Patent ID: 7704376

Claim:
A method for inhibiting the fouling of surfaces of process equipment used in the thermal upgrading of heavy oils which method comprises: a) contacting the heavy oil with an effective amount of a water-soluble inhibitor additive to provide an inhibitor additized heavy oil, which water-soluble inhibitor additive is selected from the group consisting of naphthalene-2-sulfonic acid sodium salt, naphthalene-2,6-disulfonic acid sodium salt, naphthalene-1,5-disulfonic acid sodium salt, naphthalene-1,3,6-trisulfonic acid sodium salt, anthraquinone-2-sulfonic acid sodium salt, anthraquinone-1,5-disulfonic acid sodium salt, and pyrene-1,3,6,8-tetra sulfonic acid sodium salt; and b) thermally treating said inhibitor additized heavy oil at a temperature in the range of about 250° C. to 500° C. for a time between about 0.1 to 10 hours in a thermal upgrading process unit.