AES recently commissioned RJM to solve a series of complex lignite combustion issues at its new plant at Maritza in Bulgaria.
Although the plant was purpose-built to fire lignite, there was an issue from Day 1 with incomplete combustion in the furnace, meaning that too great a volume of material (a mix of ash and partially-combusted fuel) was building up on the furnace floor, blocking the grate that was designed to enable that material to be removed via a wet ash conveyor. This meant that periodically, the plant had to be shut down to enable this material to be removed by hand. An additional issue was that when the plant was running, it was doing so outside IED-compliant NOx emissions levels.
Following successes with other AES plants at Kilroot (a coal/oil plant) in Northern Ireland and at Tisza (an oil/gas plant) in Hungary, the senior managers at AES called RJM in to identify the problems and come up with a solution to get the plant back on track with consistent, reliable firing and meeting all NOx compliance issues.
Following a combination of a detailed site survey, CFD analysis and physical modelling of key parts of the process, RJM came up with a multi-faceted solution that included new RJM-designed burner nozzles, various modifications to secondary air flows, wall air flows and OFA ports, that together resolved all the ash build-up issues and reduced NOx levels to below 200mg/Nm3.
AES' state-of-the-art, lignite-fired 690MWe power station
Peter Lithgow, former CEO and AES Country Manager during the time of the execution of the project confirmed, “This was a very critical and challenging project technically and in terms of schedule. The results enabled the plant to generate reliably while meeting the latest emissions targets.”
Olivier Marquette, present CEO of AES Bulgaria concluded, “We will definitely consider to use RJM in future projects.”
This complex performance improvement project featured in the May 2015 edition of Power Engineering International. Click here for the full article in PEI.