基于实验室对柴油车用V2O5-WO3/TiO2催化剂配方以及涂覆成型技术的大量研究,设计了一条产量为6000只/月的NH3选择性催化还原NOx (NH3-SCR)催化剂中试生产线,并对生产的催化剂产品进行了发动机台架测试。结果表明,实验室制备的V2O5-WO3/TiO2粉体催化剂和生产线产品,在空速为50000 h-1和200-450℃条件下NOx转化率均可达80%以上;采用大尺寸堇青石载体涂覆后制备的V2O5-WO3/TiO2整体催化剂经实验室小样测试,在空速为10000-30000 h-1和250-450℃条件下NOx转化率也为80%以上。发动机台架测试结果表明,该催化剂产品可使重型柴油机NOx排放达到国IV标准中欧洲稳态循环(ESC)和欧洲瞬态循环(ETC)排放限值的要求。该生产线经适当调整后也可用于生产非钒基NH3-SCR整体催化剂,以满足未来钒基NH3-SCR催化剂更新换代的需求。
A catalyst production line with a production capacity of 6000 catalyst monoliths per month for the selective catalytic reduction of NOx by NH3 (NH3-SCR) for NOx abatement in diesel vehicle exhaust was set up based on a detailed laboratory study of the catalyst formulation and washcoating tech-nology for V2O5-WO3/TiO2 catalyst. The catalyst produced by this line was tested on a bench scale diesel engine. The V2O5-WO3/TiO2 powder catalyst prepared in the laboratory and production line both achieved>80%NOx conversion at 200-450 ℃ and a GHSV of 50000 h-1. The washcoated cata-lyst used a large cordierite support and gave>80%NOx conversion at 250-450 ℃ and GHSVs of 10000-30000 h-1. The engine bench tests showed that after treatment by the catalyst, the NOx emis-sion met the European steady-state cycle (ESC) and European transient cycle (ETC) limits of the China IV standard. The production line can also be used for the production of vanadium-free NH3-SCR catalysts to meet the required replacement of the present vanadium-based NH3-SCR cata-lyst in the future.