Deactivation of the Vanadia Catalyst in the Selective Catalytic Reduction Process |
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| Authors: | J P Chen M A Buzanowski R T Yang J E Cichanowicz |
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| Institution: | 1. State University of New York , Buffalo , New York , USA;2. Electric Power Research Institute , Palo Alto , California , USA |
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| Abstract: | Results are summarized of a comprehensive study of the effects on the SCR process of all major possible poisons encountered in the combustion gases from U.S. coals. A general rule evolved from this study Is that the effect of the additive on the catalyst activity Is directly related to the basicity of the additive; poisoning Is caused by the basicity. Quantitative effects are presented, while a qualitative summary is given as follows: strong poisons-alkali metal oxides; weak poisons-oxides of alkaline earth metals, arsenic, lead phosphorus and chlorides of strong alkaline metals. SO2 is a promoter due to its acidity. HCI, although acidic, reacts with both NH3 (forming NH4CI) and V2O5 (forming VCI2 and VCI3) and consequently strongly deactivates the SCR reaction. A summary is also given for a theoretical and experimental study of the monolithic honeycomb reactor using both undoped and poison-doped catalysts. The results showed that the reactor performance can be predicted directly from the intrinsic catalyst activity through a model. |
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