Channel assembly

A channel assembly comprising a corrugated sheet 1 lying against a plate 4/5. The inner surface of the plate engages with the corrugations of the sheet to define flow channels X between the corrugations. The peaks and troughs of the corrugations are laterally offset from the central longitudinal axes of the channels. Preferably the flow channels defined by the corrugations each have a convex 1A and concave face 1B. Preferably the corrugated sheet is formed of a high thermal conductivity metal or alloy, more preferably the sheet is formed from copper, aluminium or stainless steel. Preferably the plates are formed from stainless steel. Preferably the channel assemblies may contain a reactant or catalyst. The Channel assemblies may further be arranged in a stack in communication with a fluid manifold configured to provide streams of fluid through the flow channels. This arrangement may be part of a chemical reactor enclosed in a pressure vessel. Preferably the reactor is a Fischer-Tropsch reactor, and the catalyst material contained within is a Fishcer-Tropsch catalyst.