Abstract: Disclosed are apparatus and methods for conversion of hydrocarbon feed streams into liquid products. One embodiment of an apparatus includes a pressure vessel that contains a synthesis gas production device, a synthesis gas conditioning device and a synthesis gas conversion device wherein the synthesis gas production device and the synthesis gas conditioning device are nested within the synthesis gas conversion device. One embodiment of a method includes providing a hydrocarbon feed stream and producing a synthesis gas stream from the hydrocarbon feed stream in a synthesis gas production device. Subsequently, the synthesis gas stream is conditioned by removing heat from the synthesis gas stream through a first hollow body into a reactant feed stream that is then fed into the synthesis gas production device. Finally, the synthesis gas stream is converted to form a liquid product stream.