The high-purity methanol catalyst can be used on the material resulting from the epoxidation reaction in a HPPO unit, and will ensure the quality of the final propylene oxide product. This Ni-based catalyst functions in a hydrogen gas environment by converting impurities in liquid-phase methanol, including hydrogen peroxide, acetaldehyde, dimethoxyethane, dimethoxypropane, acetone, acetonitrile, nitromethane, nitroethane, and nitropropane, into such easily desorbed substances as isopropyl alcohol, methylamine, ethylamine, and propylamine, which will facilitate the desorption of impurities from methanol during a subsequent process.

The application of high-purity methanol catalyst: The bottom stream from the PO pre-separation tower and PO purification tower will mainly consist of crude methanol containing water. This stream will also contain many impurities, as well as substances that will cause poisoning of the epoxidation catalyst must be removed through hydrogenation. Unreacted hydrogen peroxide and organic hydroperoxides will react with hydrogen gas to form water and the corresponding alcohols, which will not release oxygen gas as a byproduct. Unreacted hydrazine hydrate and hydrogen gas from the PO purification tower will react to form ammonia, and the ammonia will then react with acetaldehyde and hydrogen to form alkylamine and water. Some hydrazones will also be hydrogenated to form the corresponding amines. Acetaldehydes and acetals that cannot be converted to amines will be reduced to the corresponding alcohols. Small amounts of propylene oxide will be reduced to n-propanol and isopropanol. The pH of the reaction mixture following hydrogenation will be approximately 10. Before entering the first methanol tower, the mixture will react with sulfuric acid and be acidified, and the pH will become 2.2 ± 0.2. This method will ensure that all organic amines and ammonia are converted to the corresponding ammonium salts, and can be removed via the wastewater system.