Liberty Utilities Liquid Natural Gas Station Upgrades

Daniel O’Connell’s Sons served as the General Contractor for owner Liberty Utilities in their selective upgrading of two Liquid Natural Gas (LNG) stations. The first project was located in Tilton, NH and consisted largely of the replacement of underground glycol piping. DOC oversaw fabrication and installation of all piping to include the reconfiguration of the glycol bypass line. Both a LNG cryogenic valve and heat exchanger were retrofitted to the specification of the station’s Mechanical Process Engineer. The second job took place in Manchester, NH and though smaller was much more unique. DOC was charged with the removal, re-fabrication, installation, and commissioning of a LNG mixing valve assembly in order to comply with new DOT Specifications and Standards. This complicated process involved close coordination with the Liberty Plant Manager and Mechanical Engineer to obtain the necessary mixing and output requirements. DOC worked closely with its piping subcontractor to develop the welding, materials testing and commissioning procedures necessary to meet the requirements of the plant modernization. DOC also removed and consolidated the glycol piping to the plant heat exchanger at this location. Both stations were upgraded, tested and recertified for the upcoming heating season in two months’ time.