Uso da microcromatografia gasosa no estudo da evolução do gás CO2 no processo de destilação laboratorial de petróleo

Abstract

Petroleum remains the largest non-renewable source of energy in the world. In its raw state it has little use. However, its derivatives have high economic value. In the steps of primary processing of petroleum, a few compounds of natural occurrence are undesirable, such as the naphthenic acids, resins, asphaltenes, and metal and sulfur compounds. The corrosive power of naphthenic acids worries petroleum industries due to the damage caused in the pipes and refineries. Recent studies indicate that a portion of these acids when subjected to elevated temperatures (greater than 280°C) can undergo decarboxylation reactions and thermal degradation, forming carbon dioxide (CO2) and smaller chains acids such as degradation products. The smaller chains acids along with naphthenic acids, which remained preserved are corrosive and CO2when in contact with water forms carbonic acid (H2CO3), which may contribute to corrosion rates in refining equipment. In this paper a new methodology for "online" quantification of CO2released in petroleum distillation process was developed. The developed methodology wasbased on micro gas chromatography technique. The quantitative data ofthe CO2concentration generated by micro chromatograph were related to the values of the distillation temperature, thereby obtaining a variation in the concentration of CO2, in accordance with the oil distillation temperature. The results show that the distillate petroleum presents a tendency in the formation of CO2gas from temperatures above 230 °C. In an attempt to elucidate the possible origin of this gas, it was necessary to assume one decarboxylation mechanism for such acids