Mecanismos de degradação de materiais em uma refinaria de petróleo

Abstract

This thesis addressed four mechanisms of damage in the oil refining industry, as well as alternatives for their mitigation. The first mechanism addressed involves corrosion by ammonium disulfide in acidic water units. The second mechanism discussed was the degradation of the refractory concrete of the riser of the fluidized catalytic cracking unit. The third mechanism analyzed involved corrosion by contaminated amines in a heat exchanger of the top system of the diethanolamine regenerator tower of the cracked naphtha hydrodesulfurization unit. Finally, the fourth and last damage mechanism addressed involved corrosion by naphthenic acids acting in the vacuum distillation tower of the distillation unit. The methodology used in this work was the case study technique. Each type of damage mechanism described was analyzed based on the recommendations of the North American Petroleum Institute standard, followed by extensive bibliographic research. The research addressed operational occurrences at PETROBRAS Gabriel Passos refinery. In conclusion, the mitigating actions involving corrosion in the acidic water unit implied the proper selection of materials, monitoring of contaminants, application of coatings, injection of washing water and corrosion inhibitors to reduce the concentration of aggressive contaminants. In the catalytic cracking unit, it involved the proper selection of the refractory and the binder, adequate adoption of the refractory curing time, adequate spatial distribution of the anchor elements and investment in the catalyst regeneration process, avoiding the diffusion of coke residues for the refractory mass. In the cracked naphtha hydrodesulfurization unit, it involved installing the wash water system to dilute the concentration of the diethanolamine stream in the top system of the regenerator tower to adequate operational levels. Finally, in the distillation unit, it involved the adequate control and monitoring of the total acidity number of the oil load processed in the refinery.