Abstract: A method for the determination of molybdenum (organic molybdenum and inorganic molybdenum) in slurry bed residue hydrocrackting materials was established by using a dry ashing pretreatment method and an inductively coupled plasma optical emission spectrometry. The effects of ashing time, ashing temperature and acid treatment on the determination of molybdenum element were investigated. The results showed that the content of molybdenum (organic molybdenum and inorganic molybdenum) could be accurately determined when the ashing temperature was 430-480 ℃, ashing time was not less than 10 h, the acid dissolving the ash was hydrochloric acid or nitric acid. The relative standard deviation of this method was less than 1%, and the recovery was 97%-102%, met the general requirements of elemental analysis. Compared with GB/T 37160—2019, this method can reduce the ashing temperature, reduce the amount of acid, and determine the molybdenum content more accurately.

Key words: slurry bed, residue hydrotreating, dry ashing, molybdenum content