煤与生物质共热解的TGA-FTIR研究

利用热重分析仪和傅里叶红外光谱仪对煤与木屑混合物在惰性气氛中进行了共热解研究,考察煤阶及煤与生物质掺混比例对热解过程的影响.结果表明,煤与木屑共热解特性并不是单独煤和单独木屑热解特性的简单叠加;高阶煤与生物质共热解更有利于协同反应的发生.通过对红外吸收光谱的分析发现,木屑与不同煤化程度煤共热解析出气体的成分和含量也不同,说明煤阶对煤与生物质共热解的气态产物有明显影响,也从侧面揭示了混合物热解过程中煤与木屑之间发生了相互作用.     

生物质和煤共热解特性及催化剂对热解的影响

为研究生物质和煤程序升温共热解特性及相互作用,利用热天平和管式炉反应器对白松木屑和五彩湾烟煤的共热解特性及催化剂对生物质和煤共热解的影响进行了研究,并考察了共热解半焦的孔结构特性。结果表明：不同比例的生物质和煤在共热解过程中,两者基本保持了各自的热解特性,由于生物质和煤的主要热解阶段温度相差较大,共热解过程中没有发生明显的协同作用。生物质和煤共热解半焦产率实验值大于计算值,当生物质质量分数从75%减少至25%时,半焦产率实验值与计算值之间的差值从0.81个百分点增加到1.07个百分点。橄榄石和载镍橄榄石（NiO/olivine）的添加促进了共热解反应发生的深度。载镍橄榄石催化剂添加（原料和催化剂质量比1：1）的条件下,共热解碳转化率提高了0.5%~5.1%,随着混合物中生物质比例的增加,催化剂的催化效果更加明显。     

烟煤与生物质固定床共热解实验研究

对烟煤与木质素类生物质松木屑、纤维素类生物质秸秆在固定床反应器中共热解行为进行了系统的实验研究,并对气体产物和焦油组成进行了分析.结果表明,烟煤与两种生物质共热解时存在明显的协同作用,挥发分产率的实验值较计算值有所增加,且使用松木屑时增幅较大.松木屑与烟煤共热解时焦油中愈创木酚类含量显著提高,在400℃松木屑配比为80%时,增量高达25.89%.焦油中酚类含量比计算值高,而PAH和烃类含量则明显降低,同时焦油产生了一定的轻质化.     

生物质三组分与低密度聚乙烯共催化热解制取轻质芳烃的协同作用机理

生物质与废塑料共催化快速热解是制取轻质芳烃的重要途径。 采用不同种类的分子筛催化剂,首先研究了分子筛种类对杨木、生物质三组分和低密度聚乙烯（LDPE）单独催化快速热解轻质芳烃产率的影响,其次研究了生物质三组分与LDPE在共催化热解过程中的协同作用机理。结果表明：在杨木、生物质三组分和LDPE单独催化快速热解时,HZSM-5（25）催化剂体现出最高的轻质芳烃产率;在杨木和LDPE共催化快速热解时,随着LDPE质量的增加,轻质芳烃的产率呈先升高后降低趋势;在生物质三组分和LDPE共催化快速热解时,纤维素和半纤维素热解的呋喃类中间产物与LDPE热解的轻烯烃中间产物易发生“双烯合成”反应,表现出较强的协同催化作用,促进轻质芳烃的生成,而木质素则抑制轻质芳烃生成。     

陕北油房梁煤与生物质共热解研究

在N2气氛下,利用热重分析仪对生物质与陕北油房梁煤混合热解特性进行研究,重点考察了生物质混掺比对煤热解的影响。结果表明:相同升温速率下,生物质与煤在热解过程中表现出明显不同的热解特征;生物质与煤以不同掺混比进行共热解时,得到的共热解曲线分段呈现出生物质与煤单独热解的特性,且热解残余固体量与掺混比呈线性关系;此外,对比混合物共热解的实际特征曲线与理论计算曲线,发现实际DTG曲线也与理论计算的DTG曲线基本重合。从上述结果可预测,在热重反应器同步升温情况下,生物质与煤在共热解过程中不存在协同作用。     

NiO/HZSM-5催化松木微波热解制生物油

生物质快速热解制生物油是解决能源短缺的有效途径,通过催化剂的加入可使生物油成分定向转化为系列平台化合物,有助于其高效利用。以松木屑为原料,对其进行热重分析并研究了其热解行为。以NiO/HZSM-5为催化剂,在微波功率为800 W,热解时间为12 min条件下对松木屑快速热解,并对产物进行了计重分析和成分分析。结果表明,NiO/HZSM-5的加入能使生物油产量略有提高。对液相产物的GC-MS分析表明,所用催化剂对松木屑热解具有较好的脱氧效果,有利于平台化合物的定向转化,NiO/HZSM-5在微波加热条件下对生物油的产量及提质具有有效作用。     

生物质与废塑料催化热解制芳烃(Ⅰ):协同作用的强化

采用两段式固定床对比研究了纤维素与高密度聚乙烯（HDPE）的单独物料催化热解、混合物催化热解和分段催化热解,对热解产物分布、目标产物产率及选择性以及催化剂积炭量等参数进行考察,拟从模型化合物水平探索生物质与塑料催化热解制芳烃过程强化协同作用的可能性。结果表明,纤维素与HDPE的共催化热解（混合和分段催化热解）对芳烃的形成具有协同作用,且分段催化热解较混合催化热解表现出更显著的协同作用,可获得更高的芳烃产率及选择性,提高纤维素热解转化率并降低催化剂的积炭,其协同作用符合"双烯合成"反应理论。并结合HDPE催化热解验证实验对分段催化热解制芳烃过程协同作用的强化机理进行阐述。     

农业生物质与塑料共热解技术进展

共热解技术是将多种原料通过热化学方法转化为清洁能源的重要手段。本文综述了以农业生物质为主要原料与塑料(聚丙烯PP、高密度聚乙烯HDPE、低密度聚乙烯LDPE、聚氯乙烯PVC、聚苯乙烯PS、聚对苯二甲酸乙二醇酯PET等)共热解技术的发展现状和研究进展。分析农业生物质与塑料共热解的动力学模型以及各组分之间的协同效应,阐述农业生物质与塑料的共热解机理;总结了温度、升温速率、滞留时间、原料混配比等因素对共热解协同作用的影响规律;探究生物质与塑料共热解固、液、气三相产物特性及分布规律,总结共热解技术优势及存在问题,展望未来发展方向,可为生物质与塑料共热解制备高附加值产品提供参考,同时也为农业生物质和农膜处理问题提供新方法、新思路。     

氧含量对热解废轮胎产物影响研究

以含氧木屑为探针材料,同废轮胎以不同比例共热解以准确控制其氧含量,考察氧含量对热解废轮胎得到的气、液、固三相产物的影响及多环芳烃(PAHs)含量的影响。采用热重分析仪(TG)、元素分析仪(EA)以及气相色谱仪(GC)分别对它们热行为、热解油中氧含量及PAHs的变化规律进行了观察。TG分析表明,木屑中氧含量对废轮胎热解最大失重速率发生的温度产生了推后的影响。在木屑∶废轮胎质量为2∶1时,温度滞后3.7℃。EA分析表明,热解油中氧含量越高,氢含量较加权值越低,碳含量基本不变。GC分析表明,适量木屑所含的氧能够有效抑制PAHs的生成;对三相产物影响表明,氧含量越高,液体产率较加权值越小,气体产率较加权值越大,固体产率较加权值有所降低但与氧含量多少关联不明显。通过木屑和废轮胎共热解过程氧含量对热解产物影响的分析,为科学利用生物质、合理处置废轮胎提供科学帮助。     

塑料与煤低温共焦化的液体产物性质分析

利用GC -MS考察了不同种类塑料 (PDPE ,PP ,PPVC)单独热解及与八一焦煤低温共焦化焦油的组成。结果表明 :添加HDPE、PP使煤焦油中脂肪烃的相对收率提高 ,焦油中脂肪烃的含量明显增加和轻质化 ,可作为加氢精制汽油的原料 ;而PPVC则使脂肪烃和芳香化合物的相对收率均增加 .塑料与煤共焦化过程中同时存在物理和化学协同作用 ,减少了二次反应的机会 ,增加了焦油收率 ,同时促进了焦油中芳香化合物的甲基化 .     

Co-pyrolysis of pine cone with synthetic polymers

Biomass from pine cone (Pinus pinea L.) was co-pyrolyzed with synthetic polymers (PE, PP and PS) in order to investigate the effect of biomass and plastic nature on the product yields and quality of pyrolysis oils and chars. The pyrolysis temperature was of 500 °C and it was selected based on results from thermogravimetric analysis of the studied samples. Co-pyrolysis products namely gases, aqueous and tar fraction coming from biomass, oils from synthetic polymers and residual char were collected and analyzed. Due to the synergistic effect in the pyrolysis of the biomass/polymer mixtures, higher amounts of liquid products were obtained compared to theoretical ones. To investigate the effect of biomass content on the co-pyrolysis, the co-pyrolysis of pure cellulose as model natural polymer for biomass with polymer mixture was also carried out. In the presence of cellulose, degradation reaction leading to more gas formation and less char yield was more advanced than in the case of co-pyrolysis with pine cone. Co-pyrolysis gave polar oxygenated compounds distributed between tar and aqueous phase and hydrocarbon oils with composition depending on the type of synthetic polyolefin. Co-pyrolysis chars had higher calorific values compared to pyrolysis of biomass alone.     

条浒苔与稻壳共热解协同效应

为了进一步探究大型海藻与陆生生物质共热解的协同效应,选取条浒苔与稻壳生物质作为代表进行了单样以及不同混合比例的共热解台架试验。通过三相产物产率的计算,以及生物油产物的GC-MS、FT-IR、热值分析和对气相产物的GC分析,研究了条浒苔与稻壳共热解协同效应的影响。共热解的气相产物产率在各个混合比例下均高于理论值,说明共热解对气相产物的生成具有促进作用,同时共热解气相产物中甲烷、乙烷、乙烯、丙烷为主的小分子烃类物质产率高于理论值,生物油中以乙酸为代表的小分子产物明显增多,分析认为条浒苔灰分中Na、K等碱金属具有促进大分子产物进一步裂解的催化作用,进一步验证了条浒苔与稻壳共热解的协同效应。     

Improving hydrocarbons production via catalytic co-pyrolysis of torrefied-biomass with plastics and dual catalytic pyrolysis

To increase the low yield and selectivity of aromatic hydrocarbons during the biomass pyrolysis process, we torrefied the biomass and then co-pyrolyzing with plastics such as high-density polyethylene (HDPE), polystyrene (PS), ethylene-vinyl acetate (EVA) and polypropylene (PP) and also single and dual catalyst layouts were investigated by Py-GC/MS. The results showed that non-catalytic fast pyrolysis (CFP) of raw bagasse (RBG) generated no aromatics. After torrefaction non-CFP of torrefied bagasse (TBG) generated low aromatic yield. Indicating that torrefaction would enhance the proportion of aromatics during the pyrolysis process. The CFP of TBG_200℃ and TBG_240℃ over ZSM-5 produced the total aromatic yield of 1.96 and 1.88 times higher, respectively, compared to non-CFP of TBG. Furthermore, the addition of plastic could increase H/Ceff ratio of the mixture, consequently, increase the yield of aromatic compounds. Among the various torrefied-bagasse/plastic mixtures, the CFP of TBG/EVA (7:3 ratio) mixture generated the highest the total aromatic yield of 7.7 times more than the CFP of TBG alone. The dual catalyst layout could enhance the yield of aromatics hydrocarbons. The dual-catalytic co-pyrolysis of TBG_200℃/plastic (1:1) ratio over USY (ultra-stable Y zeolite)/ZSM-5, improved the total aromatics yield by 4.33 times more than the catalytic pyrolysis of TBG_200oC alone over ZSM-5 catalyst. The above results showed that the yield and selectivities of light aromatic hydrocarbons can be improved via catalytic co-pyrolysis and dual catalytic co-pyrolysis of torrefied-biomass with plastics.     

Pyrolysis and co-pyrolysis of Laminaria japonica and polypropylene over mesoporous Al-SBA-15 catalyst

The catalytic co-pyrolysis of a seaweed biomass, Laminaria japonica, and a typical polymer material, polypropylene, was studied for the first time. A mesoporous material Al-SBA-15 was used as a catalyst. Pyrolysis experiments were conducted using a fixed-bed reactor and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). BET surface area, N₂ adsorption-desorption isotherms, and NH₃ temperature programmed desorption were measured to examine the catalyst characteristics. When only L. japonica was pyrolyzed, catalytic reforming slightly increased the gas yield and decreased the oil yield. The H₂O content in bio-oil was increased by catalytic reforming from 42.03 to 50.32 wt% due to the dehydration reaction occurring on the acid sites inside the large pores of Al-SBA-15. Acids, oxygenates, mono-aromatics, poly aromatic hydrocarbons, and phenolics were the main components of the bio-oil obtained from the pyrolysis of L. japonica. Upon catalytic reforming over Al-SBA-15, the main oxygenate species 1,4-anhydro-d-galactitol and 1,5-anhydro-d-manitol were completely removed. When L. japonica was co-pyrolyzed with polypropylene, the H₂O content in bio-oil was decreased dramatically (8.93 wt% in the case of catalytic co-pyrolysis), contributing to the improvement of the oil quality. A huge increase in the content of gasoline-range and diesel-range hydrocarbons in bio-oil was the most remarkable change that resulted from the co-pyrolysis with polypropylene, suggesting its potential as a transport fuel. The content of mono-aromatics with high economic value was also increased significantly by catalytic co-pyrolysis.     

杉木屑真空热解制备生物油的实验研究

以杉木屑为原料,进行了真空热解制备生物油的实验研究. 考察了体系压力、热解终温、终温保持时间及升温速率等热解参数对生物油产率、生物油组分及其相对含量的影响. 结果表明,热解终温为500℃、体系压力为20 kPa、热解终温保持时间为60 min、升温速率为60℃/min的条件有利于杉木屑真空热解制备生物油的生产,其产率达67%以上. 真空热解过程中,慢速热解可得到较高的生物油产率.     

Flash co-pyrolysis of biomass with polylactic acid. Part 1: Influence on bio-oil yield and heating value

High amounts of water present in bio-oil are one of the major drawbacks for its utilisation as a fuel. One technology that shows the potential to satisfy the demand for bio-oil with a reduced water content is the flash co-pyrolysis of biomass with polylactic acid, PLA. The influence of PLA on the pyrolysis of willow is investigated with a semi-continuous home-built pyrolysis reactor. Flash co-pyrolysis of willow/PLA blends (10:1, 3:1, 1:1 and 1:2) show synergetic interaction. A higher bio-oil yield and a lower water content as a function of the willow/PLA ratios are obtained. Among the tested blends, the 1:2 willow/PLA blend shows the most pronounced synergy: a reduction in the production of pyrolytic water of almost 28%, accompanied by an increase of more than 37% in the production of water-free bio-oil. Additionally, PLA shows to have a positive influence on the energetic value of the bio-oil produced and on the resulting energy recuperation.     

Thermogravimetric characteristics and kinetic study of biomass co-pyrolysis with plastics

The pyrolysis of pure biomass, high density polyethylene (HDPE), polypropylene (PP) and polyethylene terephthalate (PET), plastic mixtures [HDPE+PP+PET (1: 1: 1)], and biomass/plastic mixture (9: 1, 3: 1, 1: 1, 1: 3 and 1: 9) were investigated by using a thermogravimetric analyzer under a heating rate at 10 °C/min from room temperature to 800 °C. Paper was selected as the biomass sample. Results obtained from this comprehensive investigation indicated that biomass was decomposed mainly in the temperature range of 290–420 °C, whereas thermal degradation temperature of plastic mixture is 390–550 °C. The percentage weight loss difference (W) between experimental and theoretical ones was calculated, which reached a significantly high value of (−)15 to (−)50% at around 450 °C in various blend materials. These thermogravimetric results indicate the presence of significant interaction and synergistic effect between biomass and plastic mixtures during their co-pyrolysis at the high temperature region. With increase in the amount of plastic mixture in blend material, the char production has diminished at final pyrolysis temperature range. Additionally, a kinetic analysis was performed to fit with TGA data, the entire pyrolysis processes being considered as one or two consecutive first order reactions.     

纤维素与木质素共热解试验及动力学分析

采用热重分析仪（TGA）对木质素与纤维素单独热解和共热解基本特性及热解动力学进行了研究。热重分析曲线表明,木质素热解过程是由两个位于不同温度段的热解过程组成,纤维素则仅在300～380 ℃的温区内迅速热解,在纤维素含量较低（≤40%）共热解时,二者表现为相互抑制作用,但随着纤维素含量增大,二者关系转变为相互促进作用。热解动力学研究表明,纤维素与木质素单独热解和共热解过程都可用一级反应动力学模型来描述,且随着纤维素含量增加,反应活化能（E）也随之增加,但其值总小于活化能线性加和值（Ec）,据此可推测共热解过程存在着一定的协同作用。     

低阶煤与玉米芯低温共热解的产物特性分析

采用低温干馏装置对不同玉米芯加入量的褐煤/玉米芯混合物进行低温共热解实验。结果表明：当玉米芯加入量为30%时,焦油产率最大为11.70%,比褐煤单独热解提高了53.75%。随着玉米芯的加入量增加,热解气中CO、CH₄和H₂含量逐渐增大。对热解焦油进行GC-MS检测,发现添加30%玉米芯后脂肪族质量分数从褐煤单独热解的24%提高到了30.67%,酚类质量分数从6.29%提高到了18.49%,杂原子质量分数从29.75%降低到了13.33%,一定程度上实现了焦油的轻质化和高品质化。对热解半焦进行SEM、比表面积分析和热值测定,发现共热解半焦表面变粗糙,孔隙结构得到改善,热值明显高于褐煤单独热解半焦热值。