Study on the Drying, Pyrolysis and Combustion Process of Tobacco and Numerical Simulation of a Burning Cigarette

吸烟与健康是烟草行业在前进过程中面临的主要挑战之一，系统而深入地研究烟草干燥工艺与热解燃烧特性，探究烟气中有害成份的形成过程以及各种变量对烟气组份分布的影响，并建立卷烟燃烧数学模型。通过模型模拟各变量对卷烟燃烧内部温度场分布、浓度场分布和卷烟烟气中主要有害成分释放量的影响。以卷烟减害为目的，根据卷烟燃烧模型反馈的信息，为烟草的干燥工艺、低危害卷烟的配方设计以及卷烟辅材料开发设计提供科学依据，这也是烟草行业从经验研究上升到理论研究的必然趋势。 本项目主要包括三方面的内容：烟草干燥工艺优化、烟草热解燃烧特性研究，以及卷烟燃烧数学模型的建立。具体研究内容如下： （1） 在实验室水平建立烟草烘箱干...The relationship between smoking and healthy continues to pose a great challenge to tobacco industry. Studying on the tobacco drying process, pyrolysis and combustion reaction, and harmful constituents forming mechanism is very important for tobacco industry development. Setting up a cigarette burning model to simulate the temperature distribution, concentration distribution and the yield of harmf...学位：博士后院系专业：化学化工学院_化学工程学号：201117002

Effects of heating rate on fast pyrolysis of cut filler of cigarette

为考察升温速率对卷烟烟丝快速热解行为的影响,采用热重-质谱联用技术对卷烟烟丝在不同升温速率(200 K·min~(-1)~800 K·min~(-1))下的热解特性进行研究,并建立了不同升温速率下卷烟烟丝的快速热解动力学模型。结果表明:(1)随着升温速率的升高,烟丝各主要成分热分解温度区间的叠加程度、热解速率以及释放特性指数均呈递增趋势,且有不同程度的热滞后现象。(2)引入升温速率校正因子的动力学模型能够克服热滞后所引起的动力学参数偏差,可以更好地预测不同升温速率下卷烟烟丝的快速热解行为。(3)高升温速率下,热解烟气产物中质荷比(m/z)为56(丙烯醛)、79(吡啶)、84(烟碱)、94(苯酚)和117(吲哚)的化合物释放量减小。在高升温速率下卷烟烟丝的快速热解特性与卷烟燃烧的真实状态更为接近,建立的卷烟燃烧数学模型更加准确。In order to study the effects of heating rate on fast pyrolysis of cut filler of cigarette, TGA(Thermogravimetric Analyzer) combined with QMS(Quadrupole Mass Spectrometers) was applied to investigate the pyrolysis characteristics of cut filler of cigarette at different heating rates(200 K·min~(-1)-800 K·min~(-1)), and a kinetic model for the fast pyrolysis of cut filler at different heating rates was developed. The results showed that: 1) With the increase of heating rates, thermal decomposition overlap region, mass loss rate and devolatilization index of each main component in tobacco were raised. Meanwhile, thermal lags of different extents were also observed. 2) The kinetic model overcame the deviation of kinetic parameters caused by thermal lag via introducing a heating rate correction factor, and predicted the fast pyrolysis behaviors of cut filler at different heating rates more accurately. 3) The release of pyrolysis products, such as acrolein(m/z=56),pyridine(m/z=79), nicotine(m/z=84), phenol(m/z=94) and indole(m/z=117) decreased with the increase of heating rate. The fast pyrolysis characteristics of cut filler are closer to the real state of cigarette combustion and the developed mathematical model for tobacco pyrolysis kinetics is more accurate at high heating rate.福建省中烟工业有限责任公司科技创新项目“卷烟燃烧数学模型的建立及其在卷烟减害中的应用”(FJZYJH2013025

Comparison between REA model and thin layer drying model based on strip drying kinetics

为了获得最适用于烟草干燥的动力学模型,达到设计、优化和控制烟草干燥过程的目的,采用湿度发生器联用热重技术(TGA)研究了65 ℃ &RH; 15%, 75 ℃ & RH 10%和85℃& RH 5%条件下片烟的干燥动力学行为,并利用REA (Reaction engineering; approach)以及8种经验或半经验的薄层干燥模型分别对不同温湿度条件下的片烟干燥行为进行模拟。结果表明:①干燥温度越高,相对湿度越小时,片烟; 的干燥速率越快,平衡含水率越低;②REA模型预测的片烟干燥动力学曲线与实验曲线能够很好地吻合,尤其是在含水率由20%降至12%阶段;8种薄层干燥; 模型中Two; term模型拟合出的R~2值最大,均方根误差(RMSE)最小,是描述片烟干燥行为较合适的模型;③薄层干燥模型仅仅是获得特定温湿度条件下相对应的动; 力学参数,而REA模型是将温度和湿度作为变量引入模型中,模型中的动力学参数可以描述任意温湿度条件下的片烟干燥动力学行为;④REA模型构造简单,预; 测准确快速,较Two term模型更具有普适性、实用性。In order to select a kinetic model best fit for the design, optimization; and control of tobacco drying process, the drying kinetic behavior of; tobacco strips under the conditions of 65 ℃ & RH 15%, 75 ℃ & RH10%, 85 ℃; & RH 5% was investigated with a humidifier combined with TGA; (Thermogravimetric analyzer). The drying behavior of tobacco strips was; simulated by REA (Reaction engineering approach) model and eight; selected thin layer drying models (semi-empirical or empirical). The; results showed that: 1) With the rise of temperature and decrease of; humidity, the drying rate of strips raised and the equilibrium moisture; content of strips lowered. 2) The drying kinetic curves predicted by REA; model well agreed with experimental curves, especially at the stage when; the moisture content decreased from 20% to 12%. Among eight thin layer; drying models, Two term model was the best for predicting the drying; behavior of strips with the highest R~2 (determination coefficient) and; the lowest RMSE (root mean square error). 3) Thin layer drying model; reflected only the kinetic parameters corresponding to specified drying; conditions, while in the REA model the temperature and humidity served; as variables, it enabled the kinetic parameters in REA model to describe; the drying kinetic behavior at any drying condition. 4) REA model was; simple in structure, fast and accurate in prediction, more universal and; practical than Two term model.福建中烟工业有限公司科技项

Numerical Simulation of Cigarette Smoldering

为了描述卷烟阴燃过程的二维数学模型,用fluEnT软件模拟了卷烟的阴燃过程,包括卷烟燃烧过程中发生的水分蒸发反应,烟草热解和氧化反应,以及质量传递、能量传递和动量传递。分析了不同时刻温度分布,烟气中氧气、一氧化碳、二氧化碳和水蒸气的浓度分布,并将模拟得到的卷烟阴燃线性燃烧速度(lbr)和最高阴燃温度值与实验值进行对比,其中实验测得的lbr为0.38 CM/MIn,而模拟值为0.44CM/MIn,最高温度的实验值和模拟值均在900~1000 k之间,说明模拟值与实验值基本相符。To develop a 2D mathematical model of cigarette smoldering process, the process was simulated with Fluent software, which included water evaporation, tobacco pyrolysis and oxidation reaction, and the transfer of mass, energy and momentum.The temperature distribution at different time and the concentration distribution of O2, CO, CO2and water vapor in the smoke were analyzed.The simulated value of linear burning rate(LBR) of smoldering was of 0.44 cm/minute, the experimental LBR value of 0.38 cm/minute; both the simulated and experimental values of maximum smoldering temperature were in the range of 900-1000 K,which indicated that the simulated values and the experimental values were basically agreed with each other

反映工艺条件对管式反应器催化反应影响的转化率方程(英文)

根据幂指函数g(u)=ua+bu的特点,借用"虚拟反应组分"和"变动级数"的概念,提出了管式反应器系统中反应转化率与工艺条件的关系式XM=1-exp[-exp(A+B/Tr+CTr)Prnpo+np1prτr multiply from i=1 to m yinyo+ny1yi]为了验证该转化率方程的普适性,考察了二乙苯催化脱氢、乙苯加氢和噻吩加氢脱硫等,并利用Matlab软件分别对这三个催化体系的实验数据进行拟合.结果表明,此方程在较宽的范围内均能很好地反映温度、反应压力、空速和物料比对转化率的影响.预测结果与实验数据之间的总平均相对偏差均小于2%,说明该方程并不是针对某一特定的催化反应或催化剂,可用于大多数的管式反应器催化反应系统中

Research progress in cigarette combustion model

综述国内外有关卷烟燃烧模型的研究进展。认为应在深入研究卷烟燃烧过程和机理的基础上,建立全面系统准确的卷烟燃烧数学模型,以便为工艺改进提供科学依据。Research progress in cigarette combustion model was reviewed.Suggestions were proposed that comprehensive,systematic and accurate mathematical model of cigarette combustion need to be established based on further research in combustion mechanism to improve blending technique

镍促进CuO-CeO_2催化剂的结构表征及低温CO氧化活性(英文)

制备了一系列CO低温氧化的Ce20Cu5NiyOx催化剂,并采用氮气低温物理吸附、X射线衍射、程序升温还原、X射线光电子能谱以及拉曼光谱等手段对催化剂进行表征.结果表明,Ce20Cu5Ni0.4Ox催化剂活性最高.NiO的添加可以使得较多的Cu物种掺杂到CeO2晶格中,通过形成铈镍固溶体产生更多的氧空位.表征结果显示,Ce20Cu5Ni0.4Ox催化剂中存在大量的Cu+,Ce3+及晶格氧,催化剂中的Cu+很容易进入到氧化铈晶格,形成Cu-O-Ce固溶体,从而增强了在还原气氛下晶格氧的释放能力.Ce20Cu5Ni0.4Ox催化剂高的催化活性主要归因于大量Cu+以及形成的Cu-O-Ce和Ni-O-Ce固溶体

Low temperature CO oxidation on Ni-promoted CuO-CeO2 catalysts

China Tobacco Fujian Industrial CorporationA series of Ce20Cu5NiyOx catalysts for CO oxidation at low temperature were prepared and characterized by N-2 adsorption, X-ray diffraction, temperature-program reduction by H-2, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Ce20Cu5Ni0.4Ox exhibited the highest catalytic activity. The addition of NiO increased the amount of copper ions doped into the CeO2 matrix and gave more oxygen vacancies in ceria by the formation of a Ni-O-Ce solid solution. XPS results showed that large quantities of Cu+, Ce3+, and lattice oxygen existed in the fresh Ce20Cu5Ni0.4Ox catalyst. Cu+ ions in the catalyst can easily migrate to the ceria lattice to form a Cu-O-Ce solid solution, which enhanced the release of the lattice oxygen of the oxides under a reducing atmosphere. The high catalytic activity of Ce20Cu5Ni0.4Ox is due to the promoter giving increased amounts of Cu+ in the catalyst and the formation of solid solutions of both Cu-O-Ce and Ni-O-Ce. (C) 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved

甘肃小陇山暖温带针阔混交林物种组成和群落结构

处于暖温带与亚热带过渡区的甘肃小陇山是我国重要的生物多样性保护区域之一。以甘肃小陇山建立的6 hm~2暖温带针阔混交林森林动态样地为基础,以样地中所有胸径(DBH)≥1 cm的木本植物为对象,分析群落结构和物种组成,探讨物种对不同生境的选择偏好。结果表明:样地内共有木本植物41735株,除去分枝和萌生的独立个体有29251株,共计124种,包含33科65属,其中重要值≥1的树种有28个,占总多度的82.9%。样地中重要值最大的前4个种依次是锐齿槲栎、白桦、小叶乌药和榛,也是该群落乔木层与灌木层的优势树种。样地内所有植株的径级分布整体表现为倒"J"型,群落自我更新良好。指示种分析发现,样地中有11个物种对不同生境表现出一定的偏好,其中2个物种(铁木和四蕊枫)表现出明显的生境偏好。冗余分析和偏分析表明,样地内的物种多度分布主要受地形影响