Patent ID: 8025862

Claim:
A process for producing a synthesis gas SG from a general feed F constituted by hydrocarbons and optionally recycled compounds, F comprising a first feed Fl, a second feed F 2 and a third feed F 3 , in which: a stream comprising the first feed Fl supplemented with steam undergoes steam reforming to produce at least one fraction of synthesis gas SG in a multi-tube reactor-exchanger R comprising a plurality of reaction tubes ( 38 ) containing a steam reforming catalyst, and a shell containing said tubes, the first feed Fl supplemented with steam circulating inside a plurality of tubes in one direction; said reaction tubes ( 38 ) are heated principally by convection by circulating a heating fluid HF external to and in direct contact with said tubes in said shell, as a cross-current but overall as a counter-current to said one direction of the circulation of Fl, in which HF comprises at least a first stream of gas from partial or total combustion of the second feed F 2 , then said fluid HF is mixed in one to four staged complementary combustion zones, separated by baffles extending across the tubes, to form a mixture inside the shell with at least a portion of the third feed F 3 and a gas containing oxygen to increase the temperature of said first stream, with the provision that at least a portion of F 3 and said gas containing oxygen are injected at a point inside the shell of the reactor-exchanger R under turbulent conditions and/or recirculation conditions sufficient to obtain homogeneous flameless combustion in at least one zone of the shell of the reactor-exchanger R, and with the further provisions that F 3 is hydrogen separated from a fraction of said synthesis gas SG, then said mixture is circulated in the reactor-exchanger R substantially throughout the shell guided by said baffles in alternating opposite directions across the tubes to provide complementary heat to the reaction tubes ( 38 ) before leaving the reactor-exchanger; and synthesis gas SG is produced from the steam reforming effluent F 1 and optionally from part or all of the HF.