What Is the Role of Non-Return Valves in HRSGs?

Heat recovery steam generators (HRSGs) are critical in capturing and utilizing waste heat from gas turbines to generate steam, which can be used for additional power generation. This process significantly boosts the overall efficiency of power plants, making them more cost-effective and environmentally friendly.

The design, installation, and operation of valves within HRSG systems must comply with relevant code jurisdictions, including:

• ASME (American Society of Mechanical Engineers): Ensures compliance with the ASME Boiler and Pressure Vessel Code (BPVC), which provides standards for the safe design, construction, and inspection of valves. An authorized inspector must be involved in the inspection and certification process to ensure all standards are met.
• Local Regulations: Adherence to regional and national codes ensures that all equipment meets local safety and operational standards. The authorized inspector’s role is crucial in verifying compliance with these local regulations.

A key component ensuring the optimal performance and safety of HRSGs is the non-return valve (NRV). Recently, SVI BREMCO successfully replaced a customer’s grade P-91 NRV in central California, highlighting the importance and intricacies of this essential component. Authorized inspectors play a vital role in overseeing the adherence to these codes and standards. Their responsibilities include:

• Inspection and Certification: Inspectors review the design and construction of HRSG valves to ensure compliance with ASME BPVC and other applicable standards.
• Safety Verification: Inspectors verify that all safety protocols are followed during installation and operation.
• Documentation and Reporting: Inspectors maintain detailed records of inspections and certifications to ensure traceability and accountability.

By adhering to these regulations and involving authorized inspectors, HRSG systems maintain high safety and performance standards, contributing to their overall efficiency and reliability.

Non-return valves (NRVs), also known as check valves, are vital components in HRSG systems. These valves ensure that steam and water flow in a single direction, preventing backflow that could damage equipment or disrupt operations. The reliability and efficiency of HRSGs heavily depend on the proper functioning of NRVs, which safeguard the system against potential hazards and inefficiencies.

Addressing Challenges with NRV Replacement

When SVI BREMCO’s customers selected and purchased their new valves, they encountered a challenge: the new valves had significantly longer stems than the previous ones, creating a space issue. SVI BREMCO resolved this problem and added a permanently mounted Davit arm to aid in routine maintenance. This project faced multiple obstacles, including a tight one-week timeframe and switchyard work that left the plant without power for most of the outage.

SVI BREMCO teamed up with its preferred heat treatment contractor and a third-party inspection company to complete the job’s required Nondestructive Examination (NDE). They supplied the necessary generators and equipment to run independently of the plant’s power and air, emphasizing the importance of meticulous planning in such outages.

Expertise in Handling Grade P-91 Material

Working with grade P-91 material can be challenging, but SVI BREMCO’s experience ensures close monitoring of all processes. By using a heat treatment contractor with both on-site technicians and remote operators monitoring the charts in real-time, SVI BREMCO has significantly reduced the worries associated with this material. They follow AWS D10.10 standards for planning wrap specifications and thermocouple placements, ensuring consistent success.

The welding process is demanding, with pipe preheated and maintained at minimum temperatures of 400°F. SVI BREMCO’s team prioritizes safety and efficiency, even in these conditions. The welders are qualified to ASME Sec IX standards and maintain their certifications with SVI BREMCO as they travel the country for upgrades and repairs. These efforts come together like a well-practiced orchestra for SVI BREMCO’s project managers, delivering lasting products that meet customers’ schedules and budgets.

Final Thoughts about Non-Return Valve in HRSGs

Non-return valves are indispensable components in Heat recovery steam generators, ensuring these systems’ safe and efficient operation by preventing backflow and protecting equipment. Understanding the different types of NRVs and their specific applications can help you select the right valve for your HRSG. Regular maintenance and testing further ensure these valves reliably perform their critical functions. By prioritizing the selection and upkeep of NRVs, power plant operators can enhance the longevity and efficiency of their HRSGs, contributing to more sustainable and cost-effective energy production.

SVI BREMCO has the knowledge and successful track record of supplying and installing replacement NRVs, ensuring the continued efficiency and reliability of HRSG systems. Contact one of our experts today to discuss your industrial valve maintenance and repair needs.