly or is damaged. However, if the refrigeration system has a lot of dirt, the coalescer likely needs cleaning to remove a clog.

Dear Rasoul

please let us know the running hour of the compressor. if it is not much, it could be a manufacturing defect. Or if is old compressor, let us know the maintenance history. Also please note, if you changed thrust bearing yourself, you have to measure all clearances before fixing. Also, if it directly coupled with steam turbine, you have to check the alignment between turbine and compressor. let us know your feedback.

our process control system include: 1.Flash Economizer pressure Controller that we had not unreasonable level or pressure during start up the compressor 2.Refrigrant /chiled water Exchenger Level control 3.Refrigerant Accumulator Level and pressure & Condenser inlet and out let temperature and BDV valve on condenser 4.compressor oil seperator T&P&l controller

If dP/dt is too rapidly downward, liquid in a vessel can flash into a foam, carrying some over to the compressor even if undetected by a level sensor. This is consistent with the starting of a large compressor. It can be mitigated by limiting the loading rate of the compressor, if the control system can accommodate this.

the running hour of the compressor is7000hours .we replace thrust bearing pads and mechanical seal rings 6thrice untill now . We measured all clearances(thrust bearing clearance=0.19 rotor discharge end clearance 0.37balance piston diameter clearance0.20mm)afther fixing. Compressor coupled with gearbox .

I think that balance of axial forces in start up time be out of sort and thrust disc contact with pad bearing and damage them