单个SMR填料的高径比及倾斜度对流场的影响

INTRODUCTION Random packing is widely used in many unit operations[1].Flow field inside a random packed bed affects the hydrodynamic and mass transfer efficiency.Study on the flow field of random packing is essential for improving hydrodynamic and mass transfer performance,while flow field investigation of single SMR packing is a foundation for random packed bed.Computational fluid dynamics (CFD)[2] may best serve for this purpose.     

聚乙烯扁环填料的流体力学与传质性能研究

在TDBY - 30 0多功能填料塔实验装置中 ,以空气 -氨气 -水为物系 ,对Φ2 5mm聚乙烯扁环填料的流体力学及传质性能进行了研究。获得了该填料的几何特性参数和ΔP/Z～Fv、H0 ～Fv、HOG～G、HETP～G及KGa～G等关系曲线。结果表明 :该填料具有压降适中、通量高、气液分布均匀及传质性能稳定等优点 ,比较适用于清洁、腐蚀性流体的气 -液吸收、精馏和萃取等传质分离工业过程     

Curing Characteristics,Fatigue and Hysteresis Behaviour of Feldspar Filled Natural Rubber Vulcanizates

Curing characteristics, fatigue, and hysteresis behaviour of feldspar filled SMR L vulcanizates and feldspar filled ENR 50 vulcanizates were studied. Two different types of natural rubber, SMR L and ENR 50 having 0 and 50 mol% of epoxide groups were used. The feldspar filled natural rubber vulcanizates were compared at similar filler loading which were used at 0, 10, 20, and 30 phr of filler loading. The curing characteristics such as scorch time (t ₂) and cure time (t ₉₀) slightly increased with increasing feldspar loading for both rubber vulcanizates. Besides t ₂ and t ₉₀, maximum torque (M _HR) significantly increased for both rubbers with increasing feldspar loading. The fatigue test showed that fatigue life decreased with increasing extension ratio, strain energy and filler loading. As the filler loading increased, the poor wetting of the feldspar by the rubber matrix gave rise to poor interfacial adhesion between filler and rubber matrix. Results also indicate that the vulcanizates with the highest feldspar loading exhibited the highest hysteresis. The feldspar filled SMR L vulcanizates showed higher fatigue life and lower hysteresis compare to feldspar filled ENR 50 vulcanizates.     

Theoretical Analysis of Solidly Mounted Film Bulk Acoustic Resonator with Nanocrystalline Diamond as High Impedance Material of Bragg Reflector

纳米金刚石（NCD）作为固贴式薄膜体声谐振器（SMR）布拉格反射栅高声阻抗材料的理论分析

鄂羽佳,张森,代兵,朱嘉琦,韩杰才

（哈尔滨工业大学 复合材料与结构研究所,哈尔滨 150001）

中文说明：

本文设计了一种采用纳米金刚石（NCD）作为布拉格反射栅高声阻抗材料的固贴式薄膜体声波谐振器（SMR）,可以显著提高布拉格反射栅的性能。利用Mathcad软件研究了布拉格反射栅对SMR性能的影响,以及由不同高声阻抗材料、不同层数组成的布拉格反射栅对SMR品质因子Q的影响。结果表明,选用纳米金刚石作为高声阻抗材料的布拉格反射栅能有效地降低能量损失,且可以有效地提高SMR的性能。高声阻抗材料的声阻抗越高,SMR性能越好。建立MASON模型,利用先进设计系统（ADS）模拟了金属钨（W）和NCD两种高声阻抗材料组成的布拉格反射栅对SMR器件所产生的寄生因素的影响。结果表明,金属材料所引起的寄生效应会显著降低SMR的品质因子Q。在6 GHz以下的频率范围内,在SMR正常工作的情况下,选用NCD作为高声阻抗材料的器件性能优于W,因此,NCD是SMR设计中高声阻抗材料的较好选择,在高频和低损耗下,器件的性能得到了改善。同时,布拉格反射栅的最佳层数为6层。

关键词：固贴式薄膜体声波谐振器（SMR）,纳米金刚石（NCD）,布拉格反射栅,品质因子（Q）,寄生效应

     

Steam methane reforming over structured reactors under concentrated solar irradiation

Intermittent nature of solar energy and solution strategies for steam methane reforming reaction powered by concentrated solar energy over Ni/mullite and Pd/CeO₂/mullite catalysts were demonstrated. The solar concentration was achieved using a parabolic mirror with a 70 cm, delivering concentrated solar flux onto a focal area that is approximately 3 cm in diameter. The solar field tests conducted on monolithic catalyst support structures were compared with the laboratory scale measurements on powdered catalysts. Despite the fluctuations in solar irradiation, CH₄ conversions higher than 90% could be obtained. Coke deposition was observed over the 15%Ni/Mullite monolith. On the 1%Pd/20%CeO₂/Mullite monolith, the oxidative nature of the catalyst resulted in oxidation reactions with local temperatures exceeding 1700 °C, inferred through the melting point of mullite. Numerical simulations revealed temperature gradients as large as 500 °C, over the refractory monoliths.     

Advanced m-CHP fuel cell system based on a novel bio-ethanol fluidized bed membrane reformer

Distributed power generation via Micro Combined Heat and Power (m-CHP) systems, has been proven to over-come disadvantages of centralized generation since it can give savings in terms of Primary Energy consumption and energy costs.The FluidCELL FCH JU/FP7 project aims at providing the Proof of Concept of an advanced high performance, cost effective bio-ethanol m-CHP cogeneration Fuel Cell system for decentralized off-grid applications by end of 2017. The main idea of FluidCELL is to develop a new bio-ethanol membrane reformer for pure hydrogen production (3.2 Nm³/h) based on Membrane Reactors in order to intensify the process of hydrogen production through the integration of reforming and purification in one single unit. The novel reactor could be more efficient than the state-of-the-art technology due to an optimal design aimed at circumventing mass and heat transfer resistances. Moreover, the design and optimization of the subcomponents for the BoP could also be improved. Particular attention has to be devoted to the optimized thermal integration that can improve the overall efficiency of the system at >90% and reducing the cost due to low temperature reforming. The main results obtained until now in terms of performance of the catalysts, membranes and the membrane reactors will be presented in this work.     

A techno-economic assessment of NuScale and DHR-400 reactors in a district heating and cooling grid

Many companies are developing small modular reactors (SMR), but only few are in a licensing or demonstration phase. Several papers have studied the economy of the SMRs, but district heating studies were carried out without a reference energy system that has a high impact on the results. We modeled NuScale CHP and DHR-400 (heat only) units as a part of a city-level district heating and cooling grid. In the studied reference system, NuScale CHP and DHR-400 look cost-efficient investments with internal rates of return from 7% to 20%. Modeled heat only reactor had better profitability than CHP reactor in almost all cases except when assuming higher than 50 €/MWh electricity prices. Large heat pumps with COP of 3.5 had similar economic performance than studied SMRs. Large heat pumps are less capital intensive than SMRs and easier to accept by public, but their potential is limited by the available heat sources.     

Updated hydrogen production costs and parities for conventional and renewable technologies

This paper provides first a review of the production costs of hydrogen from conventional, nuclear and renewable sources, reported in the literature during the last eight years. In order to analyze the costs on a unified basis, they are updated to a common year (2009), taking into account the yearly inflation rates. The study also considers whether the hydrogen has been produced in centralized or distributed facilities. From these data, the expected future costs for conventional production of hydrogen are calculated considering several scenarios on carbon emission taxations. Based on these estimations, together with the predicted future costs (2019–2020 and 2030) for hydrogen from alternative sources, several hydrogen cost-parity analyses are exposed for renewable and nuclear energies. From the comparison between these alternative technologies for hydrogen production and the conventional ones (steam methane reforming and coal gasification), several predictions on the time-periods to reach cost parities are elaborated.     

Hydrogen production by methane decomposition: Origin of the catalytic activity of carbon materials

A wide variety of carbon materials (ordered mesoporous carbons, carbon blacks, activated carbon, carbon nanotubes, coke and graphite) have been investigated as catalysts for hydrogen production by methane decomposition, with the aims of identifying the carbon properties which control in a greater extension the catalytic activity and determine the nature of the active sites involved in the reaction.The catalytic activity of the different carbon materials was determined and compared using temperature-programmed experiments in a thermobalance. The initial activity was followed through the threshold temperature, defined as the temperature at which hydrogen production starts being detected, whereas the average reaction rate was also calculated and compared. The lowest threshold temperature was observed with ordered mesoporous carbons (CMK materials), followed by activated carbon and carbon blacks. On the other hand, at long reaction times activated carbon was quickly deactivated yielding a relatively low average reaction rate. The deactivation process seems to be greatly linked to the presence of micropores while the long-term activity is retained in those materials with ordered mesoporosity (CMKs) or formed by nanoparticles (carbon blacks), which make them more resistant to deactivation by the formation of carbonaceous deposits.Whereas no clear dependence is observed between the threshold temperature and the surface area neither with the presence of polar groups in the carbon catalysts, characterization of these materials by XPS shows that a direct relationship exists with the amount of defects present on the graphene layers. This fact strongly supports that these defects are the main active sites for methane decomposition over carbon catalysts.     

核能制氢与高温气冷堆

氢是环境友好的能源载体,利用核能制氢引起了广泛的研究兴趣。本文对核能制氢的工艺,包括甲烷蒸气重整、高温电解和热化学循环进行了综述;提出了制氢过程对反应堆的要求,并介绍了高温气冷堆用于核能制氢的优势。