SO_2对燃煤电厂选择催化还原脱硝催化剂性能的影响

The Effect of SO_2 on the Performance of Selective Catalytic Reduction Denitration Catalyst in Coal-fired Power Plant

对SO_2影响燃煤电厂选择性催化还原(selective catalytic reduction,SCR)脱硝催化剂的性能进行研究。利用中试装置对新鲜和在运的18×18孔SCR脱硝催化剂进行工艺性能评价;同时对催化剂理化特性进行表征。结果发现:SO_2对新催化剂的影响具有两面性。老化过程前期,不断吸附于催化剂表面的SO3增加了酸性位数量,提高了脱硝效率;老化过程后期,吸附的SO_3含量达到"饱和"状态以及SCR反应所需的V^(5+)减少,SO_2的负作用开始凸显。随着运行时间增加,催化剂表面不断累积硫酸盐物种,催化剂的部分活性位被遮蔽,比表面积和孔容不断减小,脱硝效率开始下降,下降的速度与硫酸盐的累积速度成正比。

The effect of SO2 on SCR denitrification catalyst performance in coal-fired power plant was investigated. The process performance evaluation of SCR denitration catalyst was carried out by a test platform,meanwhile the physical and chemical properties of the catalyst were characterized,including unregulated and shipped SCR denitration catalyst in 18 × 18 holes. The results show that the effect of SO2 on the unregulated denitration catalyst has two sides. In early aging,the SO3 adsorption on the surface of the catalyst increases the acid sites＇ quantity and then improves the denitration efficiency. In later aging,the adsorption of SO3 content reached the＂saturation＂state and the decrease of V5 ＋needed for SCR response,then the negative effect of SO2 began to be highlighted. At the continuous operation,sulfate deposition on the catalyst surface caused the active bit to be obscured,the specific surface area and pore volume of the catalyst to be decreased. As a result,the denitration efficiency begins to decline,and the rate of decline is proportional to the cumulative velocity of the sulfate.