A heat exchange unit for isothermal radial or axial-radial chemical reactors (1), with an overall configuration which is substantially annular and cylindrical having a passage (11) with a predetermined diameter running through it axially, is distinguished in that it comprises a plurality of substantially rectangular, flattened box-shaped heat exchangers (13), distributed in many coaxial and concentric arrays, defining in the unit (12) a plurality of radial alignments with a substantially radial arrangement, and wherein the exchangers (13) have long sides (13a) parallel to the axis of the unit (12) and short sides (13b) extending radially, each of the exchangers (13) comprising an inner chamber (17), intended to be passed through by an operating heat exchange fluid, at least one distributor pipe (19) and at least one collector pipe (20) of the operating fluid, associated with two respective opposing sides (13a) of the exchanger (13) and extending along them, the pipes (19, 20) being in fluid communication, on the one side, with the chamber (17) through at least one opening (19a, 20a) formed therein and, on the other side, with the outside of the exchanger (13), through respective inlet and outlet fittings (21, 22) for the operating fluid.
The present invention offers an improved axial heat exchanger for exchanging heat between a gas medium and a fluid or liquid medium. The axial heat exchanger comprises a longitudinal and substantially axially extended outer channel that is adapted to enclose a flow of a first gas medium. The heat exchanger also comprises a plurality of substantially parallel inner channels that are adapted to enclose a flow of a second liquid medium. The inner channels are arranged inside the outer channel so as to extend substantially axially along the inside of said outer channel for enabling a transfer of heat between said first gas medium and said second liquid medium. The heat transfer is improved to some extent as the number of inner channels increases and it is further improved in that at least one of the inner channels is joined with at least one elongated sheet. The sheet is arranged to extend substantially axially along the inner channel so as to substantially coincide with the direction of flow of the first gas medium through the outer channel.
