Background of the Incident
In a large-scale refinery located in the industrial heartland, operations involve handling vast quantities of hydrocarbons, including methane, a highly flammable gas. The facility processes thousands of barrels daily, with pipelines and storage tanks forming an intricate network. On a routine inspection day in early 2023, maintenance crews identified subtle irregularities in pressure readings from a section of the natural gas processing unit. Initial checks revealed no visible leaks, but the refinery’s safety protocols mandated immediate deployment of monitoring equipment to assess potential risks.
Methane leaks pose significant dangers in refineries. They can lead to explosions, fires, and environmental contamination. The refinery, adhering to international standards like API 521 and OSHA regulations, had already installed basic monitoring systems. However, these were insufficient for detecting low-level leaks in real-time across the expansive site. The management decided to integrate advanced fixed gas detectors to enhance safety measures.
The Challenge: Detecting Invisible Threats
The primary challenge was the undetected migration of methane through underground pipelines and equipment joints. Methane, being odorless and colorless, evades human senses. Traditional handheld detectors required manual patrols, which were impractical for continuous 24/7 coverage in a 500-acre facility. Environmental factors like high humidity, temperature fluctuations, and dust further complicated detection accuracy.
Key Risks Identified
- Potential for methane accumulation in confined spaces, leading to explosive mixtures above 5% LEL (Lower Explosive Limit).
- Impact on worker safety, with over 300 personnel on-site during shifts.
- Regulatory compliance, as undetected leaks could result in fines exceeding $1 million under EPA guidelines.
- Operational downtime, estimated at $50,000 per hour if a shutdown occurred.
Shanghai Gewei Electronic Safety Equipment Co., Ltd. (Gewei) was selected as the provider due to our expertise in gas detection solutions. Our systems are designed for harsh industrial environments, incorporating patented intelligent sensor technology and zero-point temperature compensation for reliable performance.
Implementation of Fixed Gas Detectors
Gewei recommended deploying the GDE series fixed gas detectors, optimized for combustible gases like methane. These units utilize high-performance infrared and laser sensors, offering a lifespan over 5 years and measurement precision of ±3%. Installation began in high-risk zones: 15 units along the main pipelines, 10 in storage areas, and 5 in control rooms.
Sensor Selection and Principles
Choosing the right detection principle is critical. Infrared sensors were prioritized for methane due to their non-contact operation and immunity to poisoning, unlike catalytic sensors. The GDE series supports multiple outputs: 4-20mA analog, RS485 bus, and relay for integration with existing SCADA systems. Each detector features automatic temperature compensation, ensuring accuracy across -40°C to 70°C.
For broader coverage, we supplemented with GDC series detectors using catalytic and semiconductor principles. The GDC models, with explosion-proof designs (Exd IIC T6 Gb), are suitable for Zone 1 and 2 hazardous areas. Their response time is T90 within 20-25 seconds, allowing rapid alerts before concentrations reach dangerous levels.
- Infrared sensors in GDE: Detect methane via absorption spectroscopy, drift less than 2% per half-year.
- Catalytic sensors in GDC: Oxidize gas for heat-based detection, lifespan up to 3 years for anti-poison variants.
- Semiconductor sensors: For VOCs, providing supplementary monitoring with ±5% FS accuracy.
The system integrated with our GM810/GM820 gas alarm controllers, featuring modular design and automatic addressing for bus communication. This setup allowed seamless networking with the refinery’s DCS, enabling remote monitoring via our IoT cloud platform. Accessories like voice-light alarms and 4G modules ensured alerts reached mobile devices instantly.
Detection and Response During the Event
Two weeks post-installation, during a pressure test, the GDE detectors in the pipeline section registered a gradual rise in methane levels from 0.5% to 4.2% LEL over 15 minutes. The colored LED displays, visible up to 25 meters, showed concentration trends without needing to open covers. Low-alarm relays activated at 2% LEL, triggering the GM820 controller to isolate the affected valve automatically.
Real-Time Data and Alerts
The 4-20mA output fed data to the central system, with currents programmed as: 4-20mA for normal range, >22mA for over-range. RS485 bus transmitted data up to 1.5km, ensuring no signal loss. Operators received notifications via the cloud platform’s mobile client, pinpointing the leak to a corroded joint. Maintenance teams arrived within 5 minutes, applying a temporary seal while evacuating the area.
Without the detectors, the leak could have escalated. Historical data from similar incidents shows undetected methane releases causing explosions with damages up to $10 million. Our system’s pre-calibrated smart plug-in sensors minimized false alarms, with repeatability at ±2% FS.
Further analysis via the GDA series portable units confirmed the leak source. These compact detectors, with infrared remote operation, allowed safe close-range verification. The event underscored the value of multi-principle detection: infrared for primary monitoring, complemented by electrochemical for toxic byproducts if present.
Outcomes and Benefits
The intervention prevented a major incident. Repairs were completed in 4 hours, with zero injuries and minimal downtime—costing under $5,000. Post-event, methane emissions dropped by 95%, aligning with the refinery’s ESG goals. Annual safety audits now report full compliance, reducing insurance premiums by 15%.
Long-Term Advantages of Gewei Solutions
- High reliability: Sensors stable in 95% RH, non-condensing, with IP66 protection.
- Cost-efficiency: Bus installation cut wiring by 40%, total setup under $200,000 for 30 units.
- Scalability: IoT integration supports expansion to 100+ detectors without hardware upgrades.
- Maintenance ease: Zero-point calibration every 6 months, no special tools required.
Gewei’s commitment to innovation, backed by CCC fire approval and CPA metrology licenses, ensures our products meet GB15322-2003 standards. The refinery now plans to extend GDE and GDC deployment to auxiliary units, solidifying our partnership.
This case demonstrates how proactive gas detection systems mitigate risks in high-stakes environments. By selecting appropriate sensors and integrating robust controls, facilities can safeguard operations effectively.
Technical Specifications Recap
For reference, key specs of deployed models:
| Model | Principle | Accuracy | Response Time |
|---|---|---|---|
| GDE Series | Infrared/Laser | ±3% FS | 20-25s |
| GDC Series | Catalytic/IR | ±3-5% FS | 20-25s |
| GM820 Controller | Bus/Modular | N/A | Instant |
These specifications, combined with our cloud platform, provide comprehensive monitoring. Facilities facing similar challenges can contact Gewei for tailored solutions.