iFluids Engineering and Consultancy WLL was awarded the contract to perform Surge Analysis for Laffan Refinery Zero Liquid Discharge (ZLD) facility. This critical study ensures the safety and reliability of the pipeline system, preventing potential damages caused by transient pressure changes.
What is Surge Analysis?
Surge analysis, also known as water hammer analysis, examines transient pressure changes (surges) in pipeline systems caused by abrupt fluid flow velocity changes. This analysis is essential for designing and operating pipeline systems, ensuring the safety of pumps, valves, pipes, and other components. Proper surge analysis prevents system failures and minimizes operational risks.
Objectives of the Surge Analysis for ZLD
The study’s purpose includes:
- Assessing Pressure Variations
- Identifying maximum and minimum pressure levels during transient conditions for various scenarios.
- Verifying Design Specifications
- Ensuring the selected pipe material and specifications meet design pressure requirements.
- Recommending Mitigation Measures
- Providing recommendations to mitigate pressure surges when system design pressure is exceeded.
- Supporting Stress Analysis
- Supplying surge force/load data for piping stress analysis.
- Compliance with Standards
- Ensuring design, engineering, procurement, and construction comply with Qatar’s statutory laws, regulations, and international engineering standards.
Key Activities in the Surge Analysis
The detailed methodology includes:
- Data Collection and Review
- Gathering project information such as Process Design Basis, P&IDs, and layout plans.
- Model Development
- Creating and validating a Pipenet model using steady-state data.
- Scenario Generation
- Simulating transient scenarios in Pipenet software.
- Evaluation and Analysis
- Analyzing results and providing graphical outputs.
- Surge Relief Valve Sizing
- Designing surge relief valves (SRVs) to mitigate pressure surges.
- Providing Recommendations
- Suggesting operational and design improvements to enhance system resilience.
Scenarios Considered
The analysis evaluates several potential surge scenarios, including:
- Sudden pump trip.
- Pump trip followed by immediate startup.
- Simultaneous pump start/stop.
- Sequential pump start/stop.
- Sudden closure of manual valves.
- Pipe component failure or malfunction.
ZLD Facility Overview
The Zero Liquid Discharge (ZLD) facility treats effluent from LR1 and LR2 wastewater treatment systems. The treated water (approximately 70%) is recycled for cooling tower makeup and desalinated water in LR1 and LR2 utility facilities. The remaining 30% comprises waste streams:
- Concentrate Water
- Used for landscaping purposes.
- AW Water
- Wastewater from backwashing and neutralized chemical systems, recycled to LR1 and LR2 upstream systems.
Key Components of the ZLD Facility
- Piping systems for feed, product, and effluent transport.
- Storage tanks: TIW buffer tank, UF permeate tank, re-use water tank, and concentrate water storage tank.
- ZLD plant units:
- Activated Carbon Filtration
- Ultra-Filtration (UF)
- Reverse Osmosis (RO)
- Chemical Dosing
- Associated cleaning and backwashing facilities
- Utility and drainage systems
- Collection pits and associated pumps for accidental contamination and chemical wastewater.
Deliverables for Surge Analysis
The subcontractor is responsible for delivering:
- Comprehensive Surge Analysis Report
- Scenarios evaluated
- Simulation models with native files
- Results summary with graphical outputs
- Conclusions and recommendations
- Revisions
- IFC (Issued for Comments)
- IFA (Issued for Approval)
- ADD (Approved for Detailed Design)
- Mitigation Measures
- Recommendations to optimize system safety.
Conclusion
Surge analysis ensures that the Laffan Refinery Zero Liquid Discharge facility operates safely and efficiently, adhering to stringent engineering and regulatory standards. By identifying potential risks and providing mitigation strategies, this study plays a vital role in maintaining system reliability and environmental compliance.
