| 摘要 |
Provided is a urea synthesis method of excellent reliability and productivity, the method minimizing the amount of oxygen used as an anti-corrosion agent without using a special two-phase stainless steel. In the urea synthesis device, which has a synthesis column, a stripper and a condenser, a general purpose austenite-ferrite two-phase stainless steel with Cr content: 21-26 wt%, Ni content: 4.5-7.5 wt%, Mo content: 2.5-3.5 wt%, N content: 0.08-0.30 wt%, C content: not more than 0.03 wt%, Si content: not more than 1.0 wt%, Mn content: not more than 2.0 wt%, P content: not more than 0.04 wt%, and S content: 0.03 wt% is used as a material for the urea synthesis device in at least one of the areas in contact with corrosive fluid and the concentration of oxygen supplied with respect to carbon dioxide is 100-2,000 ppm. |
