A gasification system for the partial oxidation of a carbonaceous feedstock to at least provide a synthesis gas, comprising: a reactor chamber for receiving and partially oxidizing the carbonaceous feedstock; a quench chamber below the floor of the reactor chamber for holding a bath of liquid coolant; an intermediate section at said reactor chamber floor, the intermediate section having a reactor outlet opening through which the reactor chamber communicates with the quench chamber to conduct the synthesis gas from the reactor chamber into the bath of the quench chamber; at least one layer of refractory bricks arranged on and supported by the reactor chamber floor, the lower end section of the refractory bricks enclosing the reactor outlet opening and defining the inner diameter thereof; and a dip tube extending from the reactor outlet opening to the bath of the quench chamber, the dip tube having a widened top section.