Abstract: The present invention relates to a new type of lining with two layers, one of which, obtained by welding deposit, can be used for the protection of internal surfaces of chemical equipment capable of abide pressures lower than 100 MPa, in processes for the direct synthesis of urea. The present invention also relates to an original method for the preparation and installation of this lining, by the assembly of laminar elements with two layers, obtained by welding deposit on relatively thin stainless steel plates, so as to avoid significant distorsion effects on the plate itself.

Abstract: Method for the safety and extension of the operating life of pressure equipment having an internal chamber suitable for containing a process fluid, surrounded by a pressure-resistant body (1) equipped with weep-holes (2), made of a material subject to corrosion by contact with said process fluid operation, coated inside with an anticorrosive lining (4) made up of several elements welded to each other, wherein said lining weldings (3) are completely isolated from contact with the process fluid of the normal operating run, by a coating with adjoining strips (or plates) (10, 10′, 10″, 10′″), of the same material as said lining (4) or other corrosion-resistant material weldable thereto, which are subsequently seal-welded on the edges to said lining (4) and to each other, characterized in that the arrangement and welding of the edges of these strips (10, 10′, 10″, 10′″) are such to create a network of underlying interstices (or meati) (9,11), communicating with each

Abstract: A method for repairing and restoring the functionality of equipment subjected to internal corrosion during its operation at high or medium pressure in a plant for the synthesis of urea. The method includes the cleaning of the corroded area, the formation of suitable supporting and/or holding surfaces for the placement of a new metallic lining, the formation of a new anticorrosive sealed off lining, obtained by positioning and welding flat elements and metallic plates which are suitably shaped and placed next to each other to become adapted to the internal profile of the equipment. The spaces and interstices below this new lining all communicate with at least one weep-hole present in the pressure resistant body. The entire repair is carried out through the manhole of the equipment and enables the restoring of its functionality for times similar to the normal duration of corresponding newly constructed equipment.

Abstract: Process and apparatus for the production of urea, wherein the carbamate decomposers and/or condensers are equipped with stainless steel tubes internally lined with zirconium.