Patent ID: 7712517

Claim:
A tube bundle apparatus configured to efficiently effect thermal exchange, under high pressure and temperature conditions, between at least two fluids of which one has highly aggressive characteristics under process conditions, comprising: a hollow body equipped with an external casing, or pressure-resistant body, configured to tolerate operating pressures and including a material subject to corrosion by contact with the highly aggressive fluid, and including openings for entrance and exit of the fluids, wherein inside of the hollow body there are at least two cavities separated from each other by a third sealed cavity with respect to the at least two cavities, situated between two septa or plates hinged onto the pressure-resistant body, the two cavities communicating with each other by a series of tubes, whose internal wall is put in contact with the highly aggressive fluid and includes a material selected from titanium, zirconium, or an alloy of one of these, that is highly resistant to corrosion, forming a tube bundle situated between the two septa or plates that passes through the third cavity, wherein at least one of the two cavities is in contact with the highly aggressive fluid and is at least partly delimited by a three-layered wall comprising at least three metallic layers including: an external layer configured to tolerate a predetermined pressure load, subject to corrosion by contact with the highly aggressive process fluid; an intermediate layer made of stainless steel; and an anticorrosive lining in contact with the highly corrosive fluid, including a material selected from titanium, zirconium, or an alloy of one of these, wherein the three layered wall comprising the at least three metallic layers constitutes at least the tube-sheet plate delimiting the cavity in contact with the highly corrosive fluid, and wherein, either each tube in said bundle is a bimetallic tube comprising a stainless steel outer layer and an internal lining layer, in contact with the corrosive fluid, including a material selected from titanium, zirconium or an alloy of one of them, and said intermediate layer is strength and seal welded with the stainless steel layer of said bimetallic tubes, and said anticorrosive lining is seal welded with the internal lining of said bimetallic tubes, or each tube of said tube bundle entirely consists of a metal selected from titanium, zirconium or an alloy of one of them, and said anticorrosive lining is strength and seal welded to each of said tubes and has a thickness ranging from 2 to 10 mm.