共查询到18条相似文献,搜索用时 78 毫秒
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利用热重红外联动技术(TG-DTG-FTIR)研究了橡胶籽油中的单不饱和游离脂肪酸油酸组分在不同升温速率(5℃/min、10℃/min、20℃/min、30℃/min)下的热解特性。然后,用多元线性回归法对油酸非等温热解所得到的特性参数进行研究并计算,求得不同升温速率下对应的反应级数、活化能和指前因子,并对不同升温速率下油酸热解反应活化能和指数前因子作线性拟合。结果表明:油酸热解过程主要可分为0~268℃和268~300℃两个阶段,由红外谱图特征峰的分析可知,不同升温速率下,在油酸热解的阶段内均出现了水蒸气、CH4、CO2和CO这4种主要气体挥发分。随着升温速率的增大,油酸热解的最大失重速率随之增大,热解区间也向着高温段移动,同时计算在升温速率从5~30℃/min的过程中,反应级数n=1时,热解反应活化能由105.57kJ/mol降低至93.99kJ/mol,指数前因子由6.99×106降低至6.7×105;n≠1时,热解反应活化能由102.45kJ/mol降低至93.38kJ/mol,指数前因子由3.13×106降低至2.97×104,反应活化能和指数前因子随升温速率的增大出现明显减小。通过对不同升温速率下油酸热解反应的活化能和指数前因子进行线性拟合后发现,两者间具有较好的补偿效应。 相似文献
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利用热重红外分析仪(TG-FTIR)研究了两种不同垃圾衍生燃料(RDF)的热解特性。研究发现,尽管两种RDF的来源不同,但却具有相似的热解特性,其热解过程主要分为3个阶段:生物质组分(220~430℃)、塑料类物质(430~520℃)以及无机碳酸盐(>650℃)的分解。利用Coats-Redfern法,求得了RDF热解前两个阶段的表观动力学参数,计算结果表明高温段的反应活化能要高于低温段。通过FTIR对RDF热解析出的气体进行了在线分析,发现两种RDF热解过程中的气相产物析出规律基本一致,析出的气体主要包括H2O、CO2、CO以及CH4等烃类。HCl在低温阶段(230~400℃)即析出完毕。相比之下,NH3开始析出的温度较高(260℃),并且整个析出温度范围较广,高温下仍有少量析出。SO2在热解条件下仍有相当量的生成,其析出主要集中在300~600℃的温度范围内。 相似文献
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热解温度对生物质和煤成焦特性的影响 总被引:1,自引:0,他引:1
以麦秆、橡树木屑和华亭烟煤为原料,研究热解产物的理化特性并讨论燃料种类和热解温度对其的影响.采用BET、SEM-EDS、XRD和TGA对其进行分析表征.结果表明:在600~1 000 ℃的温度范围内,煤焦的比表面积和孔隙容积随热解温度增加而增大,而木屑焦的变化不明显,麦秆焦在800 ℃时比表面积和孔隙容积最大,更高温度则发生烧结;焦样中C元素含量随热解温度升高而增加,而H元素和O元素随之降低,麦秆焦的着火特性优于木屑焦和煤焦.木屑焦和煤焦的着火特性随热解温度升高而变差,而麦秆焦在800 ℃具有最佳的着火特性. 相似文献
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人类在面临能源短缺问题的同时面临着能源开发所引起的环境问题。而生物质作为一种具有强大的清洁性,可再生性的优势,得到了许多国内外研究者的重视。其中:利用气化、热解、和直接液化将生物质能转变为能源较为普遍。本实验通过TG-MS/FTIR和PY-GC/MS对催化共热解(CCP)中玉米秸秆衍生含氧化合物与HDPE衍生烯烃的相互反应和芳烃形成的影响机制进行研究,研究发现:玉米秸秆与HDPE在HZSM-5上的催化共热解,明显改善了产物分布:加入Cu改性的HZSM-5催化剂后,烷烃、烯烃的产率下降,芳香烃的产率提高,说明Cu改性过的催化剂使烷烃进一步向芳香烃和轻质芳烃转化。 相似文献
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矿物质对生物质热解的影响及其解决方案 总被引:5,自引:0,他引:5
通过对一年生和多年生的生物质及其热解油组成的分析,探讨了影响生物质热解油组成及其酸度的重要因素是生物质中的金属盐矿物质,金属盐舍量增加,致使热解油收率降低、酸含量增加。对现有的生物质热解工艺进行了比较和评述,提出了消除金属矿物质影响和含酸少的新型生物质热解工艺。 相似文献
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利用热重-红外分析仪(TG-FTIR)研究了手机SIM卡在不同升温速率下的热解行为,探讨了升温速率对热解参数及热解产物的影响。采用分布式活化能模型求解了热解活化能,探讨了活化能随转化率的变化规律。研究结果表明:手机SIM卡呈现一段热解,主要热解温区在350~500 ℃,最大失重速率为?62.57%/min,总失重率高达90%。随着升温速率的提高,热解初始温度和热解结束温度均增大,最大热解速率和对应的温度也都增大;热解活化能在170~204 kJ/mol变化,随转化率变化规律呈现先增大后减小再增大后逐渐减小的规律,在转化率0.2时达到最大值;主要热解产物为苯、烷烯烃等可燃成分,而且含有氯、氮等元素;升温速率对热解组分没有影响。 相似文献
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TG-FTIR联用研究半纤维素的热裂解特性 总被引:7,自引:0,他引:7
利用FT-IR、离子色谱、1H-NMR及13C NMR等手段对蔗渣半纤维素的化学结构进行了表征,并利用热重-傅里叶红外光谱(TG-FTIR)联用技术对蔗渣半纤维素在不同的升温速率下的热失重行为进行了研究。结果表明,蔗渣半纤维素主要由大量的阿拉伯糖木聚糖组成,此外还含有葡萄糖、半乳糖及葡萄糖醛酸和半乳糖醛酸,具有草类原料中典型的半纤维素结构。蔗渣半纤维素的主要热失重区间为200~315 ℃,并在230 ℃左右出现一个肩状峰,在700 ℃时焦炭残留物比例较高,约在20%。采用一级四段模型对半纤维素的热裂解过程进行了模拟,得到各段的活化能分别为118 kJ/mol、50 kJ/mol、144 kJ/mol和34 kJ/mol。蔗渣半纤维素热解气体析出过程复杂,初期先析出游离水,随后发生解聚和脱水反应,主要的苷键和碳碳键断开形成各种烃类、醇类、醛类和酸类等物质,这些大分子物质又裂解为CO2、CO等小分子气体。在线红外分析结果表明,蔗渣半纤维素热解气态产物主要有H2O、CO2、CO和CH4和其它产物。 相似文献
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采用热重-傅里叶红外光谱(TG-FTIR)联用的分析方法对造纸黑液碱木质素的热解失重特性和产物生成特性进行了研究。结果表明:碱木质素热解失重过程可分为3个阶段,其中200~500℃是碱木质素主要的热解挥发阶段,反应符合一级反应动力学模型,利用Coats-Redfern动力学模型计算得出不同升温速率下热解主反应的表观活化能为39.3~43.1 kJ/mol。FTIR的实时分析结果表明:碱木质素热解的气态产物主要有H2O、CO2、CO、CH4、甲醇、酚类和N2O;产物中的CH4、甲醇、酚类和N2O主要在300~500℃区间内释放,随着热解温度的升高,这些气态产物在420℃附近集中释放,且产量达到最大。 相似文献
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Co-firing of secondary biomass fuels with coal in coal-fired pulverized fuel boilers is facing increased application in large-scale power production. Fundamental knowledge on the thermochemical behavior of biomass and waste fuels is still lacking, especially regarding the release of the fuel bound nitrogen. Characterization of chicken litter (CL), biomass mix (BM) and meat and bone meal (MBM) and an HV coal blend was performed using TG-FTIR analysis. Three heating rate profiles were applied (10, 30 and 100 °C/min), with a final temperature of 900 °C. NH3 was found to be the major gaseous N-product, while HCN and HNCO were also released in substantial amounts. Kinetic parameters for the pyrolysis of biomass fuels were obtained using a model based on parallel first-order reactions with a Gaussian distribution of activation energies. Input files for the coal FG-DVC (functional group-devolatilization, vaporization, cross-linking) and FG-BioMass pyrolysis models were prepared. The fit of model parameters to TG-FTIR product-evolution data was found to be generally good, but the model-predicted yields for some species did not fit experimental data at all heating rates equally well. This problem can be overcome by improvements in the FG-BioMass model. The results of this study can be used to have an improved input of initial pyrolysis in CFD modeling of co-fired boilers. 相似文献
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The combustion mechanism of asphalt binder was investigated by using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer (TG-FTIR) in a mixed gas environment of 21% oxygen and 79% nitrogen. The results show that the combustion process of asphalt binder consists of three main consecutive stages at a low heating rate. The combustion reaction becomes more and more intense from the 1st to 3rd stage. The release of volatiles occurs mainly at 300-570 °C, and the gaseous products in each stage are different. The main products in the 1st stage are CO2, CO, H2O, hydrocarbons, formaldehyde, tetrahydrofuran, formic acid, aromatic compounds, etc. In the next stage, the combustion products mentioned above keep on increasing, but some new volatiles such as alcohols, phenols, styrene, etc. are present. In the last stage, the CH and CO bonds continue to fracture and aromatization reaction occurs, and the release amount of CO2, CO, and H2O reaches the maximum. But the content of other products decreases or even disappears due to burning. Among the above volatiles, CO2 is the dominant gaseous product in the whole combustion process. The concentration of CO2 and CO keeps increasing, and reaches the maximum intensity at about 520 °C. The evolution of H2O, CH4, and formic acid exhibits the trend of increase first, and then decrease. Over 570 °C, there are few products released at the end of the combustion process. Asphalt binder combustion process includes two modes of complete and incomplete combustion, and the latter may be main combustion mode of asphalt binder. 相似文献
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Heating value of biomass and biomass pyrolysis products 总被引:3,自引:0,他引:3
Studies conducted on the heating value of various types of biomass components and their pyrolysis products such as char, liquids and gases are presented. Heating values of chars are comparable with those of lignite and coke; heating values of liquids are comparable with those of oxygenated fuels such as methanol and ethanol, which are much lower than those of petroleum fuels. Heating values of gases are comparable with those of producer gas or coal gas and are much lower than that of natural gas. It is also found that the heating values of products are functions of the initial composition of biomass; correlations are developed to express these. Also, correlations are developed which explain the influence of ash elements on heating values of the pyrolysis products and on percentage distribution of energy in the products. 相似文献
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本文综述了生物质热裂解的动力学模型现状,比较了生物质及其主要组分的裂解动力学.从中得出多组分和双组分动力学模型对开发生物质高效燃油和气化技术有着重要的工程实用价值. 相似文献