停留时间对低阶煤快速热解产物分布、组成及结构的影响

利用自由落下床反应器,研究了快速热解过程中颗粒停留时间对神木烟煤和内蒙古褐煤热解过程的影响,并进一步延长快速热解新生半焦停留时间考察了半焦的二次热解过程。结果表明,快速热解过程中颗粒停留时间的增加促进了挥发分的析出,神木烟煤热解焦油产率持续增加,内蒙古褐煤热解焦油产率先增加后降低。停留时间对焦油品质有明显影响,随时间的增加,两种煤快速热解轻质油中苯类和苯酚类单环化合物含量均先增加后降低,进一步延长停留时间,多环芳烃化合物含量显著增加。快速热解半焦的二次热解主要促进了气体的生成,焦油产率和组成无明显变化,挥发分的进一步析出促进了半焦微孔的发展,神木烟煤和内蒙古褐煤半焦比表面积均显著增加。这表明,在以高品质焦油为目标产品时,采用较低的反应温度、较适宜的煤粒停留时间的快速热解工艺条件是可取的。     

生活垃圾热解半焦-热解油重整过程中水分的消耗与转移

热解炭原位重整城市固体废物的挥发分是改善热解产物的良好方法。在这个过程中,水蒸气在产品转化中起着重要作用。为了了解水分在重整过程中的作用,本研究中将热解液中的油相和水相分离,然后用D₂O代替重整过程中的水相,以跟踪液体、气体和固体之间的氢转移。热解油/焦炭重整过程在600、700和800℃下进行。用GC-MS（气相色谱质谱法）分析重整后液体中的油相;IR-MS（同位素比质谱法）分析重整后液体和固体中的氘浓度。研究发现,在实验温度范围内,水蒸气对焦炭的气化作用非常弱,当D₂O/焦炭的比例为2/1时,D₂O中2％（质量）的氘在反应后残留在炭中;但水蒸气与热解油的气化反应很强烈,在800℃时,78.68％（质量）的热解液（水油混合物）被气化,且热解油中脂肪烃被大量分解,重整液的油相组分中芳香烃占到96.17%;同时,当D₂O/油的比例为2/3时,D₂O中59％的氘转移到合成气中。研究结果将为生活垃圾热解处理控制最终产物提供理论指导。     

The relevance of laboratory studies on delayed ettringite formation to DEF in field concretes

Many laboratory studies of delayed ettringite formation (DEF) have been conducted on thin mortar bar specimens, heat treated, and then immersed in water. Under these conditions, rapid diffusion of alkali hydroxide into the surrounding water occurs and necessarily reduces the alkali hydroxide concentration of the mortar pore solution. Results reported recently by Famy indicate that the DEF process is triggered as a consequence of such leaching. When it is prevented by immersion into alkali hydroxide solution instead of water DEF expansion is delayed or prevented entirely. Results reported by Zhang indicate that 51-mm mortar cubes behave differently than more leaching-susceptible mortar bars when exposed to the same wet environment. Mortars that show severe DEF as mortar bars remain almost free of DEF symptoms if they are stored as cubes, even after 900 days. Attention is called to the fact that DEF in concrete is found commonly in thick concrete members where the possibility of leaching is remote. For such concrete, the reduction in internal alkali hydroxide concentration that occurs with ASR can substitute for the effect of leaching. It is postulated that without effective reduction of alkali hydroxide concentration by one or the other process, DEF remains latent.     

Fe2O3对高变质程度脱灰煤热解反应性与半焦结构的影响

利用热天平研究了共混合法负载Fe₂O₃高变质程度脱灰煤的热解反应性,结果表明煤粉负载Fe₂O₃后热解反应性高于无负载的热解反应性。负载Fe₂O₃煤样在程序升温加热的马弗炉中制备出半焦,利用FTIR、XRD和RAMAN 等分析了半焦结构。由TG和FTIR可知,负载Fe₂O₃煤样热解时,热解转化率增加,热解后自由基增加。由XRD可知,Fe₂O₃没有使得煤样半焦的002峰衍射角发生明显变化,但使L_a和L_c参数明显降低,说明半焦的微晶结构石墨化程度降低。另外,在XRD分析谱图中发现部分Fe₂O₃被还原成FeO。由RAMAN可知,Fe₂O₃使半焦的G峰峰面积降低,D峰峰面积增加,说明半焦的有机结构有序化程度降低。     

Study of a novel halogen‐free flame retardant system through TGA and structure analysis of polymers

Butadiene‐rubber toughened styrene polymers, such as acrylonitrile‐butadiene‐styrene (ABS) copolymer and high impact polystyrene (HIPS), are noncharring polymers. They are generally blended with polycarbonate (PC) or polyphenyleneether (PPE), which are char forming polymers, to improve char forming ability for styrenic blends containing conventional phosphate flame retardants. To achieve cost effective flame retardant system, PET was selected as a potential char‐source for ABS blends through the thermogravimetric analysis (TGA) and chemical structure analysis of various polymers. PET may contribute to the enhancement of flame retardancy of ABS/PET blends, especially in the presence of small amounts of phenol novolac (PN). The effective flame retardancy of this system is believed to be accomplished through the enhancement of interchain reactions by PN. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and characterization of high char yield polybenzoxazine/polyarylacetylene blends for resin‐transfer molding

Benzoxazine precursors (BOZP), 6,6′‐bis(2,3‐dihydro‐3‐(3‐ethynylphenyl)‐4H‐1,3‐ benzoxazinyl)ketone and 6,6′‐bis(2,3‐dihydro‐3‐(3‐ethynylphenyl)‐4H‐1,3‐benzoxazinyl)ether were synthesized and characterized by Proton nuclear magnetic resonace (¹H‐NMR) and Fourier transform infrared spectroscopy (FTIR). The polyarylacetylene (PAA) was synthesized through thermal polymerization of diethynylbenzene, and characterized by ¹H‐NMR, FTIR, and Differential Scanning Calorimetry (DSC). The BOZP/PAA blends were prepared with different contents of PAA, and their viscosity was measured using NDJ‐79 rotating visometer. The curing behavior of BOZP/PAA blends was characterized by DSC. The thermal stability of cured BOZP/PAA blends was studied using Thermogravimetric Analysis, the results show char yield at 800°C was in the range of 78–84%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

信号发生模块的Linux驱动程序设计

设计中的信号发生电路主要是由数模转换芯片DAC7725U发出模拟信号,以控制激光器按照一定规律工作。首先介绍嵌入式驱动程序的作用及模型,通过对信号发生电路原理的介绍,以基于OMAP-L137的工业控制开发板为平台,详细地阐述了基于嵌入式Linux操作系统的信号发生模块的驱动程序设计及其测试程序的编写,并实现了设计中所需的±10 V方波信号的输出,为以后更深一步地学习驱动开发奠定了基础。     

Synthesis,characterization, thermal and flame-retardant properties of silicon-based epoxy resins

A new silicon-containing oxirane triglycidyl phenyl silane oxide (TGPSO) and its corresponding silicon-containing epoxy resins are synthesized and characterized. The activation energies of TGPSO curing reaction with various curing agents, including 4,4-diaminodiphenylmethane, 4,4-diaminodiphenylsulfone, and dicyanodiaminde, are found to be 180, 196.5, and 154 kJ/mol. The curing reaction of TGPSO with diamines is determined to be a first-order reaction through means of Arrhenius plots. The introduction of the silicon-containing group results in higher curing reactivity. This silicon-containing resin possesses higher char yield as well as higher limiting oxygen index (LOI = 35) than the commercial epoxy resins, confirming the usefulness of these silicon-containing epoxy resins as flame retardants. Char yields and LOI measurements demonstrate that incorporating silicon into epoxy resins is able to improve their flame retardancy. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1231–1238, 1999     

交互反应对生物质焦炭官能团结构的影响

为解析挥发分-焦炭交互反应对生物质焦炭官能团结构的影响,利用一维固定床/流化床反应器及快速热裂解仪,采用傅里叶红外光谱仪从定性与半定量角度分析交互反应对生物质焦炭官能团结构的影响.结果表明:相比于温度的作用,交互反应对生物质焦炭官能团结构的影响更为剧烈;交互反应使焦炭中的各个特征官能团对应的特征峰强度有所减弱,峰的种类也有所减少;交互反应对焦炭烷基侧链有破坏作用,并加快了其从芳香环上的脱落;在无交互反应下,焦炭有机质的成熟度随着温度的上升而增高;在交互反应下,较低的温度时该规律成立,而较高温度时该参数逐渐下降;在高温下,挥发分裂解产生的自由基会引起芳香环的缩合,导致Car含量增多.     

Synthesis of novolac‐based char former: Silicon‐containing phenolic resin and its synergistic action with magnesium hydroxide in polyamide‐6

Novel novolac‐based char former silicon‐containing phenolic resin (SCPR) was synthesized by the reaction of novolac with γ‐aminopropyltriethoxysilane in ethanol via a dehydration reaction, and the synthesized SCPR was characterized by Fourier transform infrared (FT‐IR) spectra, proton nuclear magnetic resonance (¹H NMR) spectroscopy, and thermogravimetric analysis (TGA). Serving as a synergist of magnesium hydroxide (MH) for the flame retardancy of polyamide 6 (PA6), it shows that the introduction of silicon in the structure of novolac molecule can greatly increase the charring performance of phenolic resin, and effectively eliminate the melt drips of PA6, thus improving the flame retardancy of the PA6. Compared with conventional novolac, the thermal oxidative stability of SCPR was obviously enhanced in the presence of MH due to the decrease of phenol hydroxide groups sensitive to oxidation, as well as the high energy Si–O bond introduced in the molecular structure. Copyright © 2010 John Wiley & Sons, Ltd.