Careers HVTS® Technology Overcomes NH3 Stripper Corrosion at U.S. Coal Gasification Plant
Facility Overview
A U.S. coal gasification power plant uses modern technology to convert locally sourced, cost-effective coal into over 600 MWe for the national grid. The facility employs advanced technologies for capturing, neutralizing, and storing emissions to minimize its environmental impact.
Wastewater treatment plays a vital role in both the plant’s general operations and emissions control system. The NH3 Stripper, initially lined with gunite, experienced multiple failures over time, prompting the client to seek IGS’s expertise in developing a corrosion mitigation solution.
NH3 Stripper Corrosion Challenge
The NH3 Stripper is essential to the plant’s industrial water recirculation system, particularly within the DeNOx cycle. By deactivating high-pH wastewater and separating ammonia from the stream, the system ensures efficient water recirculation while reducing freshwater input.
The original gunite lining system, though economical and robust in many cases, faced several challenges:
- Limited repairability
- Complex construction requirements requiring specialized drying cycles
- Strict procedural adherence that was difficult to achieve outside a manufacturer’s job shop
After eight years of operation, the gunite system failed repeatedly, making a new solution necessary to ensure long-term protection.
Engineering a Solution for Ammonia Stripper
IGS conducted comprehensive corrosion tests using precise media samples obtained directly from the NH3 Stripper. To validate their solution, the team performed 200-hour exposure tests under specific conditions:
- Pressure: 90 PSI (0.62 MPa)
- Temperature: 320°F (160°C)
- Exposure Time: 200 hours
Solution Properties:
- pH: 7.7 avg
- Contents included ammonium nitrogen, H2S, and other elements
Based on these results, IGS recommended their proprietary 5470 material, known for its high noble metal content, offering superior corrosion resistance in demanding conditions.
Project Execution
During the scheduled turnaround, IGS successfully applied the selected HVTS coating to all internal surfaces of the NH3 Stripper, completing the 100 m² project in just 4.5 days. The strong partnership between IGS and the client enabled swift completion of pre-project qualification and engineering phases.
Inspection and Results
Following the 2020 application, multiple inspections confirmed the coating’s integrity and success. After four years of operation, the HVTS system remains intact with:
- No thickness loss due to corrosion
- Continued high adhesion levels ensuring complete isolation of the NH3 Stripper internals from corrosion.
Conclusion
By partnering with IGS, the client successfully mitigated NH3 Stripper corrosion and improved equipment reliability. With over 400 global projects annually and an in-house R&D center, IGS continues to deliver innovative solutions that address mission-critical asset challenges. This project showcases IGS’s ability to provide high-performance corrosion protection that ensures long-term equipment durability and operational efficiency.
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