Abstract: The fossil fuel processing apparatus of the present disclosure includes two pressure vessels, or two separators, above a single vessel footprint area in a vertically stacked configuration. The stacked configuration permits the processing of gas to occur in a space having less length and less width than that of two separators arranged tip-to-end or side-by-side, respectively. The first and second separators are configured to separate fuel from non-fuel in a footprint area of a single gas separator as the fuel moves from upstream to downstream through a gas processing system. Further, the gas processing apparatus of the present disclosure permits the two separators to fit in a housing compartment that is more easily transportable via tractor-trailer.