Studies On The Analysis Method Of Oxygen Content And Functional Oxygen Distribution In Heavy Oil

Oxygen in heavy oil always had bad effect on oil and its products. But there are few studies on the analysis method of oxygen content and the distribution of different types oxygen in heavy oil. Systematic and simple methods are lacked. For this situation, this paper has built the quantitative analytical methods of oxygen contening compounds of carboxylates and alcoholic hydroxyl, studied and built the optimum experimental conditions of the instrumental analytical method of the oxygen content in heavy oil under our laboratory conditions.With the standard solution of hexadecyl trimethyl ammonium bromide (CTAB) as the titrant, the bromocresol green as the indicator,the two-phase titration method which for the determination of carboxylates type oxygen content in heavy oil has been built. And the carboxylates type oxygen content in Karamay crude(KLMY), Venezuela crude(WNRL) and Fushun vacuum residue(FSVR) have been measured and the results are as follows: 0.01641%, 0.007408% and 0.005194%. With the standard solution of KOH-isopropanol as the titrant and the acetic anhydride-pyridine(v:v, 10:100) as the acylation reagent, the potentiometric titration method which for the determination of alcoholic hydroxyl type oxygen content in heavy oil has been built. And the alcoholic hydroxyl type oxygen content in KLMY, WNRL and FSVR have been measured and the results are as follows: 0.1764%, 0.1765%, 0.07342%. In this paper, the quantitative analytical method of phenolic hydroxyl type oxygen content in heavy oil has been improved on the basic of our team's preliminary study[5].On the basic of our team's preliminary study[41], the optimum experimental conditions of the instrumental analytical method of the oxygen content in heavy oil under our laboratory conditions has been built. Adopting the established experimental conditions, the oxygen content of typical oxygen containing compounds of carboxylic acid, alcohol, ether, ketone, phenol and ester has been measured. And it's been found that the established experimental conditions were more accurate when the oxygen containing compounds were macromolecular relative to small molecular. Through the comparison of the results between this method and element analysis method and because the oxygen containing compounds in heavy oil were mainly macromolecular, the established experimental conditions were appropriate for the oxygen content determination of heavy oil. The oxygen contents of KLMY, WNRL and FSVR were measured using the established experimental conditions and the results were as follows: 0.2783%, 0.8827% and 0.4494%.The thermal processing and hydrogenation were the most important processing methods of heavy oil. It is important to study the changes and mechanism of oxygenated compounds molecular structure of heavy oil before and after thermal reaction and hydrogenation. It must have certain guiding significance to the processing of heavy oil. In this paper, the thermal reaction and hydrogenation have been done to the KLMY, WNRL and FSVR. The conditions of the thermal reaction are as follows: temperature 400℃, 410℃and 420℃, time 60min, 90min and 120min. The conditions of the hydrogenation are as follows: temperature 420℃, time 60min, 90min and 120min.It's measured that the oxygen distributions in KLMY, WNRL and FSVR before and after thermal reaction and hydrogenation. By comparing the measured results, it can be seen that the thermal reaction and hydrogenation would affect the distribution of oxygen in heavy oil. And the content of every type oxygen was almost reduced. Analyzing Heptane asphaltene of oil sample before and after reaction by IR and XPS to determine the types and the relative content of various oxygen-containing functional groups, which further conformed the accuracy of the quantitative analytical methods of oxygen-containing functional groups in heavy oil.