The Hydrazine Hydrate urea production method first dissolves urea in water to form a urea solution, and reacts with sodium hypochlorite and caustic soda in a tubular oxidation reactor in the presence of magnesium sulfate to obtain a crude ruthenium, that is, an oxidizing solution having urea. The cerium content exceeds 2%. Since the crude oil contains a large amount of impurities such as sodium chloride, sodium carbonate and sodium hydroxide, the crude is removed by vacuum distillation through a five-layer tank, and an aqueous solution containing more than 6% of lanthanum is obtained by a fractionator. Further concentration by evaporator to obtain 40% hydrazine hydrate.
The urea process is mature and easy to master, but has many side effects. It must maintain a very low bismuth concentration (typically 2% to 3%), so a large amount of by-products need to be disposed of, and the evaporated hydrazine hydrate needs to consume a large amount of heat.
To this end, the production process of the hydrazine hydrate urea method has been improved: the production of sodium hypochlorite in the packed absorption tower; the use of a tubular heating reactor instead of the tank reactor to synthesize hydrazine hydrate, which is beneficial to increase the yield; Replace the five-layer evaporator. US evaporation; replacing the liquid inlet column with a gas inlet column to increase the concentration and reduce steam consumption; cooling the hydrated crude solution. However, sodium carbonate decahydrate was recovered, and sodium chloride by-products were recovered, which reduced production costs and improved the quality and stability of hydrazine hydrate.