含碳能源直接制氢的热力学分析与实验研究

本文在对构建的含碳能源直接制氢体系进行热力学分析的基础上,建造了含碳能源直接制氢近零排放定容实验系统,并进行了不同参数下的实验研究。热力学分析表明本文构建的系统不仅存在合适的反应条件,而且在此反应条件下可以实现体系的热平衡。实验结果表明了该系统的可行性,实现了气态产物中氢含量大于80％,二氧化碳及一氧化碳含量均小于0.1％,达到了直接制氢和近零排放的目标。     

太阳能甲醇重整制氢-发电联产系统

基于不同用能系统整合和能的综合梯级利用思路,研究提出一种新颖的太阳能甲醇重整制氢-发电联产系统.将太阳能甲醇重整制氢与发电有机整合,不仅合理地利用中低温太阳能,同时实现甲醇重整制氢弛放气的综合利用.新的联产系统具有优良的热力性能,化石能源的相对节能率达到29%,制氢单位能耗降低为0.85 GJ/GJ-H2.研究表明,减小能量转化传递过程的品位差和合理利用太阳能热是系统节能的关键所在.研究成果将为太阳能多功能能源系统发展提供新方案与新思路.     

超临界水生物质催化气化制氢实验系统与方法研究

在分析比较目前国际上较好的几种超临界水生物质催化气化制氢实验系统及实验方法的基础上，成功地设计研制出一套连续式超临界水湿生物质催化气化制氢实验系统，简要介绍了该系统的特点及使用该系统取得的初步实验结果，并对各类实验系统存在的问题及待改进处作了分析．     

基于氢储能的风光氢能源系统能质转换优化策略

西北地区拥有丰富的风光资源,近年来基于风光的新能源发电系统发展迅猛。然而由于生产力、人口等因素,西北地区的电力负荷低,加之新能源的随机、不稳定等特点,弃风弃光现象严重,有研究表明可以通过新能源发电耦合氢储能技术来解决问题。基于风光联合发电耦合电解槽制氢系统的概念和结构,以风光氢能源系统的制氢速率为研究目标,在MATLAB/Simulink系统下建立了包括风力发电系统、光伏发电系统以及电解槽的混合架构模型,通过此模型探明在西北地区自然环境下的氢气产出特性及规律。     

新型双燃料多功能能源系统开拓研究

本文开拓性地提出了一种新型多种化石能源输入(煤和天然气)、多种产品输出(电力和化工产品)的多功能能源系统。该系统将天然气／水蒸气重整过程和煤的燃烧过程有机整合,用煤燃烧替代了传统重整过程清洁的燃料天然气和弛放气燃烧,实现了煤和天然气的综合互补利用;将甲醇生产系统与发电系统有机整合,实现了化工系统弛放气的梯级利用同时,对甲醇生产系统余热进行了更加有效的利用。研究表明生产相同量的甲醇和电,多功能系统比参比系统少消耗 20％的天然气。本文工作为煤和天然气综合高效利用提供了新途径．     

微波液相放电乙醇制氢发射光谱研究

氢能作为一种高热值、无污染的清洁能源日渐受到国内外专家学者的追捧。微波液相放电技术在醇类中制氢具有光明的研究前景,为氢能的研究开发开辟了一条新的途径。通过对乙醇制氢发射光谱分析,有利于分析微波液相放电醇类制氢机理的探讨,为进一步改进微波液相放电制氢技术奠定基础。本文采用2.45 GHz频率微波在液相醇类中放电实现了微波液相等离子体制氢,并借助发射光谱仪对微波液相放电乙醇制氢光谱特性进行了研究。研究结果显示：微波液相放电乙醇制氢过程中,能产生大量的H,O,OH,CH,C₂等活性粒子;乙醇放电光谱中OH自由基、H自由基和O自由基的光谱强度要远大于纯水中OH自由基、H自由基和O自由基的光谱强度;高能粒子打开水分子中的O—H键,脱氢制氢的过程较乙醇分子难度要大,因此在微波乙醇放电制氢过程中,氢气的来源主要是乙醇分子的脱氢重组,水分解产氢的贡献度较低;在外界压力与温度一定的条件下,OH,H,O自由基的发射光谱强度随着功率的增加显著增强,而CH和C₂活性粒子发射光谱强度则出现减弱趋势,这表明较大的微波功率不仅使产生的高能粒子的能量增加,同时高能粒子的密度也有所增加,导致较多的CH和C₂基团被充分碰撞打开。     

乙醇氧化重整制氢的热力学研究

乙醇制氢是乙醇在能源领域应用的主要技术方向之一,现有的乙醇水蒸气重整制氢技术存在成本过高、能量结构不合理、转换效率低、难以持续稳定运行等一系列问题.本文根据热力学基本定律建立乙醇水蒸气重整制氢过程的数学模型;指出乙醇水蒸气重整制氢技术存在化学反应焓变过大的问题,然后提出并分析乙醇氧化重整制氢的技术原理和方案。最后使用现有的非贵金属催化技术,设计出一种乙醇氧化重整制氢装置,实现含水乙醇的可持续制氢,并通过第三方检验机构测量生成物成分和含量。检验数据与热力学模型一致表明:乙醇制氢的主要产物是H_2、CH_4、CO、CO_2、C_2H_4等可燃气体和液体杂质,在局部高温脱水且存在活性氧元素的情况下,会出现析碳现象,可通过乙醇溶液的浓度和活性氧浓度调节生成气体成分,体积分数为0.64乙醇溶液是最理想的制氢反应物。     

新型甲醇重整–化学链氢电联产系统热力学分析

本文提出了一种新颖的甲醇重整–化学链发电制氢联产系统。该系统利用化学链燃烧氧化反应的显热给甲醇重整制氢部分提供反应热,充分利用了甲醇重整制氢的驰放气,同时实现了Fe_2O_3高温热的合理利用,使新系统内部能量品位的匹配变得更加合理。重整反应部分温度为250℃左右时,该新型联产系统的效率达到了61.8%,展现出了良好的热力学性能。本文对该系统进行了分析,并以常规制氢和化学链燃烧耦合发电系统为参照进行了对比,研究了其性能。新系统的效率较高,同时实现了CO_2的无能耗分离。     

在静止O_2-N_2环境中激光点燃的碳粒的燃烧特性研究

一、引言 能源的合理利用是四化建设中的重要课题,煤占我国能源资源的70％,研究煤的燃烧具有重要意义。而固态炭的燃烧在煤的燃烧中起着主导作用。本文的内容就是关于碳粒燃烧特性的实验研究和分析,即对处于室温下、不同氧浓度静止环境中的98～170μm碳粒,用脉冲激光点燃,记录其燃烧的全过程,并把实验结果与理论分析对比。从中探讨了:     

基于化学链燃烧生物质煤互补的天然气动力联产系统研究

针对传统煤制天然气过程存在的能量利用不合理、碳捕集能耗过高等技术瓶颈,本文探索了一种能实现CO_2零排放的基于化学链燃烧的生物质煤互补天然气动力联产系统。生物质与煤互补从气化源头调节了合成气中H_2/CO比例,有利于甲烷化反应过程,化学链燃烧实现了零能耗的CO_2捕集。研究结果表明:系统总能效率(η_(en))为57.03,效率(η_(ex))为54.65,系统能源节约率高达18.6,实现了系统CO_2零排放。分析了关键参数如氧气碳比(O/C)、蒸气碳比(S/C)、生物质煤互补比例和未反应气循环倍率对系统热力学性能的影响。     

Hydrogen chemisorption on silicon (100) 2 × 1

Changes in the valence band density of states (DOS) of a (100) silicon surface that accompany he chemisorption of atomic hydrogen onto that surface are deduced from a study of the changes in the L_2,3VV Auger lineshape. Complementary changes in the conduction band DOS are inferred from changes in L_2,3VV-core-level characteristic loss spectra (CLS). The chemisorbed hydrogen layer is identified as the dihydride phase from low energy electron diffraction measurements. Upon hydrogen adsorption the DOS at the top of the valence band decreases and new energy levels associated with the Si-H bonds appear lower in the band. Assuming that the Auger signal from the hydrogen covered sample consists of a superposition of a signal from silicon atoms bonded to hydrogen in the dihydride layer and an elemental-Si signal from the substrate, a N(E) difference spectrum with features due only to the dihydride is obtained by subtracting the background corrected, loss deconvoluted L_2,3VV signal for a clean (100)Si surface rom the corresponding signal for the hydrogen covered surface. Comparisons of the energy position of the major peak in this difference spectrum with that of the main peak in a gas phase silane Si-L_2,3VV spectrum, and of the corresponding Auger energy calculated empirically, indicate a hole—hole interaction energy of ~8 eV for the two-hole final state in the gaseous system and zero for the dihydride surface system. Hydrogen induced changes in the conduction band DOS are less apparent than those of the valence band DOS with only the possibility of a decrease in the DOS at the bottom of the conduction band being inferred from the CLS measurements. Electron stimulated desorption of hydrogen from the dihydride layer is adduced from changes in the Auger lineshape under electron beam irradiation of the surface. Hydrogen induced changes in the near-elastic electron energy loss spectra (ELS) are also reported and compared with previously published ELS results.     

The state and prospects of coal and nuclear power generation in Russia (review)

Data on the modern state and development trends for coal and nuclear power engineering in Russia up to 2030 are generalized. It is emphasized that from the viewpoint of strategy, coal and uranium fuel will be the main energy carriers. The forecast of energy consumption is made; the “roadmap” of new power-generating units of heat and nuclear power plants on the territory of Russia is presented.     

半焦燃烧特性的热重试验研究

针对目前提倡的煤部分气化燃烧系统集成优化联合生产煤气和热能的新概念,在不同温度下制得四种煤的半焦,通过热天平燃烧试验研究了半焦的燃烧特性,考察了煤种和制备温度对半焦燃烧特性的影响.试验结果表明:煤种不同,所制得半焦燃烧特性不同;相同煤种制得半焦,随制备温度升高,半焦着火温度上升,燃烧活化能增加,燃烧反应活性降低.     

新型焦电联产系统集成与特性分析

本文针对传统焦炭生产工艺的不足、并应用联产系统整合思路,研究提出新型焦炭动力联产系统.新系统取消了传统炼焦工艺中直接燃用焦炉煤气为炭化室提供炼焦热量的方式,采用外置煤炭燃烧室提供热量,从而实现用低品质煤炭替代高品质焦炉煤气;节省下来的富氢、高热值的焦炉煤气作为燃料提供给联合循环,实现高效洁净发电;改进炼焦过程烟气废热回收方式,使得排烟损失大大降低.分析结果表明,新系统具有优良的热力性能,相对节能率高达15%左右.对系统关键过程的图像(火用)分析分析表明,燃烧过程和换热过程等变革与改进是系统性能提升的关键所在.本文研究将为冶金生产的可持续发展提供新思路与新系统方案.     

Thermodynamic Evaluation and Sensitivity Analysis of a Novel Compressed Air Energy Storage System Incorporated with a Coal-Fired Power Plant

A novel compressed air energy storage (CAES) system has been developed, which is innovatively integrated with a coal-fired power plant based on its feedwater heating system. In the hybrid design, the compression heat of the CAES system is transferred to the feedwater of the coal power plant, and the compressed air before the expanders is heated by the feedwater taken from the coal power plant. Furthermore, the exhaust air of the expanders is employed to warm partial feedwater of the coal power plant. Via the suggested integration, the thermal energy storage equipment for a regular CAES system can be eliminated and the performance of the CAES system can be improved. Based on a 350 MW supercritical coal power plant, the proposed concept was thermodynamically evaluated, and the results indicate that the round-trip efficiency and exergy efficiency of the new CAES system can reach 64.08% and 70.01%, respectively. Besides, a sensitivity analysis was conducted to examine the effects of ambient temperature, air storage pressure, expander inlet temperature, and coal power load on the performance of the CAES system. The above work proves that the novel design is efficient under various conditions, providing important insights into the development of CAES technology.     

Energy spectrum of cosmic protons and helium nuclei by ahybrid measurement at 4300 m a.s.l.

The energy spectrum of cosmic Hydrogen and Helium nuclei has been measured below the so-called "knee" by using a hybrid experiment with a wide field-of-view Cherenkov telescope and the Resistive Plate Chamber (RPC) array of the ARGO-YBJ experiment at 4300 m above sea level. The Hydrogen and Helium nuclei have been well separated from other cosmic ray components by using a multi-parameter technique. A highly uniform energy resolution of about 25% is achieved throughout the whole energy range (100-700 TeV). The observed energy spectrum is compatible with a single power law with index γ=-2.63±0.06.     

Hydrogen effusion: a probe for surface desorption and diffusion

Hydrogen effusion results are discussed for hydrogenated amorphous silicon (a-Si:H) and related alloys as well as for crystalline silicon (c-Si). It is demonstrated that depending on the microstructure of the material, hydrogen effusion gives information on hydrogen diffusion or surface desorption. The results suggest for compact a-Si:H and for ion implanted c-Si a similar hydrogen diffusion process, which is a trap limited motion of atomic hydrogen. Hydrogen effusion from defect-free c-Si and from void-rich amorphous semiconductors is limited by surface desorption. Both hydrogen diffusion and desorption depend on the Fermi energy if hydrogen bonds to the host material are broken.     

Hydrogen generation from photoelectrochemical water splitting based on nanomaterials

Hydrogen is potentially one of the most attractive and environmentally friendly fuels for energy applications. Safe and efficient generation, storage, and utilization of hydrogen present major challenges in its widespread use. Hydrogen generation from water splitting represents a holy grail in energy science and technology, as water is the most abundant hydrogen source on the Earth. Among different methods, hydrogen generation from photoelectrochemical (PEC) water splitting using semiconductors as photoelectrodes is one of the most scalable and cost‐effective approaches. Compared to bulk materials, nanostructured semiconductors offer potential advantages in PEC application due to their large surface area and size‐dependent properties, such as increased absorption coefficient, increased band‐gap energy, and reduced carrier‐scattering rate. This article provides a brief overview of some recent research activities in the area of hydrogen generation from PEC water splitting based on nanostructured semiconductor materials, with a particular emphasis on metal oxides. Both scientific and technical issues are critically analyzed and reviewed.