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. All the reaction gas passes into the reactor through the top inlet connection. The catalyst temperature is kept under control by means of counter-current or cross-flow heat exchange with the BFW in the plates, which partly vaporizes as it flows upwards. The reacted gas exits the converter through the bottom nozzles. The BFW-steam mixture exits from nozzles placed on the converter top.

The reactor is equipped with BFW recycling pumps and steam drum.