Energy Risk Engineering Insights

High Temperature Hydrogen Attack (HTHA) is a critical concern in the energy industry, particularly for underwriters assessing risk in facilities that handle high-pressure hydrogen-containing environments, such as refineries and petrochemical plants. HTHA occurs when hydrogen atoms diffuse into the steel structure of equipment, causing severe damage over time. This phenomenon is of utmost importance for energy risk engineers and underwriters to understand due to its potential impact on asset integrity and safety.

Key Points for Energy Underwriters:

1. Mechanism of HTHA:

• HTHA is a type of corrosion that primarily affects carbon and low-alloy steels operating at elevated temperatures and high hydrogen partial pressures.
• The process involves the diffusion of hydrogen atoms into the steel lattice, leading to the formation of brittle phases like methane and cracks in the material.

2. Conditions Favoring HTHA:

• High temperatures, typically above 400°C (750°F), are required for HTHA to occur.
• Elevated hydrogen partial pressures, often found in hydroprocessing units, increase the risk of HTHA.
• Presence of susceptible materials and operational factors like pressure and time contribute to HTHA development.

3. Risk Assessment:

• When assessing the risk of HTHA, consider factors such as operating temperature, hydrogen concentration, and material properties of the equipment.
• Utilize predictive modeling and inspection data to estimate the remaining life of equipment and potential for HTHA-induced damage.

4. Mitigation Strategies:

• Engineers and underwriters should emphasize the importance of monitoring and inspection programs, including ultrasonic testing and regular equipment assessments.
• Material selection, using HTHA-resistant alloys, can significantly reduce the risk of HTHA in high-risk areas.

5. Case Example:

• Provide a real-world case where HTHA led to equipment failure or damage in the energy industry. Detail the consequences and lessons learned from the incident.

6. Regulatory Compliance:

• Highlight industry standards and codes, such as API 941, that provide guidance on managing HTHA risks. Ensure that insured facilities are in compliance with these standards.

7. Risk Mitigation Costs:

• Discuss the financial implications of HTHA risk mitigation, including inspection costs, potential equipment replacement, and insurance premiums.

HTHA is a complex issue that demands a meticulous approach to risk assessment and management. Energy underwriters must be well-versed in the specifics of HTHA and work closely with risk engineers to evaluate and mitigate this potentially catastrophic risk effectively.