垃圾热解-挥发分重整过程中基于产物导向的催化剂选择

doi:10.11949/0438-1157.20190325

摘要/Abstract

摘要：

为进一步提升垃圾热解产物品质，提高目标产物的产量，在垃圾热解反应器下游设置自源半焦重整挥发分的反应器，并在自源半焦中混入白云石(D)和活性污泥炭(ASSC)以提升催化效果，获得更多的气体资源以及高品质的油。结果表明，550℃下垃圾热解产生的挥发分经同温自源半焦重整，气体产率可提高44.29%，热解液产率降低了41.33%；但热解油中的脂肪烃含量下降，单环芳烃含量增加。添加煅烧白云石后，热解油转化率提高，热解油中的脂肪烃含量增加。添加ASSC后，H₂、CO产率显著提高；热解液产率进一步降低。特别是与自源半焦按照等质量与ASSC混合时，热解液产率最低，自30.44%降至11.25%，同时其含水率自57.23%降至35.64%。总体上，垃圾热解自源半焦具有促进热解油中单环芳烃生成和脂肪分解的作用；而白云石和ASSC都能促使热解油中脂肪烃的浓度提升，尤其是ASSC。白云石对应着气体产物中更高的CH₄、H₂和CO的产率，而ASSC进一步促进了H₂和CO的生成、H₂O的消耗但同时抑制了CH₄的生成。当以合成气为目标产品时，推荐加入ASSC并与自源半焦按质量比1∶1混合，其产气量达到45.5%或0.50 m³/(kg MSW)，H₂+CO体积分数达到53.87%。

关键词: 垃圾热解, 半焦, 挥发分重整, 催化剂, 合成气, 热解油

Abstract:

To further improve the quality of the waste pyrolysis products and increase the yield of the target product, a reactor from the source semi-coke reforming volatiles is disposed downstream of the waste pyrolysis reactor, and dolomite (D) and activity are mixed in the self-source semi-coke. Dolomite (D) and activated sewage sludge char (ASSC) were added into the char to improve the catalytic effect and to obtain higher gas yield and oil of better quality. The research results showed that, when the volatiles generated from MSW pyrolysis (550℃) were isothermally reformed by the MSW char from the same pyrolysis process the gas yield increased by 44.29% and the pyrolytic liquid yield decreased by 41.33%. In this process the aliphatics in pyrolytic liquid decreased, while monoaromatics increased. As dolomite was added as a catalyst modifier, the pyrolytic oil and its oxygenates content were further reduced. When ASSC was used as catalyst modifier, it enhanced the conversion of the pyrolytic liquid into gas. Especially for the scenario of Char∶ASSC=1∶1 by mass ratio, the pyrolytic liquid yield decreased from 30.44% to 11.25%, and its moisture content was reduced to 35.64% from 57.23%. In general, the char from MSW pyrolysis had the effect of promoting the formation of monoaromatics and decomposition of aliphatics in liquid products, while both dolomites and ASSC, especially the later, increased the aliphatics concentration in the pyrolytic liquid. The addition of dolomite promoted the yields of CH₄, H₂ and CO in the gas product, while the addition of ASSC greatly facilitated the production of H₂ and CO based on the higher level consumption of H₂O vapor in the volatiles, but inhibited the production of CH₄. When syngas is the target product, char and ASSC mixture can be recommended with the blending ratio of char∶ASSC=1∶1, for which the gas yield reaches 45.5% or 0.50 m³/(kg MSW), and the volume percentage of the syngas (H₂+CO) achieves 53.87%.

Key words: MSW pyrolysis, char, volatile reforming, catalyst, syngas, pyrolytic oil

中图分类号:

X 705

梅振飞, 陈明, 陈德珍, 洪鎏, 胡雨燕. 垃圾热解-挥发分重整过程中基于产物导向的催化剂选择[J]. 化工学报, 2019, 70(8): 3104-3112.

Zhenfei MEI, Ming CHEN, Dezhen CHEN, Liu HONG, Yuyan HU. Product oriented catalyst choice during MSW pyrolysis and volatile reforming process[J]. CIESC Journal, 2019, 70(8): 3104-3112.

图/表 11

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Composition/%(mass)							HHV/(MJ/kg)
Kitchen wastes	Paper	Cloth and fiber		Plastics	Wood	Residue	HHV/(MJ/kg)
15.38±0.80	5.79±0.16	27.24±0.69		21.85±9.57	3.24±0.40	26.47±0.98	17.44±0.18
Ultimate analysis^①/%(mass)					Proximate analysis/%(mass)
C	H	N	O^②	S	M	A	V	FC
43.17 ±1.78	6.03 ±0.47	2.52 ±0.17	48.06 ±0.68	0.22 ±0.01	6.52 ±0.28	26.02 ±0.88	60.65 ±1.11	6.81 ±0.04

Composition/%(mass)							HHV/(MJ/kg)
Kitchen wastes	Paper	Cloth and fiber		Plastics	Wood	Residue	HHV/(MJ/kg)
15.38±0.80	5.79±0.16	27.24±0.69		21.85±9.57	3.24±0.40	26.47±0.98	17.44±0.18
Ultimate analysis^①/%(mass)					Proximate analysis/%(mass)
C	H	N	O^②	S	M	A	V	FC
43.17 ±1.78	6.03 ±0.47	2.52 ±0.17	48.06 ±0.68	0.22 ±0.01	6.52 ±0.28	26.02 ±0.88	60.65 ±1.11	6.81 ±0.04

Catalyst	CaO	SiO₂	Fe₂O₃	K₂O	Al₂O₃	P₂O₅	MgO	Na₂O	TiO₂
MSW char	26.80	14.70	10.10	4.49	3.92	3.77	1.78	1.47	0.77
dolomite	53.20	0.47	0.36	0.02	0.08	—	36.97	—	—
ASSC	3.93	13.5	11.5	44.1	5.38	6.85	0.76	0.64	0.75

Catalyst	CaO	SiO₂	Fe₂O₃	K₂O	Al₂O₃	P₂O₅	MgO	Na₂O	TiO₂
MSW char	26.80	14.70	10.10	4.49	3.92	3.77	1.78	1.47	0.77
dolomite	53.20	0.47	0.36	0.02	0.08	—	36.97	—	—
ASSC	3.93	13.5	11.5	44.1	5.38	6.85	0.76	0.64	0.75

Reaction	ΔH _298K	Number
C+H₂O?CO+H₂	+131 MJ/kmol	R1
CO+H₂O?CO₂+H₂	-41 MJ/kmol	R2
C _n H _m +pH₂O?C _n _- _p H _y +pCO+(p+(m-y)/2)H₂	>0	R3
C+CO₂ ?2CO	+172 MJ/kmol	R4
C _n H _m +nCO₂ ?2nCO+(m/2)H₂	>0	R5
CO+3H₂ ?CH₄+H₂O	-227 MJ/kmol	R6
C _n H₂ _n ₊₂ ? nC+(n+1)H₂	>0	R7
CaO+H₂O?Ca(OH)₂	-65 MJ/kmol	R8
Ca(OH)₂+CO₂ ?CaCO₃+H₂O	-113 MJ/kmol	R9