ONLINE AND REAL-TIME MONITORING OF CORROSION RATES OF STAINLESS STEEL, LOW CARBON STEEL AND COPPER IN CO_2 HYDRATE SLURRY WITH COUPLED MULTIELECTRODE ARRAY SENSORS

摘要

This paper describes the corrosion effects of saturated CO_2 solution as well as CO_2 hydrate slurry on low carbon steel, stainless steel and copper, materials which are widely used in air-conditioning, cold storage, oil and gas industry. CO_2 hydrate slurry production system and production process were described. Real-time coupled multielectrode array sensor (CMAS) probes were used to measure the maximum localized corrosion rate of type 1018 low carbon steel, copper 110 and 304L stainless steel in saturated CO_2 solution and CO_2 hydrate slurry under conditions of temperature range (1～18°C), pressure range (25～30bar). Measured real-time maximum corrosion rates are presented together with a discussion of the maximum localized corrosion depth and localized corrosion depth factor. For comparison purposes, conventional material corrosion tests were also conducted in the experimental rig for up to 17 days. Three different types of metal specimens with similar characteristics to low carbon steel, stainless steel and copper probes were immersed-into saturated CO_2 solution as well as CO_2 hydrate slurry for conventional metal corrosion test. Results obtained from these tests were compared with CMAS probes results. Type 304L stainless steel displayed very good resistance to the corrosion caused by CO_2 hydrate slurry. Copper 110 also showed good resistance to corrosion. In contrast, 1018 low carbon steel was found to have very poor resistance to the corrosion.