โ Scribed by Thorsten Butz; Hans-Henning Oelert
No coin nor oath required. For personal study only.
Asphaltenes obtained from an Arabian Mix vacuum residue were cracked under hydrogen in a batch autoclave at 410-460ยฐC for 5-90 min. The products were fractionated into gas, naphtha, oil, asphaltenes and coke. The feed and several product fractions were characterized by elemental analysis, by average molecular mass and by ~H n.m.r. The variation of product fraction yields and analyses with temperature, reaction time, reaction gas (nitrogen, hydrogen) and the presence of an inert solvent provided information about reactivity and reactions in asphaltene cracking. Bond fission generated radicals that were saturated either to oils (small radicals) or to asphaltenes of increased aromaticity (large, highly aromatic radicals). These two primary products underwent further fission, generating light products or coke (by radical combination). Dilution of the asphaltenes decelerated the cracking reactions. Hydrogen improved the radical saturation and thereby decelerated asphaltene cracking, increased the oil production and reduced the coke formation.
๐ SIMILAR VOLUMES
Khafji vacuum residue was thermally cracked using (1) ZnO<r,O, plus stabilized Co and (2) CuO-ZnO-Al,O, as catalyst under hydrogen formed in situ from methanol decomposition. Catalyst (2) was more effective in conversion than catalyst (1). Conversion increased with temperature and time, but the gas