Apparatus for Processing Highly Corrosive Agents

Abstract

An apparatus for treating highly corrosive agents comprises a tube bundle ( 14 ) heat exchanger ( 10 ), structured to carry out a heat exchange between two fluids one of which is highly corrosive and flowing inside of said tube bundle ( 14 ).

1 . Apparatus for treating highly corrosive agents, comprising a tube bundle ( 14 ) heat exchanger ( 10 ), structured to carry out a heat exchange between two fluids one of which is highly corrosive and flowing inside of said tube bundle ( 14 ), characterized in that said tube bundle ( 14 ) comprises at least one titanium or titanium alloy tube ( 14   a ), coated with a layer ( 25 ) of zirconium or zirconium alloy.  
     
     
         2 . Apparatus according to  claim 1 , characterized in that said at least one titanium or titanium alloy tube ( 14   a ) is coated on the inside by said zirconium or zirconium alloy layer ( 25 ).  
     
     
         3 . Apparatus according to  claim 1 , characterized in that said at least one titanium or titanium alloy tube ( 14   a ) has a thickness between 1.0 and 10 mm, and in that said zirconium or zirconium alloy coating layer ( 25 ) has a thickness between 0.3 and 2.0 mm.  
     
     
         4 . Apparatus according to  claim 1 , characterized in that said at least one titanium or titanium alloy tube ( 14   a ) is only partially coated with said zirconium or zirconium alloy layer ( 25 ).  
     
     
         5 . Apparatus according to  claim 4 , characterized in that said zirconium or zirconium alloy layer ( 25 ) coats solely an end portion ( 14   b ) of said heat exchange tube ( 14   a ).  
     
     
         6 . Apparatus according to  claim 3 , characterized in that said zirconium or zirconium alloy layer ( 25 ) extends in said at least one titanium or titanium alloy tube ( 14   a ) starting from an entry end ( 26 ) towards an opposite end ( 27 ) thereof, for a portion between 5 and 30%.  
     
     
         7 . Apparatus according to  claim 1 , characterized in that said at least one titanium or titanium alloy tube ( 14   a ) and said zirconium or zirconium alloy coating layer ( 25 ) are bonded together metallurgically or through welding.  
     
     
         8 . Apparatus according to  claim 7 , characterized in that said at least one titanium or titanium alloy tube ( 14   a ) and said zirconium or zirconium alloy coating layer ( 25 ) are bonded together through hot-drawing.  
     
     
         9 . Apparatus according to  claim 1 , characterized in that said heat exchanger ( 10 ) comprises respective upper and lower tube plates ( 15 ,  16 ) for supporting said tube bundle ( 14 ), said tube plates ( 15 ,  16 ) being made of titanium or titanium alloy, or being coated with a titanium or titanium alloy layer.  
     
     
         10 . Apparatus according to  claim 9 , characterized in that said upper and lower tube plates ( 15 ,  16 ) are made of carbon or stainless steel, coated on the outside with a layer of 3-15 mm of titanium or titanium alloy.  
     
     
         11 . Stripper for the decomposition of ammonium carbamate in an urea production plant, characterized in that it comprises a tube bundle ( 14 ) heat exchanger ( 10 ) comprising at least one titanium or titanium alloy tube ( 14   a ), coated with a zirconium or zirconium alloy layer ( 25 ).  
     
     
         12 . Condenser for the condensation of ammonia and carbon dioxide into ammonium carbamate in an urea production plant, characterized in that it comprises a tube bundle ( 14 ) heat exchanger ( 10 ) comprising at least one titanium or titanium alloy tube ( 14   a ), coated with a zirconium or zirconium alloy layer ( 25 ).