Two categories: one is used for the liquid phase hydrogenation process of raw materials with high boiling point liquids or solids (solids need to be dissolved in solvents or heated and melted first), such as the hydrogenation of greases and heavy oils. Lysis etc. Liquid-phase hydrogenation is often performed under pressure, and the process can be batch or continuous. Intermittent liquid phase hydrogenation often uses a pressure kettle or a bubbling reactor with a stirring device. Continuous liquid phase hydrogenation can use a trickle bed reactor or a tubular reactor with three-phase continuous flow of gas, liquid and solid. Another type of reactor is used for gas phase continuous hydrogenation processes, such as atmospheric pressure gas phase hydrogenation of benzene to produce cyclohexane, high pressure gas phase hydrogenation of carbon monoxide to synthesize methanol, etc. The type of reactor can be tubular or tower type.