A Novel Demetalation Process for Vanadyl- and Nickelporphyrins from Petroleum Residue by Photochemical Reaction and Liquid−Liquid Extraction

Abstract

A novel demetalation process for residue oils, based on a combination of photochemical reaction and liquid-liquid extraction, has been investigated. A simultaneous photoreaction and extraction process, employing an oil/water two-phase system, was first studied. The results for the demetalation, obtained for vanadyl(IV)-and nickel(II)tetraphenylporphyrin dissolved in tetralin, were compared with those obtained for actual atmospheric residue oil. It was found that this first process was able to demetalize "free"-type metalloporphyrins, but had difficulty in the demetalation of "bound"-type metalloporphyrins, which are associated strongly with the asphaltenic molecules in residue oil. To weaken this association and thus convert the boundtype metalloporphyrins to the free-type ones, a hydrogen-donating polar solvent, 2-propanol, was added to the residue oil and photoirradiated. The 2-propanol was then removed by evaporation, and the resulting residue oil was contacted with aqueous HCl solution, into which the resulting vanadium and nickel were successfully removed. According to this latter development of the process, 93% vanadium and 98% nickel were recovered from atmospheric residue and 73% vanadium and 85% nickel from vacuum residue, respectively. The overall demetalation process, involving the recovery of the 2-propanol, has been formulated as an energysaving and safe demetalation process, which is satisfactory for application in the upgrading of heavy residual feedstocks.

Photochemical Desulfurization and Denitrogenation Process for Vacuum Gas Oil Using an Organic Two-Phase Extraction System

“…Combination with Other Refining Processes. Previous studies have considered novel refining processes for the desulfurization, denitrogenation, and demetalation of petroleum-derived middle and heavy feedstocks, based on the combination of photochemical reaction and liquid−liquid extraction. − ,− From a consideration of these results and the results obtained in the present study, a possible combination of these new processes with current established refining processes is proposed; it is shown in Figure . The overall process sequence is as follows: (1) The light oil and atmospheric residue are produced by atmospheric distillation of crude oil.…”

“…(2) The latter residue oil is then separated by vacuum distillation into VGO and vacuum residue. (3) The vanadium and nickel compounds in these residual fractions are removed, by the previously proposed photochemical demetalation process, into aqueous solution, which can then be used as a source of rare metals. When the presently considered process was applied to the desulfurization and denitrogenation of residue oils, the sulfur and nitrogen concentrations were found barely decrease.…”

A Review of the Unconventional Methods Used for the Demetallization of Petroleum Fractions over the Past Decade

“…Shiraishi et al studied a unique photochemical method for the extraction of vanadium and nickel porphyrins from residua. They dissolved model VOTPP or NiTPP in tetralin and treated it to photoirradiation by subjecting it to a high-pressure mercury lamp.…”

Isolation of Porphyrins from Heavy Oil Objects

“…Metal porphyrins in oils have a negative effect on catalysts of oil refining processes [19,20], so currently, oil demetallization methods are used and developed [21][22][23]. Effective development of methods to remove vanadium and nickel from oil is impossible without having information on the structure and properties of metal porphyrins.…”