Case Study: NWI Group’s IECEx Weighing System for Beach Energy

NWI Group have installed a brand new IECEx Weighing System for Beach Energy.

Background

Beach Energy, a leading oil and gas exploration and production company, operates several offshore gas platforms. These platforms play a crucial role in extracting natural gas from beneath the ocean floor. To maintain operations and ensure the safety of these facilities, Beach Energy uses a portion of the extracted gas to power the platforms. However, during emergencies and maintenance, they rely on Liquefied Petroleum Gas (LPG) stored in large cylinders.

For one of their offshore platforms undergoing an upgrade for better standby power control, Beach Energy required an accurate and reliable way to monitor the LPG gas levels. Knowing the precise weight of the LPG cylinders would help them efficiently schedule supply ships to replace the cylinders, avoiding costly downtime and ensuring continuous operation.

Requirements

Beach Energy approached NWI Group with the following requirements for the LPG weighing system:

1. IECEx Compliance: The system needed to be certified for use in explosive atmospheres, as offshore platforms have stringent safety standards.
2. Material Durability: Construction entirely from 316 Stainless Steel to withstand the harsh, corrosive offshore environment.
3. Accurate Weight Measurement: Capability to weigh four large LPG cylinders supported within a cage.

4. Output Integration: A 4-20mA output via Ex barriers to integrate seamlessly with the existing control systems.

Challenges

Designing and implementing a weighing system for Beach Energy’s offshore platform presented two significant challenges:

1. Use of 316 Stainless Steel

The corrosive marine environment posed a threat to equipment durability and longevity. Beach Energy’s requirement for the entire system to be constructed from 316 Stainless Steel was essential to prevent rust and degradation over time.

The challenge involved ensuring that all components, from load cells to housing, met these standards without compromising performance.

Solution:

• 316 Stainless Steel Equipment Cabinets: To house the Ex-rated equipment, NWI used IP68-rated cabinets made entirely of 316 Stainless Steel. This provided complete protection against dust and water ingress, as well as corrosion resistance.

• Minebea Load Cells: NWI used some very specialised Minebea load cells, which are known for their robustness in extreme conditions. These load cells were specially coated to enhance their resistance to harsh environments. They were fitted onto 316 Stainless Steel load cell mounts, ensuring durability and precision.

• Custom Scale Platform: The scale platform was custom-designed and built in-house using 316 Stainless Steel. An open-frame design minimised water pooling, preventing potential damage and maintaining accurate measurements.

2. Withstanding Heavy Lateral Wind Loads

Offshore platforms are exposed to intense weather conditions, including heavy lateral winds that could exceed 500kg of side force loading. The scale platform needed to be robust enough to handle these forces while maintaining accurate weight measurements.

Solution:

• Rugged Scale Design: NWI developed a rugged design for the scale platform capable of withstanding significant lateral forces without compromising accuracy. This design took into account the unique wind load conditions of the offshore environment.

• Minebea Load Cell Mounting Kit: The Minebea load cell mounting kit included side load protection on all four corners of the scale. This feature ensured stability and reliability, even under extreme wind conditions.

• Finite Element Analysis (FEA): Our design process involved using FEA simulations to model wind load impacts and stress distribution across the scale platform. This allowed us to optimise the structure for maximum strength and durability.

Results and Benefits

The implementation of the IECEx weighing system brought significant benefits to Beach Energy:

• Accurate LPG Monitoring: The precise measurement capabilities of the system allowed Beach Energy to monitor LPG levels accurately, ensuring timely replacement and preventing operational disruptions.

• Enhanced Safety: The system’s compliance with IECEx standards ensured safe operation in explosive environments, reducing the risk of accidents.

• Durability and Longevity: The use of 316 Stainless Steel and specially coated components provided resistance against corrosion, extending the system’s lifespan and reducing maintenance costs.

• Operational Efficiency: By integrating the system with their control systems, Beach Energy achieved greater operational efficiency through real-time data access, enabling informed decision-making.

• Cost Savings: Accurate monitoring and efficient logistics planning resulted in cost savings by minimising unnecessary supply ship deployments.

Conclusion

NWI Group‘s IECEx weighing system successfully met Beach Energy’s requirements for their offshore platform. By overcoming challenges related to material durability and lateral wind loads, we delivered a robust solution that ensures accurate LPG monitoring and enhances operational efficiency.

This project showcases NWI Group’s expertise in designing customised solutions for challenging environments, providing our clients with reliable systems that meet the highest standards of safety and performance.