工业烟气SO_(3)吸收脱除性能研究

Performance of SO_(3)Removal From Industrial Flue Gas by Adsorption

燃用高硫煤和安装选择性催化还原(selective catalytic reduction,SCR)装置会引起烟气中SO_(3)浓度增加,带来设备腐蚀与环境污染问题。分别以Ca(OH)_(2)和Na_(2)SO_(3)为吸收剂,通过数值模拟研究吸收剂脱除工业烟气中SO_(3)的性能,讨论Ca(OH)_(2)/Na_(2)SO_(3):SO_(3)、SO_(3)浓度和降温历程对SO_(3)脱除的影响。结果表明,在SCR脱硝装置后加入2种吸收剂均能有效脱除SO_(3)。在烟气降温过程中,加入吸收剂后,SO_(3)的脱除率和吸收剂总转化率均呈现初期快速增长、后期缓慢增长的趋势。Na_(2)SO_(3)对SO_(3)的脱除性能明显优于Ca(OH)_(2)。Ca(OH)_(2)/Na_(2)SO_(3):SO_(3)增加、原始烟气SO_(3)浓度高、吸收剂加入位置烟温高均可以提高SO_(3)脱除率。其中增加Ca(OH)_(2)/Na_(2)SO_(3):SO_(3)效果最为显著,SO_(3)脱除率为90%以上。虽有烟气中其他组分的竞争反应影响,吸收剂对吸收SO_(3)的选择性在0.9左右,但吸收剂的转化率较低,在10%左右。

The use of high-sulfur coal and selective catalytic reduction(SCR)reactor increases SO_(3)concentration in the flue gas.Numerical simulation was carried out to study the industrial process of SO_(3)removal from the flue gas by adsorbents such as Ca(OH)_(2)and Na_(2)SO_(3).The influence of Ca(OH)_(2)/Na_(2)SO_(3):SO_(3),SO_(3)concentrations and the cooling process of flue gas on SO_(3)removal performance was discussed.The results showed that both two adsorbents could effectively remove SO_(3).During the cooling process of flue gas,once the adsorbents were injected into the flue gas,the SO_(3)removal efficiency and the conversion of the two adsorbents first quickly increased and then slowly increased.The performance of SO_(3)removal by Na_(2)SO_(3)was much better than by Ca(OH)_(2).The increase of Ca(OH)_(2)/Na_(2)SO_(3):SO_(3),the SO_(3)concentration of the original flue gas,and the temperature at the adsorbent-injection position promoted the SO_(3)removal.The effect of increasing Ca(OH)_(2)/Na_(2)SO_(3):SO_(3)was the most significant,and the SO_(3)removal efficiency could reach higher than 90%.Although the other components in the flue gas competitively reacted with the adsorbents,the selectivity of adsorbing SO_(3)by the adsorbents was about 0.9.However,the conversion of the adsorbents was low,which was around 10%.