350MW机组锅炉SCR脱硝系统优化

准东煤田是我国目前最大的整装煤田,但准东煤在锅炉燃烧过程中易发生结焦问题,一般掺烧高岭土缓解结焦。某燃用准东煤350 MW机组,锅炉燃煤掺烧高岭土后烟气携带灰尘颗粒及灰尘量增大,出现SCR脱硝系统烟道积灰严重和喷氨量明显偏大问题,同时在空气预热器形成硫酸氢氨堵塞,使机组不能长周期稳定运行。通过与国内同类型多台机组锅炉对比后发现,脱硝系统均存在易产生积灰的脱硝转向室、催化剂上方及空气预热器入口斜坡积灰状况等情况。针对存在的问题,通过建立改造前、后的模型计算分析,进行了导流板布置的优化设计、CFD流场分布、优化SCR系统导流板设计、声波与蒸汽吹灰器结合吹灰和氨注射栅格优化升级等工作,应用德图480风速仪实测风速试验,发现脱硝烟道原导流板设计不合理及施工安装偏差;原导流板水平段跨距大,支撑不足,造成导流板压塌变形,影响烟气流场分布;锅炉所烧煤质为高钠煤,为防止锅炉结焦掺烧高岭土后,增加了烟气飞灰颗粒及灰尘量,飞灰具有很大黏性,易沉积在烟道导流板及烟道壁面上。因此,提出对脱硝内部各处导流板进行优化改造,对脱硝系统烟道易产生积灰的部位增加声波吹灰器,对喷氨格栅喷嘴数量及氨空混合器升级,同时开展锅炉SCR脱硝喷氨热态优化调整试验工作。通过开展相关工作,SCR烟气系统的烟气流场相对标准偏差优化5%,相同负荷下液氨消耗量降低45%,彻底解决脱硝系统积灰和空气预热器堵塞问题,实现机组满负荷达标稳定运行。锅炉长期运行半年后停炉检查,发现前期脱硝系统烟道高达1 m的积灰部位彻底解决,催化剂表面干净无杂物,解决了脱硝系统积灰问题,同时配合提高空气预热器冷端综合温度的措施,彻底解决锅炉空气预热器堵塞问题。同时,经济效益显著,每年可以分别节约液氨费用70万元,节约风机电耗费用100万元,节约检修清理积灰及检修费用80万元,节约空气预热器冲洗治理费用20万元,综合节约费用270万元/a,达到预期效果实现机组长周期安全经济稳定运行。     

内热型超声雾化溶液再生系统最优内热量的研究

基于质量守恒、能量守恒定律，建立了内热型超声雾化溶液再生系统（IH-UARS）的再生性能预测模型并进行了充分的实验验证，通过研究不同内热量下IH-UARS的再生性能及其变化规律，寻求系统所需的最佳内热量并明确其可能的影响因素。结果表明：IH-UARS系统存在最优的内热量范围，使其再生系统性能最佳；所需最优内热量随着再生溶液流量增大呈显著的对数增长，但受空气流量的影响较弱；在该研究中的标准工况下，IH-UARS所需最优内热量约为275~350 W。此外研究发现：内热量的增长有益于促进初始浓度较高的溶液进一步浓缩再生，如当IH-UARS中内热量增至800 W时，其初始浓度为36%的溶液比24%的溶液浓度增量指标改善幅度高37%。研究所得结果可对提高溶液再生性能及经济性提供积极参考。     

Surface nanodeformations caused by ultrashort laser pulse

Ultrashort laser pulse is a unique nanometallurgical tool which operates at extreme conditions: ultimate strength of material, the smallest spatiotemporal scales, and nonequlibrium crystallization. Approaches to ultimate strength and to highly nonequlibrium crystallization are tightly coupled with the smallness of spatiotemporal scales. Usage of the tool opens new opportunities to create materials with enhanced surface hardness, anticorrosion properties, and diverted optical constants. To use these advantages we have first of all to develop clear and reliable physical model. The paper presents new results concerning interactions of optical or X-ray lasers with metals. It is shown that ultrashort laser pulse melts surface layer, sends shock into bulk, and foams molten metal. Dense dislocation bilayer is created thanks to fast recrystallization (the first sublayer) and plastic transformations behind strong shock (the second sublayer). Plastic shock generated at moderate laser intensities attenuates sharply during its propagation into metal. During this attenuation, a plastic shock regenerates into a powerful elastic shock. This process defines boundary between the second dislocation sublayer and undamaged solid. Mechanical breaking of foam after its strong stretching and fly away of a part of melt together with fast freezing are responsible for appearance of chaotic frozen nanostructures at an irradiated surface.     

A highly transparent and thermally stable copolymer of 1‐adamantyl methacrylate and styrene

Thermal and optical properties of copolymers of 1‐adamantyl methacrylate (AdMA) and styrene (St) prepared by free radical polymerization in the bulk are investigated. The copolymer forms an azeotrope when the composition is AdMA/St = 55/45 mol%. The glass transition temperature and decomposition temperature of the azeotropic copolymer are 170 and ca 340 °C, respectively. The refractive index increases nonlinearly with St content from 1.522 to 1.591. The light scattering loss at 633 nm is 28.1 dB km^?1, which is less than half of that of polystyrene. The total optical loss including molecular vibrational absorption, which is evaluated using a copolymer‐based optical fiber, is 292–645 dB km^?1 at 500–700 nm. These values correspond to transmittances of 86–93% for a 1 m optical path length. © 2014 Society of Chemical Industry     

Diffuse color patterning using blended electrochromic polymers for proof‐of‐concept adaptive camouflage plaques

A study using three different pairs of electrochromic polymers (ECPs) synthesized onto plaques by means of a modified vapor phase polymerization (VPP) technique is presented. Restriction of the respective polymerization times, allowed both faster and slower polymerizing monomers to be controlled, and produced blended plaques with visually diffuse interfaces. The ECPs within the blended plaques retain their individual electrochromic behavior and when encapsulated into an electrochromic device, show outstanding optical switching performance with little degradation evident over 10,000 cycles, coupled with a switching time of the order of 1 second. Blends also allow multiple diffuse color changes within an electrochromic device, due to the difference in oxidation potentials of the individual ECPs, making them candidates for adaptive camouflage use. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42158.     

Metal–organic frameworks for electronics: emerging second order nonlinear optical and dielectric materials

Metal–organic frameworks (MOFs) have been intensively studied over the past decade because they represent a new category of hybrid inorganic–organic materials with extensive surface areas, ultrahigh porosity, along with the extraordinary tailorability of structure, shape and dimensions. In this highlight, we summarize the current state of MOF research and report on structure–property relationships for nonlinear optical (NLO) and dielectric applications. We focus on the design principles and structural elements needed to develop potential NLO and low dielectric (low-κ) MOFs with an emphasis on enhancing material performance. In addition, we highlight experimental evidence for the design of devices for low-dielectric applications. These results motivate us to develop better low-dielectric and NLO materials and to perform in-depth studies related to deposition techniques, patterning and the mechanical performance of these materials in the future.     

Experimental investigation and simulation analysis of the thermal performance of a balcony wall integrated solar water heating unit

A balcony wall type solar water heater system was designed and constructed in a high-rise building. The U-type evacuated glass tube solar collector is fixed vertically on the balcony wall. The water, heated in the solar collector, flows through the exchanger coil in the water tank and then flows back to the solar collector. With regard to the hot water supply system, the cold water, heated by the heat exchanger, is sent to the point of use. Considering storeys and water consumption pattern, four apartments are selected for testing. Meanwhile, the theoretical analysis with TRNSYS was presented. According to the experimental results, mean daily collector efficiency is about 40%. Solar fraction is high in summer and autumn for the relative high radiation and high ambient temperature. Under given conditions, the annual energy extracted from tank is 2805.3 MJ/m², and the annual solar fraction is 40.5%. When the tank volume-to-collector area ratio is decreased to 37.5 L/m², the solar fraction can be increased to 50%. The results show that the family to use water all day round gets higher solar fraction than the family using hot water mostly in the morning and night.     

房建施工中防渗漏技术的实际应用探讨

随着我国社会经济的快速发展，人们生活水平的不断提高，人们对以住房为代表的生活品质有了更高的要求。渗漏是房屋建筑工程中对人们生活品质有严重影响的问题，其在房屋建设活动中的频繁出现引起了社会各界的关注。从实际应用的角度出发，结合房建施工的实际，对房建施工中防渗漏技术的实际应用进行了简要的分析。     

Transparent niobate glass-ceramics for optical limiting

The construction of nonlinear optical materials featuring asymmetric transmission of light is of great technological importance for various applications, including optical switching and optical power limiting. A significant challenge is the scalable fabrication of material candidates with good photochemical stability, high optical transmittance, and excellent optical limiting performance. Here, we present a nanocrystallization avenue for constructing hybrid optical limiting materials that exhibit ultrafast and robust optical limiting performance. The experimental results show that the controllable relaxation of a niobate glass may lead to the clustering of Nb-O units and contracting of the bandgap. It results in the notable improvement in nonlinear optical properties, including the enhanced saturation irradiance (380 GW/cm²), doubly increased nonlinear coefficient, and decreased limiting threshold (200 GW/cm²). Our results suggest a promising material that exhibits promising applications for protecting eyes and sensitive components from laser-induced damage.     

Evolution of microstructure,optical, and magnetic properties in multiferroic CuFe1-xSnxO2 (x = 0–0.05)

Evolution of the microstructure, optical, and magnetic properties have been investigated systematically in multiferroic CuFe_1-xSn_xO₂ (x?=?0–0.05) ceramics. Substitution of Sn⁴⁺ for Fe³⁺ results in expansion of CuFeO₂ lattice, and reduces the density of the material, but the metal oxidation states are unchanged. Observation of the optical properties shows that the value of the direct optical band gap (E_g) decreases with increasing Sn doping level, and that the CuFe_1-xSn_xO₂ (x?=?0–0.04) series with values >?3.1?eV. Magnetic susceptibility measurements show that Sn⁴⁺ doping decreases the Curie-Weiss temperature, i.e. weakens the strength of the antiferromagnetic interaction between high-spin Fe³⁺ ions, but does not affect the stability of the antiferromagnetic phase, and all samples undergo successive magnetic transitions at about T_N1 =?15?K and T_N2 =?11?K. However, magnetization curves show that changes occur in the magnetic interactions and both ferromagnetism and antiferromagnetism co-exist in the Sn⁴⁺-doped samples. The maximum value of the saturation magnetization of 1.8?emu·g^?1 was observed for the x?=?0.03 sample in a 2.5?kOe field. The changes in the magnetic behavior are closely related to the lattice distortion and charge compensation, which are discussed in detail in this work.