Abstract: A heat exchanger or chemical reactor comprising a heat exchange body defining a plurality of flow passages and a removable insert defining secondary heat exchanger surfaces retained within at least one of the flow passages by insert retention means. The insert comprises one or more plate(s) having perforations to define discreet fluid flow channels extending across the plate(s) and wherein said one or more of the plates is provided with a carrier for a catalyst or adsorbent.

Abstract: Heat exchange and/or chemical reactor apparatus (10; 100) comprises a series of plates which are stacked and bonded together in a fluid-tight manner, the series of plates comprising alternate first (30; 130 ) and second (90; 190) plates or groups of plates along the stack providing flow paths for respective first and second fluids, each plate forming said first (30; 130) and second (90; 190) plates or groups of plates having an inlet (42, 90) and an outlet (43, 91) between which respective first or second fluid is flowable and a continuous wall (34, 84) to contain the flow of fluid, and characterised in that each plate (30, 90; 130; 190) comprises an outer wall (43, 83) continuous wall (34, 84) to define a space (35, 85) therebetween, the spaces (35, 85) of each plate (30, 90; 130; 190) of the stack being in fluid communication to form a compartment running along the stack.