煤制氢零排放系统

氢能在未来可持续能源系统中，可望成为与电力并重而又互补的主要终端能源。煤制氢具有重要的战略地位。本文构造并分析煤制氢零排放系统。主反应器中部分炭转化为氢的系统冷煤气效率可达９０％，分析揭示了系统中的热集成情况和能量平衡。     

CO2准零排放的IGCC系统探索研究

本文基于能源与环境综合思路和关键技术的进展,从系统集成层次探索控制CO2的新途径、凝练零排放系统的设计概念与原则,提出由氢燃料热力系统和含碳燃料热力系统并联组成新颖的CO2准零排放双循环整体煤气化联合循环系统(DC-IGCC),并对典型系统方案进行模拟分析,得出系统特性规律与有价值的结论.     

碳制氢过程的比较及直接制氢分析

本文对不同碳制氢过程进行了热力学分析,比较了相同进料条件下,采用不同过程进行碳制氢时,过程的冷煤气效率以及最终产物组成,并分析了“一步制氢”中温度、压力、不同进料比对最终产物组成的影响。结果表明,直接制氧适宜的气化温度为923-973 K;增加水蒸气分压力(气化压力随之增加),气体产物的量增加;吸收剂有一最佳的量。     

新型CO2近零排放中低温太阳能化石能源互补系统研究

本文提出了新的CO₂近零排放中低温太阳能化石能源互补系统（ZE-SOLRGT）并对其进行了热力性能分析。该系统在SOLRGT系统基础上引入纯氧燃烧,构成以水为工质的准联合循环。中低温太阳能集热与水蒸发过程相集成,改善了换热匹配,增大了工质流量,提高了输出功与热效率;并通过热化学反应品位得以提升,最终借由燃机循环实现高效热功转换。系统以低能耗实现了CO₂近零排放。研究表明ZF-SOLRGT相对SOLRGT尾气排放（火用）损减少了50.5%,热效率提高了3.6%,实现了CO₂分离与能源高效利用的一体化集成。     

高温氦气加热甲烷蒸汽重整制氢热力学分析

对高温氦气加热的甲烷蒸汽重整制氢过程进行了热力学分析。结果表明,在较高温度条件下压力对系统重整性能的影响很小。在重整压力大于1 MPa,水碳比大于2时,随着温度的升高,热效率先增加到最大值然后又缓慢下降;在温度800~1000℃范围内,随着水碳比的增加热效率先升高后下降。分析表明,利用高温气冷堆氮气供热的甲烷蒸汽重整制氢系统,选择较高的水碳比和重整温度有利于提高系统热效率和制氢性能。得到了匹配高温气冷堆供热系统且能使氢气产量和热效率的接近最大值的甲烷蒸汽重整反应优化操作参数范围.     

现代热力学基础简介

从热力学基本定律的现代表达式 (diS≥ 0 ,diS是体系的熵产生 )能直接预测同时发生的反应有发生反应耦合 [diS1<0 ,diS2 >0和diS1 diS2 ≥ 0 ;diS1和diS2 是反应的熵产生 ]的可能 ,但是长期以来无法得到定量证明 .在激活低压气相生长金刚石的热力学研究中 ,发现该体系就是反应耦合的定量化例证 ,相应地得到了一个非平衡零耗散热力学 [diS1<0 ,diS2 >0和diS1 diS2 =0 ]的全新热力学分支领域 .非平衡定态相图的计算就是该领域的重要结果 ,并与大量的金刚石气相生长实验相符 .非平衡零耗散体系是在外界强制条件下的一种定态体系 ,强制条件减弱为零时就成为平衡体系 .现代热力学对开放体系相关的近代高新科技领域有重要意义 .     

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。     

化学链燃煤系统的过程模拟

化学链燃烧是一个基于(近)零排放理念的先进能源利用技术。针对以NiO/NiAl_2O_4为氧载体的煤直接化学链燃烧系统,本文利用Aspen Plus软件进行了详细的模拟计算和热力学分析,研究了主要运行参数对系统性能的影响,得到了系统优化的运行工况,即燃料反应器的温度和压力分别为816.41℃和0.1 MPa,空气反应器的温度和压力分别为1200℃和0.1 MPa,氧载体煤北为14.0,空气煤北为7.8;并北较和评价了化学链燃煤系统和常规空气燃煤系统,发现化学链燃煤系统在热效率、(?)效率、碳捕捉率、NO_x和CO排放量等方面有优势,但SO_x排放量与常规燃煤系统相近。     

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。     

低品位余热氨水吸收式制冷机理论与实验研究

利用工业企业300℃以下烟气余热实现工作区域供冷,解决企业生活区域供冷的同时实现节能减排。建立了余热式氨水吸收式制冷的热力学模型,在此基础上通过实验验证了不同操作条件下制冷系统运行的状态。针对实验样机得到余热烟气温度为280℃时系统存在最优的能源利用效率,冷却水进口温度升高5℃,制冷系数COP下降了0.047,实验样机COP不低于0.42,为优化利用低品位余热资源的制冷系统提供一定的理论基础。     

人造金刚石低压气相生长的相图计算

用非平衡热力学耦合模型计算了由CH₄/H₂，CO/H₂和乙炔火焰等气相体系生长金刚石的相图．与经典平衡热力学理论计算结果不同的是这些相图都有一个金刚石生长区存在．相图中的金刚石生长区是实现金刚石气相生长的热力学基础，它的存在体现了超平衡氢原子等激活粒子对石墨的激活和对金刚石的稳定作用．计算的相图与报道的实验结果基本相符，因而对金刚石气相生长的理论和实验研究具有重要的指导意义 关键词：     

High temperature equation of state of metallic hydrogen

The equation of state of liquid metallic hydrogen is solved numerically. Investigations are carried out at temperatures from 3000 to 20 000 K and densities from 0.2 to 3 mol/cm³, which correspond both to the experimental conditions under which metallic hydrogen is produced on earth and the conditions in the cores of giant planets of the solar system such as Jupiter and Saturn. It is assumed that hydrogen is in an atomic state and all its electrons are collectivized. Perturbation theory in the electron-proton interaction is applied to determine the thermodynamic potentials of metallic hydrogen. The electron subsystem is considered in the randomphase approximation with regard to the exchange interaction and the correlation of electrons in the local-field approximation. The proton-proton interaction is taken into account in the hard-spheres approximation. The thermodynamic characteristics of metallic hydrogen are calculated with regard to the zero-, second-, and third-order perturbation theory terms. The third-order term proves to be rather essential at moderately high temperatures and densities, although it is much smaller than the second-order term. The thermodynamic potentials of metallic hydrogen are monotonically increasing functions of density and temperature. The values of pressure for the temperatures and pressures that are characteristic of the conditions under which metallic hydrogen is produced on earth coincide with the corresponding values reported by the discoverers of metallic hydrogen to a high degree of accuracy. The temperature and density ranges are found in which there exists a liquid phase of metallic hydrogen.     

关于吸收式碳捕集热力学机制的探索

热再生吸收式碳捕集的传统认识难以揭示其热力学机制,一种新的认识是"热-化学能"转换中存在中间能量形式。本文从热力学碳泵概念出发,对吸收式碳捕集理想系统进行了解耦,其可视为"热机-碳泵"的热力学组合,探索了极限效率的表达,并采用第二定律效率作为评价参数对已有中试试验系统进行了性能水平探索。结果表明,理想循环性能系数仅取决于热源汇温度、碳源汇浓度;中试系统第二定律效率普遍低于20%。本文探索了热驱动的吸收式碳捕集热力学机制,为新型吸收剂设计提供了新思路。     

基于分块平滑投影二次重构算法的单像素成像系统

单像素成像系统是通过无空间分辨能力的单像元探测器来获取目标二维分布信息的计算光学成像技术,与传统直接成像技术相比具有高能量收集效率、高灵敏度等一系列优点,在高能物理诊断技术领域有着广阔的应用前景。针对实际单像素压缩感知成像系统在复杂诊断环境中存在的重建噪声较大的问题,提出并实现了基于分块平滑投影Landweber二次重构算法的单像素成像系统。根据算法观测矩阵分布特性以及数字微镜硬件输入要求实现了实际投影观测矩阵的变换,利用二次重构算法实现了单像素诊断的仿真分析与实验测试。仿真结果表明,在采样率为20%～30%的条件下,重建图像峰值信噪比大于20 dB,结构相似性高于0.8。进一步搭建单像素成像平台完成实验研究及验证,实验结果表明,利用二次重构算法模型对目标场景进行恢复的效果优于其余两种传统算法。二次重构单像素成像系统在采样率仅为20%的条件下能够重建出清晰的原始图像,具有较好的噪声抑制特性。     

An Experimental Study of Reactions of Co and H2 in a Continuous Flow Microwave Discharge Reactor

The reactions of CO/H2 mixtures in a flowing microwave (2450 MHz) reactor system have been studied experimentally. This versatile microwave plasma source catalyzes the reactions selectively to products, mainly methane and acetylene. For reaction times of 0.1 to 0.5 seconds in the pressure range of 10 to 90 torr conversions of CO to hydrocarbons ranged from 4 to 19%. Electric and magnetic field configurations in the reactor, i. e. various electromagnetic modes, appear to have only minor effects on the chemical reactions. It was observed that the conversion of CO to hydrocarbons is enhanced by high ratios of H2/CO. Based on analysis of experimental data, hydrogen radical production appears to be the controlling mechanism for producing both methane and acetylene.     

费托合成工艺热力学性质的计算化学研究

本文采用高精度的G4方法,全面计算了不同反应条件下费托合成工艺中可能的1287个产物的热力学数据,然后用这些数据得到的热力学量用于分析实际化工生产的热力学和分析费托合成的产物分布.结果表明:降温、加压和增大氢碳比(H_2/CO)时,热力学上可能生成的产物数目增多.在低温、高压和高碳氢比下,很多产物都在热力学上可以生成,其中产物的选择性主要由动力学因素控制.另一方面,升温或者降压可以提高小分子产物的选择性.值得注意的是在降温、加压和增大碳氢比到一定条件时,产物的平衡产率会达到最大值并且不随条件改变而变化,这说明优化条件改变产率是有一定限度的.热力学分析同样对设计和评价费托合成的反应机理有重大意义,其中甲醛的平衡产率很低,可以排除含有甲醛的反应路径.近期有一些采用金属氧化物-分子筛双功能催化剂高选择性获得C_(2-4)烯烃和芳烃的报道,其中有很多可能进入分子筛孔道的中间体,分析结果显示乙烯酮、甲醇和二甲醚是可能的中间体.     

CO_2两相流引射循环制冷系统性能的数值模拟

对引射器内部简化热力学模型进行了改进,建立了CO2两相流制冷系统的数学模型。利用MATLAB语言编写程序对该系统性能进行了模拟计算,分析了工况参数及引射比对引射循环系统性能的影响。模拟结果表明:CO2两相流引射循环制冷系统在较低的引射比条件下,就可以实现稳定运行,系统COP对气冷器出口温度的变化比较敏感,同时存在最优高压侧压力使系统COP达到最大;对于不同工况条件,CO2两相流引射循环制冷系统的COP比同工况条件下的传统系统的COP,理论上分别提高了11%～18%。     

CO concentration and temperature measurements in a shock tube for Martian mixtures by coupling OES and TDLAS

CO concentration and gas temperature distribution are diagnosed behind a strong shock wave simulating the Martian atmosphere entry processes by coupling optical emission spectroscopy (OES) and tunable diode laser absorption spectroscopy (TDLAS). The strong shock wave (6.31 ± 0.11 km/s) is established in a shock tube driven by combustion of hydrogen and oxygen. Temperature of the shock-heated gas is inferred through a precise analysis of the high temporal and spatial resolution experimental spectral of CN violet system (B ² Σ ⁺ →X ² Σ ⁺, Δv = 0 sequence) using OES. A CO absorption line near 2,335.778 nm is utilized for detecting the CO concentration using scanned-wavelength direct absorption mode with 50 kHz repetition rate. Combined with temperature results from OES, CO concentration in the thermal equilibrium region is derived. The current experimental results are complementary for determining an accurate rate coefficient of CO₂ dissociation and validation relevant chemical kinetics models in Mars atmosphere entry processes.     

基于TDLAS技术的天然气中痕量硫化氢分析的PLS算法应用

基于可调谐二极管激光吸收光谱技术的光谱分析仪测量天然气中硫化氢浓度的过程中,各种轻烃和二氧化碳等背景成分对光谱产生干扰,导致多个吸收峰叠加,对提取吸收光谱真实特征造成影响.应用偏最小二乘法消除背景成分的干扰,设计了检测天然气中硫化氢气体的可调谐二极管激光吸收光谱实验系统,采用偏最小二乘法和最小二乘法模型,分别检测了天然气中0~50ppm硫化氢成分的直测光谱和差分光谱.偏最小二乘法算法的测量结果均优于最小二乘法算法,且偏最小二乘法算法对于直测谱的测量误差保持在±1ppm范围内,满足分析仪器2%的准确度要求.利用偏最小二乘法算法避免了最小二乘法所必须的大量参考光谱数据的存储,分析仪可省掉复杂的差分光谱系统,从而达到降低成本、提高系统鲁棒性和实时性的效果.     

Hydrogen adsorption,absorption and diffusion on and in transition metal surfaces: A DFT study

Periodic, self-consistent DFT-GGA(PW91) calculations are used to study the interaction of hydrogen with different facets of seventeen transition metals—the (100) and (111) facets of face-centered cubic (fcc) metals, the (0001) facet of hexagonal-close packed (hcp) metals, and the (100) and (110) facets of body-centered cubic (bcc) metals. Calculated geometries and binding energies for surface and subsurface hydrogen are reported and are, in general, in good agreement with both previous modeling studies and experimental data. There are significant differences between the binding on the close-packed and more open (100) facets of the same metal. Geometries of subsurface hydrogen on different facets of the same metal are generally similar; however, binding energies of hydrogen in the subsurface of the different facets studied showed significant variation. Formation of surface hydrogen is exothermic with respect to gas-phase H₂ on all metals studied with the exception of Ag and Au. For each metal studied, hydrogen in its preferred subsurface state is always less stable than its preferred surface state. The magnitude of the activation energy for hydrogen diffusion from the surface layer into the first subsurface layer is dominated by the difference in the thermodynamic stability of these two states. Diffusion from the first subsurface layer to one layer further into the bulk does not generally have a large thermodynamic barrier but still has a moderate kinetic barrier. Despite the proximity to the metal surface, the activation energy for hydrogen diffusion from the first to the second subsurface layer is generally similar to experimentally-determined activation energies for bulk diffusion found in the literature. There are also some significant differences in the activation energy for hydrogen diffusion into the bulk through different facets of the same metal.