COMPARISON OF INHIBITOR ONDANSETRON HYDROCHLORIDE AND ASAM ASKORBAT ON DECREASING CORROSION RATE API 5L GRADE X56 STEEL IN ACIDIC ENVIRONMENT

• Main Author: Permata Sari Frm, Mira
• Format: Final Project
• Language: Indonesia
• Subjects: Metalurgi
• Online Access: https://digilib.itb.ac.id/gdl/view/38193
• Institution: Institut Teknologi Bandung

Carbon steel can be used for pipeline construction in the oil industry, especially for crude oil transportation. Carbon steel that can be used is API 5L grade X56 which is classified as mild steel. Steel corrosion in crude oil pipelines can be caused by hydrochloric acid which appears during the oil exploitation process from chloride hydrolysis contained in brine water or high salinity formation water from oil wells. The corrosion resistance of carbon steel is low, so it requires inhibitor as a corrosion control mechanism. Organic inhibitors pharmacy compound based have been used because they are not toxic, environmentally friendly, and high availability. Therefore, this organic inhbitors needs to be learned with variety of inhibitor types and concentrations. In this experiment, the inhibitor of ondansetron hydrochloride (ODSH) and ascorbic acid have been used as organic corrosion inhibitors with corrosion medium 1M HCl. Duration of immersion for two days. Corrosion rate, efficiency, and adsorption mechanism on solution containing 0 ppm, 50 ppm, 100 ppm, and 200 ppm inhibitor were determined by weight loss measurement method. Corrosion potential and inhibitor efficiency were measured by Electrochemical method. This method was performed using Potentiostat on solutions containing 0 ppm and 200 ppm inhibitor. Besides that, steel surface was examined using scanning electron microscope dan energy dispersive X-ray spectroscopy (SEMEDX). Immersion test result showed that corrosion rate decrease while inhibitor efficiency increase as a function of inhibitor concentration. The lowest corrosion rate on solution containing of each 200 ppm ODSH and ascorbic acid were about 0,79 mm / year and 2,55 mm / year, respectively. On the other hand, the highest efficiency on solution containing of each 200 ppm ODSH and ascorbic acid were about 87,45% and 59,44%. Meanwhile on EIS test, efficiency solutions containing 200 ppm ODSH and ascorbic acid were 84,43% and 59,77% respectively. This is because in ODSH there are three heteroatoms N whereas in ascorbic acid there is only one heteroatom O. Adsorption behavior of ODSH and ascorbic acid inhibitor is mixed (physisorption and chemisorption). The displacement in corrosion potential on addition of ascorbic acid and ODSH inhibitors were considered to be less significant, so this two inhibitors were classified as mixed-type. The electrical equivalent circuit model on inhibitors addition are Rs-(CPEi(Ri(CPEdl/Rp))), indicates that the passive layer was formed on the steel surface but not evenly distributed.