US Patent 7128828 Process for producing food grade wax

A process for producing food grade wax which contains exceedingly low levels of nitrogen, sulfur and aromatic compounds. A waxy feedstock is firstly hydrotreated in a first hydrogenation zone to reduce the level of contaminants such as sulfur, nitrogen and aromatic compounds, and the resulting effluent from the first hydrogenation zone is introduced into a hot, high pressure stripper and contacted with a hot, hydrogen-rich stripping gas to remove ammonia and hydrogen sulfide. The stripped, hot liquid hydrocarbons are removed from the bottom of the hot, high-pressure stripper to further reduce the concentration of aromatic compounds by being hydrogenated in a second hydrogenation zone containing a platinum or palladium catalyst.