二甲醚选择性催化还原NO_x的试验研究

使用7%MoO3/γ-Al2O3(质量分数)为催化剂,对二甲醚(DME)作为还原剂选择性催化还原(SCR)降低NOx进行了试验研究.分别考察了反应温度、氧含量、DME与NO的比例对NO转化率的影响,测定了产物中的碳分布,并对NO与NO2分别作为NOx源进行了转化率比较.研究结果表明:常压条件下,在250~500℃内,随着反应温度的升高,NOx转化率先增大后减小;醚氮比对NO转化率的影响不明显;随着氧含量的增加,NOx转化率先增大后减小,当φO2=5%时,NO最高转化率约为53%;NO2比NO更容易被DME催化还原;含碳主要产物为CO、CO2,有少量甲醇(CH3OH)、甲醛(H2CO)生成.

Experimental Study on Dimethyl ether SCR NOx Reduction

Selective catalytic reduction (SCR) activity for NOx conversion to N2 over 7% MoO3/γ Al2O3 (mass fraction) was investigated with Dimethyl ether (DME) as a reductant. The effects of the reaction temperature, DME/NO ratio as well as the oxygen inlet concentration were studied respectively. The carbon containing product distributions were presented. NOx conversion with NO and NO2 respectively as NOx source was also investigated. The results show that between the range of 250℃ to 500℃, under atmospheric pressure, when operation temperature increases, NOx conversion increases at the beginning and then decreases. DME/NO ratio has a little impact on NO conversion. When the oxygen inlet concentration increases, NOx conversion increases at the beginning and then decreases, and the highest conversion rate of NO is about 53% when the oxygen inlet concentration is 5%. NO2 is easier for selective reduction than NO with DME as the reductant. The main carbon containing products are CO and CO2, while a little CH3OH and H2CO have also been detected during the experiment.