Abstract: A method of hydroprocessing is performed wherein non-petroleum feedstocks, such as those containing from about 10% or more olefinic compounds or heteroatom contaminants by weight, are treated in a first reaction zone to provide reaction products. The process involves introducing the feedstock along with diluents or a recycle and hydrogen in a first reaction zone and allowing the feed and hydrogen to react in a liquid phase within the first reaction zone to produce reaction products. The reaction products are cooled and/or water is removed from the reaction products. At least a portion of the cooled and/or separated reaction product are introduced as a feed along with hydrogen into a second reaction zone containing a hydroprocessing catalyst. The feed and hydrogen are allowed to react in a liquid phase within the second reaction zone to produce a second-reaction-zone reaction product.