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Hydrogen production using advanced reactors by steam methane reforming: A review 先进反应器蒸汽甲烷重整制氢研究进展
Pub Date : 2023-04-14 DOI: 10.3389/fther.2023.1143987
A. Ganguli, Viraj Bhatt
The present review focuses on the current progress on harnessing the potential of hydrogen production by Methane Steam Reforming (MSR). First, based on the prominent literature in last few years, the overall research efforts of hydrogen production using different feed stocks like ethanol, ammonia, glycerol, methanol and methane is presented. The presented data is based on reactor type, reactor operating conditions, catalyst used and yield of hydrogen to provide a general overview. Then, the most widely used process [steam methane reforming (SMR)/methane steam reforming (MSR)] are discussed. Major advanced reactors, the membrane reactors, Sorption Enhanced methane steam reforming reactors and micro-reactors are evaluated. The evaluation has been done based on parameters like residence time, surface area, scale-up, coke formation, conversion, space velocity and yield of hydrogen. The kinetic models available in recently published literature for each of these reactors have been presented with the rate constants and other parameters. The mechanism of coke formation and the rate expressions for the same have also been presented. While membrane reactors and sorption enhanced reactors have lot of advantages in terms of process intensification scale-up to industrial scale is still a challenge due to factors like membrane stability and fouling (in membrane reactors), decrease in yield with increasing WHSV (in case of Sorption Enhanced Reactors). Micro-reactors pose a higher potential in terms of higher yield and very low residence time in seconds though the volumes might be substantially lower than present industrial scale conventional reactors.
综述了国内外利用甲烷蒸汽重整制氢潜力的研究进展。首先,根据近年来的重要文献,介绍了乙醇、氨、甘油、甲醇和甲烷等不同原料制氢的总体研究成果。提出的数据是基于反应器类型,反应器操作条件,催化剂的使用和氢气的产量,以提供一个总的概述。然后讨论了应用最广泛的蒸汽甲烷重整(SMR)/甲烷蒸汽重整(MSR)工艺。对主要的先进反应器、膜反应器、吸附强化甲烷蒸汽重整反应器和微反应器进行了评价。根据停留时间、表面积、放大倍数、焦炭形成、转化率、空速和氢气产率等参数进行了评价。在最近发表的文献中,每种反应器的动力学模型都给出了速率常数和其他参数。给出了焦炭的形成机理和速率表达式。尽管膜反应器和吸附增强反应器在工艺强化方面有很多优势,但由于膜稳定性和污染等因素,扩大到工业规模仍然是一个挑战,随着WHSV的增加(在吸附增强反应器的情况下),产量会下降。尽管体积可能大大低于目前工业规模的常规反应堆,但微反应堆在高产量和极短的停留时间(以秒为单位)方面具有更大的潜力。
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引用次数: 5
Specialty grand challenge: Thermal energy storage and conversion 专业大挑战:热能储存与转换
Pub Date : 2023-03-09 DOI: 10.3389/fther.2023.1157794
B. Saha, Tahmid Hasan Rupam
The world is experiencing rapid technological advancement on a multidimensional scale but at the expense of its environmental sustainability. In this ever-developing world, the hunger for energy is increasing day by day. Natural resources for energy production, such as fossil fuels, are on the brink of extinction due to their extensive use to meet this ever-growing demand for energy. Most of the fossil fuel-burned energy in today’s world is spent on the continuous production of drinkable water, heating, cooling applications, and power generation (Rupam et al., 2022a). Along with irreversible resource exhaustion, burning fossil fuels causes excessive emissions of greenhouse gases and other pollutants responsible for global warming. Keeping in mind the catastrophic effects of the rising temperature, in recent times, there has been a global urge for the development of energy-saving, eco-friendly systems for water production, HVAC applications, power generation, etc. Although renewables are advancing at a fast pace, it has not yet reached a satisfactory level where all the energy-intensive systems can be operated with that. Apart from that, renewables are overly dependent on environmental constraints. For example, at night time or on gloomy days, solar energy cannot be harvested, or the energy conversion rate of photovoltaics drastically decreases. On the other hand, when there is plenty of sunshine, solar photovoltaics produce more energy than the required amount at that time. Most often, this surplus energy ends up being wasted due to the lack of proper energy storage or conversion systems. In this regard, thermal energy conversion and storage systems can offer reasonably realistic alternatives due to their multifaceted features. Thermal energy storage systems can store surplus energy in favorable conditions and provide clean and affordable energy in adverse situations in various forms such as heating, cooling, drinking water, or even power generation. Contrarily, thermal energy conversion systems can pave the way to further increase the share of renewables in the energy mix and play a significant role in the future decarbonized society. Globally, there are a variety of thermal energy storage and conversion (TESC) technologies currently being extensively researched. Figure 1 illustrates some of the most prominent technologies associated with the vast research field of TESC. Although the TESC technologies hold enormous potential, their utilization is subjected to various challenges associated with them. Depending on the applications and working conditions, certain obstacles can come forward, and to overcome those, efforts from both science and engineering fields are required. This speciality grand challenge aims to address the major drawbacks and discuss future research directions for overcoming these challenges associated with current TESC technologies. OPEN ACCESS
世界正在经历多方面的快速技术进步,但这是以环境的可持续性为代价的。在这个不断发展的世界里,对能源的需求日益增长。用于能源生产的自然资源,如化石燃料,由于被广泛使用以满足日益增长的能源需求,正处于灭绝的边缘。当今世界,大部分化石燃料燃烧的能源用于饮用水的连续生产、加热、冷却应用和发电(Rupam et al., 2022a)。随着不可逆转的资源枯竭,燃烧化石燃料导致温室气体和其他导致全球变暖的污染物的过量排放。考虑到气温上升带来的灾难性影响,近年来,全球都迫切需要开发节能、环保的水生产、暖通空调应用、发电等系统。虽然可再生能源正在快速发展,但它还没有达到令人满意的水平,即所有的能源密集型系统都可以用它来运行。除此之外,可再生能源过度依赖环境约束。例如,在夜间或阴天,太阳能不能被收集,或者光伏的能量转换率急剧下降。另一方面,当阳光充足时,太阳能光伏发电产生的能量多于当时所需的能量。大多数情况下,由于缺乏适当的能量储存或转换系统,这些多余的能量最终被浪费了。在这方面,热能转换和储存系统可以提供合理的现实的替代方案,由于其多方面的特点。热能储存系统可以在有利的条件下储存多余的能量,在不利的情况下以各种形式提供清洁和负担得起的能源,如加热、冷却、饮用水,甚至发电。相反,热能转换系统可以为进一步增加可再生能源在能源结构中的份额铺平道路,并在未来的脱碳社会中发挥重要作用。在全球范围内,目前有各种各样的热能储存和转换(TESC)技术正在广泛研究。图1说明了与TESC的广阔研究领域相关的一些最突出的技术。虽然TESC技术具有巨大的潜力,但其利用受到与之相关的各种挑战。根据应用和工作条件的不同,可能会出现一些障碍,为了克服这些障碍,需要科学和工程领域的努力。这一专业重大挑战旨在解决主要缺陷,并讨论未来的研究方向,以克服与当前TESC技术相关的这些挑战。开放获取
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引用次数: 1
Effect of meniscus curvature on phase-change performance during capillary-enhanced filmwise condensation in porous media 多孔介质中半月板曲率对毛细管增强膜状冷凝相变性能的影响
Pub Date : 2023-02-20 DOI: 10.3389/fther.2023.1131363
Ruisong Wang, D. Antao
Sustainably enhancing condensation heat transfer performance is a major challenge in thermal management and energy systems, since typical condensation enhancement methods (i.e., dropwise condensation with low surface energy coatings) have limited lifetime/durability, restricted compatibility with working fluids, and sustainability concerns due to the coating composition (e.g., fluorinated compounds). The robust and scalable capillary-enhanced filmwise condensation mode presented in this work demonstrates high heat transfer coefficients for water and low surface tension liquids condensing in a porous wick. Thin porous wicks offer the highest enhancements in heat transfer, however such thin porous wicks have thickness-dependent permeability, and the effective liquid thickness of the wick depends on the shape of the liquid-vapor interface. In this study, we leverage a spatially-discretized porous media model to characterize the effect of the wick thickness on condensation heat transfer performance. The model uses a spatially-varying permeability that depends on the local liquid-vapor interface shape/curvature and the resulting effective wick thickness. We apply this model to investigate the correlation between the heat transfer enhancement and various geometric factors, which enables the design of optimal porous structures for relevant phase-change application. We also predict favorable enhancement in condensation performance with a few common hydrocarbon and fluorocarbon fluid refrigerants. This study provides fundamental insight into the effects of the shape of the liquid-vapor interface on the phase-change performance in the capillary-enhanced filmwise condensation mode.
持续增强冷凝传热性能是热管理和能源系统中的一个主要挑战,因为典型的冷凝增强方法(即低表面能涂层的逐滴冷凝)的寿命/耐用性有限,与工作流体的兼容性有限,以及由于涂料组合物(例如氟化化合物)引起的可持续性问题。本工作中提出的稳健且可扩展的毛细管增强膜状冷凝模式证明了水和低表面张力液体在多孔芯中冷凝的高传热系数。薄多孔芯在热传递方面提供了最高的增强,然而,这种薄多孔芯具有依赖于厚度的渗透性,并且芯的有效液体厚度取决于液体-蒸汽界面的形状。在本研究中,我们利用空间离散多孔介质模型来表征芯厚度对冷凝传热性能的影响。该模型使用了空间变化的渗透率,该渗透率取决于局部液体-蒸汽界面形状/曲率和由此产生的有效芯厚度。我们应用该模型来研究传热增强与各种几何因素之间的相关性,这使得能够为相关的相变应用设计最佳的多孔结构。我们还预测,使用几种常见的碳氢化合物和氟碳化合物流体制冷剂,冷凝性能会得到有利的提高。这项研究为毛细管增强膜状冷凝模式下液-汽界面形状对相变性能的影响提供了基本的见解。
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引用次数: 0
Effect of methane supplementation on the performance, vibration and emissions characteristics of methane-diesel dual fuel engine 添加甲烷对甲烷-柴油双燃料发动机性能、振动及排放特性的影响
Pub Date : 2023-01-17 DOI: 10.3389/fther.2023.1101333
G. Tripathi, Sarthak Nag, Priybrat Sharma, A. Dhar
The increasing energy demands, especially in transportation sector, and the challenges of excess pollution and environmental degradation caused due to the conventional fuels, as well as their limited availability has highlighted the need to look for alternative fuels to sustain future needs. Methane is capable of catering to these demands due to its wide availability, both in renewable and non-renewable energy sources. The present work explores the effect of methane supplementation on the performance and emission characteristics as well as the vibrations in internal combustion engines. A four-stroke compression ignition engine is modified to run as a methane-diesel dual fuel engine where methane is inducted through intake manifold and diesel is directly injected into cylinder. Tests are performed by varying engine load and methane energy levels up to 75%. Our study shows that the participation of methane at lower load conditions is weak due to its higher auto ignition temperature and higher calorific value. The emissions, particularly CO and NO, are observably higher at 75% load conditions due to the efficient combustion and higher temperature at higher load conditions. The vibration studies on the dual fuel combustion indicates that the introduction of methane also suppresses the frequency spectrum of combustion noise and reduces the ringing intensity level of vibration for complete spectrum of engine loads, with the effect being prominent at higher loads. Overall, our results suggests that combustion of methane in dual fuel diesel engine shows distinct characteristics at contrasting load conditions.
日益增加的能源需求,特别是在运输部门,以及由于传统燃料造成的过度污染和环境退化的挑战,以及它们的有限供应,突出了寻找替代燃料以维持未来需求的必要性。由于甲烷在可再生和不可再生能源中的广泛可用性,它能够满足这些需求。本工作探讨了甲烷补充对内燃机性能和排放特性以及振动的影响。将四冲程压缩点火发动机改造成甲烷-柴油双燃料发动机,甲烷通过进气歧管吸入,柴油直接注入气缸。测试通过不同的发动机负载和高达75%的甲烷能量水平进行。研究表明,由于甲烷的自燃温度和热值较高,其在低负荷条件下的参与作用较弱。由于高负荷条件下的高效燃烧和更高的温度,在75%负荷条件下的排放量,特别是CO和NO明显更高。双燃料燃烧的振动研究表明,甲烷的引入也抑制了燃烧噪声的频谱,降低了发动机全谱负荷振动的振铃强度等级,在高负荷时效果突出。总的来说,我们的研究结果表明,在不同的负载条件下,双燃料柴油发动机的甲烷燃烧表现出明显的特征。
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引用次数: 0
Electric field assisted reduction of NOx emission: A numerical study 电场辅助减少氮氧化物排放的数值研究
Pub Date : 2023-01-16 DOI: 10.3389/fther.2022.1079789
Sheikh F. Ahmed, A. C. Aghdam, Jackson Pleis, R. Geiger, T. Farouk
The paper reports simulation results on the influence of a direct-current driven radial electric field on the emission characteristics; especially NOx and CO of a premixed methane/air laminar jet flame. A multi-physics computational model is developed in the OpenFOAM framework to simulate electric-field-coupled premixed combustion process. The computational framework consists of coupled species, momentum and energy conservation together with a Poisson’s equation solver to resolve the electric field distribution. Electron and ion conservation equations are resolved to consider the ionic wind body force in the momentum conservation equation and the associated possible electric field distortion due to the space charge distribution. The simulations are conducted for a stochiometric and fuel rich condition and over a range of jet flow rates for a configuration representative of a test-scale experimental setup. The model predictions show that for an applied voltage of 50 kV, the flame structure changes significantly for both the stoichiometric and fuel rich conditions. The flame is stretched significantly by the electric field due to ionic wind. For the fuel rich condition, the ionic wind allows additional mixing of the fuel rich stream with the surrounding air and drastically altering the flame structure. The electric field was found to reduce the NOx emission significantly for both stoichiometric and rich conditions. Over the entire range of flowrate conditions, the stochiometric fuel-oxidizer mixture showed a decrease in maximum NOx by a factor of 1.6 in presence of electric field. For the fuel rich case, however as the flow rate is increased, the NOx reduction factor decreased from 12.0 to 1.6. For CO emissions, the presence of electric field reduces the concentration under fuel rich conditions and vice versa for the stoichiometric flame. The role of kinetics is analyzed and discussed.
本文报道了直流驱动径向电场对发射特性影响的仿真结果;特别是预混合的甲烷/空气层流喷射火焰的NOx和CO。在OpenFOAM框架下,建立了一个模拟电场耦合预混燃烧过程的多物理计算模型。该计算框架由耦合物种、动量和能量守恒以及泊松方程求解器组成,用于求解电场分布。求解电子和离子守恒方程,以考虑动量守恒方程中的离子风体力以及由于空间电荷分布而可能产生的电场畸变。模拟是在代表试验规模实验装置的配置的随机和富燃料条件下,在一定范围的射流流速下进行的。模型预测表明,对于50kV的外加电压,在化学计量和富燃料条件下,火焰结构都会发生显著变化。离子风产生的电场使火焰明显伸展。对于富燃料条件,离子风允许富燃料流与周围空气的额外混合,并显著改变火焰结构。发现电场在化学计量和富条件下都能显著降低NOx排放。在整个流量条件范围内,在存在电场的情况下,化学计量燃料-氧化剂混合物的最大NOx减少了1.6倍。然而,对于富燃料的情况,随着流速的增加,NOx还原因子从12.0降低到1.6。对于CO排放,电场的存在降低了富燃料条件下的浓度,化学计量火焰的浓度反之亦然。对动力学的作用进行了分析和讨论。
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引用次数: 0
A design approach for thermal enhancement in heat sinks using different types of fins: A review 一种使用不同类型散热片的散热器热增强设计方法:综述
Pub Date : 2023-01-12 DOI: 10.3389/fther.2022.980985
A. Gaikwad, A. Sathe, S. Sanap
This article provides an in-depth overview of thermal heat sink design and optimization. Heat transfer enhancement strategies are discussed in detail, followed by fin design trends and geometries, and a discussion on different fin configurations and their merits is also presented. Important results and findings of experiments concerning the design and optimization of fin geometries have been summarized. For complex heat dissipation applications, researchers have been studying different fin arrangements especially, inclined fins, to maximize the performance of the heat sinks. Along with innovative fin designs, microchannels for heat dissipation are gaining attention due to their. Recent advances in this domain have been discussed. New components are becoming more compact and advanced as a result of technological breakthroughs in electronics and control systems; hence, the use and optimization of heat sinks for modern applications are also discussed in this article.
本文提供了一个深入的概述,热散热器的设计和优化。详细讨论了增强传热的策略,然后讨论了翅片的设计趋势和几何形状,并讨论了不同的翅片结构及其优点。综述了有关翅片几何形状设计和优化的重要实验结果和发现。对于复杂的散热应用,研究人员一直在研究不同的散热片布置方式,特别是斜散热片,以最大限度地提高散热片的性能。随着创新的散热鳍设计,微通道散热越来越受到关注,因为他们的。讨论了这一领域的最新进展。由于电子和控制系统的技术突破,新组件变得更加紧凑和先进;因此,本文还讨论了现代应用中散热器的使用和优化。
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引用次数: 2
Editorial: Thermal management of electrochemical energy devices or systems 社论:电化学能源装置或系统的热管理
Pub Date : 2023-01-10 DOI: 10.3389/fther.2022.1121606
Zhiguo Qu, P. Ming, Kui Jiao, M. Secanell, Xianguo Li
MOE Key Laboratory of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi, China, School of Automotive Studies and Clean Energy Automotive Engineering Center, Tongji University (Jiading Campus), Shanghai, China, State Key Laboratory of Engines, Tianjin University, Tianjin, China, Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada, Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON, Canada
西安交通大学能源与动力工程学院热流体科学与工程教育部重点实验室,同济大学(嘉定校区)汽车学院与清洁能源汽车工程中心,天津大学发动机国家重点实验室,天津,阿尔伯塔大学机械工程系,加拿大埃德蒙顿,机械与机电工程系,滑铁卢大学,滑铁卢,安大略省,加拿大
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引用次数: 0
Experimental study on heat transfer characteristics of steam underwater direct-contact condensation 蒸汽水下直接接触冷凝换热特性实验研究
Pub Date : 2023-01-10 DOI: 10.3389/fther.2022.1030998
Chen Qian, L. Hui, Li Dongyang, Wen Jiming, L. Yong, Xiao Qi, Tan Sichao
Introduction: The direct-contact condensation (DCC) of steam under water injection is the basic thermodynamic process of the bubble deaerator. In order to understand the complex coupling behavior of strong turbulence and fast phase-change heat transfer involved in the process. Methods: This study uses a visualized method and convective heat transfer model. Results: Since the contact area is affected by steam injection flow and sub-cooled degree is affected simultaneously, the trend of the condensation heat-transfer coefficient depends on the degree of their respective effects under each condition, and the maximum variation of the coefficient exceeds 104 W/m2.°C. Moreover, they still effect the period of steam plume, and the maximum variation of the period was beyond 80 ms. Discussion: Calculated the average condensation heat transfer coefficient and then produces the variation law of heat transfer coefficient under various conditions in one steam plume evolution period.
注水蒸汽的直接接触冷凝(DCC)是气泡除氧器的基本热力过程。为了了解该过程中所涉及的强湍流和快速相变传热的复杂耦合行为。方法:采用可视化方法和对流换热模型。结果:由于接触面积受到注汽流量的影响,过冷度同时受到影响,因此各工况下冷凝换热系数的变化趋势取决于两者各自的影响程度,其最大变化超过104 W/m2.℃。此外,它们还会影响蒸汽羽流的周期,且周期的最大变化在80 ms以上。讨论:计算平均冷凝换热系数,得出一个蒸汽羽流演化周期内不同条件下换热系数的变化规律。
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引用次数: 0
Design of a temperature-feedback controlled automated magnetic hyperthermia therapy device. 一种温度反馈控制自动磁热疗装置的设计。
Pub Date : 2023-01-01 DOI: 10.3389/fther.2023.1131262
Anirudh Sharma, Avesh Avinash Jangam, Julian Low Yung Shen, Aiman Ahmad, Nageshwar Arepally, Hayden Carlton, Robert Ivkov, Anilchandra Attaluri

Introduction: Magnetic hyperthermia therapy (MHT) is a minimally invasive adjuvant therapy capable of damaging tumors using magnetic nanoparticles exposed radiofrequency alternating magnetic fields. One of the challenges of MHT is thermal dose control and excessive heating in superficial tissues from off target eddy current heating.

Methods: We report the development of a control system to maintain target temperature during MHT with an automatic safety shutoff feature in adherence to FDA Design Control Guidance. A proportional-integral-derivative (PID) control algorithm was designed and implemented in NI LabVIEW®. A standard reference material copper wire was used as the heat source to verify the controller performance in gel phantom experiments. Coupled electromagnetic thermal finite element analysis simulations were used to identify the initial controller gains.

Results: Results showed that the PID controller successfully achieved the target temperature control despite significant perturbations.

Discussion and conclusion: Feasibility of PID control algorithm to improve efficacy and safety of MHT was demonstrated.

简介:磁热疗(MHT)是一种微创辅助治疗,能够使用暴露于射频交变磁场的磁性纳米颗粒破坏肿瘤。MHT的挑战之一是热剂量控制和脱靶涡流加热对浅表组织的过度加热。方法:我们报告了一种控制系统的发展,在MHT期间保持目标温度,具有自动安全关闭功能,符合FDA设计控制指南。在NI LabVIEW®中设计并实现了一种比例-积分-导数(PID)控制算法。在凝胶模体实验中,采用标准参考物质铜线作为热源,验证了控制器的性能。采用耦合电磁热有限元分析仿真,确定了控制器的初始增益。结果:结果表明,PID控制器成功地实现了目标温度控制,尽管有明显的扰动。讨论与结论:论证了PID控制算法提高MHT疗效和安全性的可行性。
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引用次数: 1
Water sorption-based thermochemical storage materials: A review from material candidates to manufacturing routes 基于水吸附的热化学存储材料:从候选材料到生产路线的综述
Pub Date : 2022-12-01 DOI: 10.3389/fther.2022.1003863
A. Palacios, M. Navarro, C. Barreneche, Yulong Ding
A comprehensive and updated review is provided in this article, with a focus on water sorption-based thermochemical storage (WSTCS) materials, covering materials and their manufacturing routes. The state of the art of 22 most relevant salt hydrates is classified into seven groups (bromides, sulphates, carbonates, chlorides, nitrates, hydroxides, and sulphides) and studied as candidates. This is followed by a discussion on TCS material manufacturing, covering both conventional (shaping, pelletizing, etc.) and more advanced routes (e.g., extrusion, 3D printing, encapsulation, etc.). Finally, concluding remarks are presented, including limitations and future potentials for TCS research.
本文对基于水吸附的热化学存储(WSTCS)材料进行了全面和最新的综述,涵盖了材料及其制造路线。22种最相关的盐水合物的现有技术被分为七类(溴化物、硫酸盐、碳酸盐、氯化物、硝酸盐、氢氧化物和硫化物),并作为候选者进行研究。接下来讨论了TCS材料的制造,包括传统的(成型、造粒等)和更先进的路线(如挤出、3D打印、封装等)。最后,总结了TCS研究的局限性和未来潜力。
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引用次数: 1
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Frontiers in thermal engineering
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