Abstract: A bimetallic tube consisting of at least one tubular element in a first metal resistant to the corrosive and/or erosive action of a process fluid with which it is put in contact, having at least one end, or an area close to an end, externally coated with a layer of a second metal, different from the first and more suitable, with respect to this, for being seal-welded to a support. Tube bundle equipment to be used for thermal exchange operations at high temperatures and pressures, under conditions of high aggressiveness of the process fluids, wherein the tube bundle comprises at least one tube having the above characteristics. Said equipment is particularly used as a heat exchanger and decomposer, for example as a stripper, in the cycle of urea synthesis processes where there are conditions of high pressure, high temperatures, high aggressiveness of the process fluids, and in which the tube bundle consists of at least one tube having the above characteristics.

Abstract: A bimetallic tube consisting of at least one tubular element in a first metal resistant to the corrosive and/or erosive action of a process fluid with which it is put in contact, having at least one end, or an area close to an end, externally coated with a layer of a second metal, different from the first and more suitable, with respect to this, for being seal-welded to a support. Tube bundle equipment to be used for thermal exchange operations at high temperatures and pressures, under conditions of high aggressiveness of the process fluids, wherein the tube bundle comprises at least one tube having the above characteristics. Said equipment is particularly used as a heat exchanger and decomposer, for example as a stripper, in the cycle of urea synthesis processes where there are conditions of high pressure, high temperatures, high aggressiveness of the process fluids, and in which the tube bundle consists of at least one tube having the above characteristics.

Abstract: A process for the recovery of ammonia contained in a gaseous purging stream produced in a synthesis process of urea.

Abstract: The present invention relates to a process for the recovery of ammonia contained in a gaseous purging stream produced in a synthesis process of urea, comprising the following phases: a) subjecting the gaseous purging stream to a washing with an aqueous acidic solution, at a pH ranging from 1 to 6, with the formation of a first purified gaseous stream and an aqueous solution containing an ammonium salt; b) subjecting the aqueous solution containing the ammonium salt coming from phase a) to stripping, after treatment with a strong base, at a temperature ranging from 50 to 250° C.

Abstract: A tube bundle apparatus for thermal exchange operations at high pressures and temperatures, under conditions of high aggressiveness of process fluids. The tube bundle includes a series of tubes whose internal wall includes a material selected from titanium, zirconium, or an alloy thereof, resistant to aggression of fluids, in which at least one of access chambers to the tube bundle is delimited by a wall including at least the following three metallic layers in succession: a) an external layer for tolerating pressure load, subject to corrosion by contact with the highly aggressive process fluid; b) an intermediate layer of stainless steel; (c) an anticorrosive lining in contact with the highly corrosive fluid, of a material selected from titanium, zirconium, or an alloy thereof. The apparatus can be particularly used as an exchanger/reactor, for example as a stripper, in the high pressure cycle of synthesis processes of urea.

Abstract: A bimetallic tube consisting of at least one tubular element in a first metal resistant to the corrosive and/or erosive action of a process fluid with which it is put in contact, having at least one end, or an area close to an end, externally coated with a layer of a second metal, different from the first and more suitable, with respect to this, for being seal-welded to a support. Tube bundle equipment to be used for thermal exchange operations at high temperatures and pressures, under conditions of high aggressiveness of the process fluids, wherein the tube bundle comprises at least one tube having the above characteristics. Said equipment is particularly used as a heat exchanger and decomposer, for example as a stripper, in the cycle of urea synthesis processes where there are conditions of high pressure, high temperatures, high aggressiveness of the process fluids, and in which the tube bundle consists of at least one tube having the above characteristics.

Abstract: A tube bundle apparatus for thermal exchange operations at high pressures and temperatures, under conditions of high aggressiveness of process fluids. The tube bundle includes a series of tubes whose internal wall includes a material selected from titanium, zirconium, or an alloy thereof, resistant to aggression of fluids, in which at least one of access chambers to the tube bundle is delimited by a wall including at least the following three metallic layers in succession: a) an external layer for tolerating pressure load, subject to corrosion by contact with the highly aggressive process fluid; b) an intermediate layer of stainless steel; (c) an anticorrosive lining in contact with the highly corrosive fluid, of a material selected from titanium, zirconium, or an alloy thereof. The apparatus can be particularly used as an exchanger/reactor, for example as a stripper, in the high pressure cycle of synthesis processes of urea.