Petroleum containing higher levels of sulfur is called sour crude oil. Sweet crude oil contains small amounts of hydrogen sulfide and carbon dioxide. High-quality, low-sulfur crude oil is commonly used for processing into gasoline and is in high demand, particularly with heavy processing-global producers.

During the past 10 years, exploration and production companies in both North America and Europe have developed newer technologies to extract fossil fuels in deeper elevations of the subsea floor. These formations are producing higher temperatures and higher pressures (HTHP) with elevated concentrations of Hydrogen sulfide (H2S).

Typical wells are producing fossil fluids with a highly corrosive and abrasive content indicating < 10% of hydrogen sulfide. Mitsubishi Chemical Advanced Materials, a leader in engineered thermoplastics for the energy market has been supporting this industry with engineered thermoplastics such as Ketron® PEEK which has been tested to meet the regulatory conditons set forth by NORSOK M-710, in a multi-phase liquid combination.

Mitsubishi Chemical Advanced Materials’s material solution for corrosive environments

Fluorosint® 500 – Used as an abradeable seal, most commonly applied in “Tooth on Rotor” designs
Ketron® PEEK – Applied in Compressors with “Tooth on Stator” used in higher temperature, and those units with criticalspeeds

In the above picture, the upper seal has degraded from service in a corrosive environment and the teeth are slightly mushroomed. Due to direct impact, which does not deflect back to original position causing a larger radical clearance and increased flow path that delivers insufficient performance. The lower seal is a metal labyrinth seal, is a PEEK seal where teeth deflect under contact or rubbing condition. Rebound to the original position to continue operating and improving compressor efficiency with a restricted flow path.

Recently, the energy market has seen further increase in H2S levels >10% up to 35% by concentration. Mitsubishi Chemical Advanced Materials is continuing its R&D efforts to develop new Ketron® PEEK grades to meet the industry challenge and complete the testing required per NORSOK M-710 and the upcoming ISO 23936-2 specification for elevated levels of sulfur in sour crude as a replacement of metal labyrinth seals which are chemically attacked signaling poor and insufficent compressor performance in the industry.

Most commonly used polymers for Labyrinth Seals

Ketron® CA30 PEEK [30% Carbon fibre reinforced grade]

Max allowable temperature in air: 250 °C
Tensile strength 131 MPa at 23 °C

Product Data Sheet

Ketron® 1030 HT PEK [30% Carbon fibre filled PEK HT]

Max allowable temperature in air: 250 °C
Tensile strength 110 MPa at 23 °C

Product Data Sheet (Link to MATWEB Database)

Duratron® T4540 PAI [Compression molded bearing grade PAI]

Max allowable temperature in air: 260 °C
Tensile strength 62 MPa ata 23 °C

Product Data Sheet (Link to MATWEB Database)

Fluorosint® 500 [Reinforced with a reinforced synthetic mica]

Max allowable temperature in air: 250 °C
Tensile strength 7 MPa at 23 °C

Product Data Sheet