Energas commissioned a High-Pressure-Customer-Metering Station (HPCMS) for a major tile factory in Mozambique.

Matola Gas Company signed a large industrial client, Safira, that requires natural gas for their new tile factory in Mozambique.  Energas scope included the fabrication, supply and commissioning of six gas conditioning skids as follows:

• Inlet Skid
• Metering Skid
• Heater Skids x2
• Pressure Reduction Skid
• Knock-out Pot skid

The skids are prefabricated in a workshop.  It allows the contractor to work in a controlled environment not influenced by rainy weather, site delays, local labour restrictions, etc.  All welding, NDT, pressure testing, painting, inspections, assembly and acceptance testing can be done in the workshop before the skids are transported to the remote site in Mozambique.

High-integrity equipment from Energas product partners has been specified on the station.  Reliability and knowledgeable maintenance support of the station’s equipment by Energas’ competent team are crucial when selecting equipment.  The following equipment has been installed:

For the tie-in between the transmission line and HPCMS station, RMA’s HKSF-W fully welded 8” trunnion-mounted ball valves with extension spindles are used.  The ball valves’ primary metal and secondary soft sealing method with the RMA-sealing system offers the following advantages: each of the seating rings on both the inlet as well as the outlet side are composed of two sealing planes.  With this primary metal seal, sealing is ensured on both sides.  The double block and bleed function also provides proof of sealing even under the maximum operating pressure of the valve.  The underground valves get a high-quality PUR coating suitable for underground service and a design life of 50 years.  RMA’s ball valves with high-integrity sealing are also used throughout the above-ground station for isolation.

The first piece of equipment on the inlet skid is an RMA Insulation Joint to electrically isolate the station & pipeline.  Delta Mobrey’s explosion-proof temperature and pressure transmitters are used to monitor the process conditions on the station.  A junction box is mounted on each skid and all equipment and earthing is pre-wired for easy site installation.

After the inlet skid, the station splits in a dual run to the dust liquid filter separators from GTS Thielmann. The main run and standby run are identical, each designed for 100% of the flow capacity to ensure continuous gas supply to Safira in case of maintenance.  The filters are very important in protecting the downstream equipment from impurities such as black powder.   A differential pressure transmitter from Delta Mobrey & Vega level switch will indicate when the filters must be cleaned, and elements changed.  Tai Milano’s pressure safety valves are installed on the filters as well as the heaters to comply with the Pressure Equipment Regulation & ASME VIII Div 1. 

RMG’s USM-GT-400 4” Ultrasonic flow meter with ERZ-2000 Flow computer has been specified for custody transfer metering.  The USM GT-400 ultrasonic meter from RMG delivers the highest accuracy, reliability and long-term stability in the most demanding environments. It’s a multipath meter with multipath advantages: field-proven electronics, sophisticated diagnostics, user-friendly software to monitor the health of the low metering system and a superior six-path measuring technology.  Its patented live precision adjustment/echo measurement reduces metering uncertainty.  Regardless of pressure and temperature, the gas meter only measures the gas volume flowing through it.    Since gas can be compressed, the quantity flowing through the meter must be calculated considering the pressure and temperature at the flow conditions.  The ERZ-2000 flow computer performs gas volume corrections using pressure, temperature and compressibility of the gas. The compressibility value is calculated from the gas composition. The ERZ is easy to operate and provides an enhanced user experience to simplify operation with an HMI touchscreen, remote maintenance software capabilities and an optional USB port for the use of an external keyboard during maintenance.

The next two skids are identical electrical heater skids for the main and standby run.  The heaters are required due to the Joule-Thompson temperature drop, during pressure reduction.  The electric in-line heaters will ensure that the station’s outlet temperature is kept above the dewpoint at a target of 5°C.   The explosion-proof electric heaters were designed and fabricated in Germany by OhmEx.  The heaters are custom-built to meet the station’s specifications and are suitable for zone 2 hazardous areas.  A thyristor control system ensures that the gas temperature can be monitored and adjusted automatically. 

The pressure-regulating skid is the heart of the station and therefore high integrity and reliable control valves from Gas Flow Solutions (GFS) have been selected.  Two GFS SAGES safety shut-off valves and two GFS REGES pressure regulating valves (monitor and worker) are installed in series with a duplicate standby run.  The main and standby runs have automated changeover between the two runs.  The GFS valves’ key features are high accuracy, fast response with rapid closure, robust design that can cope with high velocity and system vibrations, non-bleed direct shut-off and easy in-line maintenance.  

A knock-out pot from GTS Thielmann has been added to the station’s outlet to ensure no liquid is transferred to the downstream client.  The GTS knock-out pot was designed & fabricated in Germany.  It has a diameter of 800mm and stands 3.2m tall. Energas managed to successfully deliver all pre-fabricated skids & equipment to the site on time within 24 weeks.