Hi
I currently design an expander with a tandem dry gas seal.
On the primary vent line (connected to flare)a Pressure control valve set at 3 barg is installed. This valve allowed to have always a minimum differential pressure across segondary DGS (required by DGS manufacturer).
However, before pressurisation at separation and secondary gas start up (and expander stopped and non pressurised) this valve will create a reversal differential pressure across the primary DGS (3 barg un vent VS 0 barg on seal gas injection cavity (process side (hich is not allowed by DGS manufacturer.
Someone know the reason or this requirement or have already saw such requirement ?
I currently design an expander with a tandem dry gas seal.
On the primary vent line (connected to flare)a Pressure control valve set at 3 barg is installed. This valve allowed to have always a minimum differential pressure across segondary DGS (required by DGS manufacturer).
However, before pressurisation at separation and secondary gas start up (and expander stopped and non pressurised) this valve will create a reversal differential pressure across the primary DGS (3 barg un vent VS 0 barg on seal gas injection cavity (process side (hich is not allowed by DGS manufacturer.
Someone know the reason or this requirement or have already saw such requirement ?