Landfill gas extraction constant flow control method and device

摘要

A control method and apparatus for regulating gas flow from landfill gas wells uses a differential pressure-regulating valve to maintain a set flow through a constant flow wellhead assembly. This wellhead assembly maintains a constant flow from the well despite normal variations in environmental factors affecting gas flow. The wellhead assembly includes a second valve that is used in series with the pressure-regulating valve to adjust the operating conditions of the regulating valve to keep it within its operating range. The pressure-regulating valve configuration allows a simple automatic control to position the valve. Periodic manual sampling of extracted gas and adjustment of the valve conditions is used to adjust for longer-term variations in well conditions.