石油系重質残油の熱処理物中のバナジウムのX線状態分析

概要

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Oxidation states of vanadium in samples were estimated by comparing the X-ray parameters of the K_<a1> width, K_<a1>/K_<a2> intensity ratio, and K_<a1> shift with those of the pure compounds of vanadium in the +3, +4. and +5 oxidation states. Vanadium K_<a1> and K_<a2> spectra were measured automatically by a step scanning method at regular interval of 0.005° 2θ with a two-crystal X-ray spectrometer equipped with Ge(III) crystals. A chromium X-ray tube and a flow proportional counter were used. All X-ray parameters of n-hexane insoluble materials from Khafii and Gachsaran vacuum residue and Canada oil sand bitumen showed that most of vanadium was present in the +4 oxidation state in the samples. No remarkable changes in these parameters were found in the heat-treated products of the original samples at 450℃ for 2 hours in a flow of nitrogen gas. When the products were further heat-treated at 1000℃ for one hour, the parameters came close to those of the +3 vanadium compounds. The changes in the parameters indicate that vanadium is reduced gradually from +4 to+3 state by hydrogen and hydrogen sulfide gases produced by the pyrolysis of the samples. This reduction process of vanadium during heat-treatments above 450℃ was confirmed from the changes in the parameters of vanadyl phthalocyanine added to Khafji residual oil.
社団法人日本分析化学会の論文
1978-03-05