Urea process steels itself against corrosion
7 Apr 2000
Stainless steel tubes from Sandvik Steel are still in operation after 25 years at the Indian Farmers Fertiliser Co-operative manufacturing plant. The tubes were installed in the stripper which is the most aggressive part of the urea process.
In modern urea plants, urea is manufactured by reacting CO2 with NH3 at 160-220 atm and 170 degrees-190 degrees C, where initially ammonium carbamate is formed. Although urea itself is not a very corrosive substance, the carbamate intermediate is extremely corrosive. Further developments in the stripper have seen the use of bimetallic tubes, replacing titanium tubes.
