What is a hydrogenation reactor? What is its working principle?

In experiments, we often encounter gas purging using nitrogen or hydrogen, or hydrogenation reactions, in which we need to replace the air inside the reactor with the desired reaction gas. Generally, there are two common methods: One is to first introduce the required gas into the reactor, then close the inlet valve and open the exhaust valve; after repeating this process three times, the gas inside the hydrogenation reactor will be completely purged. The other method involves evacuating the reactor to a vacuum and then introducing the gas to be reacted into the laboratory reactor for the reaction to take place. Our company offers hydrogenation reactors at reasonable prices and with a comprehensive range of options. Let’s first take a closer look at the working principle of hydrogenation reactors.

Basic principle of hydrogenation reactors: Hydrogenation is a reversible, exothermic reaction involving a decrease in the number of molecules. According to Le Chatelier’s principle, lower temperatures and higher pressures favor the shift of the hydrogenation reactor toward the hydrogenation direction at chemical equilibrium. The temperature required for the hydrogenation process depends on the activity of the catalyst used—higher catalyst activity corresponds to lower reaction temperatures. For hydrogenation reactions with small equilibrium constants at reaction temperatures (such as the hydrogenation of carbon monoxide to methanol), in order to increase the equilibrium conversion rate, the reaction must be carried out under high pressure, which also helps to accelerate the reaction rate. Using an excess of hydrogen not only enhances the conversion rate of the hydrogenated substance and speeds up the reaction but also facilitates the removal of reaction heat; the excess hydrogen can be recycled for subsequent use.

There are two commonly used types of hydrogenation reactors: One is designed for liquid-phase hydrogenation of high-boiling-point liquids or solids (solids must first be dissolved in a solvent or melted by heating), such as hydrocracking of heavy oil products and hydrogenation of fats and oils. Liquid-phase hydrogenation is typically carried out under pressure, and the process can be either batch or continuous. Batch hydrogenation usually employs pressurized reactors equipped with agitators or bubble-column reactors. For continuous liquid-phase hydrogenation, trickle-bed reactors or tubular reactors—where gas, liquid, and solid phases flow continuously in the same direction—are often used. The other type of reactor is used for continuous gas-phase hydrogenation processes, such as the atmospheric-pressure gas-phase hydrogenation of benzene to cyclohexane and the high-pressure gas-phase hydrogenation of carbon monoxide to methanol. These reactors can be either tubular or tower-type. At high temperatures and pressures, hydrogen can combine with carbon atoms in steel to form methane, causing the steel to become brittle—a phenomenon known as hydrogen embrittlement. Therefore, high-pressure hydrogenation reactors are made from alloy steels. Hydrogen is highly flammable and explosive; thus, safety measures must be carefully considered during the hydrogenation process.

The hydrogenation reactor consists of a reactor body, a reactor lid, a jacket, a stirrer, a drive unit, a shaft sealing device, and a support frame. The materials typically used include composite materials such as carbon-manganese steel, stainless steel, zirconium, and nickel-based alloys. Under conditions of high pressure, high temperature, high rotational speed, high vacuum, suspension, and convection, the hydrogenation reactor ensures that the reaction medium remains completely sealed under static conditions within the high-pressure vessel, enabling safe reactions involving hazardous media that are flammable, explosive, or highly toxic.