Project Scope

Design, Engineering, Supply, and Commissioning of a PLC/SCADA-Based Control System for a Sea Water Reverse Osmosis Plant.

Background:

Reverse Osmosis (RO) is a critical water treatment technology that uses pressure to force water molecules through a semipermeable membrane, removing contaminants and providing clean, potable water. Our client required a fully automated control system for their new Sea Water Reverse Osmosis (SWRO) Plant, which has a capacity of 1000 cubic meters per day. This system aimed to enhance the efficiency, reliability, and operational safety of the plant.

System Description:

The SWRO plant processes water through several stages, starting from raw water extraction to final storage. The plant’s automation system was designed to handle the following sequence of operations:

1. Raw Water Extraction:
   • Raw water is pumped from bore wells and stored in Raw Water Storage Tanks.
   • The system maintains appropriate water levels to ensure continuous plant operation.
2. Pre-Treatment:
   • Raw water is pumped from the storage tanks through Multimedia Filters (MMF) by Filter Feed Pumps.
   • Filtered water is stored in an Intermediate Tank.
3. RO Pass 1:
   • Filtered water from the Intermediate Tank is pumped through three skids of RO Pass 1 using High-Pressure Pumps.
   • Water is then stored in the RO Pass 1 Storage Tank.
   • Critical quality parameters like Total Dissolved Solids (TDS) and pH are monitored using analytical instruments.
4. Quality Control:
   • If water quality parameters are within the desired limits, the RO Feed Pump transfers the water to the Final Storage Tank via a bypass valve.
   • If parameters exceed limits, water is further processed through RO Pass 2 using another High-Pressure Pump before transferring to the Final Storage Tank.

Automation and Control:

The entire plant operation and monitoring are managed by a PLC & SCADA-based control system, which includes:

• PLC System:
  • Mitsubishi Electric IQR Series PLC for robust and reliable control.
  • Around 350 slice I/O modules from Mitsubishi Electric, organized into two Remote I/O Racks and one main PLC Rack.
  • Modular Enclosure System from Phoenix Contact housing the PLC and auxiliary devices.
• SCADA System:
  • Genesis64 SCADA from Mitsubishi Electric for real-time monitoring and control.
  • The SCADA system provides a comprehensive graphical interface displaying real-time data, alarms, and trends.
  • Operators can monitor critical parameters such as water levels, flow rates, pressure, TDS, and pH.
• Field Instruments and Actuators:
  • Various sensors and transmitters to measure water quality and process parameters.
  • Pneumatic control valves for precise flow regulation.
  • Emergency bypass valves for safety and operational flexibility.

Project Outcomes

The implementation of the PLC & SCADA-based control system has significantly enhanced the operational efficiency and reliability of the SWRO plant. Key benefits include:

• Automated Control:
  • Seamless and automated plant operations, reducing manual intervention and human error.
  • Improved process consistency and product quality through precise control of water treatment parameters.
• Real-Time Monitoring:
  • Continuous real-time monitoring of critical process parameters.
  • Immediate detection and response to deviations or alarms, enhancing safety and reducing downtime.
• Operational Efficiency:
  • Optimized energy and resource usage through efficient pump and valve control.
  • Reduced operational costs and improved overall plant performance.
• Scalability and Flexibility:
  • The modular design allows for future expansion and integration of additional processes or equipment.
  • Customizable SCADA interface for easy adaptation to changing operational needs.

Overall, the advanced automation system has provided the client with a reliable, efficient, and scalable solution for their sea water reverse osmosis plant, ensuring consistent delivery of high-quality potable water.