Efficient corrosion control of gas condensate pipelines by pH-stabilization

Conference · Mon Nov 01 04:00:00 EST 1999

OSTI ID:697053

Dugstad, A; Dronen, P E ^[1]

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1. Inst. for Energy Technology, Kjeller (Norway)

The corrosion rate of gas condensate pipelines can be substantially reduced by increasing the pH artificially. The technique is called pH stabilization and has been used with success in gas condensate pipelines. The reduction is based on the precipitation of protective corrosion products on the steel surface. When corrosion product films are formed, it is the transport of reactants and corrosion products through the film which governs the corrosion rate. Film properties like porosity, thickness and composition therefore become important. All these properties are strongly related to the precipitation process which depends very much on supersaturation and temperature. A large number of flow loop and glass cell experiments have been carried out in order to study these aspects. In addition to the CO{sub 2} partial pressure, the hydrate preventer, the flow velocity, and the pH, a number of variables related to the steel surface conditions and the operation of a real pipeline were studied in the experiments. The last group of variables included the presence of mill scale and rust on the steel surface prior to exposure, periods without flow (shut down), draining of the pipeline and scratches in the protective film. The paper discusses how these parameters affected the performance of carbon steel in water-glycol(50%) systems with 0.6 MPa CO{sub 2} partial pressure and with sodium bicarbonate added as pH stabilizer.

• OSTI ID: 697053
• Report Number(s): CONF-990401--
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
36 MATERIALS SCIENCE
CARBON DIOXIDE
CARBON STEELS
CORROSION
CORROSION PRODUCTS
GAS CONDENSATES
GLYCOLS
PH VALUE
PIPELINES
SODIUM CARBONATES