Water consumption and transfer during MSW pyrolysis char-vaporized pyrolysis oil reforming process

doi:10.11949/0438-1157.20190663

Abstract

Abstract:

The in situ reforming of volatiles from municipal solid waste by pyrolytic carbon is a good method for improving pyrolysis products. In this process water vapor plays an important role on product conversion. In order to understand the role of water vapor during the reforming process, oil phase and aqueous phase in the pyrolysis liquid are separated and then D₂O was used to replace the aqueous phase to mix with oil so that hydrogen transfer between liquid, gas and solid can be tracked in the reforming process. The vaporized oil/char reforming process was performed at 600℃, 700℃ and 800℃, respectively. The oil phase and deuterium concentration in the liquid (oil and aqueous phase together) after reforming were measured with help of GC-MS and IR-MS(isotope ratio mass spectrometry); at the same time deuterium concentration in the solid phase was also checked. It has been found that char gasification by water vapor at all testing temperature ranges is very weak, at 700℃ 2% of deuterium in D₂O was remained in the char when the ratio of D₂O/char was 2/1. While oil gasification by water vapor during char-catalytic reforming process is very intense: at 800℃ 78.68% of total oil-water mixture is gasified, and the aliphatic hydrocarbons in the oil are decomposed to a large extent, but the aromatic hydrocarbons are found to account for 96.17% of the oil phase after reforming. Simultaneously 59% of deuterium in D₂O was found to transfer into syngas when the ratio of D₂O/oil was 2/3. The research results obtained here will provide guide for improving the final products of MSW pyrolysis.

Key words: pyrolysis char, pyrolysis oil, isotope, deuterium, hydrogen transfer

摘要：

热解炭原位重整城市固体废物的挥发分是改善热解产物的良好方法。在这个过程中，水蒸气在产品转化中起着重要作用。为了了解水分在重整过程中的作用，本研究中将热解液中的油相和水相分离，然后用D₂O代替重整过程中的水相，以跟踪液体、气体和固体之间的氢转移。热解油/焦炭重整过程在600、700和800℃下进行。用GC-MS（气相色谱质谱法）分析重整后液体中的油相；IR-MS（同位素比质谱法）分析重整后液体和固体中的氘浓度。研究发现，在实验温度范围内，水蒸气对焦炭的气化作用非常弱，当D₂O/焦炭的比例为2/1时，D₂O中2％（质量）的氘在反应后残留在炭中;但水蒸气与热解油的气化反应很强烈，在800℃时，78.68％（质量）的热解液（水油混合物）被气化,且热解油中脂肪烃被大量分解，重整液的油相组分中芳香烃占到96.17%；同时，当D₂O/油的比例为2/3时，D₂O中59％的氘转移到合成气中。研究结果将为生活垃圾热解处理控制最终产物提供理论指导。

关键词: 热解半焦, 热解油, 同位素, 氘, 氢转移

CLC Number:

X 705

Kaiyuan LEI, Dezhen CHEN. Water consumption and transfer during MSW pyrolysis char-vaporized pyrolysis oil reforming process[J]. CIESC Journal, 2019, 70(12): 4795-4803.

雷开元, 陈德珍. 生活垃圾热解半焦-热解油重整过程中水分的消耗与转移[J]. 化工学报, 2019, 70(12): 4795-4803.

Figures/Tables 14

References 24

1	中华人民共和国国家统计局. 中国统计年鉴2018[M]. 北京: 中国统计出版社, 2018.
	National Bureau of Statistics of People s Republic of China. China Statistical Yearbook 2018[M]. Beijing: China Statistics Press, 2018.
2	Chen D, Yin L, Wang H, et al. Reprint of: pyrolysis technologies for municipal solid waste: a review[J]. Waste Management, 2015, 37: 116-136.
3	Zhang Q, Chang J, Wang T, et al. Review of biomass pyrolysis oil properties and upgrading research [J]. Energy Conversion and Management, 2007, 48(1): 87-92.
4	Xie Y R, Shen L H, Xiao J, et al. Influences of additives on steam gasification of biomass(1): Pyrolysis procedure[J]. Energy & Fuels, 2009, 23(10): 5199-5205.
5	Azuara M, Fonts I, Bimbela F, et al. Catalytic post-treatment of the vapors from sewage sludge pyrolysis by means of γ-Al₂O₃: effect on the liquid product properties[J]. Fuel Processing Technology, 2015, 130: 252-262.
6	Huang Q, Lu P, Hu B, et al. Cracking of model tar species from the gasification of municipal solid waste using commercial and waste-derived catalysts[J]. Energy & Fuels, 2016, 30(7): 5740-5748.
7	李佳珊. 城市生活垃圾热解过程中重金属残留实验研究[D]. 沈阳: 东北大学, 2009.
	Li J S. Experimental study on heavy metal residues in pyrolysis of municipal solid waste[D]. Shenyang: Northeastern University, 2009.
8	Liu S, Yin W, Wu R, et al. Fundamentals of catalytic tar removal over in situ and ex situ chars in two-stage gasification of coal[J]. Energy & Fuels, 2014, 28(1): 58-66.
9	Min Z, Yimsiri P, Asadullah M, et al.Catalytic reforming of tar during gasification (Ⅱ): Char as a catalyst or as a catalyst support for tar reforming[J].Fuel, 2011, 90(7): 2545-2552.
10	Wang N, Chen D, Arena U, et al. Hot char-catalytic reforming of volatiles from MSW pyrolysis[J]. Applied Energy, 2017, 191: 111-124.
11	King H H, Stock L M. Aspects of the chemistry of donor solvent coal dissolution. The hydrogen-deuterium exchange reactions of tetralin-d₁₂ with Illinois No. 6 coal, coal products and related compounds[J]. Fuel, 1982, 61(3): 257-264.
12	Cronauer D C, Mcneil R I, Young D C, et al. Hydrogen/deuterium transfer in coal liquefaction[J]. Fuel, 1982, 61(7): 610-619.
13	Brandes S D, Graff R A, Gorbaty M L, et al. Modification of coal by subcritical steam: an examination of modified Illinois No. 6 coal[J]. Energy & Fuels, 1989, 3(4): 494-498.
14	Wilson M A, Vassallo A M, Collin P J, et al. Deuterium as a tracer in coal liquefaction (2): Non-catalytic studies[J]. Fuel Processing Technology, 1984, 8(3): 213-229.
15	Collin P J, Wilson M A. Use of INEPT and GASPE n.m.r. pulse sequences: assignment of position of incorporation of deuterium into tetralin during coal hydrogenation[J]. Fuel, 1983, 62(11): 1243-1246.
16	Skowronski R P, Ratto J J, Goldberg I B, et al. Hydrogen incorporation during coal liquefaction[J]. Fuel, 1984, 63 (4): 440-448.
17	Wang L, Pan T, Liu P, et al. Hydrogen transfer route during hydrothermal treatment lignite using isotope tracer method and improving pyrolysis tar yield[J]. Energy & Fuels, 2016, 30(6): 121-134.
18	连奕新, 杨意泉, 方维平. 钴钼基水煤气变换催化剂及其催化反应工艺[J].石油化工, 2011, 40(4): 347-357.
	Lian Y X, Yang Y Q, Fang W P. Cobalt-molybdenum-based water gas shift catalyst and catalytic reaction process thereof[J]. Petrochemical Industry, 2011, 40(4): 347-357.
19	Lima A A G, Nele M, Moreno E L, et al. Composition effects on the activity of Cu-ZnO-Al₂O₃ based catalysts for the water gas shift reaction: a statistical approach[J]. Applied Catalysis A General, 1998, 171(1): 31-43.
20	Klinghoffer N B, Castaldi M J, Nzihou A. Influence of char composition and inorganics on catalytic activity of char from biomass gasification[J]. Fuel, 2015, 157: 37-47.
21	Badger G M, Kimber R W L, Spotswood T M. Mode of formation of 3, 4-benzopyrene in human environment[J]. Nature, 1960, 187(4738): 663-665.
22	Nelson P F, Smith I W, Tyler R J, et al. Pyrolysis of coal at high temperatures[J]. Energy & Fuels, 1988, 2(4): 391-400.
23	Stock L M, Wasielewski M R. The trifluoromethyl group in chemistry and spectroscopy. Carbon-fluorine hyperconjugation[M]//Taft R W. Progress in Physical Organic Chemistry. John Wiley & Sons, Inc., 1981: 253-313.
24	翟建荣, 钟梅, 马凤云, 等. 水蒸气对煤焦油模化物裂解行为及析碳的影响[J]. 化工学报, 2019, 70(8): 2898-2908.
	Zhai J R, Zhong M, Ma F Y, et al. Effect of steam atmosphere on cracking behavior and carbon deposition of coal tar model compounds [J]. CIESC Journal, 2019, 70(8): 2898-2908.

Composition/%(mass)					Residue	HHV/(MJ/kg)
Kitchen wastes	Paper	Cloth and fiber	Plastics	Wood	Residue	HHV/(MJ/kg)
14.23±0.88	6.32±0.27	27.54±1.14	22.44±0.98	3.42±0.41	26.05±1.03	15.77±0.21

Composition/%(mass)					Residue	HHV/(MJ/kg)
Kitchen wastes	Paper	Cloth and fiber	Plastics	Wood	Residue	HHV/(MJ/kg)
14.23±0.88	6.32±0.27	27.54±1.14	22.44±0.98	3.42±0.41	26.05±1.03	15.77±0.21

Proximate analysis			Ultimate analysis
A	V	FC	C	H	S	N
41.74±1.01	11.05±0.77	47.21±1.23	41.39±1.12	1.19±0.12	0.71±0.09	1.07±0.11

Proximate analysis			Ultimate analysis
A	V	FC	C	H	S	N
41.74±1.01	11.05±0.77	47.21±1.23	41.39±1.12	1.19±0.12	0.71±0.09	1.07±0.11

Experiment scenario	Reactant	Temperature/℃	Liquid product	Gas product	Residue char
1	water	600	RL1	RG1	RC1
2	water	700	RL2	RG2	RC2
3	water	800	RL3	RG3	RC3
4	water +oil	600	RL4	RG4	RC4
5	water +oil	700	RL5	RG5	RC5
6	water +oil	800	RL6	RG6	RC6
7	water +oil	800	RL7	RG7	—