Page 289 - Compression Machinery for Oil and Gas

274 SECTION II Types of Equipment

FIG. 6.20 Double DGS.

liquids, therefore this seal arrangement is not suitable for dirty or wet gases. The
seal nitrogen must be filtered carefully and must be dry.
If no high-pressure nitrogen is available a tandem dry gas seal as per
Fig. 6.21 may be used. Here two dry gas seals are placed in a series. A clean
and dry buffer gas is fed into the annulus upstream the primary seal and prevents
the process gas from entering the dry gas seal. The largest part of the buffer gas

FIG. 6.21 Tandem DGS.