常压程序升温热解-质谱系统在煤脱羧过程中的应用

设计了在线监测煤和其它含高挥发分组份样品的热解气体的反应器,将此反应器与商品型质谱(MS)联用,建立了常压程序升温热解-质谱(AP-TPP-MS)系统。用模型化合物和真实样品检验了该系统的可靠性和重复性,并探讨了通过预处理前后煤热解时CO2的逸出情况来反映煤脱羧效果的可行性。结果表明,此系统用于模型化合物热解时能获得响应好、重叠拖尾少、对称性好的气体逸出峰;用于氧化煤时能清晰可辨地显示同一热解气体的多个逸出峰;系统的稳定性和重复性较好。可利用此系统监测CO2的逸出情况,反映预处理对煤的脱羧效果。     

水城褐煤热解的气体产物析出特征及甲烷的生成反应类型研究

利用傅里叶红外光谱仪研究了煤中主要官能团的分布,利用热重-质谱联用（TG/MS）在10℃/min的条件下研究了水城褐煤的热解行为,获得了煤热解主要挥发分气体（H₂、CH₄、H₂O、CO、CO₂）生成的速率曲线。采用分峰拟合的方法将甲烷的生成速率曲线分解为五个峰,通过化学动力学分析,结合煤的结构特性、热解特性及其他挥发分气体的生成特征,认为甲烷的生成主要由一个脱吸附过程和四个化学反应组成。     

型煤中硫的还原热解MS和GC/MS分析(英文)

以煤和生物质为主要原料的商用型煤为研究对象，采用还原热解（AP-TPR）在线质谱（MS）联用，以及离线色谱/质谱（GC/MS）分析法，定性和定量研究了家用型煤释放的含硫化合物。不同组成的型煤表现出各自不同的硫释放特性。对于生物型煤来说，仅检测到少量二烷基硫醚和脂肪硫醇的存在。褐煤型煤检测到种类最多的有机硫化物。在高阶煤制成的型煤中没有检测到氧化态的硫化物，其典型特征是存在一些噻吩类硫化物。     

TGA和Py-GC/MS研究不同氛围下烟草的热失重和热裂解行为

应用热重红外联用技术(TG-FTIR)和热裂解气相色谱-质谱联用技术(Py-GC/MS)对卷烟烟丝的热失重和热裂解行为及其裂解产物进行研究.采用热重分析法测定不同气氛下卷烟样品的热失重(TG)、微商热重(DTG)曲线,以及热裂解过程中H2O、CO2、CO、NH3和CH4等气体物质的释放量.结果表明,裂解气氛不同可以显著...     

热重-流动载气液滴微吸附体系的建立及其应用于卷烟纸的热解产物分析

将液相微萃取技术用于流动载气条件下热重逸出组分的吸附,自行设计和建立了热重-流动载气液滴微吸附(TG-GFSDMA)联用装置,并结合气相色谱-质谱(GC-MS),建立了可以进行热重逸出组分分析的检测系统.使用该系统并结合划分温度段连续取样法,研究了卷烟纸在主失重区的热失重行为及其热解逸出产物,并考察了热重载气流量对液滴...     

水城褐煤热解的气体产物析出特征及甲烷的生成反应类型研究

利用傅里叶红外光谱仪研究了煤中主要官能团的分布,利用热重-质谱联用(TG/MS)在10℃/min的条件下研究了水城褐煤的热解行为,获得了煤热解主要挥发分气体(H2、CH4、H2O、CO、CO2)生成的速率曲线。采用分峰拟合的方法将甲烷的生成速率曲线分解为五个峰,通过化学动力学分析,结合煤的结构特性、热解特性及其他挥发分气体的生成特征,认为甲烷的生成主要由一个脱吸附过程和四个化学反应组成。     

预测混合煤燃烧性能的数学模型

用热重分析法研究了单种煤的DTG和TG曲线特征，建立了预测混合煤燃烧性能的数学模型。结果表明，各单种煤的DTG曲线呈单峰，峰值温度tmax与其燃料比F的对数呈线性相关关系，tmax=68.86 ln（F）+512.2 （℃）。由组成混合煤的单种煤的燃料比F可推断出混合煤的DTG曲线特征，从而预测混合煤的燃烧性能。如果混合煤的煤质指标满足标准煤的煤质指标要求，则当Fmax/Fmin≤3.20时，混合煤的燃烧性能好；当3.205.71时，混合煤的燃烧性能较差。     

固态废弃物和煤混合燃烧过程中有机氯化物形成机理的研究

对几种煤和城市固体废弃物（MSW）如PVC和纤维素中的主要可燃成分进行了实验研究,热重－质谱－红外（TGA／MS／FTIR）分析以原料和其混合物为对象,收集得到的燃烧特征图显示出不同的热力学行为。结果表明共燃中快速加热比慢速加热形成有机化合物的可能性要大,管式炉中的实验表明在MSW燃烧过程中Cl2是生成有机氯化物的重要媒介,提出的形成机理包括Deacon反应,用纯有机化合物进行的实验证实此反应为一可能的途径。燃烧过程中SO2对Cl2生成的作用也被检查,结果表明SO2的加入可以降低Cl2的生成量,从而大大减少有机氯化物的生成。     

热分析联用技术在高分子材料热性能研究中的应用

主要综述了热重-傅里叶变换红外(TG-FTIR)、裂解-色谱/质谱(Py-GC/MS)以及热重-质谱(TG-MS)三种常见的热分析联用技术的测试方法、原理,近几年这几种方法在高分子材料热性能研究中的应用进展和成果表明它们为材料的热分解过程和机理的探索提供了切实可行的研究方法,文章最后还展望了这些方法在热分析技术发展中的重要前景。     

热重逸出气中挥发酚类物质的剑桥滤片-吸收瓶捕集和HPLC测定

建立了热重/差热分析(TG/DTA)-剑桥滤片-吸收瓶捕集-高效液相色谱(HPLC)联用装置,将该联用装置应用于热重逸出气体中七种挥发酚物质的定量研究,并验证了其可靠性。首先在10℃/min升温速率、300mL/min的氮气流量下对烟丝进行热失重分析,根据TG和DTG曲线得到其主要热失重区间为室温～600℃之间,然后采用剑桥滤片-吸收瓶对该温度区间内逸出气体中的七种挥发酚物质捕集,用HPLC进行定性和定量分析。结果表明,联用装置中剑桥滤片和吸收瓶两种不同的捕集方式有选择性地捕集了逸出气体中的挥发酚物质,剑桥滤片更利于对-苯二酚、间-苯二酚、邻-苯二酚的捕集,而吸收液更利于苯酚、间,对-甲酚、邻-甲酚的捕集;同样条件下热重逸出气体中的酚类物质含量不同,苯酚和对-苯二酚的含量较高,分别为1.858、1.675mg/g;间-苯二酚的含量最低,为0.032 mg/g。5次平行实验得到各挥发酚物质生成量的相对标准偏差(RSD)均在10%以内,由此验证了该联用装置的可靠性,可用于程序升温下样品裂解逸出气体中挥发酚物质的定量研究。     

A thermal analysis study of the combustion characteristics of Victorian brown coals

Simultaneous TG, DTA techniques have been applied to investigate the combustion characteristics of Victorian brown coal derived from different coal fields and including various lithotypes. TG and DTA profiles of the entire combustion process were obtained to provide a set of parameters which characterize the oxidation potential of these coal samples. These parameters can also be used to predict the combustion performance of pulverized coal in industrial furnaces. The area of the major DTA combustion peak is closely related to the heat released during the combustion process and therefore provides a means of determining the specific energy of the coal. Different lithotypes are also characterized by their corresponding TG and DTA burning profiles.     

Chlorinated organic compounds evolved during the combustion of blends of refuse-derived fuels and coals

The objective of this study was to examine the possible formation of chlorinated organic compounds during the combustion of blends of refuse derived fuels (RDF) and coal under conditions similar to those of an atmospheric fluidized bed combustion (AFBC) system. A series of experiments were conducted using a TG interfaced to FTIR. Additional experiments using a tube furnace preheated to AFBC operating temperatures were also conducted. The combustion products were cryogenically trapped and analyzed with a GC/MS system. The chlorination of phenols and the condensation reactions of chlorophenols were investigated in this study. A possible mechanism for the formation of chlorinated organic compounds such as dibenzodioxins and dibenzofurans, by chlorination and condensation reactions involving phenols, was proposed.The financial support for this work received from the U.S. Department of Energy (Contract No. DE-FG22-94PC94211) and from the Huntsman Thermal Analysis Fellowship is gratefully acknowledged.     

Investigation of reaction mechanisms by electrospray ionization mass spectrometry: characterization of intermediates in the degradation of phenol by a novel iron/magnetite/hydrogen peroxide heterogeneous oxidation system

Electrospray ionization (ESI) mass spectrometry (MS) and tandem mass spectrometry (MS/MS) were used to monitor the oxidation of phenol by a novel heterogeneous Fenton system based on a Fe(0)/Fe(3)O(4) composite and H(2)O(2). On-line ESI-MS(/MS) shows that this heterogeneous system promotes prompt oxidation of phenol to hydroquinone, which is subsequently oxidized to quinone, other cyclic poly-hydroxylated intermediates and an acyclic carboxylic acid. A peroxide-type intermediate, probably formed via an electrophilic attack of HOO(.) on the phenol ring, was also intercepted and characterized. ESI-MS(/MS) monitoring of the oxidation of two other model aromatic compounds, benzene and chlorobenzene, indicates the participation of analogous intermediates. These results suggest that oxidation by the heterogeneous system is promoted by highly reactive HO(.) and HOO(.) radicals generated from H(2)O(2) on the surface of the Fe(0)/Fe(3)O(4) composite via a classical Fenton-like mechanism.     

Polyethylene as a novel low-temperature inhibitor for lignite coal

Polyethylene was firstly used as a inhibitor for prevent lignite coal from spontaneous combustion. According to inhibition test results, it was showed that the CO generation of lignite coal with polyethylene inhibitor was obviously lower than that of lignite coal without one, indicating that the polyethylene can hinder the oxidation of lignite coal. TG results showed that polyethylene can be thoroughly decomposed at 500 °C. Moreover, the introduction of polyethylene has little influence on the combustion of lignite coal. These characteristics of polyethylene may help to develop a new class of inhibitors.     

无机酸洗脱对胜利褐煤微晶结构及其自燃倾向性的影响

利用XRD、Raman、XPS和FT-IR表征技术,研究无机酸洗脱(HCl、H2SO4、HCl-HF)处理的胜利褐煤微晶结构的变化,采用自行设计的表面吸附仪-GC联用装置,对样品进行不同温度的低温脉冲氧化实验,考察了煤样在不同温度下氧吸附量的变化规律,通过低温脉冲氧吸附规律与TG/DTG和固定床燃烧实验关联,考察了煤样的自燃倾向。结果表明,无机酸洗脱对矿物质的脱除使得煤结构的有序度增加,石墨化程度提高,无机酸洗脱煤样与原煤相比吸氧量明显下降。随着吸附温度的升高,各煤样吸氧量明显增加,且随着脱除矿物质程度的增加,吸氧量呈减小的趋势,导致自燃倾向降低。     

Effective direct chemical looping coal combustion with bi-metallic Fe–Cu oxygen carriers studied using TG-MS techniques

This paper contains the results of research on a promising combustion technology known as chemical looping combustion (CLC). The noteworthy advantage of CLC is that a concentrated CO₂ stream can be obtained after water condensation without any energy penalty for CO₂ separation. The objective of this work was to prepare novel bi-metallic Fe–Cu oxygen carriers and to evaluate the performance of these carriers for the CLC process with hard coal/air. One-cycle CLC tests were conducted with supported Fe–Cu oxygen carriers in thermogravimetric analyzer (TG) utilizing hard coal as a fuel. The effects of the oxygen carrier chemical composition, particle size, and steam addition on the reaction rates were determined. The fractional reduction, fractional oxidation, and the reaction rates were calculated from the TG data. Notably, the support had a considerable effect on the reaction performance. Moreover, bi-metallic Fe–Cu oxygen carriers exhibited significantly improved reactivity compared with monometallic Fe oxygen carriers. Furthermore, the addition of a second reactive metal oxide stabilized the oxygen carrier structure. The oxidation reaction was significantly faster than the reduction reaction for all supported Fe–Cu oxygen carriers. The TG data indicated that these oxygen carriers had stable performances up to 900 °C and may be effectively used for direct coal CLC reactions.     

外来水分对煤自燃过程影响及作用机制研究

通过浸泡方法制备一系列不同外来水分含量的煤体,利用程序升温氧化实验模拟煤自燃过程,研究外来水分对煤自燃特性的影响;结合热分析和孔结构表征实验,探讨外来水分对煤自燃过程影响作用机制。外来水分对煤自燃过程的作用机制随着煤自燃状态发展而发生变化,主要表现出四个阶段。在缓慢氧化阶段,外来水分主要隔离煤与氧气的接触反应,对煤自燃起到物理抑制作用;在加速氧化阶段,水分可直接参与煤氧反应,起到化学促进作用;经过缓慢氧化阶段和加速氧化阶段,大量外来水分的蒸发导致煤颗粒表面裂隙增大,水分越大的煤生成的活性点位会更多,当煤自燃进入快速氧化阶段,外来水分对煤氧化反应的影响表现出延迟促进效应;当煤体温度达到180℃后,随着煤体温度进一步升高,不同初始外来水分含量的煤体自燃特征逐渐趋于一致。     

Study of the Kinetics of the Combustion Reaction on Shuangya Mountain Coal Dust by TG

The combustion behavior of Shuangya Mountain (SYM) coal dust has been investigated by means of TG in this paper. The reaction fraction can be obtained from isothermal TG data. The regressions of g(), an integral function of vs. t for different reaction mechanisms were performed. The mechanism of nucleation and nuclei growth is determined as the controlling step of the coal dust combustion reaction by the correlation coefficient of the regression, and the kinetic equation of the SYM coal dust combustion reaction has been established.This revised version was published online in November 2005 with corrections to the Cover Date.     

Simultaneous thermogravimetric-mass spectrometric study on the co-combustion of coal and sewage sludges

To combust coal together with a small percentage (<10%) of sewage sludge may be an option for the management of these wastes. Combustion of two different sewage sludge, one semianthracite coal and several sludges-coal blends (containing different dried mass% of each of the two sewage sludges) were studied by simultaneous TG/MS dynamic runs carried out at 5°C min^–1 in the temperature range 100–800°C. No interactions have been observed between coal and sludge during the blends combustion. Neither the combustion process, neither the studied emissions have changed appreciably for the mass% of sludge in the blends considered in this work.     

油页岩与煤的混烧特性研究

使用STA409型热综合分析仪进行了桦甸油页岩与高硫合山煤的混烧特性实验研究，得到了油页岩和高硫煤混烧的TG和DTG曲线，分析了不同Ca/S对油页岩和高硫煤混烧特性的影响规律，同时运用Freeman-Carroll法计算得到了不同Ca/S下的油页岩燃烧特性化学反应动力学参数。研究表明，在高硫煤中加入少量的油页岩，高硫煤的燃烧特性有所改善，燃烧特性趋好；油页岩的加入使得高硫煤低温段的燃烧产物初析温度降低，着火温度提前；在高硫煤中加入20%左右的油页岩作为可燃脱硫剂从燃烧角度讲是切实可行的。