The IMC is a quasi-isothermal converter in which the heat transfer surfaces are plates and the catalyst is loaded outside the cooling plates.

The converter includes only one isothermal bed, traversed by the process gas in an axial or axial-radial path. The cooling medium circulating through the plate heat exchanger elements is the incoming reactor feed gas. The plates are designed in order to assure the co-current flow arrangement between the coolant inside the plates and the reacting gas outside the plates either foraxial and axial-radial layout.