Abstract: The invention relates to a heat exchanger, in particular for a synthesis gas installation, for the heat exchange between a first and a second medium (W, G), comprising a shell (10), which is made to extend along a longitudinal axis (L) and bounds a shell space (M) for receiving the first medium (W), a tube space (R), which is surrounded by the shell space (M), for receiving the second medium (W), and a pass baffle (20), which is arranged in the shell space (M) and made to extend along the longitudinal axis (L), for directing the first medium (W), carried in the shell space (M), along the longitudinal axis (L). According to the invention, it is provided that the pass baffle (20) is welded to the shell (10).