In the gathering and transportation of natural gas pipelines, hydrogen sulfide detectors are widely used. Due to the presence of more H2S gas in pipelines, the problem of corrosion in pipelines caused by H2S is widespread and is one of the hidden dangers in the gathering and transportation of natural gas pipelines. Therefore, the use of hydrogen sulfide detector must also consider the problem of corrosion of the instrument. This article will elaborate from the corrosion mechanism, influencing factors and protective measures of H2S.
Hydrogen sulfide
- H2S corrosion mechanism
H2S is the simplest type of S hydride. At room temperature, it is a colorless, flammable, and odorous highly toxic egg. H2S has high solubility in water. After dissolving in water, it forms a weak acid called hydrosulfuric acid, which is corrosive and can cause the metal substrate to show comprehensive corrosion and local corrosion.
- Influencing factors of H2S corrosion
The influencing factors of H2S corrosion include environmental factors and material factors. Among them, environmental factors mainly include H2S partial pressure, CO2 partial pressure, medium temperature, pH value, degree of mineralization, flow rate and flow state, etc .; material factors include types of pipeline materials, alloy elements Cr, Ni, Si, Mo, Cu, etc Content, material overlays, etc.
- H2S corrosion protection measures
China requires natural gas pipelines to remove mechanical impurities before entering the pipeline, limit water dew point and hydrocarbon dew point temperature, and limit H2S content. For gases that do not meet the above quality requirements, corresponding protective measures must be taken. The main ways to control H2S corrosion are: correct selection of pipeline metal materials, reasonable treatment of environmental media, increased electrochemical protection, and coarse cap protection.