Corrosion Activity of Operating Conditions for the Steel Equipment and Pipelines in the Plants Extracting CO₂-Containing Gases

The current stage of development of promising gas and gas-condensate fields on the territory of Russia is realized at the extracting plants whose products contain carbon dioxide (CO₂). The presence of carbon dioxide, in combination with moisture and other factors, stimulates the intense development of corrosion processes and requires careful and well-justified analysis of the corrosion activity of working media with subsequent choice of the engineering solutions ensuring the reliable safe operation of hydrocarbon-extracting plants. We analyze the accumulated experience of testing of carbon steels and corrosion-resistant alloys in the presence of aggressive CO₂, which leads to the development of dangerous local corrosion defects. These defects are developed especially rapidly under the conditions of condensation of moisture, which is most intensely accumulated in the process of the gas extraction in the first sections of the pipeline for the highest temperature drops. The tests carried out at the Gazprom VNIIGAZ, LLC demonstrated that local defects may develop on carbon and low-alloy steels (such as 09G2S steel) under the operating conditions of extracting plants in the presence of CO₂ and moisture condensation. Especially high corrosion resistance was exhibited only by the alloy whose chromium content is ≥ 13%.