New Coal Burner Upgrade Project

Key Challenges

This modern, supercritical, opposed-firing boiler, delivering 615 MW to the national grid in Turkey and firing a mix of local and imported bituminous coals was experiencing a number of issues around poor combustion performance, including unplanned outages due to tube leaks, poor boiler efficiency and unacceptably high levels of NOx and CO.

RJM’s Site Survey, Combustion Audit and detailed CFD analysis identified that: The existing burners were over-sized, resulting in long flames and uncontrolled combustion; The burners also showed varying degrees of damage due to some flames being too close the burner; The OFA system was not operating correctly; The tertiary air dampers were not set up correctly; The furnace was coated in a layer of silica which reduced heat transfer; CO levels were fluctuating between 300 mg/Nm³  – 600 mg/Nm³. 

RJM Solution

RJM developed an innovative solution which included the provision of 24 bespoke sets of ultra-low NOx burner modifications. This ensured that all the performance-critical components were replaced, but also that as many non-critical components as possible could be retained. This kept overall project costs down and ensured a shorter outage period. In addition, the redesign was engineered to keep all the existing burner-to-boiler and OFA interfaces to maintain OFA performance and minimise the introduction of any new potential problems.  

Results

As well as delivering the performance objectives in terms of resolving combustion stability, poor efficiency, burner and reheater damage, high CO and high NOx, the performance results confirmed that the plant is now able to generate the same amount of power, using less fuel and less reagent. This also delivers significant operational savings in terms of fuel, reagent and capital cost savings extending the life of the SCR catalyst. 

After the commissioning phase, overall performance of the plant far exceeded the contractual Performance Guarantees and the project more than met all of Eren Enerji’s objectives and expectations. Summary of key savings below:

• Five mills now in service rather than six
• NOx reduced by 47%
• Carbon in Ash reduced by 50%
• Boiler efficiency up by 2%
• Mill motors and fans using 14% less current (A)
• Mill mechanicals using 9% less power (kW)
• Reduction in reagent usage of 70% (kg/day)
• 80,000 tonnes of CO2 savings per annum

RJM is now working on other plants owned and operated by Eren Enerji to deliver similar performance upgrade projects.

“We are very happy with the project and it has surpassed our expectations,” confirmed Ömer Buğer, CEO, Eren Enerji.

Read the full article in Modern Power Systems magazine here: 014_017mps0325_Power plant upgrade ZETES

Checking burner dimensions during installation

Eren and RJM team following successful commissioning