TOBACCO EXTRACT AS CORROSION INHIBITOR FOR CARBON STEEL IN NACL SOLUTION CONTAINS H2S

• Main Author: Prakarsa, Clarissa
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/48260
• Institution: Institut Teknologi Bandung

Chemical industry is a chemical process sub-sector whose products are identified as chemical substances. Many industries use carbon steel as process equipments material, such as petroleum industry, fertilizer industry and cement industry. Fluid flow rate and the presence of impurities like hydrogen sulfide and chloride ions have potencies in increasing the corrosion rates. Corrosion control for carbon steel in H2S containing NaCl solution has been developed, such as using an inhibitor, made of inorganic as well as organic compounds. Tobacco extract is one of the organic compound that can be used as corrosion inhibitor. This research intend to determine the effectiveness of tobacco extract as corrosion inhibitor of carbon steel in NaCl solution containing H2S. This experiment has been conducted at room temperature and pressure. The corrosion rate was measured by using potentiodynamic method, and the corrosion mechanism was determined by using cyclic voltammetry, electrochemical impedance spectroscopy, meanwhile, corrosion product was analyzed by using scanning electron microscope, X-ray diffraction and Fourier transform infrared spectroscopy. The results of this study indicate that the corrosion rate of carbon steel in NaCl 3,5% solution augment with increasing flow rate and H2S dissolution in electrolyte. However, the corrosion rate due to both factors can be suppressed by addition of tobacco extract as an inhibitor that will work by forming protective layers. Inhibition efficiency of 1000 and 2000 ppm tobacco extract in NaCl solution ranges from 24 to 69%. The interaction between flow rate and inhibitor concentration in the electrolyte affect significantly the corrosion rate of carbon steel. Carbon steel corrosion in NaCl solution begins with the formation of iron oxide in the form of magnetite (Fe3O4) as a corrosion product. The presence of H2S in the electrolyte results in the formation of iron-sulfide compounds namely mackinawite (FeS).