Two-stage high-temperature preheated steam gasifier

A two-staged gasifier (21) for producing synthesis gas and, optionally, activated carbon, from a coarse carbonaceous feedstock, which gasifier comprises:

• a first reactor (3) provided with an inlet (2) for a coarse carbonaceous feedstock (1), a first inlet (7) for steam;
• and
• a second reactor (4) provided with a second inlet (9) for steam, optionally together with air or oxygen;
• and an outlet (12) for synthesis gas;
• wherein the first and second reactors are separated by a narrowed portion (20) having a reduced cross-section for restricting passage from the first reactor to the second reactor of solid carbonaceous unreacted substance, wherein the first reactor is capable of being operated at a temperature of at least 600° C., and the second reactor is capable of being operated at a higher temperature, characterized in that the second reactor (4) is the lower reactor, and the first reactor (3) is the upper reactor and is a fixed bed reactor, a grate (8) is provided at the bottom end of the first reactor, inlet (7) is located adjacent to the bottom of the first rector, so as to enable preheated steam having a temperature of at least 700° C. to be fed into the first reactor from below grate (8) via inlet (7), said second reactor is provided with an inlet (19) for a fine solid carbonaceous feedstock and/or a liquid carbonaceous feedstock, inlet (9) is located adjacent to the bottom of the second rector so as to enable preheated steam having a temperature of at least 700° C., optionally together with preheated air or oxygen of same temperature, to be fed to the second reactor from below via inlet (9), and in that a second narrowed portion (18) having a reduced cross-section is provided at the bottom end of the second reactor (4).