Abstract: A natural gas system includes a pneumatic controller configured to discharge vent gas, an expansion vessel configured to discharge an expanded pilot gas, wherein the expansion vessel includes an internal volume configured to expand the vent gas discharged from the pneumatic controller whereby the expanded pilot gas discharged from the outlet port falls within a predefined discharge pressure range, a vent gas flowpath extending from the pneumatic controller to the expansion vessel, a burner assembly coupled to the expansion vessel and configured to ignite the expanded pilot gas discharged by the expansion vessel, and a pilot gas flowpath extending from the expansion vessel to the burner assembly.