135MW机组CFB锅炉设备稳定运行问题研究与应用

结合大屯发电厂2台440t／h CFB锅炉运行情况．就影响机组稳定运行的炉膛及冷渣器排渣、炉膛布风板漏渣、原煤仓堵煤、给煤口积煤、耐火保温材料选择、施工及烘烤、燃煤粒径控制等问题进行了分析研究,提出了运行技术优化调整办法。     

600MW W火焰锅炉卫燃带改造与结渣分析

针对某600MW W火焰锅炉侧墙卫燃带结渣严重问题,为降低侧墙温度、减轻结渣,将原侧墙卫燃带局部去除,采用CFD软件对多工况下的炉内速度场和温度场进行数值模拟,将计算结果与现场试验进行对比,验证了计算模型的准确性,并结合现场运行情况综合分析了下炉膛侧墙易结渣的原因.结果表明:锅炉侧墙压力偏低导致煤粉气流向侧墙流动,过高的侧墙温度使结渣情况加重;减少侧墙卫燃带面积使侧墙温度降低,可缓解侧墙结渣.     

热解温度对生物质半焦特征的影响

对稻壳和稻秸进行了机理性热解试验,并采用TG、SEM、EDS和XDR方法研究和分析了半焦的孔隙结构、结渣特性、氯和硫元素迁移和无机化合物晶相等物化特性的变化规律．结果表明：在500～800℃,生物质热解半焦孔隙结构的变化较大．当热解温度为1000℃时,稻壳半焦的凸面呈现熔融现象,稻秸半焦呈现熔融黏结现象．在800～1000℃,半焦中剩余的氯和硫大部分会析出;在稻壳和稻秸热解过程中,当终温为1000℃时,物相发生较大变化并且出现非晶态的无机化合物．     

准东煤燃烧过程中Na/Ca/Fe对结渣行为影响的机理研究

在一维沉降炉实验系统中进行准东煤燃烧实验,采用非冷却的取样探针在不同烟气温度下收集灰样并进行分析,以获得烟气中不同无机成分在结渣前的形态及灰颗粒间的结合方式.结果表明:当烟气温度为1 000℃时,存在熔融态Na的硅酸盐、硅铝酸盐和CaSO_4,这些熔融态的灰颗粒会撞击、黏附在管壁上;当渣层逐渐增厚时,表面温度升高,可能在渣层表面形成熔融态的膜,以捕捉其他灰颗粒;Fe具有助熔作用,可与硅钙镁铝钠体系形成低温共熔物,当Fe_2O_3颗粒撞击到焦体熔融表面时,其助熔作用会降低焦体表面的熔点而形成新的焦体.     

生物质锅炉高温过热器腐蚀机理的研究

本文分析了生物质锅炉高温过热器腐蚀垢样的主要成分及熔融特性,结合现场实际和相关文献,研究了腐蚀发生过程,以及在碱金属氯化物对高温熔融腐蚀的作用,并对腐蚀的典型温度区间、普遍存在性和持续性的特点进行了分析,最后提出了防止腐蚀的措施和方法。     

陶瓷板卫燃带及其在电站煤粉炉上的应用

分析了煤粉锅炉传统卫燃带的局限性,提出了安装维修方便,成本低的可拆卸式陶瓷隔热板卫燃带,详细介绍了这种新型卫燃带技术的工程实施方案,给出了确定陶瓷隔热板卫燃带板热物理参数的设计计算方法与结果.最后介绍了这种新型卫燃带技术在400 t/h、1 025 t/h电站煤粉炉上的应用情况.     

锅炉结渣过程数值模拟研究进展

传统、单一的预测结渣经验指数不能充分描述和预测复杂的结渣过程，但结渣过程的数值模拟能克服这一不足，详细地描述结渣的形成及结渣轻重的位置分布．结渣模型包括煤粉空气气固两相流动和燃烧子模型、飞灰形成子模型、飞灰颗粒与壁面的碰撞和黏结子模型以及结渣生长过程子模型．本文对近十几年来各种模型的研究进展进行了综合评述，同时也指出了为提高精确性需要继续进行研究的方向．     

基于表面温度控制的卫燃带设计方法

提出了基于卫燃带向火面表面温度计算及控制的卫燃带设计方法,并根据炉内火焰与水冷壁管及卫燃带间的集总参数换热模型及卫燃带向火面至水冷壁管内工质各个环节的传热模型,建立了将卫燃带向火侧的表面温度与锅炉负荷、卫燃带材料导热系数、卫燃带敷设厚度与面积关联的代数模型,并运用该模型对1台燃用阳沁无烟煤的1025 t/h四角切圆燃烧煤粉锅炉的卫燃带进行了传热计算.结果表明:锅炉负荷对卫燃带的表面温度影响最大,并且成近似线性关系;卫燃带厚度对表面温度的影响显现出对数函数的特性;卫燃带表面温度随材料导热系数的下降快速升高;卫燃带表面温度随面积的增加而缓慢增加;计算结果与国内1025 t/h同类型煤粉锅炉卫燃带的实际应用情况吻合.     

杜仲药渣与煤的混烧特性及灰熔融特性研究

本文采用热重分析仪分析了杜仲药渣和石下江煤的混合样品的燃烧特性,采用灰熔点测试仪、X射线荧光仪、X射线衍射仪及扫描电子显微镜对混合物灰样的灰熔融特性变化进行了分析.结果表明:药渣掺混比为40%时着火温度最低;加入90%药渣时,稳燃性指数、综合燃烧特性指数、最大燃烧速率和平均燃烧速率值均达到最大,燃尽温度最小;在杜仲叶渣和煤的共燃过程中,发生了协同作用,生成了一些新的矿物质,混合灰样的灰熔融温度随着药渣质量分数的增多而减小.     

基于表面温度计算与控制的卫燃带设计方法及应用

提出了基于卫燃带向火侧表面温度计算及控制的卫燃带设计准则,并根据炉内火焰与水冷壁管及卫燃带间的集总参数换热模型及卫燃带向火面至水冷壁管内工质各个环节的传热模型,建立了将卫燃带向火侧的表面温度与锅炉负荷、卫燃带材料导热系数、卫燃带敷设厚度与面积关联起来的代数模型,并运用该模型对一台燃用松藻无烟煤的400t/h四角切圆燃烧定压运行煤粉炉的卫燃带进行了设计传热计算.结果表明锅炉负荷对卫燃带的表面温度影响最大,且近似呈线性关系;卫燃带厚度对表面温度的影响显现出对数函数的特性;卫燃带表面温度随材料导热系数的下降快速升高并随面积的增加而增加;对于导热系数为12 W/(m·k),厚度为60 mm的卫燃带,其计算的敷设面积为50～100 m2,与国内外400t/h同类型煤粉炉卫燃带的实际应用情况吻合良好.     

Base effects on electrochemical oxidation of indoline

The electrooxidation of indoline was studied as the first step in exploring its utility as a model liquid hydrogen carrier. Electrochemical oxidation of indoline in the presence of nitrogen-containing bases resulted in a cathodic shift in the onset of the oxidation. A linear correlation was found between the pK_a of the base and the magnitude of the cathodic shift of indoline oxidation. A hydrogen bonding complex model is proposed to account for this effect, and ¹H NMR spectroscopy and cyclic voltammetry experiments were conducted to support this proposed mechanism.     

黏接技术在煤矿开采中的应用

介绍了黏修煤矿机械设备的常用方法,分析了黏接技术在煤矿机械设备维修中的作用,对黏接技术在煤矿机械设备修复中的应用进行了探讨。通过研究,发现黏接技术可有效避免焊接操作中存在的问题,能在煤矿开采中发挥非常重要的作用。     

Metal-oxygen bonding nanoarchitectonics for regulation of oxygen evolution reaction performance in FeNi-codoped CoOOH

Bimetallic doping is widely used to enhance the oxygen evolution reaction (OER) activity of layered transition metal oxyhydroxides. However, the synergistic enhancement effect of different doping elements on the intrinsic OER activity is still obscure. In this study, the FeNi-codoped cobalt oxyhydroxide (CoOOH) as OER electrocatalyst was prepared successfully by simple electrodeposition and anodic oxidation methods, which exhibits superior OER activity to the single-metal doped CoOOH systems. Based on both experiments and first-principles calculations, the results show that the reaction kinetics enhance due to the codoping of Fe and Ni. Fe-doping changes the active site from Co to Fe and enhances the hydroxyl group adsorption. Ni doping benefits the electron transfer between Fe and intermediates, thereby enhancing the Fe–O covalent component to further balance the two steps of hydroxyl group adsorption and the deprotonation step. The essential mechanism of bimetal-doping in CoOOH provides theoretical support for the design and development of bimetal-doped Co-based OER catalysts.     

Thermal transport properties of monolayer phosphorene: a mini-review of theoretical studies

Phosphorene, a two-dimensional (2D) elemental semiconductor with a high carrier mobility and intrinsic direct band gap, possesses fascinating chemical and physical properties distinctively different from other 2D materials. Its rapidly growing applications in nano-/opto-electronics and thermoelectrics call for fundamental understanding of the thermal transport properties. Considering the fact that there have been so many studies on the thermal transport in phosphorene, it is on emerging demand to have a review on the progress of previous studies and give an outlook on future work. In this mini-review, the unique thermal transport properties of phosphorene induced by the hinge-like structure are examined. There exists a huge deviation in the reported thermal conductivity of phosphorene in literature. Besides, the mechanism underlying the deviation is discussed by reviewing the effect of different functionals and cutoff distance in calculating the thermal transport properties of phosphorene. It is found that the van der Waals (vdW) interactions play a key role in the formation of resonant bonding, which leads to long-ranged interactions. Taking into account of the vdW interactions and including the long-ranged interactions caused by the resonant bonding with large cutoff distance are important for getting the accurate and converged thermal conductivity of phosphorene. Moreover, a fundamental insight into the thermal transport is provided based on the review of resonant bonding in phosphorene. This mini-review summarizes the progress of the thermal transport in phosphorene and gives an outlook on future horizons, which would benefit the design of phosphorene based nano-electronics.     

Protic amino-2-propanol hydrochloride-based deep eutectic solvents with multiple hydrogen bond sites for efficient capture of NH3

The ammonia (NH₃) emitting into the atmosphere during the industrial process of synthesizing ammonia not only constitutes serious air pollution, but also causes a waste of ammonia resources. Therefore, there is an urgent need to develop efficient ammonia capture technology. In this work, we report an efficient capture of NH₃ by protic amino-2-propanol hydrochloride-based deep eutectic solvents (DESs). These DESs with multiple hydrogen bond sites exhibit remarkable NH₃ uptake with up to 0.244 g NH₃ per g DES at 293 K and 1 bar and good recyclability. Further mechanism study suggested that the introduction of hydrogen bond donors with rich hydroxyl groups provides a large number of hydrogen bond sites to achieve efficient absorption of NH₃ through the intermolecular hydrogen bonds interaction. This research has obtained an alternative absorber for the capture of NH₃, and it also provides ideas for the design of high-efficiency NH₃ deep eutectic solvents absorbent.     

氨水储槽泄漏的粘接修复

阐述了氨水储槽破裂的原因及粘接修复工艺过程。破裂部位在经过清洗打磨,18%的浓盐酸处理液中室温处理5~10 min后,选用无碱无蜡玻璃纤维布和环氧-聚硫胶为修复材料,采用涂胶与玻璃布贴敷交替进行,最后室温固化24 h,完成整个粘接修复过程。     

Characterization of hydrogenated niobium interlayer and its application in TiAl/Ti2AlNb diffusion bonding

Hydrogenation of niobium foil was achieved by cathodic charging and its application as the interlayer facilitates a sound joint of TiAl/Ti₂AlNb. The microstructure and mechanical properties of hydrogenated niobium were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), nano-indentation and thermogravimetry (TG) analysis. It is demonstrated that the plasticity of the surface of niobium interlayer is improved and dislocation density in niobium crystal lattice increases significantly, owing to the process of niobium interlayer hydrogenation and subsequent dehydrogenation. To investigate the effect of the hydrogenation of the niobium interlayer on the TiAl/Ti₂AlNb diffusion bonding joint, the pure niobium foil was also applied as the interlayer for comparison. The effect of the bonding parameters on the interfacial microstructure evolution and mechanical properties of the joints were systematically analyzed by SEM coupled with an energy-dispersive spectroscopy (EDS) and shear test. The typical microstructure of the joint is found to be TiAl/B2 phase/Nb/δ phase/β phase/Ti₂AlNb. With the increase of the hydrogen content, bonding temperature, holding time and bonding pressure, the bonding defects decreased and the thickness of the diffusion layer increased correspondingly. The shear strength of joint reached 258.9 MPa at 950 °C for 40 min under a pressure of 5 MPa with the hydrogenated niobium interlayer of 1.0 wt% hydrogen content.     

起重机械保护接地与检验检测

根据IEC相关标准要求和起重机械电气设备的用电特点，对起重机械保护接地概念和措施进行梳理，对有关规范的要求进行探讨。强调起重机本体应设置独立保护导线，尽可能装设剩余电流动作保护器，保护接地电路应始终保持连通，尽量实施等电位联结。提出保证起重机械接地故障防护本质安全的系统检验要求，并对检验项目进行法定检验的分工和划分。     

In-situ synthesis of BiVO4 QDs/cellulose fibers composite for photocatalytic application

In this work, a biofiber was used as the natural polymer carrier to design a BiVO₄ QDs/cellulose fiber composite for photocatalytic application. The biofiber was obtained from bamboo, which was green, abundant and short growth cycle in Asia. Naturally rich groups of biofiber provided many sites to absorb the Bi³⁺ to form the uniform distribution for BiVO₄ QDs. Moreover, a series of results indicated the strong connection was formed between biofiber and BiVO₄ QDs, which could increase the stability and electron transfer. Therefore, the new composite photocatalyst exhibited better stability and effectively photocatalytic activity. Moreover, the possible mechanism of synthesis and photocatalytic were discussed, which provided insight for synthesizing photocatalytic based on biomaterials.     

Theoretical study of the synthesis,characterization and hydrogen storage properties of a high-density hydrogen storage material: (CH3NH3)BH4

Inspired by both alkaline metal borohydrides and organic-inorganic hybrid perovskite, we predict a pair of complex structures of (CH₃NH₃)BH₄ with tremendous high hydrogen capacity (21.27 wt.%). Through comparison and analysis of the electronic structures of alkali metal atoms, CH₃NH₃, NH₄, and NH₃BH₃ molecule, it is concluded that similar spatial and electronic structures show the feasibility of synthesizing (CH₃NH₃)BH₄ by a substitution reaction. Firstly, theoretical structures (S₁ and S₂ in P₁) with stable configurations have been reconstructed by cation substitution followed by a series of restrictive structural optimizations, and both the lattice parameters and the position coordinate information of (CH₃NH₃)BH₄ are obtained. Ignoring the relatively mobile hydrogen, the structural symmetries of S₁ and S₂ are I4mm and P4/nmm, respectively. X-ray diffraction characterizations of S₁ and S₂ are consistent with the experimental results. Secondly, the calculated elastic constants of (CH₃NH₃)BH₄ (S₁ and S₂) with P₁ symmetry indicate that angles α, β and γ oscillate at right angles due to the influence of the cation orientation. The calculated spatial dependence of bulk (B), Young's (E), and shear (G) modulus obviously show that the two P₁ phases all have strong elastic anisotropy. Thirdly, the calculated electronic properties show that the protonic amine-H, hydridic borane-H, and neutral methane-H are widely distributed in (CH₃NH₃)BH₄, which allow for weaving in a planar dihydrogen bonding network, which in turn influences the dehydrogenation reaction. Last and most important, we propose the following dehydrogenation process of (CH₃NH₃)BH₄ via the intermediate compounds: 2(CH₃NH₃)BH₄ → CH₃NH₂BH₂NHCH₃BH₃+3H₂. For each dehydrogenation step, the free energy change is negative, which means (CH₃NH₃)BH₄ can decompose spontaneously, similar to ammonium borohydride, which is strongly related to the planar dihydrogen bonding network.