Sour gas is a natural gas composed of large amounts of H2S (hydrogen sulfide), created through the anaerobic decomposition of materials in oil, natural gas, swamps, sewage, stockyards, and paper/pulp processing. This corrosive, lethal gas is flammable, colourless, and has a recognizable sulfur smell. Compressing H2S is tricky as it makes carbon, high hardness, and high-strength steels brittle. It deteriorates martensitic/magnetic stainless steels. H2S collects in low-lying spots and impairs breathing. Precautions are necessary to protect equipment and people (supervision and training of personnel, detailed drilling plans, emergency response plan, regular inspections of equipment, etc.). Companies must carefully consider the machinery they use in H2S environments.
What To Consider When Choosing Compressors For Use With H2S
If you are buying/renting equipment for use in high H2S conditions, consider:
- Equipment composition/materials: For use in a high H2S environment, companies consider compressor configuration options, method of manufacture, chemical composition of metals, microstructure, heat treatment condition, and product strength/form/hardness. Non-lubricated cylinder construction is recommended, and NACE SS valves are required. The packing case must withstand an external purge pressure of 15 to 20 psi above the drain/vent pressure. Stainless steel piston rods are recommended with H2S content of 100 ppm or more. Field experience and laboratory testing are taken into account.
- Operational parameters: To increase compressor longevity and safety when working with H2S, allow for lower discharge temperatures (275°F for discharge, 135°C for selection, 325°F for shutdown) and operate at slower piston speeds. Suitable, well-maintained vent/purge systems are necessary to contain H2S.
- Arrangement of distance pieces: A single long-distance piece (with wiper seal purge) or a two-compartment distance piece is required, creating a vent/purge system that separates the crankcase and atmosphere from leakage. The two-compartment distance piece is best for H2S levels greater than 2%. The single piece doesn’t offer enough flexibility or protection at 2% or greater H2S levels.
- Flushing lube: The use of cylinder flushing lube is recommended for sour gas situations with greater than 2% H2S content, ensuring corrosion protection for valves (body and spring).
What GasPro Compression Corp Provides
GasPro specializes in quiet, dependable compressors with an effective, simple, low-maintenance design. Our compressors have a long life. They boast a noise-attenuated package, dependable/fuel-efficient engines, come in various sizes, and can be customized to individual well flow parameters. Qualified technicians are available for scheduled service. Gas measurement and detection options are available. Packages are available for rent, purchase, or rent-to-own. When it comes to H2S, GasPro provides:
- Single-stage sour service reciprocating compressors: We provide efficient, reliable, versatile, single-stage reciprocating compressors for use with sour gas/H2S. Durable rotary blades/vanes (carbon or synthetic polymer) are housed in a cylindrical chamber. Vapour/gas enters the chamber through an inlet port. As the rotor spins, the chamber’s volume decreases, compressing the gas, which is discharged at a high pressure through the outlet port (ready for further processing or utilization). Our single-stage compressors handle a range of gases (abrasive, corrosive, viscous), making them perfect for loading/unloading tank trucks, transferring liquefied gases, and vapour recovery systems. Used in many industries (petrochemical, chemical, gas/oil, etc.), they require minimal maintenance and have a simple design/operation. Their long service life and low operating cost are due to the absence of metal-to-metal contact in their internal design. A minimal leakage and optimal compression process reduces energy usage and operating expenses. Versatile capabilities, robust construction, and low maintenance needs set these compressors apart.
- Two–stage sour service reciprocating compressors: GasPro’s two-stage sour service reciprocating compressors (two pistons and cylinders that compress in two stages) offer all the advantages of our single-stage design.
Contact GasPro for the right compressor for high-H2S environments.
