生物质组分对生物油中酚类产物的调控规律研究

发布时间：2018-04-21 11:04

本文选题：酚类化合物 + 木质素　；参考：《山东理工大学》2017年硕士论文

【摘要】：生物质主要由纤维素、半纤维素、木质素和碱类金属等构成,其快速热解产物包含热解气、生物油和焦炭。生物油富含上百种有机化合物,其中的酚类可用作酚醛树脂胶黏剂、消毒剂、显影剂等,是一种高附加值的化工产品。木质素热解产物是生物油中酚类化合物的主要来源。本文以酚类为目标产物,以木质素产酚特性为研究对象,以微晶纤维素、木聚糖、碱性木素、玉米秸秆、氯化钾和氯化钙为实验原料,按质量将纤维素-木质素和木聚糖-木质素进行配比(3:1、2:1、1:1),利用盐酸脱除玉米秸秆中的碱类金属,将木质素分别与不同质量分数(0.2、2、20wt%)的氯化钾和氯化钙自然混合后,在固定床管式炉内进行快速热解实验,反应温度为450、500、550和600°C,探究生物质主要组分对木质素热解产物分布及生物油中酚类产物变化规律的影响,为生物油向高品位化学品的转化利用提供有价值的基础数据。研究结果表明:随着温度的升高,纤维素和木质素、木聚糖和木质素混合热解的生物油产率先增加后减少,且均在500°C获得最高产油率。纤维素与木质素共热解时存在交互作用,对热解产生气体的产生有促进作用,对生物油和焦炭的产生有抑制作用,并且随着纤维素含量的增加,对产物的影响增强。随着木聚糖含量的增加,木聚糖与木质素共热解时对生物油的抑制作用增强,同时,木聚糖和木质素共热解抑制了焦炭的产生,促进了气体的产生。利用数理统计总体评估法、权重计算法以及峰面积比值法,研究纤维素和木聚糖分别对木质素热解产酚特性的影响。研究表明:随着温度的升高,纤维素和木聚糖分别对木质素热解产酚的影响增强。随着纤维素或木聚糖含量的增加,对木质素热解产酚的影响减弱。对于羟基苯酚类、愈创木酚类和紫丁香酚类,纤维素促进了三种酚类的生成,木聚糖抑制了愈创木酚类和紫丁香酚类的产生,促进了羟基苯酚类的产生。随着纤维素和木聚糖含量的增加,对三种酚类的作用增强。对玉米秸秆进行酸洗预处理实验结果表明:酸处理抑制了玉米秸秆热解产生焦炭和气体产物,促进了生物油的产生。对比处理前后酚类产物的含量,碱类金属促进了酚类的产生,对羟基苯酚类和愈创木酚类的影响较明显。利用氯化钾和氯化钙分别对木质素混合热解,探究两种金属盐对木质素热解特性及其产酚规律的影响:氯化钾和氯化钙均促进了木质素热解产生焦炭,抑制其产生生物油,且氯化钾的作用要强于氯化钙。氯化钾促进了愈创木酚类的生成,且随着氯化钾和氯化钙质量分数的增加,二者对羟基苯酚类的促进作用均增强。
[Abstract]:Biomass is mainly composed of cellulose, hemicellulose, lignin and alkali metal. Its rapid pyrolysis products include pyrolysis gas, bio-oil and coke. Biological oil is rich in hundreds of organic compounds, and phenols can be used as phenolic resin adhesives, disinfectants, developer and so on. Lignin pyrolysis products are the main sources of phenolic compounds in bio-oil. In this paper, phenols were taken as target products, lignin phenol-producing characteristics were studied, and microcrystalline cellulose, xylan, alkaline lignin, corn straw, potassium chloride and calcium chloride were used as experimental materials. Cellulose lignin and xylan lignin were mixed with potassium chloride and calcium chloride by using hydrochloric acid to remove alkali metal from corn straw. A rapid pyrolysis experiment was carried out in a fixed bed tube furnace at the reaction temperatures of 450500550 掳C and 600 掳C. the effects of the main components of biomass on the distribution of lignin pyrolysis products and the variation of phenolic products in bio-oil were investigated. To provide valuable basic data for the conversion of bio-oil to high grade chemicals. The results showed that with the increase of temperature, the bio-oil yield of cellulose, lignin, xylan and lignin mixed pyrolysis increased first and then decreased, and the highest oil yield was obtained at 500 掳C. There is interaction between cellulose and lignin in co-pyrolysis, which can promote the production of gas, inhibit the production of bio-oil and coke, and increase with the increase of cellulose content. With the increase of xylan content, the inhibition of bio-oil was enhanced by co-pyrolysis of xylan and lignin. At the same time, the co-pyrolysis of xylan and lignin inhibited the production of coke and promoted the production of gas. The effects of cellulose and xylan on the phenol-producing properties of lignin pyrolysis were studied by means of mathematical statistical total evaluation method, weight calculation method and peak area ratio method. The results showed that the effects of cellulose and xylan on the pyrolysis of lignin increased with the increase of temperature. With the increase of cellulose or xylan content, the effect of lignin pyrolysis on phenol production weakened. For hydroxybenzophenols, guaiacol and eugenol, cellulose promoted the formation of three phenols, xylan inhibited the production of guaiacol and eugenol, and promoted the production of hydroxybenzophenols. The effect of cellulose and xylan on the three phenols was enhanced with the increase of cellulose and xylan content. The results showed that acid treatment inhibited the pyrolysis of corn straw to produce coke and gas products and promoted the production of bio-oil. Compared with the content of phenolic products before and after treatment, alkali metals promoted the production of phenols, and the effects of phenols on phenols and guaiacol were more obvious. The mixed pyrolysis of lignin by potassium chloride and calcium chloride was used to investigate the effects of two kinds of metal salts on the pyrolysis characteristics of lignin and the law of phenol production: both potassium chloride and calcium chloride promoted the pyrolysis of lignin to produce coke and inhibited the production of bio-oil. The effect of potassium chloride is stronger than that of calcium chloride. Potassium chloride promoted the formation of guaiacol, and with the increase of the mass fraction of potassium chloride and calcium chloride, both of them enhanced the promotion of hydroxybenzophenols.
【学位授予单位】：山东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ07;S216

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