Sulfur Seal Leg

Sulfur Seal Leg

In-ground Sulfur Seal for SRU Rundown Lines


Historically, the oil and gas industry has used two types of devices to achieve a vapor seal in sulfur rundown lines. One type is the in-ground device, commonly referred to as a seal leg. This traditional in-ground sealing device, has been employed in SRU’s for over 50 years. The other type is above ground sealing such as SxSeal® 1000 and SxSeal® 2000.

During normal operation, liquid sulfur flows into the seal leg via a rundown. Once inside the seal leg, sulfur flows downward through the inlet piping to the bottom of the leg, and then upward through the annular outlet piping to the sulfur outlet.  Similar to a P-trap, liquid sulfur in the bottom of the seal leg establishes a vapor seal, preventing H2S and SO2 vapor from passing from a condenser through the seal leg into the sulfur pit or collection vessel.

Standard Features:

  • P-trap style functionality, liquid sulfur crates a vapor seal
  • Below ground depth, 20’ or more, depth determined by upstream pressure
  • Jacketed piping heating technology


  • Prevents H2S and SO2 vapor from passing to sulfur pit or collection vessel
  • Supplemental pressure relief path