Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

OP-III-3Analysis of the results shows that ammonia storage/release and inhibition of the SCRreactions by NH 3 are the key processes for an understanding of the transient performance ofthe SCR catalyst [4]. The dynamic behaviour of the Fe zeolite catalyst proves surprisinglysimilar to the vanadium based catalyst.The model was validated successfully by a transient temperature sequence including steeptemperature rises. Figure 1 shows the temperature program together with the emissions andthe model output of NH 3 .T vk[K]800600TemperatureNH 3[ppm]4000 2000 4000 6000 8000 10000 12000 14000 16000Time [s]12001000800600400200NH 3InputNH 3OutputNH 3Model00 2000 4000 6000 8000 10000 12000 14000 16000Time [s]Figure 1: Temperature validation sequence carried out with fixed feedgas concentrations(600 ppm NO, 600 ppm NH 3 , 6 % O 2 , 5 % H 2 O, GHSV 25000 h –1 ).The model is able to reproduce the emissions of the catalyst under transient and constanttemperature conditions. The ammonia peaks evolving during the heating phases and theammonia storage during cooling times are as well mapped as the steady state conversionlevels.References1. Long, R.Q., Yang, R.T., J. Catalysis 2002, 207, 224-231.2. Devadas M. et al., Catalysis Today 2007, 119, 137-144.3. Chatterjee D. et al., Society of Automotive Engineers 2005, 2005-01-0965.4. Malmberg et al., Topics in Catalysis 2007, 42–43, 33-36.98