碱／碱土金属催化松木屑快速热解机制

doi:10.19894/j.issn.1000-0518.210037

摘要/Abstract

摘要：

研究碱／碱土金属（AAEM）对生物质的热解及其热解产物组成的影响规律，可为生物质热解特性研究和热解产物的高效利用提供重要的理论依据。本文以松木屑为原料，将原样进行酸洗，并对酸洗样分别用K、Ca、Na和Mg氯化盐溶液浸渍，在500℃和Ar气氛下对各样品进行快速热解，考察了4种金属离子对松木屑热解产物组成分布的影响规律；通过热重分析考察了各个样品的热解特性；通过对热解生物油的气相色谱／质谱（GC／MS）分析考察了快速热解的焦油成分。研究结果表明：AAEM对松木屑有明显的催化作用，AAEM的存在能够提高热解气体和固体的产率，降低热解焦油的产率；AAEM能够降低热解温度，使热解更加容易进行；快速热解的焦油成分主要有酚类、酮类、醛类、芳烃、醇类、脱水糖类、呋喃类以及酸类，AAEM显著影响焦油产物组成，特别是呋喃类和芳烃的含量会有所增加。本文为优化生物质的热解条件与提高热解生物油品质具有重要意义。

关键词: 松木屑, 快速热解, 碱／碱土金属, 生物油

Abstract:

The effect of alkali/alkaline earth metals (AAEM) on biomass pyrolysis and the composition of pyrolysis products can provide important theoretical basis for the study of biomass pyrolysis characteristics and the efficient utilization of pyrolysis products. In this paper, pine sawdust was used as pyrolysis raw materials, and the acid washed sample was soaked with potassium, calcium, sodium and magnesium chloride solution, respectively. The samples were rapidly pyrolyzed at 500℃under Ar atmosphere. The influence of four metal ions on the composition and distribution of pine sawdust pyrolysis products was investigated. The pyrolysis characteristics of each sample were investigated by thermo-gravimetric analysis. The tar components of the fast pyrolysis were investigated by gas chromatography/mass spectrometry (GC/MS). The results show that: AAEM has obvious catalytic effect on pine sawdust, the existence of AAEM ions can improve the yield of pyrolysis gas and solid, reduce the yield of tar; AAEM can reduce the pyrolysis temperature and make the pyrolysis easier; the tar components of fast pyrolysis mainly include phenols, ketones, aldehydes, aromatics, alcohols, dehydrated sugars, furans, acids and AAEM will cause changes in the relative contents of these substances, especially furans and aromatics. These experimental results provide an important reference for optimizing the pyrolysis conditions of biomass and improving the quality of pyrolysis bio-oil.

Key words: Pine sawdust, Fast pyrolysis, Alkali/alkaline earth metal, Bio-oil

中图分类号:

O614

王锐, 高明洋, 曹景沛. 碱／碱土金属催化松木屑快速热解机制[J]. 应用化学, 2022, 39(02): 289-297.

Rui WANG, Ming-Yang GAO, Jing-Pei CAO. Effects of Alkali/Alkaline Earth Metals on Fast Pyrolysis of Pine Sawdust[J]. Chinese Journal of Applied Chemistry, 2022, 39(02): 289-297.

图/表 10

表1 松木屑的工业分析和元素分析

Table 1 Proximate and ultimate analysis of pine sawdust

序号	?	项目	质量分数
No.	?	Item	w／%
1	工业分析Industry analysis	Mar（收到基水分Moisture on as received basis）	10.88
?	?	Ad（干燥基灰分Ash on dry basis）	0.68
?	?	Vd（干燥基挥发分Volatile matter on dry basis）	86.46
?	?	FCd（干燥基固定碳Fixed carbon on dry basis）	12.86
2	元素分析Elemental analysis ^a	C	46.33
?	?	H	7.88
?	?	N	0.56
?	?	S	0.05
?	?	O ^b	45.18

图1 热解实验装置图

Fig.1 Pyrolysis experimental device

图2 松木屑酸洗前后TG（A）和DTG（B）曲线

Fig.2 TG（A）and DTG（B）curves of pine sawdust before and after pickling

图3 氯化钾负载样的TG（A）和DTG（B）曲线

Fig.3 TG（A）and DTG（B）curves of KCl loaded sample

图4 氯化钠负载样的TG（A）和DTG（B）曲线

Fig.4 TG（A）and DTG（B）curves of NaCl loaded sample

图5 氯化钙负载样的TG（A）和DTG（B）曲线

Fig.5 TG（A）and DTG（B）curves of CaCl loaded sample

图6 氯化镁负载样的TG（A）和DTG（B）曲线

Fig.6 TG（A）and DTG（B）curves of MgCl loaded sample

图7 不同样品500℃下热解产物分布图（A）和气体组成（B）

Fig.7 Distribution of pyrolysis products（A）and gas composition（B）of different samples at 500℃

图8 松木屑原样（A）和焦油（B）红外光谱图

Fig.8 Infrared spectra of pine sawdust（A）and tar（B）

图9 不同样品热解生物油的GC／MS分析

Fig.9 GC／MS analysis of pyrolysis bio oil from different samples

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