烤烟、白肋烟和香料烟的燃烧行为和热解气相产物比较

为了解烤烟、白肋烟和香料烟的燃烧行为,利用微燃烧量热仪研究比较了3种烟草燃烧热释放规律,并采用热重红外联用模拟考察了3种烟草在卷烟阴燃状态下主要热解气相产物CO2,CO,H2O和羰基化合物的生成规律.燃烧热释放和热重红外联用的研究结果表明:烤烟、白肋烟和香料烟的燃烧温度区间主要在150～600℃之间;香料烟与白肋烟的燃...     

阻燃剂PDPTP应用于PET材料时的阻燃机理研究

主要对一种含硫聚膦酸盐,聚硫代苯基膦酸（9,10－二氢－9－氧杂－10－膦酰杂菲）苯撑酯（PDPTP）在聚对苯二甲酸乙二醇酯（PET）中的阻燃机理进行了研究。采用裂解色谱-质谱分析（PY-GC-MS）、热重-红外分析（TG/FT-IR） 和X射线光电子能谱（XPS）等方法对PET/PDPTP复合材料的热解产物进行分析。结果表明,PDPTP的存在有利于炭层的形成,延迟了炭层的分解;PDPTP中的硫元素在较低温度下会以SOx的形式挥发到气相中,对其中的小分子可燃物产生稀释而阻燃;而磷元素则在阻燃PET的第二分解阶段才会挥发,产生的含磷小分子物质可捕获火焰中的H·等自由基而中断燃烧过程中的链反应。PY-GC-MS分析表明,PDPTP可抑制PET的深度裂解反应,减少裂解中小分子可燃物的产生。XPS分析表明,PDPTP中磷元素在PET开始分解后会在表面炭层形成富集,并以磷酸和偏磷酸的形式存在。由于磷酸和偏磷酸是较强的脱水剂,可促进聚合物直接脱水成炭,避免了热解过程中小分子可燃物的产生,同时促进焦炭层的形成。     

比较研究纤维素、果胶和淀粉的燃烧行为和机理

本文利用微燃烧量热仪（MCC）比较研究了烟草中主要碳水化合物（纤维素、果胶和淀粉）的燃烧行为,并考察了燃烧气氛和升温速率对燃烧行为的影响。此外,利用热重-红外联用仪（TG-FTIR）比较研究了其在惰性气氛和10%氧气浓度下的热解过程,特别是主要热解气相产物（H2O、CO2、CO和羰基化何物）的形成规律,探讨了其燃烧机理。MCC测试结果发现,在相同的燃烧条件下,纤维素的燃烧性较优于淀粉,而果胶的燃烧性最差。升温速率较燃烧气氛对纤维素、果胶和淀粉燃烧行为的影响更大。TG-FTIR测试结果发现,果胶在燃烧过程中较淀粉和纤维素具有更好的焦炭化能力,且释放出更多的不可燃气相产物H2O和CO2,从而使其燃烧能力较纤维素和淀粉相对较弱。      

利用TG-FTIR研究O2/CO2气氛下焦炭氮的转化

在热重分析仪(TGA)上进行了O(2)/CO(2)及O(2) /Ar气氛下煤焦的燃烧实验,同时利用傅立叶变换红外光谱仪(FTIR)对燃烧产物进行实时检测.结果表明,在焦炭颗粒的燃烧过程中焦炭氮会转化为HCN、HNCO、N(2)0等.与O(2)/Ar气氛下的燃烧相比,0(2) /CO(2)气氛煤焦燃烧焦炭氮的转化时间延长...     

桉木化学机械浆碱木素热解特性初步研究

采用酸析法分离桉木碱性过氧化氢法(APMP)制浆废液中的碱木素,应用热重红外联用(TG-FTIR)分析方法对碱木素的热解特性进行初步研究,并对热解过程中挥发性产物释放规律进行追踪。热重分析(TG)结果表明,热解主要分为玻璃态转化、主要热解、残留物质缓慢分解3个阶段;傅里叶红外光谱(FTIR)分析结果表明,热解阶段可挥发性产物有H2O、CO2、CO、CH4、酚醇类化合物和醛酮类化合物,反应时间在2000 s以后的高温阶段热解产物主要为CO和CO2。其中,CH4、醛酮类化合物、酚类和醇类化合物释放主要集中在300～600℃之间,且产率均较高。     

添加剂抑制CaSO4高温分解的TG-FTIR研究(Ⅰ)氧化物系列

固硫产物CaSO4在高温下易分解，导致钙基固硫剂在高温下固硫率急剧下降，限制了燃烧过程中固硫技术在工业锅炉中的应用，固硫产物的稳定性是影响高温固硫率的重要因素，采用TG—FTIR联用技术，在线测定了不同种类的添加剂对CaSO4高温热分解的影响规律，结果表明：分别添加一定比例的Al2O3，MgO和ZnO等氧化物对CaSO4晶体在高温下(1000℃～1450℃)的分解有明显的抑制作用。     

煅烧过程中水泥原料含硫物质的转化形式

以水泥生料,粘土,石膏和氧化钙为原料,配制不同含硫量的生料经高温煅烧制备出水泥熟料.采用XRD衍射仪、SEM扫描电镜及热重-红外联用仪研究该生料在制备水泥熟料过程中含硫物质的转化形式.实验结果表明:随着温度升高到800℃以上时,生料中的CaCO3开始分解.分解产物CaO与SO2反应生成CaSO4.在温度超过1 380℃...     

废弃汽车塑料保险杠材料热解特性及动力学研究

通过红外光谱分析及热重分析可知,汽车塑料保险杠的主要成分为聚丙烯和三元乙丙橡胶。应用热重-红外联用技术考察了其热解特性,采用Doyle积分法分析了塑料保险杠在不同升温速率下的热解规律。     

Study on combustion mechanism of asphalt binder by using TG-FTIR technique

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.     

Detection of natural oxidation of coking coal by TG-FTIR—mechanistic implications

The natural oxidation/weathering of coal continues to be a subject of interest both scientifically and industrially, in part due to the complexity of the molecular processes at hand as well as to the commercial implications involved. It is widely recognized that coking can be adversely affected by weathering whereas, combustion processes appear to be enhanced as result of oxidation.Combustion techniques are commonly used in the analysis of coal, and organic compounds in general, for the determination of elemental hydrogen, carbon and nitrogen. For oxygen, the method in common practice involves the determination by difference from directly determined values for moisture, ash, sulphur, hydrogen, carbon and nitrogen. This has led us to consider the use of thermogravimetry coupled to gas analysis by infrared spectroscopy (TG-FTIR) to measure organic oxygen in coal directly. Although this technique, developed by Solomon and coworkers, has been extensively used by our group and others, it appears not to have been considered for this particular purpose.Recently, we have shown that TG-FTIR is capable of measuring all the organic oxygen in both fresh and oxidized coal by simultaneous measurement of the three main oxygen-containing gases H₂O, CO and CO₂ evolved during rapid pyrolysis. This gives us a way of measuring quantitatively the oxygen introduced into the coal matrix during oxidation and at least a partial capability of establishing oxygen speciation.We have found, using TG-FTIR, that the early stages of coal oxidation results in the appearance of O-containing functional groups not present in the original coal. The nature of these functional groups is directly related to the oxidation reaction mechanism. These results will be presented and discussed in detail.