Liquefied Hydrogen Tank Gas Detection Solution: Reliable Safety Protection for Hydrogen Operations

With the rapid development of the hydrogen industry, liquefied hydrogen (LH₂) has become a widely used high-density, high-purity storage medium in hydrogen fuel cell refueling stations, industrial hydrogen supply, aerospace, and other applications. However, liquefied hydrogen tank areas carry extremely high safety risks: hydrogen is highly flammable and explosive (4%–75% VOL explosion limits), has a very low boiling point (-252.8℃), and rapidly vaporizes and disperses upon leakage. Contact with fire or static electricity can trigger explosions or chain reactions.

Recent hydrogen leak accidents highlight the critical need for continuous monitoring. Installing professional online gas detection systems is essential for ensuring safe operations in liquefied hydrogen storage areas. The Nexisense SGA-500 Series online hydrogen detector offers high reliability, explosion-proof design, and rapid response to provide effective protection for hydrogen storage and transportation.

Unique Safety Challenges in Liquefied Hydrogen Tank Areas

• High explosion risk: Hydrogen’s lower explosion limit is low, and mixed with air, it can ignite easily from sparks or static electricity.

• Rapid dispersion: Vaporization expands volume ~850 times, forming large explosive clouds.

• Low temperature and high pressure: Tanks at -253℃ and high-pressure piping can cause brittle fractures or ice blockages upon leaks.

• Invisible hazard: Hydrogen is colorless and odorless, making early detection difficult.

According to the "Technical Specification for Hydrogen Infrastructure Construction" (GB/T 37252-2018) and "Safety Technical Regulations for Hydrogen Use" (AQ 3054-2018), hydrogen concentration alarm settings are typically 1% VOL (25% LEL) warning and 2% VOL (50% LEL) critical alarm. Traditional inspections cannot meet continuous monitoring needs, making fixed online detection the preferred solution.

Why Professional Online Monitoring is Required

• Real-time concentration monitoring and trend analysis

• Second-level sound and light alarms for over-limit concentrations

• Automatic linkage with fans, shut-off valves, and spray systems

• Remote data transmission, supporting centralized control room management

The Nexisense SGA-500 Series is optimized for hydrogen applications, with high sensitivity, anti-interference capability, explosion-proof, and low-temperature tolerance.

Key Advantages of SGA-500 Series

• Original imported catalytic combustion or electrochemical sensors with secondary optimization

• Measurement range: 0–100% LEL / 0–4% VOL optional

• High resolution: 0.1% LEL

• Response time: T90 ≤ 30 seconds

• Explosion-proof rating: Ex d IIC T6 Gb, suitable for Zone 1/2

• Output signals: 4–20mA, RS485 Modbus RTU, supports PLC/DCS integration

• Protection level: IP65+, low-temperature design (-40℃~+70℃)

• Local display: LCD shows real-time concentration and status, ≥85dB audible and visual alarm for over-limit

• Anti-interference: selective against common hydrocarbons and CO

  
  

Recommended Detector Placement

• Tank bottoms, valve assemblies, flange connections

• Unloading/refueling platforms, pipeline supports

• Low-temperature pump areas, near vaporizers

• Outside control rooms, inspection paths

• Consider hydrogen's upward movement: install 0.5–2 meters above potential leak sources

For large tank areas, 8–16 detectors are recommended to form a grid monitoring network.

Complete Alarm and Emergency Linkage System

• Multi-channel input with centralized display

• Tiered alarms (warning + critical)

• Automatic linkage: exhaust fans, shut-off valves, water spray or nitrogen purge

• Independent sub-systems for each tank group, centrally managed

• Data platform: cloud upload, mobile app monitoring, SMS alerts

Portable Inspection Support: SGA-600 Series

• Compact, lightweight (<500g), one-hand operation

• One-button start, real-time display of concentration, battery, and status

• Explosion-proof certified, suitable for tanks, warehouses, laboratories

• Built-in data storage with USB export

Installation, Maintenance, and Long-Term Reliability

Installation tips:

• Secure detector heads, avoid high vibration areas

• Use shielded explosion-proof cables

• Calibrate zero and span with standard hydrogen before commissioning

Routine maintenance:

• Monthly inspection for cleanliness and no ice formation

• Quarterly calibration

• Sensor lifespan generally 2–3 years, replace modules as needed

  
  

FAQ

1. Alarm thresholds: tiered alarms, level 1 warning 0.4%–1.0% VOL (10%–25% LEL), level 2 critical 1.6%–2.0% VOL (40%–50% LEL), adjusted based on ventilation, CFD simulation, and risk assessment.

2. Low-temperature environment: SGA-500 sensors operate -40℃~+70℃, anti-icing design maintains performance during LH₂ leaks.

3. Emergency linkage: SGA-800 controller uses relay outputs or Modbus RTU to drive fans, valves, and other devices for sound/light alarms + shutdown + purge.

4. Sensor lifespan: affected by high hydrogen exposure, humidity, dust/oil, and temperature fluctuations. Typical 2–4 years; extend life with protective covers, quarterly calibration, and timely replacement.

5. Coverage: effective radius 5–15m depending on leak rate, wind, obstacles; add points for each major source.

6. Cross-interference: hydrogen-specific sensors reduce response to hydrocarbons and CO (<5–10%), verified periodically.

7. Explosion-proof certification: Ex d IIC T6 Gb for Zone 1/2 compliance with LH₂ tank safety regulations.

8. Data management: local + cloud storage for real-time trends, alarm logs, calibration records, and emergency actions; supports safety management and compliance audits.

Conclusion

Liquefied hydrogen tank safety is critical for the hydrogen industry and public safety. The Nexisense SGA-500 online detector combined with SGA-800 alarm controller offers a reliable, fast-response, and easily integrated protection solution. Deploying professional gas monitoring systems prevents leaks, safeguards personnel and equipment, and enhances operational safety and market competitiveness.