The diolefins and alkenyl aromatics are very unstable components which can give gums by polymerization.In giving olefins and alky aromatics the hydrogenation improves the product quality.

二烯烃和烯基芳烃是稳定的组分，聚合产生凝。给定烯烃和烷基芳烃，氢化以改善产品质量。