Reactor for catalytic chemical reactions comprising a catalyst bed with an annular-cylindrical form crossed by a radial flow or mixed axial-radial flow, wherein the bed is delimited by cylindrical walls made gas-permeable by means of slits and the catalyst bed is formed by particles of catalyst with a nominal minimum size such that: the ratio between a transverse dimension of the slits and the nominal minimum size of the particles of catalyst is smaller than or equal to 0.6; the catalyst bed contains no more than 3% by weight of particles with an actual size smaller than said nominal size.

Reactor for catalytic chemical reactions comprising a catalyst bed with an annular-cylindrical form crossed by a radial flow or mixed axial-radial flow, wherein the bed is delimited by cylindrical walls made gas-permeable by means of slits and the catalyst bed is formed by particles of catalyst with a nominal minimum size such that: the ratio between a transverse dimension of the slits and the nominal minimum size of the particles of catalyst is smaller than or equal to 0.6; the catalyst bed contains no more than 3% by weight of particles with an actual size smaller than said nominal size.

A floating support grid system including a plurality of support beams and a plurality of profile wire screen panels wherein the support beams are connected to the profile wire screen panels via one or more first floating connections, wherein the support beams are configured to connect to a horizontal ammonia converter basket via one or more second floating connections, and wherein at least some the profile wire screen panels are configured to connect to a horizontal ammonia converter basket via one or more third floating connections, wherein each of the first, second, and third floating connections independently defines one or more gaps to accommodate movement caused by thermal expansion.