Why does the transformer oil purifier produce hydrogen?

After the transformer is in operation, whether it is a thermal fault or an electrical fault, the insulating medium will decompose and produce various characteristic gases. Since the bond energy of the carbon-hydrogen bond in the transformer oil-paper insulation structure is low, hydrogen is usually produced first during the decomposition process, so hydrogen is one of the main components of various fault characteristic gases.

(1) Electrolysis of water and chemical reaction with iron When there is water in the oil, water will be electrolyzed to produce hydrogen under the action of the electric field; water also reacts with iron to produce hydrogen.

(2) Cracking reaction of alkanes We know that transformer oil is mainly composed of alkanes, cycloalkanes and aromatics, among which alkanes have poor thermal stability. These organic compounds will crack at high temperatures and become small molecular alkanes, unsaturated hydrocarbons (olefins and alkynes) and hydrogen. Gas chromatography and the three-ratio method are based on five components: hydrogen, methane, ethane, ethylene and acetylene.

(3) Cyclohexane dehydrogenation Cyclohexane is one of the main components of petroleum. In the refining process of transformer oil, due to the limitations of process conditions, a small amount of cycloalkane components (including cyclohexane) will inevitably remain. In this way, under the catalyst or at the right temperature, the dehydrogenation reaction (aromatization to produce benzene and hydrogen) may occur due to it.

The reaction is reversible, the forward direction is an endothermic reaction, and the reverse direction is an exothermic reaction. When there is more hydrogen at room temperature, the equilibrium shifts to the left, which is conducive to the formation of cyclohexane. When the temperature rises and there is no or only a small amount of hydrogen in the system, the equilibrium shifts to the right, which is conducive to the formation of hydrogen and benzene.

During the on-site installation of the transformer, it is very important to prevent the transformer from getting damp. The treatment process of the transformer oil is closely related to preventing the transformer from getting damp. The transformers installed now have larger capacities and higher voltage levels.