The present invention is a process for producing styrene by dehydrogenation of
ethylbenzene, which contains the steps of (i) feeding a raw material gas containing
ethylbenzene and steam to a first dehydrogenating step to produce a reacted gas
containing ethylbenzene, styrene and hydrogen in the presence of a dehydrogenation
catalyst, (ii) feeding the reacted gas obtained in the first dehydrogenating step
to an oxidizing step to combust at least part of hydrogen in the presence of an
oxidation catalyst, and (iii) feeding the reacted gas obtained in the oxidizing
step to a second dehydrogenating step to produce styrene from ethylbenzene in the
presence of the dehydrogenation catalyst, with maintaining the carbon dioxide-generating
ratio in the second dehydrogenating step at a level less than 2.1 times that at
the initial stage of the reaction.
