OCR Text |
Show Influence of L o N O v Burners on a Coal Flame c Fig 5 shows very clearly that using a multiple staged air burner with lower excess air produces quieter flames which show a drastic reduction in the higher frequency content of the flicker spectra. This means that with very Lo N O x burners there is a very large difference in signal when fuels switch from oil to pulverised fuel. As Lo N O x PF burners have become extremely "quiet" and "lazy" flames, the oil support/ignition burners have kept the same spectral characteristics, this has, on some installations, meant that in order to monitor, with a sufficiently high gain, the lower level coal signal the instrument was "blinded" by the oil flame signal. Fig 5 FREQUENCY, kHz FLICKER SPECTRA JSH/22.8.97 6 |