EFFECT OF SOLUTION FLOW RATE, NaCl CONCENTRATION, AND H2S CONCENTRATION TO CARBON STEEL CORROSION

• Main Author: Dwi Rachmawati, Indah
• Format: Final Project
• Language: Indonesia
• Subjects: Teknologi kimia industri
• Online Access: https://digilib.itb.ac.id/gdl/view/38266
• Institution: Institut Teknologi Bandung

Chemical industry is an industry that process the raw material to product that fulfill the people needs. Plastic industry that use chlorine gas from brine electrolysis, petroleum industry, and geothermal power plant industry are some examples of chemical industries that use steel pipe in their process. Hydrogen sulfide, chloride ion, and fluid flowrate have potencies to cause corrosion on process equipments made of steels. This research intend on the effect of solution flow rate, NaCl concentration, and H2S concentration to carbon steel corrosion rate and mechanism in NaCl solution containing H2S. These experiments have been conducted at room temperature and pressure. The corrosion rate of carbon steel in NaCl solution containing H2S was measured by using potentiodynamic method, the corrosion mechanism was determined by cyclic voltammetry and electrohemical impedance spectroscopy methods, and was approved by corrosion product composition analyzed using X-ray diffraction and SEM methods. The results of this study indicate that the corrosion rate of carbon steel in NaCl solution containing H2S increase with increasing flow rate, H2S concentration, and NaCl concentration. However, the corrosion rate decrease in the range of 60 to 500 ppm H2S due to the deposition of iron-sulfide compound on the steel surface. The corrosion mechanism of carbon steel in a NaCl solution containing H2S begins by iron dissolution that formed mackinawite which changed consecutively to pyrrhotite and finally becomes pyrite. The interaction effect of flow rate and NaCl concentration as well as the interaction effect of H2S concentration and NaCl concentration increased synergistically the steel corrosion rate. The interaction of H2S concentration and flow rate as well as the interaction of H2S concentration, NaCl concentration, and flow rate did not affect the corrosion rate.