摘要
我国以煤为主的能源结构以及日趋严格的氮氧化物排放标准催生了选择性催化还原法(SCR)脱硝技术的广泛应用,由于化学失活或物理结构破损等导致大量的废弃脱硝催化剂产生,造成严重的环境污染。然而,SCR催化剂的主要成分钒、钨、钛等有价金属具有重要的经济和战略价值。随着SCR催化剂的广泛使用,脱硝领域将面临严峻的环境污染和资源浪费问题。针对从废SCR催化剂回收TiO_(2)、WO_(3)、V_(2)O_(5)等金属元素,目前主要有酸法、碱法或氯化法等主要回收技术路线。在此过程中,通过化学反应,催化剂中钒、钨、钛等金属转变为其他形式化合物或进入到液相,再经过氧化、水解、结晶及煅烧等反应过程,实现产物分离以及产品性能提升的目的。回收的TiO_(2)既可以作为催化剂的载体,也可以用作涂料、光催化剂等其他材料;WO_(3)、V_(2)O_(5)、MoO_(3)等可以直接作为原料用于脱硝催化剂再生或制备中,也可用于生产其他化工产品。从我国特有的煤电局面,以及钒、钨、钛冶金工业为基础,以资源循环利用的未来绿色化工为理念,从废脱硝催化剂的成分及原料性质出发,建议因地制宜、因时制宜及因材制宜地选择技术路线和生产。通过冶金和化工过程回收其有价金属,从强化工艺、高效回收利用、清洁生产三个方面考虑,探索低温反应降低能耗,减少酸碱用量、水耗,缩短工艺流程,提高产量和品质,从而优化整合出一套适合于废SCR脱硝催化剂回收的工艺,实现脱硝催化剂“生产-再生-回收”绿色循环。本文归纳了废钒-钛系脱硝催化剂回收的研究进展,分别对酸法、碱法和氯化法回收钛白,以及钒-钨分离提纯工艺等进行介绍,分析了废脱硝催化剂回收面临的问题并展望其前景,以期为开发出一套高效清洁的废脱硝催化剂回收技术提供参考。
China’s coal based energy structure and more strict NO X emission standard have led to the extensive application of selective catalytic reduction(SCR)denitration catalyst.Due to chemical deactivation or physical structure damage,a large number of spent SCR catalyst have been produced,which cause serious environmental pollution.On the other hand,the main components of SCR catalysts,such as vanadium,tungsten and titanium,have important economic and strategic value.The wide application of SCR catalyst will led to serious environmental pollution and resource waste.For the recovery of TiO_(2),WO_(3),V_(2)O_(5) and other metal elements from waste SCR catalyst,there are mainly acid,alkali and chlorination methods.In these processes,vanadium,tungsten,titanium and other metals in the catalyst are transformed into other forms of compounds or dissolved into liquid phase and then separated through oxidation,hydrolysis,crystallization and calcination.The recovered TiO_(2) can be used not only as catalyst carrier,but also as coating,photocatalyst and other materials;WO_(3),V_(2)O_(5) and MoO_(3) can be directly used as raw materials catalyst production or regeneration.Based on China’s unique situation of coal power situation and vanadium,tungsten,titanium industry,and the concept of future green chemical industry,it is suggested that the recovery process should be considered according to location,time and materials itself.The process optimization is suggested to further develop to improve the product quality and recovery rate,to reduce energy consumption and waste emission.This review offers a retrospection of the research efforts with respect to recovery of spent vanadium-titanium based SCR catalyst,including acid leaching,alkali leaching,and chlorination process,followed by separation and purification process of vanadium and tungsten.We then pay attention to the problems confronting the current state-of-the-art spent SCR catalyst recovery processes.We have confidence that a life-cycle process of SCR catalyst has a bright future in terms of“Production-Regeneration-Recycling”.
作者
王宝冬
刘子林
林德海
曹子雄
何发泉
路光杰
肖雨亭
WANG Baodong;LIU Zilin;LIN Dehai;CAO Zixiong;HE Faquan;LU Guangjie;XIAO Yuting(National Institute of Clean and Low Carbon Energy,Beijing 102211,China;Beijing Guodian Longyuan Environmental Protection Engineering Co.,Ltd.,Beijing 100039,China;Jiangsu Longyuan Catalyst Co.,Ltd.,Yixing 214201,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2021年第15期15001-15010,共10页
Materials Reports
基金
国家重点研发计划(2019YFC1907500)。
关键词
脱硝催化剂
回收
选择性催化还原
钛白
钒
钨
DeNO_(x) catalyst
recycling
SCR
titanium oxide
vanadium
tungsten
