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高炉喷吹煤粉燃烧性与反应性的研究与应用 总被引:1,自引:0,他引:1
为了研究高炉喷吹煤粉的冶金性能,采用热重分析法对6种无烟煤和1种烟煤进行燃烧性与反应性研究。结果表明,与无烟煤相比,烟煤在不同温度下的燃烧性和反应性均明显高于无烟煤。混煤的燃烧率实测值大于加权值,使用混煤可以发挥无烟煤和烟煤各自的优点,加快燃烧过程,提高混煤燃烧率。随着混煤中粒度小于74 μm煤粉所占比例的增加,燃烧率增大。在高煤比喷吹条件下,混煤煤粉粒度小于74 μm的比例控制在75%左右。结合无烟煤的燃烧性和反应性试验结果,建议喷吹煤粉采购中应尽可能多地采购无烟煤C资源,同时控制无烟煤E的采购量;高炉提煤比操作中应将无烟煤C确定为喷吹用无烟煤的首选煤种,以提升混煤燃烧率和发挥未燃煤粉保护焦炭的作用。 相似文献
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Characteristics of reaction and product microstructure during light calcination of magnesite in transport bed
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A gas-heating laboratory transport bed was adopted to simulate the industrial transportbed reactor for flash calcination of magnesite, and a method based on TG analysis of a reacted sample was further developed to calculate the decomposition rate or conversion of its containing MgCO3. The study investigated how the conversion and product reactivity as well as microstructure vary with reaction conditions including temperature, particle size and times of re-calcination for powder magnesite. Magnesite powder (<150 μm) calcination is a quick reaction that reaches 98% decomposition of its containing MgCO3 in 1—2 s,corroborating the feasibility of magnesite flash-calcination in transport bed reactors. The coloration time given by the citric acid chromogenic method was 17—55 s and 294 s for the obtained products from transport and fixed beds, respectively. This proves the obviously higher activity and thus improved microstructure of the product from transport bed. During the calcination process, the MgO grain size of the product gradually increases, and the surface structure changes from loose and porous to dense and smooth. This structural change can be completed within a few seconds. 相似文献
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轻烧MgO的制备工艺决定其作为混凝土膨胀剂的性能。该文研究了菱镁石的矿物组成和热分解特性,并研究了煅烧温度、保温时间、升温速率以及冷却方式等煅烧工艺参数对轻烧MgO的反应活性以及水化热的影响规律。结果表明:选用适宜粒度的菱镁石可以制备高活性MgO粉体,煅烧温度超过700℃后,随着煅烧温度的升高, MgO化学活性显著降低,当煅烧温度高于700℃时,随着煅烧时间的延长,虽然烧失量逐渐增大,菱镁石分解更加完全,但MgO化学活性随之降低,在相同煅烧温度和保温时间下,升温速率越快MgO活性越高,快速冷却方式制得MgO反应活性较高。 相似文献
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Döne Demirgöz Rodrigo Navarro Mónica Pérez Helmut Reinecke Alberto Gallardo 《应用聚合物科学杂志》2010,115(2):896-900
2‐Hydroxyethylmethacrylate (HEMA) and acrylamide (AA) have been copolymerized via free radical mechanism, in the presence of 5 mol % of four different crosslinker systems, the symmetric ethylenglycoldimethacrylate (EGDMA), bisacrylamide (BIS), a mixture of EGDMA and BIS, and the asymmetric acrylamideethylenmethacrylate (METAA). The polymerizations have been monitored with a rheometer, exhibiting the gel obtained with the asymmetric METAA, an elastic modulus that is dramatically increased compared with those of the gels prepared with the other three crosslinker systems. A kinetic analysis using the terminal model has been used to build probabilistic surfaces that give information about how the crosslinker is incorporated into the network. This analysis shows a high dissimilarity between the reactions using the asymmetric and the mixture of symmetric crosslinkers, what has been correlated to the difference in modulus. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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Recent conceptualizations of alcohol expectancies relate cognitive schemas to their neurobiological underpinnings; cue reactivity paradigms lend themselves well to testing this broadened conceptual framework. In the present study, we examined the relationship between self-reported alcohol expectancies and responses to alcohol-related and affective picture cues among fifty-five young adults. In addition to traditional subjective and psychophysiological indices of cue reactivity, the startle eyeblink reflex was obtained during picture cue presentations to address both attention-arousal (early probes) and affective-motivational (late probes) aspects of cue processing. Analyses indicated that participants reporting greater positive, arousing, and social alcohol expectancies rated alcohol cues as more pleasant, arousing, and craving-inducing. In addition, participants displayed inhibited startle reactivity to late alcohol cue probes, indicative of an appetitive reaction. Finally, startle responding to early probes indicated that participants with greater alcohol expectancies displayed blunted attention to negative affect cues. Findings are discussed in terms of the utility of the startle reflex and cue reactivity paradigms for clarifying the relationship between alcohol expectancies and motivated attention to salient cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
Based on the mood-behavior-model (Gendolla, 2000), this study tested the idea that moods only have effects on effort mobilization in settings that directly call for this and in which people can thus use their moods as task-relevant information. Fifty university students were randomly assigned to a 2 (Mood: negative vs. positive) × 2 (Memorizing: intentional vs. incidental) × 2 (Time: mood induction vs. task performance) mixed model design. Effort mobilization was operationalized as systolic blood pressure (SBP) reactivity. As expected, in the intentional-memorizing condition, SBP reactivity was stronger in a negative mood than in a positive mood. Mood had no impact in the incidental-memorizing condition, which did not call for effort mobilization. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献