REPAIR WORKS IN UREA SYNTHESIS REACTOR - ANTICORROSIVE LINING WITH TITANIUM


Processes for the production of urea normally used in industry comprise at least one section which operates at high temperatures and pressures (synthesis loop), at which the process fluids, i.e. water, ammonia and especially saline solutions, become particularly aggressive. Normal carbon steel is not capable of resisting the corrosion of these fluids at a high temperature and undergoes a progressive deterioration which weakens the structure causing external losses and even explosions.


Corrosion or erosion is particularly caused in urea reactors by contact with solutions of ammonium carbamate at the high temperatures and pressures necessary for the synthesis of urea. There are numerous metals and alloys capable of withstanding for sufficiently long periods, the potentially corrosive conditions arising inside a synthesis reactor of urea.


Anticorrosive titanium lining of urea reactor is obtained by the assembly of titanium element having adequate resistance to corrosion, so as to form, at the end, a hermetically sealed structure at the high operating pressure. Titanium material used for the protective lining is capable of tolerating contact with the process fluids without undergoing corrosion or alterations in urea reactor for prolonged periods.