American Midstream (AlaTenn) LLC is seeking US Federal Energy Regulatory Commission authorization to abandon in-place four existing compressor units at its Decatur Compressor Station in Limestone County, Alabama, USA, and install two new compressor units and appurtenances at its Decatur Compressor Station. American Midstream states that its proposed Athens-Huntsville Compressor Station Upgrade Project will allow it to provide additional firm transportation service to the City of Huntsville, Alabama, and improve system reliability.
American Midstream is proposing to abandon four existing compressors (three Clark HMA-8 350 hp [261 kW] two-cycle units, and one Waukesha F3521GG 405 hp [302 kW] four-cycle unit), which have a combined 1455 hp (1085 kW). The existing compressors and building will be abandoned in place; likewise, the piping connecting the abandoned units to the suction/discharge headers and mainline will be disconnected. American Midstream will install two used compressor units (Caterpillar 3606 units) with a combined 3550 hp (2499 kW). A new building will be constructed to house the replacement units within the currently owned property. Required staging areas, temporary workspace and permanent operational footprint will be within the fenced compressor station yard.
The proposed compressor station modifications will include two Caterpillar 3606 gas engines (1775 hp [1324 kW] each) with Ariel JCG-4 gas compressors; one 12-inch (304-mm) diameter station suction and discharge line to connect the existing 12-inch diameter suction and discharge header; one separator sized 100 MMcfd (2 x 106 m3/d); one blowdown silencer and vent stack; one below ground oily water sump tank with pump; one engine oil storage tank; one engine coolant storage tank; and one above-ground storage tank for water waste.
The new compression will increase the discharge pressure beyond the current existing compression limit of 600 psi (41 bar), up to 800 psi (55 bar), thereby maximizing the potential use of the existing pipeline system, particularly downstream of the Decatur Compressor Station.