Situation: The process capacity of the new furnace had been limited by NOx emissions. The OEM attributed the higher than design NOx emission to poor mixing and recommended that new burners be installed. This would require significant modification to the furnace (tearing out hearth) resulting in an extended outage as well significant capital cost.
Action: A Becht Furnace expert conducted an on-site cold eyes review of the furnace design and operation to determine the root cause behind the higher than design NOx emissions and the difference in the continuous oxygen analyzer and CEM oxygen measurements.
Conclusions: The Becht Furnace expert determined that the CEM oxygen was reading correctly, but more importantly determined that new burners were not required to reduce the NOx emissions – only new burner replacement tips. This action takes advantage of the excess fuel pressure available to increase the amount of recirculated flue gas entrained by the staged tips. The solution (with which the OEM agreed) not only minimized capital cost, but could be installed without taking the unit out of service.
Client was so appreciative of this work that similar cold eyes reviews
were requested for several other furnaces in the refinery.