Sulfur Handling & Degassing

The PTI team has accumulated over three decades of experience on over 50 units worldwide, addressing the design challenges of molten sulfur storage, handling, and degassing.

Our team has the experience and expertise required to design reliable and efficient molten sulfur, degassing, storage, and loading facilities. Our design approach addresses the challenges of H2S fire and exposure, temperature management, and ensuring pump and piping systems are carefully heated to work with sulfur's unique viscosity characteristics.

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Sulfur is perhaps one of the most interesting elements on the periodic table, albeit not the most valuable. As temperature increases, pure liquid sulfur transforms into different allotropes easily as Sx –with x commonly ranging from 6-20 atoms. When produced from the Modified-Claus process, liquid sulfur in the presence of H2S forms polysulfides that keep H2S in the liquid sulfur stream. The concentration of H2S in the combined sulfur product of a Modified-Claus unit typically ranges from 250-300 ppmw, with the sulfur product from the thermal stage reaching concentrations as high as 700 ppmw.

H2S can naturally liberate from polysulfides in liquid sulfur by the simple agitation that occurs in storage and handling operations creating high concentrations of H2S in storage vessel head spaces or the loading hatches of trucks and railcars creating a hazard to personnel in the area. The design of Sulfur Handling and Degassing systems needs to address these unique properties of molten sulfur produced in the Modified-Claus process.

To further complicate the process, fully degassed molten sulfur presents its own challenges due to the sharp viscosity spike of pure molten sulfur near the polymerization transition temperature.

PTI’s sulfur storage and handling systems start with an evaluation of your permit and operations needs. For small capacity facilities, and considering the H2S contained in newly produced liquid sulfur tends to break away and evolve out of the liquid state naturally, low-capacity SRU’s can often use simple pump-around systems or natural degassing (sometimes called weathering) combined with a properly designed pit or tank sweep system.

For larger facilities, the natural degassing and weathering process is not feasible and the high total volume of degassed H2S needs special consideration. PTI’s team has experience with a broad range of sulfur degassing technologies including:

Natural Degassing/Weathering and Pit Sweep Design
Pump Around/Agitation Systems
Pump Around + Catalyst Systems
Air Sparge and Contactor Systems

From simple storage, handling, and truck loading units to advanced high-volume facilities incorporating forced degassing, solidification, and rail transport. Our team brings the know-how required for your sulfur project.