Effect of Inorganic Species on Organic Matter Formation in Crude Oil Fouling

This is the authors' abstract. We don't add key points for this paper.

Fouling within the preheat train exchangers in atmospheric crude distillation units is a common problem that reduces energy efficiency of oil refineries. The fouling deposits contain organic matter, salts, and iron sulfide, which forms as a result of corrosion. In this study, fouling deposits recovered from the highest-temperature heat exchangers for crude oil at four refineries were analyzed to investigate the effects of inorganic species on the molecular structure of organic matter in the deposits. After the removal of toluene-soluble components and demineralization, the fouling samples were analyzed by using elemental analysis, thermogravimetry, X-ray diffraction, scanning electron microscopy, mass spectrometry, and infrared spectrometry. Average molecular structure models of organic matter were estimated using the resulting data. In those models, the number of aromatic carbons increased as the iron and sulfur contents increased, suggesting that inorganics, such as iron sulfides and sulfur, may contribute to the formation of aromatic rings in fouling deposits, potentially leading to progressive fouling. Such a tendency was not observed in the sample recovered from the lower-temperature heat exchanger, likely due to the lower reaction temperature.