New mass loss kinetic model for thermal decomposition of biomass

Based on non-isothermal experimental results for eight Chinese biomass species, a new kinetic model, named as the 損seudo bi-component separate-stage model (PBSM)? is developed in this note to describe the mass loss behavior of biomass thermal decomposition. This model gains an advantage over the commonly used 損seudo single-component overall model (PSOM)?and 損seudo multi-component overall model (PMOM)? By means of integral analysis it is indicated that the new model is suitable to describe the mass loss kinetics of wood and leaf samples under relatively low heating rates (e.g. 10℃/min, used in this work).

Thermal Decomposition Kinetics of Lead 2,4,6-Trinitroresorcinate Monohydrate

The non-isothermal decomposition of lead 2,4,6-trinitroresorcinate monohydrate, Pb(TNR)·H\-2O, was investigated by means of TG-DTA, DSC and IR. The thermal decomposition mechanism and the dissociated kinetics were also investigated. The kinetic parameters were obtained from the analysis of the DSC curves by integral and differential methods. The most probable kinetic model function of the dehydration reaction of \{Pb(TNR)·H\-2O\} was suggested by the comparison of the kinetic parameters.

A Study of Estimating the Safe Storage Life, Self-accelerating Decomposition Temperature and Critical Temperature of Thermal Explosion of Double-base Propellant Using Isothermal and Non-isothermal Decomposition Behaviours

A method of estimating the safe storage life （τ）, self-accelerating decomposition temperature （TsADT） and critical temperature of thermal explosion （Tb） of double-base propellant using isothermal and non-isothermal decomposition behaviours is presented. For double-base propellant composed of 56±1wt% of nitrocellulose （NC）, 27±0.5wt% of nitroglycerine （NG）, 8.15±0.15wt% of dinitrotoluene （DNT）, 2.5±0.1wt% of methyl centralite, 5.0±0.15wt% of catalyst and 1.0±0.1wt% of other, the values of r of 49.4 years at 40℃, of TSAOT of 151.35℃ and of Tb of 163.01℃ were obtained.

Crystal structures and thermal decomposition mechanism of four lanthanide complexes with halogen-benzoic acid and 1,10-phenanthroline

This paper describes syntheses and structure determination of four lanthanide complexes [Nd(2-Cl-4-FBA) 3 phen] 2 (1, 2-Cl-4-FBA = 2-chloro-4-fluorobenzoate, phen = 1,10-phenanthroline), [Ln(2,5-DClBA) 3 phen] 2 (Ln = Sm(2) and Tb(3), 2,5-DClBA = 2,5-dichlorobenzoate) and [Sm(2-Cl-4,5-DFBA) 3 (phen)(H 2 O)] 2 (4, (2-Cl-4,5-DFBA = 2-chloro-4,5-difluorobenzo- ate). The complexes were characterized by elemental analysis, infrared and ultraviolet spectra, and X-ray single-crystal diffraction. In the molecular structures of 1 4, two Ln 3+ ions are linked by four carboxyl groups, with two of them in a bridging bidentate mode and the other two in a bridging-chelating tridentate mode, forming four binuclear molecules. In addition, each Ln 3+ ion is also chelated to one phen molecule and one carboxyl group in the complexes, except each Sm 3+ ion in 4 which is bonded to one carboxyl group by unidentate mode and one H 2 O molecule. There are two different coordination polyhedrons for each Nd 3+ ion in the two similar molecular structures of 1 and they are a distorted monocapped square antiprismatic and a distorted tricapped triangular prism conformation, respectively. The coordination polyhedron for each Ln 3+ ion in 2 4 is a nine-coordinated distorted mono-capped square antiprismatic conformation. The complex 3 exhibits green luminescence under the radiation of UV light. The thermal decomposition behaviors of the complexes have been discussed by simultaneous TG/DSC-FTIR technique. The 3D surface graphs for the FTIR spectra of the evolved gases were recorded and the gaseous products were identified by the typical IR spectra obtained at different temperatures from the 3D surface graphs. Meanwhile, we discussed the nonisothermal kinetics of 1 4 by the integral isoconversional non-linear (NL-INT) method.

RDX热分解的TG-DSC-QMS-FTIR同步动力学

采用TG-DSC-QMS-FTIR同步动力学技术对RDX的热分解过程进行了研究,结果表明,RDX在熔融之后发生分解,可以确定RDX的产物有C、H2O、CH2O、N2O、CO、CO2、NO2,可能有CH4和NH3,而几乎没有NO。采用多元非线性拟合技术进行动力学参数计算,结果表明,RDX的分解过程大致可以分为3个连续步骤,第1步反应的活化能为235kJ/mol,指前因子log(A/s-1)为22,反应级数为0.6,主要气体产物为CO2、NO2和CH2O;第2步反应的活化能为110kJ/mol,指前因子log(A/s-1)为1.5,反应级数为1.7,主要的气体产物是N2O、H2O、CH4、NH3、C2O+/C3H+4、CN+/C2H3+、CHO+/C2H+;第3步反应的活化能为223kJ/mol,指前因子log(A/s-1)为20.9,反应级数为4,主要的产物是C和CO。

TG-DSC-MS联用研究不同气氛下腰果壳油改性热塑性酚醛树脂的热裂解特性

采用热重-差示扫描量热-质谱联用技术（TG-DSC-MS）研究了腰果壳油改性热塑性酚醛树脂在不同气氛下热分解过程中质量、能量、气体产物的变化规律,利用Coats-Redfern法计算了腰果壳油改性热塑性酚醛树脂热分解的动力学参数.结果表明,裂解气氛能显著影响样品的热解过程：与氮气气氛下相比,样品在空气气氛下的失重区间总数和主失重区温度范围均增加,且有2个主失重区,裂解更加完全;氮气气氛下,在主失重区表现明显的吸热效应,而在空气气氛下,第Ⅰ主失重区的热效应与升温速率有关,第Ⅱ主失重区放热明显;在反应深度α为0.10～0.90的区间内,分别采用一级四段、一级六段对样品在氮气、空气气氛下的热裂解过程进行模拟,得到氮气气氛下各段的平均活化能为17、65、32、13 kJ＆#183;mol-1,空气气氛下各段的平均活化能为72、23、14、12、19、57 kJ＆#183;mol-1.不同气氛下,MS总离子流图信号强度与TG曲线的变化规律具有一致性,但气氛种类对裂解产物种类和相对含量有较大影响：惰性气氛（Ar气）下,样品更容易裂解成烷基酚（苯酚、甲基苯酚、乙基苯酚、二甲苯酚、三甲苯酚）、烷基苯（苯、甲苯、二甲苯、三甲苯、乙基甲苯）等芳香烃类和烷烃类（甲烷、丙烷、丁烷、戊烷、己烷）等气态产物,芳香烃化合物为主产物,生成量在305～333℃达到第一个峰值,408～460℃附近达到第二峰值;而在有氧的空气气氛中,CO2、H2O和甲酸为主要气体产物,释放量明显比惰性气氛下大,芳香烃类化合物只在第一个主失重区有逸出,种类和释放量明显较少,且未检测到烷烃类化合物.

从不同升温速率下的DSC曲线数据计算/确定含能材料放热分解反应Arrhenius/非Arrhenius动力学参数的方法

提出了从不同恒速升温速率(β)条件下的DSC曲线起始温度(T0)、onset温度(Te)、峰温(Tp)、Te和Tp处的反应转化率αe和αp及相应各等转化率αi的βi、Tα,i(i=1,2,…,L)数据计算/确定含能材料放热分解反应Arrhenius/非Arrhenius动力学参数的方法。用该法得到了四水双(3-(5-硝基-1,2,4-三唑))钠[Na2(BNT)(H2O)4]放热分解反应的Arrhenius/非Arrhenius动力学参数。用所得非Arrhenius动力学参数计算了[Na2(BNT)(H2O)4]的热爆炸临界温度(Tb),并与用Arrhenius动力学参数所得的Tb值作了比较。验证了本工作所得[Na2(BNT)(H2O)4]非Arrhenius动力学参数的有效性和可靠性。

用DSC法研究配合物[Sm(m-BrBA)_3phen]_2·2H_2O脱水反应的动力学

合成了稀土配合物[Sm(m-BrBA)3phen]2.2H2O(m-BrBA,间溴苯甲酸;phen,邻菲罗啉)。用差示扫描量热(DSC)技术研究了该配合物脱水反应的动力学方程和动力学参数。实验数据用双等双步法处理,得到脱水反应的动力学方程为dα/dt=Aexp(-E/RT)2(1-α)[-ln(1-α)]1/2。表观活化能E为237.26kJ.mol-1,指前因子A为4.40×1018/min-1,分别获得了脱水过程的热力学参数ΔH≠,ΔG≠和ΔS≠的值。

头孢曲松钠非等温DSC热分解动力学研究

实验研究了不同升温速率下头孢曲松钠非等温DSC热分解动力学。采用Málek法求得了动力学三因子,确定了最概然模型函数是两参数的SB(m,n)。非等温DSC实验值与模型预测值一致性好。

2,4-二硝基苯酚钠非等温DSC热分解动力学研究

首先用同步热分析仪(STA)测定了一定温度区间内2,4-二硝基酚钠的比热容,利用Origin8.0软件回归比热容随温度变化的方程式,拟合系数为0.913 6,标准偏差为0.005 9。然后分别在空气和氮气气氛下对2,4-二硝基酚钠进行了TG/DSC测试,并与单硝基酚钠(邻、间、对位)的热分解性能进行了比较。通过在氮气气氛不同升温速率下的测试,用Kissinger法得到2,4-二硝基酚钠热分解反应的表观活化能、指前因子等动力学参数。研究表明:2,4-二硝基酚钠在300℃以下具有良好的热稳定性,Kissinger法得到的2,4-二硝基酚钠表观活化能为244.8 kJ/mol,指前因子为2.5×10^(18)s^(-1)。

Thermal Characterization and Lifetime Estimation of the Humus Lombricospt

Through this study, the humus produced in the breeding place of Universidad Autonoma de Occidente was thermally characterized. The humus was submitted to a heating program controlled by the Differential Scanning Calorimetry (DSC) technique to characterize the type of transition, Thermogravimetry (TGA) to study the equilibrium of phasesand Mass Spectrometry (MS) coupled to TGA to identify detached elements in a temperature range. The temperature range used in this study was 30℃ ℃. The energy required for the water desorption in the humus has been found in this study. The humus showed a quick desorption between 30℃ ≤ TDesorption ≤ 110℃ at a heating rate of 10℃/min and presented decomposition around 250℃. Moreover, the kinetics of the desorption of the humus was studied to obtain the activation energy three TGA measures for three different heating rates. The average activation energy was about 26 kJ/Mol. This result was carried out to obtain an estimation of the desorption time of water in the range from room temperature to the decomposition temperature around 350℃.

Thermal Decomposition Kinetics of Triethylene Glycol Dinitrate

The thermal behavior and kinetic parameters of the decomposition reaction of triethylene glycol dinitrate (TEGDN) in a temperature-programmed mode at different pressures (0.1, 2, 4 and 6 MPa) have been investigated by means of DSC and TG-DTG. The results show that the properties of the thermal decomposition of TEGDN are affected by the change of pressure, and the kinetic model function, the apparent activation energy Ea and pre-exponential factor A of this reaction are []122(1)ln(1)aa---, 106.54 kJ昺ol-1 and 109.17 s-1 at 0.1 MPa, and 120.82 kJ昺ol-1 and 1010.56 s-1 at 2 MPa, respectively. The critical temperature of thermal explosion of TEGDN obtained by the values Teo and Tpo of the onset temperature Te and the peak temperature TP when the heat-ing rate tends to zero are 191.05, 209.86 ℃ at 0.1 MPa, 207.59 and 221.65 ℃ at 2 MPa, respectively.

电解法制备氢氧化镁粉体的非等温动力学解析

氢氧化镁分解动力学对研究氧化镁的生产具有重要的理论意义.本文中以隔膜电解法制备的氢氧化镁粉体为样品(纯度可达到99.02%,片状结构),采用热分析技术获得了氢氧化镁在不同升温速率下的热分解动力学数据,并利用等转化率法对其进行动力学解析.研究结果表明:采用Kissinger法计算的氢氧化镁热分解反应活化能分别为121.68和110.43 kJ/mol,指前因子分别为2.050×10^(10)和1.426×10^(9)min^(-1);采用FWO法计算的活化能为130.18 kJ/mol,分解反应的机理函数为n=1.5的随机成核和生长机理模型.该研究结果可为制备性能优良的氧化镁奠定理论基础.

α-AlH_3的合成及热分解动力学

以LiAlH4和AlC13为原料制备α-AlH3,采用XRD、SEM对其结构和形貌进行表征。采用TG/DTG-DSC联用技术研究其热分解过程,通过计算获得了热分解动力学参数。结果表明,α-AlH3热分解反应遵循随机成核与核增长模型,其反应活化能、指前因子、机理函数分别为Ea=110.89 kJ/mol,lnA=26.94 s-1,f(α)=-ln(1-α)1/4,其热分解反应动力学方程为dα/dT=(2.004×1011/β)exp(-1.333 78×104/T)(1-α)[-ln(1-α)]3/4。

阿司匹林的热解机理及热动力学研究

在用热重法研究了阿司匹林的热稳定性实验的基础上,通过量子化学方法(abinitioDFT)计算了阿司匹林分子的键级,据此计算结果提出了阿司匹林的热解机理,按此机理得到的理论计算值与实验结果一致;运用Freeman-Carroll、Kissinger和Ozawa三种方法分别计算了阿司匹林的热解动力学参数:活化能(E)、反应级数(n)和指前因子(A),其热解动力学方程为:dα/dt=4.74×1011犤exp(-(100.34±5.18)×103/RT)犦(1-α)2.8±0.3;用差示扫描量热法测定的该物质的熔点、摩尔熔化焓和摩尔熔化熵分别为(409.19±0.22)K、(29.17±0.41)kJ·mol-1和(71.09±1.06)J·mol-1·K-1.

ZnAc_2·2H_2O在空气中的热分解动力学研究

用TG/DTA,DSC和XRD技术研究了固态物质ZnAc2.2H2O在空气中的热分解过程.结果表明,ZnAc2.2H2O在空气中发生两步分解,其失重率与理论计算失重率相符.XRD结果表明,ZnAc2.2H2O分解的最终产物为ZnO.用Friedm an法和F lynn-W all-Ozawa(FWO)法求得分解过程的活化能E,并通过多元线性回归方法给出了可能的机理函数.ZnAc2.2H2O在空气中两步分解的活化能分别为119.82和66.82 kJ/mol.

基于差示扫描量热技术的生物质热解两步连续反应模型研究

采用差示扫描量热分析仪对我国的一种生物质试样在空气气氛中进行了实验,发现试样从常温到923K高温的低速升温过程中,经历了两步明显的放热过程.对放热机理的分析表明,第一步主要是由半纤维素和纤维素的有氧热解过程控制,第二步放热过程则受木质素热解和炭的氧化反应的共同作用.采用等转化率方法和优化计算方法,对热解过程的动力学模型进行了研究,结果表明,两步连续反应机理可用于描述生物质在空气气氛中热解的放热动力学.

CoC_2O_4·2H_2O在空气中的热分解动力学研究

The thermal decomposition processes in solid state CoC2O4·2H2O have been studied in air using TG/DTA, DSC and XRD techniques. TG/DTA, DSC curves showed that the decomposition proceeded through two well-defined steps in air. Mass loss of the thermal decomposition of CoC2O4·2H2O was in good agreement with the theoretica1 one. XRD showed that the final product of the thermal decomposition was Co3O4. The activation energies were calculated through the ASTM E698 and Flynn-Wall-Ozawa (FWO) methods, and the possible conversion functions had been estimated through the multiple-linear regression method. The activation energies for the two steps decomposition of CoC2O4·2H2O were 140.18 kJ·mol-1 and 134.61 kJ·mol-1, respective1y.

超细六硝基茋的热分解性能

为了解超细六硝基艹氐(HN S)的热分解性能,通过DSC-TG实验研究HN S-Ⅳ的热分解过程,用K iss inger法和O zaw a法计算了HN S-Ⅳ热分解反应动力学参数。结果表明,HN S-Ⅳ的热稳定性与HN S-Ⅱ相当。K iss inger法和O zaw a法得到的HN S-Ⅳ分解表观活化能分别为221.4 kJ/m o l和220.3 kJ/m o l,比静态气氛下HN S-Ⅱ热分解反应的表观活化能减小27 kJ/m o l。

几种乳化炸药的热分解动力学行为

采用DSC-TG联用热分析技术以升温速率分别为2.0,2.5,5.0,7.5,10 K.min-1对五种乳化炸药热分解特性进行了研究,通过非模函数Ozawa法、Coats-Redfern法和atava-esták法计算了动力学参数。计算结果表明,三种动力学分析方法计算得到的活化能比较一致,五种乳化炸药热分解动力学参数计算结果可靠,推断出五种乳化炸药热分解反应的最概然机理函数。1#样品对应随机成核和随后生长机理函数;2#和5#样品对应n=2/3的幂机理函数;3#和4#样品对应三维扩散机理函数。