A gasification system for the partial oxidation of a carbonaceous feedstock to at least provide a synthesis gas, the system comprising: a reactor chamber for receiving and partially oxidizing the carbonaceous feedstock; a quench section below the reactor chamber for holding a bath of liquid coolant; and an intermediate section connecting the reactor chamber to the quench section, the intermediate section comprising: a reactor chamber floor (54, 86, 87) provided with a reactor outlet opening through which the reactor chamber communicates with the quench section to conduct the synthesis gas from the reactor chamber into the bath of the quench section; at least one coolant conduit arranged on an outer surface of the reactor chamber floor (54, 86, 87); and a pump system communicating with a source of a liquid coolant for circulating the liquid coolant through the at least one coolant conduit, wherein at least one layer of refractory bricks arranged on and supported by the reactor chamber floor (54, 86, 87), the refractory bricks enclosing the reactor outlet opening a lower end of the reactor chamber floor (54, 86, 87) comprising a cylindrical section extending downwardly from a conical section, and a horizontal section extending inwardly from a lower end of the cylindrical section, the cooling conduit enclosing at least the cylindrical section of the reactor chamber floor (54, 86, 87). a reactor chamber for receiving and partially oxidizing the carbonaceous feedstock; a quench section below the reactor chamber for holding a bath of liquid coolant; and an intermediate section connecting the reactor chamber to the quench section, the intermediate section comprising: a reactor chamber floor (54, 86, 87) provided with a reactor outlet opening through which the reactor chamber communicates with the quench section to conduct the synthesis gas from the reactor chamber into the bath of the quench section; at least one coolant conduit arranged on an outer surface of the reactor chamber floor (54, 86, 87); and a pump system communicating with a source of a liquid coolant for circulating the liquid coolant through the at least one coolant conduit, wherein at least one layer of refractory bricks arranged on and supported by the reactor chamber floor (54, 86, 87), the refractory bricks enclosing the reactor outlet opening a lower end of the reactor chamber floor (54, 86, 87) comprising a cylindrical section extending downwardly from a conical section, and a horizontal section extending inwardly from a lower end of the cylindrical section, the cooling conduit enclosing at least the cylindrical section of the reactor chamber floor (54, 86, 87). a reactor chamber floor (54, 86, 87) provided with a reactor outlet opening through which the reactor chamber communicates with the quench section to conduct the synthesis gas from the reactor chamber into the bath of the quench section; at least one coolant conduit arranged on an outer surface of the reactor chamber floor (54, 86, 87); and a pump system communicating with a source of a liquid coolant for circulating the liquid coolant through the at least one coolant conduit, wherein at least one layer of refractory bricks arranged on and supported by the reactor chamber floor (54, 86, 87), the refractory bricks enclosing the reactor outlet opening a lower end of the reactor chamber floor (54, 86, 87) comprising a cylindrical section extending downwardly from a conical section, and a horizontal section extending inwardly from a lower end of the cylindrical section, the cooling conduit enclosing at least the cylindrical section of the reactor chamber floor (54, 86, 87).