Effects of aromatic cycle oils on performance of residue hydrotreating

Hydrotreating, as an important pretreatment process of residue catalytic cracking, is used to eliminate metals, S and N contaminants and partly process asphaltene from streams so that the products can be efficiently processed in downstream conversion units. We investigated the effects of aromatic additives on residue hydrtreating (RHT) by adding various types and contents of high aromatic cycle oils into atmosphere residue (AR). The aromatic additives modify the colloidal structure of asphaltene in AR and improve the liberation of heteroatomic compounds bound in nucleus. Therefore, the amount of carbon residue in blending oils decreases and the removal efficiency of Ni, V, S and N increases obviously. The increase of conversion is greater for nitrogen than for sulfur, and hydrodevanadium reveals a distinct advantage over hydrodenickel. However, excessive amount of light cycle oil (more than 20% wt) is not helpful for removing the Ni and V since a little of metalloporphyrins stubbornly bond with the superstructure of nucleus.