#boilerrecirculation

  Power generation plants rely on boiler feed pumps to deliver a reliable and consistent flow of water to the boilers, which create the steam that powers the turbine, which creates electricity. After 45 years in service the boiler feed pumps needed to be replaced and Sulzer managed to achieve an impressive return on investment of just over two years.

Annual running costs at the power plant have dropped dramatically. (Image Source: Shutterstock – Belish) A major UK waste-to-energy plant was experiencing considerable reliability issues with its six boiler feed pumps. Routine maintenance involved a complete refurbishment every two years and the costs for this work were increasing. Sulzer only became involved after one of its turbine specialists was discussing current issues with the maintenance manager. Dale Jarvis, Business Development Engineer with Sulzer, explains: “I had been working with this plant for some time, providing support for the steam turbine, and during one visit the discussion turned to the boiler feed pumps. Knowing that Sulzer has considerable expertise in boiler feed pumps, I invited one of my colleagues to visit the plant and see what we could offer.” The plant has six boiler feed pumps that have been operating since the site was commissioned over 45 years ago. Over the years, the pumps have been regularly maintained, but more recently, they have required major refurbishments to keep them operational. Turnkey solution

Sulzer’s expertise in boiler feed pump design ensured a cost-effective and efficient solution. As a pump manufacturer and independent service provider, Sulzer was well-placed to deliver a turnkey solution that would include the removal of the legacy equipment and the installation and commissioning of new pumps. Having established the specifications of the old pumps, it was possible to source new pumps that would exactly match the original performance characteristics of the old pumps but with improved efficiency. Sulzer’s proposal was to replace two pumps each year, allowing the plant to spread the cost of the project and also appreciate the benefits of the new pumps before committing to the next stage of the installation. The financial benefits were obvious from the outset. The cost of each new pump was only marginally more than the refurbishment costs of the equipment it replaced, giving a return on investment of just over two years.

  The Mojave 280 MW solar plant generates clean electricity to power approximately 90'000 households, preventing the emission of 350'000 tons of CO2 annually. (Photo by Dennis Schroeder) © Dennis Schroeder/Abengoa Solar Sulzer is collaborating with Atlantica, a global player with a strong portfolio in sustainable infrastructure, to install its Blue Box advanced analytics solution on the performance-critical pumps at two solar power plants. Located 100 miles northeast of Los Angeles, US, the Mojave 280 MW solar plant generates clean electricity to power approximately 90'000 households, preventing the emission of 350'000 tons of CO2 annually. KaXu Solar One in South Africa has a capacity of 100 MW and saves emissions to the amount of 315'000 tons annually. The Blue Box advanced analytics solution on the boiler feedwater and heat transfer fluid pumps will strengthen Atlantica's own anomaly detection capabilities and thus increase uptime, improve reliability and eliminate operational risks of their renewable energy plants. After successful completion, Atlantica aims to implement Sulzer's cloud-based technology in all its assets worldwide as a part of their enterprise-level digitalization efforts.

  Boiler feed pumps are essential pieces of equipment for power generation plants. High energy requirements mean they need to be efficient as well as reliable. For one liquified natural gas (LNG) plant in South East Asia, nine boiler feed pumps needed urgent attention and Sulzer was called in to deliver the most effective solution. Having been installed for well over 30 years, the original boiler feed pumps were showing signs of their age. The original design for the installation intended seven pumps to be in service while the remaining two offered reserve capacity that enabled maintenance to be completed without interrupting the boilers. The toll of time Unfortunately, several decades in service had taken their toll and worn seals, increased clearances, and a need to improve efficiency resulted in the engineering manager contacting Sulzer, a company he had worked with before. In fact, the situation had reached such a point that all nine pumps were required to be operating to keep up with demand from the boilers. Once the initial inspection had been completed, the results showed that six of the nine pumps had leakage figures of around 25 m³/hour. Manish Talwar, Head of Retrofits for Pump Services, Asia Pacific, comments: “The original pumps had performed remarkably well, but over the last few years, they have not been running anywhere near peak efficiency. It was clear that we could offer some immediate assistance as well as a plan for the long-term performance of the pumps.” The discussions with the plant engineering manager revealed that the original equipment manufacturer (OEM) had been contacted with a view to repairing or replacing all of the pumps. However, both the proposed costs and the projected lead times for this work were well beyond the expectations of the customer.

Sulzer’s repair and replacement program for the pumps will bring the plant back to original specification but with improved efficiency. Fast fixes The initial contract for Sulzer was to repair and upgrade two of the pumps so that they could operate close to their original performance figures. This involved installing mechanical upgrades to the coupling system, seal improvements and efficiency upgrades through non-metallic wear parts, before returning them to normal service. Given the cost of energy production at the power plant, Sulzer’s engineers were able to calculate the payback period of the overall upgrade project. Having been assessed in the company’s service center in Singapore, it was concluded that the investment in the pump refurbishment would be paid off in less than three years. As a pump OEM, Sulzer has considerable expertise and experience in designing and manufacturing pump components as well as installing upgrades to existing equipment. It was this knowledge, and the ability to deliver the repairs quickly, that convinced the customer to choose Sulzer for the project. Advanced manufacturing

The new pumps will offer a 5 % increase in efficiency and have a lower power requirement delivering on-going cost savings. The new parts were designed and manufactured using state-of-the-art equipment, including 3-dimensional laser scanning technology to create the engineering models that were used with the latest casting techniques to produce the parts. This manufacturing method greatly reduces the lead time compared to traditional pattern making processes. It also simplifies the manufacture of future replacement parts. Manish continues: “By adapting design concepts from Sulzer pumps, our engineers have managed to improve the performance of the existing pump and complete all the design calculations to verify the existing barrel would be safe in operation. A final hydro test was conducted to test the barrel and pipework to confirm its integrity before it was installed.” As well as creating new parts, Sulzer also updated the design of the drive coupling, which was previously a gear coupling. In its place, Sulzer installed a membrane coupling, which offers stable performance, absorbs damping vibration and is easy to maintain. Bespoke replacements At the same time, Sulzer also discussed the repair or replacement of the remaining seven pumps. Considering the age of the original pumps and the improvements that could be delivered by modern replacements, it was decided the most cost-effective solution would be to replace them with custom-made models from Sulzer’s GSG range of boiler feed pumps.