Transcontinental Gas Pipe Line Company (Transco), a Williams company, has filed an application with the US Federal Energy Regulator Commission (FERC) seeking authorization to construct and operate the St. James Supply Project in St. James Parish, Louisiana, USA.
The project will enable Transco to provide 161,500 dekatherms per day of firm transportation capacity from Transco’s existing Station 65 Zone 3 Pool in St. Helena Parish, Louisiana, southward along Transco’s Southeast Louisiana Lateral to a new interconnection delivering natural gas to its customer, YCI St. James Enterprises LLC, at the Yuhuang Chemical Plant, a methanol manufacturing plant proposed to be constructed in St. James Parish.
In order to create the incremental firm transportation capacity under the project, Transco requests authorization to construct and operate the following facilities:
St. James Supply Lateral
The St. James Supply Lateral will consist of approximately 0.72 miles (1.15 km) of new, 20-inch (508-mm) diameter pipeline extending from the Old River Road metering and regulating (M&R) station to the pig receiver site and will be located entirely in St. James Parish, Louisiana.
Compressor Station 63
Existing Compressor Station 63 will be modified by replacing six actuators on side gate valves and three remotely-operated actuators on the block valves. The actuators will be connected to a new programmable logic controller (PLC) that will be connected to the station control room.
Compressor Station 65
Existing Compressor Station 65 will be modified by removing three, 24-inch (609-mm) check valve flappers, installing one, 24-inch ball valve, and adding over pressure protection (OPP) on four existing side gate valves between Transco’s existing mainlines “A”, “B”, “C”, and “D” and SELA lines “A”, “B”, and “C”. This modification will allow gas to flow south on the SELA lines from Station 65 and adds OPP on the Transco mainline from the SELA Laterals. The OPP actuators will be connected to a new field PLC, which will be connected to the station control room to allow automatic operation. Additionally, the Project will include the installation of three, new 24-inch ball valves with actuation, the addition of actuators on six side gate valves, and the installation of one, 10-inch (254 mm) pressure regulator. The valves will be automated to allow flow to shut-off during unexplained pressure drops in the SELA lines, since the check valve flappers are being removed. The actuators will be connected to the new field PLC, which will be connected to the station control room.
Cajun Road M&R Station
The proposed Cajun Road M&R station will be constructed by Transco and sized to flow up to 300,000 dekatherms/day. The M&R station will include a 250-gallon (946-L) condensate tank, piping, meter skid with two ultrasonic meters, regulators, an RTU building, a GC Building, flow computer, radio tower, and gas chromatograph. The radio tower will communicate directly with the existing Compressor Station 60 control room.
At MP 72.37 on the SELA Laterals, the existing SELA “B” and SELA “C” 30-inch (762-mm) diameter pipelines will be tied into the proposed Project and will accommodate the bi-directional flow of natural gas. The SELA “B” and “C” tie-ins will each require the installation of a 30-inch diameter mainline block valve setting and two, 20-inch (508-mm) diameter valves to control the flow to and from the proposed Old River Road M&R station through two, new 20-inch diameter supply and discharge lines. The SELA Interconnect site also will have a communications tower and associated equipment enabling communication with nearby existing Compressor Station 63 and Transco Gas Control.
Old River Road M&R Station
The proposed Old River Road M&R station will be connected to the St. James Supply Lateral and will be located within the YCI methanol facility fence line. The M&R station will include a 250-gallon condensate tank, yard piping and valves, a meter skid with two, 10-inch ultrasonic meters, and one, 4-inch (101-mm) ultrasonic meter, a 20-inch valve switching skid, a back pressure regulating skid with three, 10-inch control valves, and one, 4-inch control valve, an RTU building including flow computers, a gas chromatograph (GC) building, and communications equipment that will communicate directly with the existing Compressor Station 63 control room and Transco Gas Control.
Pig Receiver Site
The proposed Pig Receiver will be located at the end of the St. James Supply Lateral at MP 0.72. The site will be located within the YCI methanol facility.