煤的工业分析及其影响因素

煤的工业分析包括煤的水分、灰分、挥发分以及固定碳的分析[1]。本文介绍了煤的水分、灰分以及挥发分含量的测定方法,由于固定碳含量通过计算求得,本文不做介绍。其中,影响水分测定的因素有煤样状态、环境湿度等;影响灰分测定的因素有温度、冷却时间等;影响挥发分测定的因素有煤化程度、煤岩组成、煤的粒度以及升温速度等。为了提高测定的准确度,必须正确分析各测定项的影响因素。     

无烟煅烧技术在水泥回转窑上的应用

1　无烟煤煅烧技术的现状 我们一般将挥发分<15％的煤定为低挥发分煤,将挥发分<10％的煤定为无烟煤。在我国水泥行业中,回转窑煅烧熟料所使用的燃料主要是低位热值大于21　000 kJ/kg、挥发分含量高于20％的烟煤。无烟煤由于挥发分过低,着火温度高,点火困难,燃尽时间长,不容易完全燃烧,对工况的变化比较敏感,操作上难度较大,致使无烟煤长期以来在回转窑系统中未能得到充分的应用。 在我国许多地区均有无烟煤资源,尤其南方一些省份无烟煤资源特别丰富,当地无烟煤的价格大大低于从外地采购、长途运输进厂的烟煤的价格,在一些地方,两者价格差有的甚至高达200元/t左右。近年来,随着技术的发展和市场的变化,工厂对降低水泥成本愈来愈重视。为了提高企业自身的经济效益和社会效益,利用当地廉价的无烟煤作为回转窑煅烧熟料的燃料,已经成为水泥行业的发展趋势,并在实际应用中取得了可喜的成绩。     

转炉除尘灰与纳米催化剂对不同煤阶燃料燃烧特性的影响

利用热分析法研究了转炉除尘灰与纳米催化剂对高挥发分煤、低挥发分煤、无烟煤、石墨等四种不同煤阶样品燃烧过程中着火温度、燃尽指数、最大燃烧速率和最大燃烧速率所对应的温度等燃烧特征参数的影响。结果表明:催化剂对高挥发分煤和低挥发分煤催化效果不明显,对无烟煤和石墨起到了降低着火温度、提高燃尽指数和最大燃烧速率等催化效果。催化剂添加量为4%(质量分数,下同)时,Fe_2O_3对无烟煤催化效果最佳,转炉除尘灰对石墨催化效果最佳,而CaO对无烟煤和石墨的催化效果均最差。对于无烟煤,分别添加2%CaO、4%转炉除尘灰和10%Fe_2O_3时催化效果达到最佳。对于无烟煤和石墨,与纳米催化剂相比,转炉除尘灰催化效果更加明显。无烟煤和石墨在加入催化剂后,整个燃烧过程中的放热量均有所增加,但过高添加量对释放热量有明显的抑制作用。     

低温氧化条件下煤质特性变化的研究

为了探究煤质特征变化的原因和煤分子结构变化的规律,通过测定煤样的水分、发热量、挥发分、粘结指数的变化,采用差热扫描分析仪、傅里叶变换红外光谱、扫描电镜等手段,验证了低温氧化条件下煤样煤质特征的变化情况,表明了低温氧化煤质特征的变化机理。实验结果表明:随着低温氧化时间的不同,褐煤和长烟煤的水分含量发生明显的降低,而中等变质程度以上的烟煤,水分含量受低温氧化的影响较弱;随着煤变质程度的升高,低温氧化对其发热量的影响逐渐减小;低温氧化使煤样的挥发分和粘结性呈现下降的趋势,且随着煤变质程度的增高,氧化对挥发分的影响逐渐减小,而气煤和焦煤的粘结性下降较明显。     

低挥发分煤在新型干法窑生产中的应用

对劣质煤、低挥发分煤的燃烧特性分析,工艺设备分析,提出预分解窑烧劣质煤、低挥发分煤的可能性、必要性,为我公司烧劣质煤、无烟煤打下了基础。     

煤的挥发分对机立窑煅烧的影响

无烟煤在立窑中起到燃烧和配料的双重作用,煤质对立窑熟料产质量影响很大,本文结合我厂不同煤种的立窑煅烧情况,着重从燃料燃烧学和传热学的角度分析煤的挥发分对着火温度的影响及全黑生料的燃烧过程,阐述煤的挥发分不同对立窑燃烧的影响,不妥之处请专家和同行们指导。1 我厂采用不同种类无烟煤煅烧的基本情况 我厂先后用过阳泉煤、京西煤、柳     

混煤燃烧过程中的交互作用:过量空气系数对混煤燃尽特性的影响

在沉降炉上对无烟煤、贫煤、烟煤、褐煤以及不同配比(25%、50%、75%)混煤开展了过量空气系数对混煤燃尽特性影响的实验研究。结果表明,混煤燃烧中挥发分高的煤对挥发分低的煤存在促进和抑制2种交互作用。"炉外"掺烧方式下,低挥发分煤与高挥发分煤掺混时,抢风抑制作用表现明显;尤其是掺烧75%高挥发分煤时,抢风抑制作用最为显著;提高过量空气系数可以改善贫氧气氛,减弱混煤燃烧中的抢风抑制作用,提高混煤燃尽率。"炉内"掺烧方式下,过量空气系数的增加,交互作用减弱,各单煤的燃烧独立性增强,混煤燃尽率逐渐接近计算线性燃尽率。     

利用非线性回归分析研究中国无烟煤挥发分和氢含量的关系

深入研究了中国无烟煤的挥发分和氢含量的内在联系，并利用多元非线性回归分析方法推导出了计算中国主要无烟煤矿区煤的氢含量的回归方程式。     

全黑生料法生产中有关问题的讨论

目前,采用全黑生料法生产的立窑水泥厂逐渐增多,现仅就采用该法生产中出现的有关问题及解决的方法提出个人意见,以供参考。1.熟料烧成热耗与煤挥发分之间的关系立窑煅烧熟料一般用无烟煤、焦炭末等低挥发分燃料。我厂在(?)1.5×7M 双辊简易机窑(风机8—18—1018D)上曾使用过高、中、低挥发分的煤,熟料热耗悬殊较大,波动在1300～1700千卡/公斤之间。在我厂,煤挥发     

影响无烟煤热爆裂的因素研究

研究了高煤阶无烟煤的热爆特性，结果表明热爆裂强弱顺序为：四望嶂〉郭二庄〉门头沟〉万年〉前岭￣章村煤，热稳定性值为１０％￣９７％。加热环境温度越高，煤的热爆性越强。增加预处理时间和提高预处理温度，煤的热稳定性显著提高，有的煤达到９９％以上，热爆性显著下降。煤中内在水分高温下产生的热膨胀应力超过煤自身的极限抗张强度是导致煤爆裂的主要因素之一。挥发分产率和碳酸盐含量对有的煤热爆性产生微弱作用。     

Impact of ammonia fiber expansion (AFEX) pretreatment on energy consumption during drying,grinding, and pelletization of corn stover

Pretreatment and densification of biomass can increase the viability of bioenergy production by providing a feedstock that is readily hydrolyzed and able to be transported over greater distances. Ammonia fiber expansion (AFEX?) is one such method targeted for use at distributed depots to create a value-added and densified feedstock for bioenergy use. However, the pretreatment process results in a high-moisture material that must be dried, further size reduced, and pelletized, all of which are energy-intensive processes. This work quantifies the energy consumption required to dry, grind, and densify AFEX-pretreated corn stover compared to non-pretreated stover and explores the potential of reduced drying as a means to conserve energy. The purpose of this work is to understand whether material property changes resulting from AFEX pretreatment influence the material performance in downstream formatting operations. Material properties, heat balance equations, and a rotary drum dryer model were used to model a commercial-scale rotary drum dryer for AFEX-pretreated corn stover, showing the potential to reduce dryer energy consumption by up to 36% compared to non-pretreated corn stover. Laboratory-measured grinding and pelleting energies were both very sensitive to material moisture content. Overall, the total energy required for drying, grinding, and pelleting amounts to a savings of up to 23 kWh/dry Mg for the AFEX-pretreated material when dried to a low moisture content, equating to up to 0.61 $/Mg savings for gas and electricity. Grinding and pelleting of high-moisture AFEX-pretreated stover was shown to be more costlier than the savings collected through reduced drying. Although the energy and cost savings shown here are modest, the results help to highlight operational challenges and opportunities for continued improvement.     

Application of EIS and SKP methods for the study of the zinc/polymer interface

Electrochemical impedance spectroscopy (EIS) and Scanning Kelvin probe (SKP) were applied to study the zinc/polymer interface. The coating capacitance and the drop of potential across the zinc/epoxy interface are investigated as a function of water penetration and hydrolysis of adhesion bonds. Water penetrates to the interface, decreasing thus the potential drop and increasing the capacitance. Further removal of water leads to the restoration of bonds accompanied by a decrease in capacitance and the return to the initial potential distribution across the interface. Commercial high-performance coil coatings applied to galvanized steel were studied in order to correlate the interface stability and the tendency to blistering. EIS and SKP measurements allowed the evaluation of the electrochemical conditions at the interface. Local adhesion failures caused non-uniformity in the potential profile measured by SKP. Monitoring of changes in impedance at low frequency related to the interface during temperature cycling may be useful for the evaluation of the tendency to blistering.     

基于高斯混合模型的MWPCA高炉异常监测算法

大型高炉是钢铁制造过程中的重要装备,由于高炉运行过程复杂,干扰因素繁多,经常会有异常炉况发生。为及时监测异常炉况、保证高炉顺行,本文利用高炉运行数据,开发了一种基于MWPCA和高斯混合模型的算法对高炉异常过程进行监测。由于高炉运行数据存在非高斯分布和时变的特点,利用高斯混合模型改进了传统PCA监测模型的T²统计量,使算法可以适应高炉数据的独特分布特征,并加入了滑窗机制,使算法具有实时更新的能力。随后,将算法应用在华南某大型钢铁集团的真实高炉数据上,检测了算法的有效性,并将其与基础算法进行了对比分析,证明了算法在高炉异常监测能力上有所提高。     

Microwave improvement of catalyst performance in soot oxidation without additives

The application of microwaves allows to overcome technical hitches related to the regeneration of soot-filters allowing to perform it independently on the engine operating conditions. The performance of a SiC foam filter during microwave regeneration was investigated with and without a catalyst coating. The regeneration efficiency and the energy required for regeneration were evaluated for catalytic and uncatalytic SiC foams by varying the operating conditions of soot trapping.

Results showed that for both catalytic foams, Fe/V/K and Cu/V/K, the capability to be heated independently of the amount of soot allows to maintain temperature sufficiently high to perform a complete foam filter regeneration. Moreover, the microwave absorbing properties of the catalytic phases allow to perform regeneration with a lower energy consumption with respect to the uncatalytic case. The presence of a catalyst also allows to overcome the dependence of microwave-assisted regeneration process on the operating conditions of soot loading.     

高校环境类化学实验室建设和管理的思考

本文从几个方面论述了高校环境类化学实验室的建设、管理与改革。提出建设综合性的实验室,充分利用和再开发实验室资源。建立先进的设备网络管理平台,使用现代化的管理手段,在学校甚至更大范围内实现资源共享。建立实验室设备专管人员制。开放部分实验室,使得学生有机会进行自己的科学研究。对人员的管理应该有明确的责、权、利,根据每个人的特长把责任落实到人。理论课教师、实验教师、实验室管理和技术人员需密切配合,共同搞好实验室的工作。     

难降解有机污染物的生物处理

难降解有机物对环境危害巨大,生物技术是去除这类物质的重要途径。近年来国内外从不同角度研究了强化难降解有机物生物处理效率的方法。从自然环境中筛选分离有效菌和构建工程菌是强化生物处理的首要方法。针对目标污染物的结构性质,以合适的共代谢基质作为诱导物,采取共代谢的方式也可以提高难降解有机物的生物降解速率。此外,通过优化微生物的生存环境、提高微生物耐毒能力和竞争能力等工艺研究同样能够提高生物反应速率。生物技术处理难降解有机物的发展方向趋于三方面:高效菌种库和基因库的建设与丰富,新型反应器与工艺的发明以及各种交叉技术的应用。     

The annual cycle of Flehmen in black-tailed deer (Odocoileus hemionus columbianus)

Flehmen is a stereotyped response of ungulates and other mammals to urine. In black-tailed deer, Flehmen occurs typically in males (rarely in females), and its frequency shows an annual cycle. Flehmen in response to female urine was most frequent in November, and to male urine in January. The response minimum to both types of urine occurred in May. Fifty-five to 100% of initial responses to female urine resulted in Flehmen. The deer responded more often to female urine, and the difference between the responses to female and male urine increased from May to November. A male's own urine released Flehmen more often than did urine of other males. The response intensity varied with the spatial orientation of the male to the urinating female, and responses were usually limited to distances of 15 m or less.     

Explicit Treatment of Non-Michaelis-Menten and Atypical Kinetics in Early Drug Discovery**

Biological systems are highly regulated. They are also highly resistant to sudden perturbations enabling them to maintain the dynamic equilibrium essential to sustain life. This robustness is conferred by regulatory mechanisms that influence the activity of enzymes/proteins within their cellular context to adapt to changing environmental conditions. However, the initial rules governing the study of enzyme kinetics were mostly tested and implemented for cytosolic enzyme systems that were easy to isolate and/or recombinantly express. Moreover, these enzymes lacked complex regulatory modalities. Now, with academic labs and pharmaceutical companies turning their attention to more-complex systems (for instance, multiprotein complexes, oligomeric assemblies, membrane proteins and post-translationally modified proteins), the initial axioms defined by Michaelis-Menten (MM) kinetics are rendered inadequate, and the development of a new kind of kinetic analysis to study these systems is required. This review strives to present an overview of enzyme kinetic mechanisms that are atypical and, oftentimes, do not conform to the classical MM kinetics. Further, it presents initial ideas on the design and analysis of experiments in early drug-discovery for such systems, to enable effective screening and characterisation of small-molecule inhibitors with desirable physiological outcomes.     

我国炼油企业节水减排的技术与措施

分析了炼油企业节水减排的有效途径与措施。一是充分利用循环水和蒸汽凝结水,节约新鲜水;二是提高循环冷却水浓缩倍数,实现节水运行;三是重视污水处理与回用,减少污水排放;四是优化用水系统,提高用水效率;五是推行清洁工艺,从源头节水减排;六是依靠科学管理,落实节水工作。