A catalytic reactor is provided with one or more reaction zones each
formed of set(s) of reaction tubes containing a catalyst to promote
chemical reaction within a feed stream. The reaction tubes are of helical
configuration and are arranged in a substantially coaxial relationship to
form a coil-like structure. Heat exchangers and steam generators can be
formed by similar tube arrangements. In such manner, the reaction zone(s)
and hence, the reactor is compact and the pressure drop through
components is minimized. The resultant compact form has improved heat
transfer characteristics and is far easier to thermally insulate than
prior art compact reactor designs. Various chemical reactions are
contemplated within such coil-like structures such that as steam methane
reforming followed by water-gas shift. The coil-like structures can be
housed within annular chambers of a cylindrical housing that also provide
flow paths for various heat exchange fluids to heat and cool components.