MnOx/PG低温SCR催化剂二氧化硫中毒及再生特性
Sulfur dioxide poisoning and regeneration characteristics of MnOx/PG low temperature SCR catalysts
-
摘要: 采用等体积浸渍法制备了锰氧化物负载凹凸棒石(MnOx/PG)低温SCR(Selective Catalytic Reduction)催化剂,在含硫气氛中进行低温SCR催化脱硝反应后受SO2的毒化作用而失活.考察了热处理和水洗两种再生方式及再生工艺条件对中毒后的MnOx/PG催化剂活性恢复的影响.结果表明,热处理不能有效恢复催化剂活性,而水洗再生可以使中毒催化剂的活性完全恢复;两种再生方法的工艺条件均对催化剂活性恢复效果不大.通过BET、SEM、元素分析等表征手段对催化剂中毒机理和中毒前后性能变化进行分析.结果表明,硫酸铵盐和多聚SO42-的形成是导致MnOx/PG催化剂活性降低的主要原因.热处理使催化剂部分活性恢复的原因在于表面硫酸铵盐的分解,而水洗再生可以有效的去除催化剂表面的硫酸铵盐和SO42-聚合体,进而催化剂活性完全恢复.
-
关键词:
- 低温SCR /
- MnOx/PG催化剂 /
- 二氧化硫中毒 /
- 水洗再生
Abstract: Manganese oxide supported palygorskite (MnOx/PG) as low temperature SCR catalyst was prepared by means of equal volume impregnation. After being used for lower temperature SCR in SO2 contained gases, catalysts were found to be deactivated drastically. Regeneration of the poisoned MnOx/PG catalyst was carried out by heat-treatment and water-washing, respectively. It was found that the heat-treatment partly restoreed poisoned catalyst activity, and the water regeneration completely restore the activity of the poisoning catalyst. Heat-treatment regeneration and water-washing regeneration had no obvious effect on regeneration results under different conditions. Poisoned mechanism of catalyst and performance changes were analyzed by BET, SEM, elemental analysis and other characterizations. The results show that the formation of ammonium sulfate salt and SO42- polymer were the main reason for the decrease of MnOx/PG catalyst activity. Further studies have shown that heat-treatment regeneration restores partly activity of the catalyst due to the decomposition of the surface ammonium sulfate salt. However, the water-washing regeneration can effectively remove the ammonium sulfate salt as well as the polymerized SO42- species, resulting in complete recovery of the catalyst activity. -
-
[1] GARCIA-BORDEJE E, PINILLA J L, LAZARO M J, et al. Role of sulphates on the mechanism of NH3-SCR of NO at low temperatures over presulphated vanadium supported on carbon-coated monoliths[J]. Journal of Catalysis, 2005, 233(1):166-175. [2] LI J H, CHANG H Z, MA L, et al. Low-temperature selective catalytic reduction of NOx with NH3 over metal oxide and zeolite catalysts-A review[J]. Catal Today,2011, 175(1):147-156. [3] LI Y, DIAO Y F, LIU X. Ce-Mn mixed oxides supported on glass-fiber for low temperature selective catalytic reduction of NO with NH3[J]. Rare Earth, 2014, 32(5):409-415. [4] LEE S M, KIM S S, HONG S C. Systematic mechanism study of the high temperature SCR of NOx by NH3 over a W/TiO2 catalyst[J]. Chemical Engineering Science 2012, 79(1):177-185. [5] LIU F D, YU Y B, HE H. Environmentally-benign catalysts for the selective catalytic reduction of NOx from diesel engines:Structure-activity relationship and reaction mechanism aspects[J]. Cheminform, 2015, 45(36):8445-8463. [6] TIAN W, YANG H S, FAN X Y, et al. Catalytic reduction of NOx with NH3 over different-shaped MnO2 at low temperature[J]. Journal of Hazardous Materials, 2011, 188(1-3):105-109. [7] 李金虎, 张先龙, 陈天虎, 等. 凹凸棒石负载锰氧化物低温选择性催化还原催化剂的表征及对氨的吸脱附[J]. 催化学报, 2010, 31(4):454-459. LI J H, ZHANG X L, CHEN T H, et al. Characterization and ammonia adsorption-desorption of palygorskite-supported manganese oxide as a low-temperature selective catalytic reduction catalyst[J]. Chinese Journal of Catalysis, 2010, 31(4):454-459(in Chinese)
[8] ZHANG L F, ZHANG X L, Lü S, et al. Promoted performance of a MnOx/PG catalyst for low-temperature SCR against SO2 poisoning by addition of cerium oxide[J]. Rsc Advances, 2015, 5(101):82952-82959. [9] WU Z B, JIN R B, WANG H Q, et al. Effect of ceria doping on SO2 resistance of Mn/TiO2 for selective catalytic reduction of NO with NH3 at low temperature[J]. Catalysis Communications, 2009, 10(6):935-939. [10] XU W Q, HE H, YUY B. Deactivation of a Ce/TiO2 catalyst by SO2 in the selective catalytic reduction of NO by NH3[J]. Journal of Physical Chemistry C, 2009, 113(11):4426-4432. [11] JIN R B, LIU Y, WU Z B, et al. Relationship between SO2 poisoning effects and reaction temperature for selective catalytic reduction of NO over Mn-Ce/TiO2 catalyst[J]. Catalysis Today, 2010, 153(3):84-89. [12] SHEN B X, LIU T, ZHAO N, et al. Iron-doped Mn-Ce/TiO2 catalyst for low temperature selective catalytic reduction of NO with NH3[J]. Journal of Environmental Sciences, 2010, 22(9):1447-1454. [13] 张力, 刘伟. 活性炭吸附烟气脱硫的展望[J]. 辽宁化工, 1996, 145(5):16-18. ZHANG L, LIU W. Prospect of adsorption of flue gas desulfurization by activated carbon[J]. Liaoning Chemical Industry, 1996. 154(5):16-18(in Chinese).
[14] KHODAYARI R, ODENBRAND C U I. Regeneration of commercial SCR catalysts by washing and sulphation:Effect of sulphate groups on the activity[J]. Applied Catalysis B Environmental, 2001, 33(4):277-291. [15] XIE G Y, LIU Z Y, ZHU Z P, et al. Reductive regeneration of sulfated CuO/Al2O3 catalyst-sorbent in ammonia[J]. Applied Catalysis B Environmental, 2003, 45(3):213-221. [16] MA J R, LIU Z Y, LIU S J, et al. A regenerable Fe/AC desulfurizer for SO2 adsorption at low temperatures[J]. Applied Catalysis B Environmental, 2003, 45(4):301-309. [17] RICHTER E. Carbon Catalyst for Air Pollution Control[J]. Catalysis Today, 1990, 7(2):93-112. [18] 黄海凤, 俞河, 张峰, 等. 低温NH3选择性催化还原脱硝催化剂MnFexCe1-x/TiO2抗硫再生性能研究[J]. 中国电机工程学报, 2011, 31(35):29-30. HUANG H B, YU H, ZHANG F, et al. Study on the sulfur tolerance and regeneration of Mn1FexCe1-x/TiO2 catalyst for low temperature NH3-selective catalytic reduction[J]. Proceedings of the CSEE, 2011,31(35):29-30(in Chinese).
[19] 张峰. SCR脱硝催化剂的抗硫再生性能和整体化制备研究[D]. 杭州, 浙江工业大学, 2010. ZHANG F. Study on sulfur tolerance and regeneration and preparation of SCR denitration catalyst[D]. Hangzhou:Zhejiang University of Technology,2010(in Chinese). [20] 张翠平, 张先龙, 吴雪平, 等. SO2对MnOx/PG催化剂低温脱硝的影响机理研究[J]. 环境科学学报, 2013,33(10):2686-2693. ZHANG C P, ZHANG X L, WU X P, et al. The mechanism of SO2 influence on the denitration of MnOx/PG catalysts at low temperature[J]. Acta Scientiae Circumstantiae, 2013, 33(10):2686-2693(in Chinese).
[21] JUNG S M, GRANGE P. Characterization and reactivity of pure TiO2-SO42- SCR catalyst:influence of SO42- content[J]. Catalysis Today, 2000, 59(3-4):305-312. [22] WU Z B, JIM R B, WANG H Q, et al. Effect of ceria doping on SO2 resistance of Mn/TiO2 for selective catalytic reduction of NO with NH3 at low temperature[J]. Catalysis Communications, 2009, 10(6):935-939. [23] MIN K, PARK E D, JI M K, et al. Manganese oxide catalysts for NOx reduction with NH3 at low temperatures[J]. Applied Catalysis A General, 2007, 327(2):261-269. [24] ROMEO M, BAK K, FALLAH J E, et al. XPS Study of the reduction of cerium dioxide[J]. Surface and Interface Analysis, 1993, 20(6):508-512. [25] SHEN B X, LIU T. Deactivation of MnOx-CeOx/ACF catalysts for low-temperature NH3-SCR in the presence of SO2[J]. Acta Physico-Chimica Sinica, 2010, 26(11):3009-3016. -

计量
- 文章访问数: 1734
- HTML全文浏览数: 1734
- PDF下载数: 100
- 施引文献: 0