NOx storage and reduction with propylene on Pt/BaO/alumina
NOx storage and reduction with propylene on Pt/BaO/alumina
复制标题
Pt/BaO/氧化铝上的丙烯储存和还原 NOx
DOI：
10.1002/aic.10208
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发表时间：
2004
期刊：
影响因子：
3.7
通讯作者：
M. Harold
中科院分区：
文献类型：
--
作者：
Rachel L. Muncrief;Karen S. Kabin;M. Harold
在Pt/BaO/Al2O3催化剂上进行了周期性NOx（NO + NO2）储存和还原的实验研究。根据进料组成和温度、还原剂脉冲持续时间和总循环时间评估了还原剂（丙烯）喷射策略对时间平均NOx转化率的影响。确定了时间平均NOx转化率超过90%的条件。在注入过程中的氧化剂的比例和总的周期时间都被发现是实现高转化率的关键因素。时间平均转化率的上下界分别是用与循环的富燃和贫燃部分具有相同组成的进料获得的稳态转化率。对于丙烯的固定供应，高浓度的短脉冲比降低浓度的长脉冲有效得多。当固定占空比的丙烯脉冲为净还原时，NOx转化率在中间总循环时间处达到最大值。高转化率可在宽温度范围（200 - 400 ° C）内保持。提出了一个简单的存储减少周期，阐明了研究中的主要发现。高NOx转化率的关键因素是与高催化剂温度相结合的缺氧条件的暂时产生，这两者都是由丙烯的间歇催化氧化引起的。
An experimental study was carried out of periodically operated NOx (NO + NO 2 ) storage and reduction on a model Pt/BaO/Al 2 O 3 catalyst powder. The effect of the reductant (propylene) injection policy on time-averaged NOx conversion was evaluated in terms of feed composition and temperature, reductant pulse duration, and overall cycle time. Conditions giving time-averaged NOx conversions exceeding 90% were identified. The reluctant-to-oxidant ratio during the injection and the total cycle time are both found to be critical factors to achieve high conversion. The time-averaged conversion is bounded above and below by the steady-state conversions obtained with feeds having the same compositions as that during the rich and lean part of the cycle, respectively. For a fixed supply of propylene, short pulses of high concentration are much more effective than longer pulses of reduced concentration. The NOx conversion achieves a maximum value at an intermediate overall cycle time when the propylene pulse of fixed duty fraction is net reducing. High conversions are sustained over a wide temperature window (200-400°C). A simple storage-reduction cycle is proposed that elucidates the main findings in the study. The key factor for high NOx conversion is the temporal production of oxygen-deficient conditions coupled with high catalyst temperatures, both resulting from the intermittent catalytic oxidation of propylene.