焦化厂SCR脱硝催化剂积碳失活研究

摘要: 以焦化厂烟气脱硫前脱硝中失活的板式选择性催化还原(selective catalytic reduction,SCR)催化剂为研究对象,采用比表面及孔径分布分析仪、元素分析仪、热重∕差示扫描量热分析(TG∕DSC)、X射线光电子能谱(XPS)对失活催化剂进行表征,并对未经焙烧和经焙烧处理的失活催化剂的脱硝性能进行测试。结果表明:相较新鲜催化剂,失活催化剂比表面积和孔容大幅下降;失活催化剂表层吸附了大量的硫酸氢铵(NH₄HSO₄)∕硫酸铵〔(NH₄)₂SO₄〕和积碳,其中积碳以单质碳(C)形式存在,C浓度达0.87%;350 ℃焙烧可清除失活催化剂表面附着的NH₄HSO₄,使催化剂活性得到小幅度的恢复,400~500 ℃焙烧使积碳氧化生成二氧化碳从催化剂表面脱离,从而使催化剂活性得到大幅度的恢复;积碳是导致SCR脱硝催化剂失活的主要原因,可在脱硝前设置布袋除尘器,捕集烟气中的焦油积碳等有害物质,以降低积碳对SCR脱硝催化剂的有害作用。
- 脱硝催化剂 /
- 失活 /
- 积碳 /
- 脱硝性能 /
- 焦化厂
Abstract: The plate type SCR catalyst which was deactivated in flue gas denitration before desulfurization in a coke-oven plant was studied. Specific surface and pore size distribution analyzer, elemental analyzer, TG-DSC analysis, and X-ray photoelectron spectroscopy (XPS) were used to characterize the deactivation catalyst, and the denitration activity test of the untreated catalyst with that of the calcined catalyst was compared. The results showed that compared with fresh catalyst, the specific surface area and pore volume of deactivation catalyst were greatly reduced. The surface of catalyst was seriously polluted, and a large amount of ammonium bisulfate∕ammonium sulfate and coke deposit was adsorbed on the surface of catalyst. The coke deposit existed as element carbon with the content of 0.87%. The calcination temperature of 350 ℃ could remove the ammonium bisulfate on the surface of the deactivated catalyst, resulting in the recovery of a small part of the catalyst activity; however, after the treatment of 400-500 ℃, the appearance and activity of the catalyst were greatly restored. This was because the deposited coke was oxidized to carbon dioxide at 400-500 ℃ and was separated from the catalyst surface, resulting in the recovery of catalytic activity. The results of denitration activity test further proved that the coke deposition was the main cause of catalyst deactivation. A bag filter could be set before denitration to catch the tar, coke and other harmful substances in the flue gas, so as to effectively reduce the harmful effect of coke deposition on the SCR denitration catalyst.
- denitration catalyst /
- deactivation /
- coke deposition /
- denitration activity /
- the coke-oven plant

HTML全文

参考文献(21)

[1]	赵宝杰 . 国内焦化企业烟气脱硫脱硝技术现状分析[J]. 中国新技术新产品, 2018,363(5):127-131.
[2]	蒋国辉, 宋翔宇 . SCR催化剂失活机理分析及防治措施[J]. 中国环保产业, 2014(5):40-42.
[3]	XIE X H, LU J D, HUMS E , et al. Study on the deactivation of V₂O₅-WO₃∕TiO₂ selective catalytic reduction catalysts through transient kinetics[J]. Energy & Fuels, 2015,29(6):3890-3896.
[4]	刘少冕, 龚德喜, 王翔 . 焦化厂传统脱硫脱硝工艺的比较[J]. 化学工程师, 2017(10):83-86. LIU S M, GONG D X, WANG X . Comparison of the process of desulfurizing and denurization of coking plant[J]. Chemical Engineer, 2017(10):83-86.
[5]	王勇 . 焦化厂焦炉烟气脱硫脱硝工艺技术分析[J]. 化工管理, 2018(13):190-191.
[6]	周白鸽, 路聪聪, 李建萍 . 焦炉烟道气脱硫脱硝技术探讨[J]. 环境工程, 2018,36(增刊):179-181. ZHOU B G, LU C C, LI J P . Discussion on desulfurization and denitration technologies for coke oven flue gas[J]. Environmental Engineering, 2018,36(Suppl):179-181.
[7]	商雪松, 陈进生, 赵金平 , 等. SCR脱硝催化剂失活及其原因探讨[J]. 燃料化学学报, 2011,39(6):465-470. SHANG X S, CHEN J S, ZHAO J P , et al. Discussion on the deactivation of SCR denitrification catalyst and its reasons[J]. Journal of Fuel Chemistry and Technology, 2011,39(6):465-470.
[8]	WANG D, LUO J M, YANG Q L . Deactivation mechanism of multipoisons in cement furnace flue gas on selective catalytic reduction catalysts[J]. Environmental Science & Technology, 2019,53(12):6937-6944.
[9]	PENG Y, LI J H, SI W Z , et al. Deactivation and regeneration of a commercial SCR catalyst:comparison with alkali metals and arsenic[J]. Applied Catalysis B:Environmental, 2015,168∕169:195-202.
[10]	STREGE J R, ZYGARLICKE C J, FOLKEDAHL B C , et al. SCR deactivation in a full-scale cofired utility boiler[J]. Fuel, 2008,87(7):1341-1347.
[11]	束航 . SCR烟气脱硝过程中硫酸(氢)铵细颗粒生成及分解特性研究[D]. 南京:东南大学, 2015.
[12]	中国石油和化学工业联合会. 平板式烟气脱硝催化剂:GB∕T 31584—2015[S∕OL].(2016-01-01)[2019-05-25].
[13]	刘科伟, 陈天朗 . 硫酸铵的热分解[J]. 化学研究与应用, 2002,14(6):737-738. LIU K W, CHEN T L . Studies on the thermal decomposition of ammonium sulfate[J]. Chemical Research and Application, 2002,14(6):737-738.
[14]	马双忱, 金鑫, 孙云雪 , 等. SCR烟气脱硝过程硫酸氢铵的生成机理与控制[J]. 热力发电, 2010(8):12-17. MA S C, JIN X, SUN Y X , et al. The formation mechanism of ammonium bisulfate in SCR flue gas denitrification process and control thereof[J]. Thermal Power GenerationThermal Power Generation, 2010(8):12-17.
[15]	张萼松, 于洁, 王乐乐 , 等. 燃煤电厂SCR催化剂的失活及再生实验研究[J]. 燃料化学学报, 2018,46(10):1249-1256. ZHANG E S, YU J, WANG L L , et al. Deactivation and regeneration of commercial SCR catalysts used in coal fired power plant[J]. Journal of Fuel Chemistry and Technology, 2018,46(10):1249-1256.
[16]	孙刚森, 尹华, 吕文彬 , 等. 焦炉烟气脱硫除尘脱硝及其热解析一体化工艺[J]. 燃料与化工, 2015,46(6):40-41. SUN G S, YIN H, LÜ W B , et al. Integrated process for desulfurization,dedusting,denitration and thermal decompositioin of coke oven flue gas[J]. Fuel & Chemical Processes, 2015,46(6):40-41.
[17]	安璐 . 乙酸蒸汽催化重整制氢研究[D]. 北京:华北电力大学, 2010.
[18]	MOUDLER J F, STICKLE W F, SOBOL P E , et al. Handbook of X-ray photoelectron spectroscopy[M]. Minnesota:Physical Electronics Division,Eden Prairie, 1992.
[19]	OKAZAKI N, OSADA S, TADA A . Deactivation by sulfur dioxide of alumina-based catalysts for selective catalytic reduction of nitrogen monoxide by ethene[J]. Applied Surface Science, 1997,121(97):396-399.
[20]	刘昭铁, 周敬来 . 催化剂失活原因探讨[J]. 煤炭转化, 1993(6):30-37.
[21]	吴春领, 徐怀兵 . 焦化烟气脱硫脱硝除尘一体化工艺技术探讨[J]. 中国资源综合利用, 2018,36(6):110-112. WU C L, XU H B . Discussion on integrated technology of coking flue gas desulphurization,denitrification and dust removal[J]. China Resources Comprehensive Utilization, 2018,36(6):110-112.