A system includes a gasifier that may gasify a feedstock to produce a syngas (110) and a syngas cooler (116) that includes a cooling chamber (228) having a tapered configuration (229). The cooling chamber (228) includes a first section (230) that may separate particulates from the syngas (110) and includes a first opening (234) and a second opening (236). The first opening (234) has a smaller width than the second opening (236). The system also includes a second section (232) in fluid communication with the first section (230) that includes a plurality of tubes (244) surrounding the first section (230). A first portion of the plurality of tubes (244) is arranged parallel to a longitudinal axis (200) of the cooling chamber (228) and a second portion of the plurality of tubes (244) is angled such that the second portion of the plurality of tubes (244) forms the tapered configuration (229). The system further includes a passage (220) to flow a seal gas (218) between a shell (208) of the syngas cooler (116) and the second section (232). The shell (208) encloses the cooling chamber (228).