选择性催化还原工艺中硫酸氢铵形成机理及影响因素

Formation mechanism and influencing factors of ammonium bisulfate during the selective catalytic reduction process

论述了选择性催化还原(SCR)烟气脱硝过程中硫酸氢铵(ABS)的形成机理,并分析了温度、氨逃逸量、SO3浓度、飞灰等对ABS形成的影响规律。分析表明:ABS的形成温度为190~240℃;当温度在320~345℃时ABS为气相,当温度高于345℃时ABS开始分解;为减少ABS的生成量,可通过控制NH3/NOx摩尔比在0.8~1.2之间,以减少氨逃逸量,同时尽可能减少烟气中SO2氧化率;调节SCR工艺运行温度,控制ABS在催化剂中的沉积,可避免催化剂堵塞和腐蚀。

The formation mechanism of ammonium bisulfate （ABS） during the flue gas denitrifica- tion process was presented. The effect of such parameters as the temperature,ammonia escape a- mount,SO3 concentration, and fly ash on formation of the ABS was investigated. The analysis shows that,formation temperature of ABS is between phase within temperature range from 320 ℃ to 345 ℃ 190 ℃ and 240 ℃ The ABS exhibits as gas , while it will decompose when the tempera- ture is higher than 345 ℃. To reduce the formation of ABS,the ammonia escape amount should be reduced by controlling the mole ratio of NH3 to NOx within range from 0.8 to 1.2,and the oxida- tion rate of SO2 in flue gas should be decreased as much as possible. Aiming at avoiding catalyst clogging and corrosion, it is essential to select the appropriate operation temperature to control the ABS^s deposition on catalyst.