生物滤塔和NRB在有氧条件下去除废气中的NO_x

Removal of nitrogen oxides from waste gases by bio-filter and NRB under aerobic conditions

研究了有氧条件下氮氧化物在生物滤塔内的传质机理,结果表明,当含NOx废气中氧气含量为20%、氧化度为80%时,被生物滤塔内微生物吸附分解的NOx仅占被净化的NOx的12%左右,而88%左右的NOx没有被微生物及时分解,而是转入液相中形成NO3-和NO2-。在此基础上,提出了采用生物滤塔和硝酸盐脱除反应器(nitrate removal bioreactor,简称NRB)联合净化有氧条件下含NOx废气的工艺,并进行了实验研究,结果表明,生物滤塔和NRB联合工艺对有氧条件下含NOx废气具有较好的净化效果,当停留时间为9.42 s时,对初始浓度为1 488.92 mg/m3的含NOx废气的净化率达到90.23%,NRB反应器出水中的NO3-和NO2-的浓度低于5 mg/m3。

The mass transfer mechanism of nitrogen oxides under aerobic conditions in biofilter was studied.The results showed that when oxygen content was about 20% and oxidation rate was 80%,only about 12% of NOx which were removed by biofilter were absorbed and decomposed by microorganisms,and 88% of NOx were not timely decomposed by microorganisms,but transferred into liquid phase in the form of NO-2 and NO-3.On the basis of this,the integrated process of biofilter and NRB was put forward to remove NOx from exhaust gases under aerobic conditions,a series of experimental were carried out.The results showed that the removal efficiency of NOx achieved 90.23% for the inlet NOx concentration of 1 488.92 mg/m3 when the residence time was 9.42 s,and the concentration of NO-2and NO-3 at the outlet of NRB was less than 5 mg/m3.