Understanding Corrosion in Water Pipelines: A Guide for Pipeline Designers


Hydrogen Sulfide Scavenger (H2S Scavenger)

Last updated: July 22, 2020

What Does Hydrogen Sulfide Scavenger (H2S Scavenger) Mean?

A hydrogen sulfide (H2S) scavenger is a specialized chemical or fuel additive widely used in hydrocarbon and chemical processing facilities. These specialized chemicals react selectively with and remove H2S to help meet product and process specifications.

Products treated for H2S include crude oil, fuels, and other refined petroleum products in storage tanks, tanker ships, rail-cars and pipelines.

Hydrogen sulfide can cause damage to pipework, either by reacting directly with steel to create an iron sulfide corrosion film, or by increasing the acidity of the liquid/gas mixture in the pipes. When dissolved in water, H2S may be oxidized to form elemental sulfur. This can also produce an iron sulfide corrosion film when in direct contact with the metal surface. Therefore, it is essential to remove H2S from crude oil as quickly and efficiently as possible.


Corrosionpedia Explains Hydrogen Sulfide Scavenger (H2S Scavenger)

Hydrogen sulfide occurs naturally in crude oil and can be generated from refining processes, including hydro-cracking, hydrolysis and elemental sulfur production. Removal of H2S is required where the presence of bacteria and organic matter result in the generation of this noxious gas. The presence of H2S can also reduce overall system efficiency and operational reliability, as the gas is corrosive and can lead to iron sulfide fouling.

Hydrogen sulfide scavengers can provide a cost-effective alternative to conventional gas/liquid sweetening processes, such as amine units or solid dry bed processes, to prevent hydrogen sulfide corrosion. H2S scavengers can provide successful treatment in a wide range of applications, including:

  • H2S removal from gas streams
  • H2S removal from sour hydrocarbon liquids (condensate and NGL streams)
  • H2S reduction in sour liquid tank vapor spaces

Scavenger programs are selected depending on the nature of the H2S problem being addressed and the petroleum product being treated. There are three types of H2S scavengers:

  • Water-soluble scavengers – The most common scavengers and often the product of choice for applications at temperatures below 200°F (93°C). These are the preferred additives for use in flare gas, LPG, residues and crude oils.
  • Oil-soluble scavengers – Used in high-temperature applications or when water tolerance of the hydrocarbon is an issue. These products are typically amine-based.
  • Metal-based scavengers – Answer the specific needs of very high-temperature and high-H2S concentration applications, typically used to treat asphalt.

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