ABSTRACT
The characterization of the thermal cracking products (visbreaking) from Athabasca vacuum residue (ATVR) and Arabian Light vacuum residue (ALVR) as a function of severity is presented. Information on elemental analysis (CHNSO), metal content (Ni, V), molecular mass (MM), aromaticity, total naphthenic carbon, total secondary methylene groups, chain length, and solubility parameter were determined to assess structural information. All of them were found to vary as a function of thermal cracking severity. For example, a reduction in H/C, MM, total secondary carbon, and chain length along conversion is observed. In addition, heteroatom contents also changed with residue conversion, leading to products enriched in nitrogen and oxygen but depleted in sulfur as severity increased. Interaction of such products with well-designed macroporous solid surfaces such as Ca-kaolin and Ca-Ba-kaolin indicated that adsorption uptakes depend on the structural properties of the products and on the textural properties of the solids. For both solids, adsorption uptakes for visbroken products from ATVR increase as a function of residue conversion. Parameters such as aromaticity, asphaltene content, and nitrogen content seem to be the drivers for adsorption uptake. In contrast, for ALVR, lower uptakes were found than in ATVR. For ALVR, adsorption also seems to be governed by aromaticity, asphaltene content, and nitrogen content of the visbroken products, as well as by surface properties.
