In response to regulatory requirements, a large global population of tangential-coal fired units have been modified with low NOx firing systems. Many more are still pending conversions once in-country NOx emission regulations are finalized and then mandated. Numerous OEM’s and dozens of independent suppliers have joined this market, each offering their own versions of tangential low NOx firing systems. Many retrofits have achieved their NOx emissions performance, but a large number are not meeting their emissions and long term operational expectations, so plant owners are now looking for proven solutions for their combustion system problems.
In the early 1970’s, the first low NOx firing systems began being installed in the US when the US Environmental Protection Agency (EPA) issued its New Source Performance Standards (NSPS). Since then and through many additional emissions reduction mandates, thousands of US units have been retrofit. Nearly every coal fired unit in the US has now been in operation for many years with some type of low NOx combustion system. The lessons-learned from this long term experience have been incorporated into improved process design and application standards. US owners of coal fired units are now focusing toward upgrades that will extend operational reliability, while also maintaining existing or further lowering NOx emissions.
R-V Industries Inc. (RVII), Honey Brook PA, USA, has been designing and manufacturing conventional and low NOx tangential firing equipment and solutions for over 40 years. Numerous boiler original equipment suppliers as well as an increasing number of power stations (over 150) from around world continuously rely on RVII for solutions to their combustion system challenges. The paper presents key points from 40 years of lessons-learned tangential firing system design and application experience. This has strong relevance for all the tangential fired units in South East Asia to improved performance, availability and emissions. In addition, it provides insight for plant operations and maintenance personnel on the latest upgrades and components being applied in the US to maintain emission and operational control between extended outage intervals.