According to one embodiment, an inlet system comprises first and second incoming fluid ducts configured to be disposed outside of a vessel and to receive a first incoming fluid stream in a first direction through the first incoming fluid duct and a second fluid stream through the second incoming fluid duct in a second direction substantially parallel to the first direction. An internal fluid duct is configured to be disposed inside the vessel and to discharge internal fluid from the first and second incoming fluid streams in a third direction within the vessel substantially parallel to the first and second directions. The inlet system also comprises first and second fluid channels coupling the first and second incoming fluid ducts outside the vessel to the first internal fluid duct such that the first and second incoming fluid streams are communicated to the first internal fluid duct.