CNG PRESSURE REDUCING UNIT (PRU) STATION
The PRU, or Pressure Reducing Unit, is a CNG pressure reduction station installed at the customers site as part of the supply chain: NG Gas – CNG Compression Station – Tanker Truck – Transportation – PRU – Gas-consuming Equipment
❖ Why Use a PRU Station?
For areas such as industrial parks, export processing zones, factories, and residential users near a Gas Distribution Center (GDC), natural gas is typically transported and distributed through pipelines. In Vietnam, typical GDCs include:
- Phu My, My Xuan Industrial Park Gas Distribution Station
- Nhon Trach Industrial Park Gas Distribution Station
- Hiep Phuoc Industrial Park Gas Distribution Station
- Tien Hai Thai Binh Industrial Park Gas Distribution Station
For areas far from central gas distribution stations, natural gas must be compressed to high pressures (up to 250 Bar, typically 180-230 Bar) to be transported efficiently. This compressed gas is known as CNG.
Specialized tanker trucks transport the CNG to consumption sites (factories, end-users). However, the inlet equipment at customer sites can only handle pressures of 2-7 bar. Therefore, a PRU station is required to reduce the pressure from 250 bar (storage tank) to 2-7 bar at the stations outlet, supplying it to the customer.
❖ PRU Station Components
A PRU station includes the following main components (comprising two branches, one main branch, and one backup branch):
- Filling post and flexible hoses connecting from the CNG tanker truck
- High-pressure pipeline (250 bar)
- High-pressure gas filter
- Emergency shutdown valve
- First-stage pressure regulator reducing from 250 bar to 30 bar
- Heating equipment (boiler and heat exchanger)
- Gas flow meter
- Second-stage pressure regulator reducing from 30 bar to 2-7 bar (as per customer requirements)
- Liquid separator
- Pressure, temperature, and differential pressure gauges
- Control cabinet and HMI screen
- Power supply cabinet
- Gas detection and alarm system (siren, lights, emergency push buttons)
- On-site fire-fighting equipment
- Warning signs, caution signs, and operating procedures
❖ PRU Station Requirements
A CNG PRU station is designed based on the following requirements:
- Maximum flow rate per hour: PRU 500 Sm3/hr, 1000 Sm3/hr, 2000 Sm3/hr...
- Daily output: 3000 Sm3/day, 10000 Sm3/day, 20000 Sm3/day...
- Customer-required outlet pressure: 2 bar, 3 bar, 5 bar...
Contact our hotline for the quickest information on installing a PRU station. We look forward to collaborating with you!
