生物质/塑料共催化热解过程中HZSM-5失活分析

doi:10.16085/j.issn.1000-6613.2020-1767

摘要/Abstract

摘要：

利用管式炉热解装置进行HZSM-5在线共催化热解玉米秸秆/高密度聚乙烯过程中的循环和再生利用实验，对玉米秸秆进行酸洗预处理，考察原料酸洗预处理对HZSM-5催化性能的影响。采用GC-MS（气相色谱-质谱联用仪）对生物油的化学组成进行分析，并对反应前、反应后以及再生催化剂进行TG（热重分析）、ICP-MS（电感耦合等离子体发射光谱仪）、SEM/EDS（场发射扫描电镜）、BET、NH₃-TPD（程序升温脱附技术）等表征分析。研究表明，HZSM-5催化玉米秸秆/高密度聚乙烯热解的主要产物为芳烃，随着催化剂重复利用次数的增加，芳烃含量逐渐降低，催化剂的比表面积、孔容、酸性等也随之降低，说明催化剂的活性逐渐降低；原料经酸洗预处理后有利于热解中间体的生成，加速了催化剂的结焦失活速率；催化热解酸洗玉米秸秆/高密度聚乙烯的催化剂经焙烧再生后其活性基本恢复至原有水平，而催化热解未处理玉米秸秆/高密度聚乙烯的催化剂再生后其活性有所降低，碱/碱土金属在HZSM-5催化剂上发生累积，从而引起酸性位点“中毒”失活，而原料经酸洗预处理后可有效降低催化剂上碱/碱土金属的累积量，有利于延长催化剂的使用寿命。

关键词: 生物质, 塑料, 热解, HZSM-5, 失活, 碱/碱土金属

Abstract:

The reuse and regeneration of HZSM-5 zeolite in the catalytic co-pyrolysis of corn stover/high-density polyethylene was investigated using a tube reactor. The effect of acid washing treatment of corn stover on the catalytic activities of HZSM-5 zeolite was studied. The composition of the obtained bio-oil was analyzed by GC-MS, and the properties of fresh, spent, and regenerated HZSM-5 catalysts were measured using TG, ICP-MS, SEM/EDS, BET, and NH₃-TPD, respectively. The results showed that aromatics were the main products for the catalytic co-pyrolysis of corn stover/high-density polyethylene with fresh HZSM-5. With the increase of HZSM-5 reuse times, the yield of aromatics decreased gradually, and the BET area, pore volume, and acidity of the catalyst decreased sharply, indicating the reduced catalytic activities of HZSM-5. The acid washing pretreatment of corn stover enhanced the formation of oxygen-containing intermediates, which accelerated the deactivation of HZSM-5 zeolite. The catalytic activity of the regenerated HZSM-5 over acid washing corn stover/high-density polyethylene was recovered, while the catalytic activity of the regenerated HZSM-5 over raw corn stover/high-density polyethylene was slightly lower than that of fresh HZSM-5. This was due to the fact that alkali/alkaline earth metals were significantly accumulated over the HZSM-5 catalyst, which couldn’t be removed by calcination and thus could deposit on the strong acid sites, causing the “poisoning” deactivation of the catalyst. The above results suggest that the deactivation of HZSM-5 caused by coke can be regenerated by calcination, while that caused by alkali/alkaline earth metals is difficult to recover. The acid-washing pretreatment can effectively eliminate the effect of alkali/alkaline earth metals, which is beneficial to prolong the lifetime of the catalyst.

Key words: biomass, plastics, pyrolysis, HZSM-5, deactivation, alkali/alkaline earth metals

中图分类号:

张东红, 任夏瑾, 蔡红珍, 易维明, 柳善建, 林晓娜. 生物质/塑料共催化热解过程中HZSM-5失活分析[J]. 化工进展, 2021, 40(8): 4259-4267.

ZHANG Donghong, REN Xiajin, CAI Hongzhen, YI Weiming, LIU Shanjian, LIN Xiaona. Deactivation of HZSM-5 during the catalytic co-pyrolysis of biomass and plastic[J]. Chemical Industry and Engineering Progress, 2021, 40(8): 4259-4267.

图/表 10

参考文献 28

1	SHAO Shanhan, ZHANG Huiyan, XIAO Rui, et al. Evolution of coke in the catalytic conversion of biomass-derivates by combined in-situ DRIFTS and ex-situ approach: effect of functional structure[J]. Fuel Processing Technology, 2018, 178: 88-97.
2	王洋, 董长青. 生物质燃烧和热解中钾的释放规律研究进展[J]. 化工进展, 2020, 39(4): 1292-1301.
	WANG Yang, DONG Changqing. Release of K during biomass combustion and pyrolysis:a review[J]. Chemical Industry and Engineering Progress, 2020, 39(4): 1292-1301.
3	Tomás CORDERO-LANZAC, PALOS Roberto, ARANDES José María, et al. Stability of an acid activated carbon based bifunctional catalyst for the raw bio-oil hydrodeoxygenation[J]. Applied Catalysis B: Environmental, 2017, 203: 389-399.
4	王敬茹, 姚宗路, 丛宏斌, 等. 生物质炭催化玉米秸秆热解气重整提质研究[J]. 农业工程学报, 2019, 35(16): 258-264.
	WANG Jingru, YAO Zonglu, CONG Hongbin, et al. Upgrading biomass pyrolysis gas from corn stalk by charcoal catalytic reforming[J]. Transactions of the Chinese Society of Agricultural Engineering, 2019, 35(16): 258-264.
5	HU Changsong, XIAO Rui, ZHANG Huiyan. Ex-situ catalytic fast pyrolysis of biomass over HZSM-5 in a two-stage fluidized-bed/fixed-bed combination reactor[J]. Bioresource Technology, 2017, 243: 1133-1140.
6	BARTHOLOMEW Calvin H. Mechanisms of catalyst deactivation[J]. Applied Catalysis A: General, 2001, 212: 17-60.
7	郭慧敏, 李翔宇, 王海彦, 等. 纤维素和聚丙烯共催化热解热重分析及动力学研究[J]. 太阳能学报, 2017, 38: 2705-2711.
	GUO Huimin, LI Xiangyu, WANG Haiyan, et al. Thermogravimetric analysis and kinetics of co-catalytic pyrolysis of cellulose and polypropylene blends[J]. Acta Energiae Solaris Sinica, 2017, 38: 2705-2711.
8	XUE Yuan, KELKAR Atul, BAI Xianglan. Catalytic co-pyrolysis of biomass and polyethylene in a tandem micropyrolyzer[J]. Fuel, 2016, 166: 227-236.
9	LI Xiangyu, ZHANG Haifeng, LI Jian, et al. Improving the aromatic production in catalytic fast pyrolysis of cellulose by co-feeding low-density polyethylene[J]. Applied Catalysis A: General, 2013, 455: 114-121.
10	In Yong EOM, KIM Jae Young, KIM Tae Seung, et al. Effect of essential inorganic metals on primary thermal degradation of lignocellulosic biomass[J]. Bioresource Technology, 2012, 104: 687-694.
11	Qitai ERI, ZHAO Xinjun, RANGANATHAN Panneerselvam, et al. Numerical simulations on the effect of potassium on the biomass fast pyrolysis in fluidized bed reactor[J]. Fuel, 2017, 197: 290-297.
12	Güray YILDIZ, RONSSE Frederik, VENDERBOSCH Robbie, et al. Effect of biomass ash in catalytic fast pyrolysis of pine wood[J]. Applied Catalysis B: Environmental, 2015, 168/169: 203-211.
13	MULLEN Charles A, BOATENG Akwasi A. Accumulation of inorganic impurities on HZSM-5 zeolites during catalytic fast pyrolysis of switchgrass[J]. Industrial & Engineering Chemistry Research, 2013, 52: 17156-17161.
14	XUE Yuan, BAI Xianglan. Synergistic enhancement of product quality through fast co-pyrolysis of acid pretreated biomass and waste plastic[J]. Energy Conversion and Management, 2018, 164: 629-638.
15	HERNANDO Héctor, Sergio JIMENEZ-SANCHEZ, FERMOSO Javier, et al. Assessing biomass catalytic pyrolysis in terms of deoxygenation pathways and energy yields for the efficient production of advanced biofuels[J]. Catalysis Science & Technology, 2016, 6: 2829-2843.
16	LIU Changjun, WANG Huamin, KARIM Ayman M, et al. Catalytic fast pyrolysis of lignocellulosic biomass[J]. Chemical Society Reviews, 2014, 43: 7594-7623.
17	PARK Young Kwon, SIDDIQUI Muhammad, KANG Yejin, et al. Increased aromatics formation by the use of high-density polyethylene on the catalytic pyrolysis of mandarin peel over HY and HZSM-5[J]. Catalysts, 2018, 8: 656.
18	武杰. 烃分子动力学直径与分子筛择形催化性能的相关性[J]. 化工进展, 2016, 35(S1): 167-173.
	WU Jie. Research on the correlation between dynamic diameters of hydrocarbon molecules and zeolites shape-selective catalytic performance[J]. Chemical Industry and Engineering Progress, 2016, 35(S1): 167-173.
19	KALOGIANNIS Konstantinos G, STEFANIDIS Stylianos D, KARAKOULIA Stamatia A, et al. First pilot scale study of basic vs acidic catalysts in biomass pyrolysis: deoxygenation mechanisms and catalyst deactivation[J]. Applied Catalysis B: Environmental, 2018, 238: 346-357.
20	MULLEN Charles A, DORADO Christina, BOATENG Akwasi A. Catalytic co-pyrolysis of switchgrass and polyethylene over HZSM-5: catalyst deactivation and coke formation[J]. Journal of Analytical and Applied Pyrolysis, 2018, 129: 195-203.
21	KALOGIANNIS Konstantinos G, STEFANIDIS Stylianos D, LAPPAS Angelos A. Catalyst deactivation, ash accumulation and bio-oil deoxygenation during ex situ catalytic fast pyrolysis of biomass in a cascade thermal-catalytic reactor system[J]. Fuel Processing Technology, 2019, 186: 99-109.
22	尉东光, 周敬来, 张碧江. 焙烧对HZSM-5分子筛结构的影响[J]. 分子催化, 1996, 10: 445-448.
	WEI Dongguang, ZHOU Jinglai, ZHANG Bijiang. The influence of calcination on the structure of HZSM-5[J]. Journal of Molecular Catalysis, 1996, 10: 445-448.
23	PERSSON Henry, DUMAN I, WANG Shule, et al. Catalytic pyrolysis over transition metal-modified zeolites: a comparative study between catalyst activity and deactivation[J]. Journal of Analytical and Applied Pyrolysis, 2019, 138: 54-61.
24	MA Zhingqiang, TROUSSARD Ekaterina, BOKHOVEN Jeroen A. Controlling the selectivity to chemicals from lignin via catalytic fast pyrolysis[J]. Applied Catalysis A: General, 2012, 423/424: 130-136.
25	SAMOLADA M C, PAPAFOTICA A, VASALOS I A. Catalyst evaluation for catalytic biomass pyrolysis[J]. Energy & Fuels, 2000, 14: 1161-1167.
26	唐松山, 泮泽优, 张长森, 等. 碱改性HZSM-5催化热解木质素催化剂失活分析[J]. 化工学报, 2017, 68(12): 4739-4749.
	TANG Songshan, PAN Zeyou, ZHANG Changsen, et al. Deactivation analysis of catalyst for modified HZSM-5 catalytic lignin pyrolysis[J]. CIESC Journal, 2017, 68(12): 4739-4749.
27	GAYUBO Aguayo G, AGUAYO Andrés T, ATUTXA Alaitz, et al. Deactivation of a HZSM-5 zeolite catalyst in the transformation of the aqueous fraction of biomass pyrolysis oil into hydrocarbons[J]. Energy & Fuels, 2004, 18: 1640-1647.
28	尹海云, 李小华, 张蓉仙, 等. HZSM-5在线提质生物油及催化剂失活机理分析[J]. 燃料化学学报, 2014, 42(9): 1077-1086.
	YIN Haiyun, LI Xiaohua, ZHANG Rongxian, et al. Online catalytic cracking of bio-oil over HZSM-5 zeolite and analysis of catalyst deactivation[J]. Journal of Fuel Chemistry and Technology, 2014, 42(9): 1077-1086.

样品	工业分析（干燥基）/%			元素分析（干燥无灰基）/%
样品	灰分	挥发分	固定碳	N	C	H	O（差值法）
玉米秸秆	7.55	75.64	16.81	1.55	46.61	5.29	46.55
酸洗玉米秸秆	3.15	84.28	12.57	0.48	47.91	6.01	45.6

样品	工业分析（干燥基）/%			元素分析（干燥无灰基）/%
样品	灰分	挥发分	固定碳	N	C	H	O（差值法）
玉米秸秆	7.55	75.64	16.81	1.55	46.61	5.29	46.55
酸洗玉米秸秆	3.15	84.28	12.57	0.48	47.91	6.01	45.6

样品	K/mg·kg^-1	Ca/mg·kg^-1	Na/mg·kg^-1	Mg/mg·kg^-1
玉米秸秆	9397	2857	160	1188
酸洗玉米秸秆	28	348	39	87

样品	K/mg·kg^-1	Ca/mg·kg^-1	Na/mg·kg^-1	Mg/mg·kg^-1
玉米秸秆	9397	2857	160	1188
酸洗玉米秸秆	28	348	39	87

样品	Na/mg·kg^-1	Mg/mg·kg^-1	K/mg·kg^-1	Ca/mg·kg^-1
新鲜 HZSM-5	326	50	38	65
CS/HDPE共催化热解所用HZSM-5
Run 1	311	159	798	344
Run 5	408	324	2078	481
再生HZSM-5	321	350	2126	580
ACS/HDPE共催化热解所用HZSM-5
Run 1	290	40	56	54
Run 5	428	103	99	206
再生HZSM-5	363	78	143	260