一种新的氯化钠热化学分解循环

提出了一种新的热化学分解循环.研究了循环中各主要化学反应的适宜条件,并从热力学计算出了循环中的能量流动过程;用TG法研究了循环中多相反应的动力学问题,实验和理论证明了该循环具有很大的节能优势.     

Determination of the ionization constant of water between 100 to 200°C by emf measurements,with some derived thermodynamic quantities

The first experimentally derived values of the ionization constant of water and associated thermodynamic quantities, by emf measurements, are reported, within the range 100–200°C. The derived values of the ionization constant of pure water from these measurements support the findings obtained by purely thermochemical observations. The effects of a recalculation of the observed discrepancies, both in the heats of ionization and molal heat capacity, between emf measurements and thermochemical values at 25°C are also discussed, by an appraisal of the empirical methods that are available and that have been used for the treatment of experimental data. A method, producing a new family of equations based on theoretical-structural considerations, is also suggested for the behaviour of the ionization constant of water as a function of temperature. Values for the heats of ionization of water between 100 and 200°C are also proposed.     

Systematic generation of thermochemical cycles for water splitting

Based on the observation that a thermochemical cycle is tantamount to a reaction route (RR) we employ the well-developed concepts of response reactions (RERs) and direct reaction routes (RRs) to develop an algorithm for a systematic enumeration of thermodynamically feasible thermochemical cycles for water splitting. The input is a set of chemical species along with their thermodynamic characteristics. A unique set of reactions is next generated from a list of species using the formalism of RERs. These are further screened and reduced to a subset of thermodynamically favorable RERs. Alternatively, the reactions may be selected from a separately build database of chemical reactions. The reactions are next assembled into direct RRs (thermochemical cycles), i.e., linear combinations of reactions that produce the desired overall reaction (OR), i.e., 2H₂O = 2H₂ + O₂. Only the direct RRs that satisfy the thermodynamic feasibility condition are further retained. The proposed algorithm is a new powerful tool for automatic generation and screening of thermodynamically feasible thermochemical cycles.     

Thermodynamic properties and structure of gaseous metaborates

A review is presented of the data available in the literature on the thermodynamic properties and structure of gaseous metaborates studied by high-temperature mass spectrometry, gas-phase electron diffraction, spectroscopy, and quantum-chemical methods. The reliability and inconsistency of the thermodynamic properties and structural data obtained by these methods for gaseous metaborates are discussed. The specific features of the application of the above methods for investigating the thermodynamic properties and structure of gaseous metaborates at high temperatures are analyzed.     

生物质热化学法制氢技术的研究进展

介绍木质生物质热化学法生产氢气的四条主要技术路线,分别是生物质气化制氢、生物质热解油制氢、生物质超临界水气化制氢、源于生物质的小分子有机物催化重整制氢方法,着重从化学反应机理、热力学模拟、催化剂种类、工艺开发、工业化进展等方面总结生物质热化学制氢技术的最新研究进展,分析了各类小分子制氢的热力学规律,并指出工业化过程存在...     

Thermochemical conversion of fuels into hydrogen-containing gas using recuperative heat of internal combustion engines

The problem of the thermochemical recuperation of heat from the exhaust gases of internal combustion engines (ICEs) as a method of increasing of the efficiency of fuels has been considered. The thermodynamic analysis of thermochemical recuperation conditions was performed, and maximum efficiency conditions were determined. Catalysts for the steam conversion of oxygen-containing fuels into syngas were developed, and the Co-Mn/Al₂O₃ catalyst was shown to be the most promising. The model of a thermochemical heat recuperation system was developed and manufactured, and its bench tests in the conversion of alcohols were performed using the simulated exhaust gases from a heating device. Mathematical models for calculating units of the heat recuperation system were developed. A recuperation system was manufactured and tested in the ICE-free and ICE-integrated variants. Based on the test results, the equivalent fuel consumption characteristics of a recuperative ICE was revealed to decrease by 11–22% depending on its load with a decrease in the concentration of hazardous emissions by 8–12 times for CO, 2–3.5 times for CH, and 18–25 times for NO _x .     

REVIEW OF SIMULATION METHODS OF THE DISTILLATION COLUMN AND THERMODYNAMIC MODELS IN THE HI DECOMPOSITION SECTION OF THE IODINE-SULFUR PROCESS

The iodine-sulfur thermochemical water-splitting process (I-S process) is one of the most promising and efficient mass hydrogen production methods without greenhouse gas emissions. To a large extent, distillation in the HI decomposition section of the I-S process affects the efficiency of the entire process. This article summarizes the simulation methods for HI distillation in the iodine-sulfur process, including thermodynamic models, design schemes, and parameter analyses. The performance of the thermodynamic models and heat duties of different flow sheets were compared, and the preferable model and flow sheet are recommended. This study can provide a reference for the selection of thermodynamic models and it is also meaningful for the design and simulation of the HI distillation column.     

Comparison thermochemical and thermophysical performances analysis in laser processing by dynamic heat-matter diffusion coupling simulation and corresponding experiment validation

The laser-matter interaction contains complex thermophysical and thermochemical responses. The variation of energy and composition happen in thermophysical and thermochemical process will totally change the interaction behaviors. In order to obtain an accurate mechanism and promote the understanding of laser-matter interaction, all thermophysical and thermochemical responses, especially the thermochemical part, should be considered and investigated. In this study, a coupled heat-matter diffusion model based on thermodynamic chemical equilibrium finite-element method and thermochemical ablation theory was established. The materials with complex reaction enthalpy change in high temperature environment were chosen to validate the model. The results show that this model is accurate, as the maximum error of back-surface temperature response is just 4.0% between experimental and calculation values. The detailed variations of composition, temperature and optical reflection were obtained and analyzed, which is in good agreement with the experiment. This coupled heat-matter diffusion model including all thermophysical and thermochemical response has the great potential in nearly all laser-matter interaction involved application.     

Influence of product species selection on thermochemical equilibrium calculations. Part I: Energetic materials

Chemical equilibrium calculations are made for a number of Carbon C, Hydrogen H, Nitrogen N, and Oxygen O, explosive compositions. A methodology is established to systematically limit the number of product species available in thermochemical equilibrium calculations. The calculations are then compared with “baseline” results obtained using an extensive product species library consisting of 900 gas-phase and 600 condensed-phase product species. Errors in bulk thermodynamic properties (detonation velocity and pressure) and in product chemical composition are quantified in terms of the number of species considered as products of reaction. The properties at states along an expansion isentrope are also presented.     

Was leistet die statistische Thermodynamik für den Verfahrens-Ingenieur?

What does statistical thermodynamics do for the chemical engineer? Statistical thermodynamics introduces molecular properties of a particular system into model equations for the thermodynamic functions of fluid mixtures. It thus contributes to the prediction, extrapolation or estimation of fluid properties, in particular phase and reaction equilibria, which are fundamental to numerous processes in thermochemical engineering. For systems of small, rigid molecules, as frequently encountered in natural gas and refrigeration applications, this method has reached a high level that is beginning to be introduced into industrial practice. For systems of complicated organic molecules, models from molecular thermodynamics have firmly established themselves in industrial applications.     

Combustion of GAP/HMX and GAP/TAGN Energetic Composite Materials

Energetic composite materials (ECM) have high thermodynamic potential and flexible design capability. Two types of ECM were formulated as mixtures of glycidyl azide polymer (GAP) and crystalline materials. The crystalline materials evaluated were cyclotetramethylene tetranitramine (HMX) and triaminoguanidine nitrate (TAGN). The thermochemical properties of HMX and TAGN were different to each other: HMX is a high energy material but the burning rate is lower than that of TAGN. TAGN produces hydrogen as a combustion product and the thermodynamic potential becomes high even though the flame temperature is low. The results of burning rate measurement tests indicate that the burning rates of both ECM are decreased significantly by the addition of HMX and TAGN even though the burning rates of GAP, HMX, and TAGN are higher than those of the ECM. The temperature sensitivity of burning rate of GAP is reduced significantly by the addition of HMX and remains unchanged by the addition of TAGN. The reduced burning rates of GAP/HMX and GAP/TAGN are caused by the reduced heat flux transferred back from the gas phase to the burning surface. The reduced heat release at the burning surface of GAP/HMX is responsible for the reduced temperature sensitivity.     

CO2混合物热物性在CCS研究中的作用:实验数据、理论模型和典型应用

二氧化碳捕集与封存（CCS）各工艺过程的设计、运行都依赖于对CO₂及其混合物热物理性质的深入理解。同时，CCS的规模化发展和商业化进程，对CO₂混合物及其热物性的准确性提出了更高的要求。本文从实验数据、理论模型和典型应用3个方面综述了CO₂及其混合物热物性的发展现状，并尝试对发展趋势进行归纳。在实验研究方面，CO₂混合体系的研究进展视组分不同，差异较大，其中CO₂-N₂、CO₂-CH₄、CO₂-H₂O和CO₂-H₂二元体系已形成较完善的物性数据库，而CO₂-NH₃、CO₂-NO _x 和CO₂-CO体系的物性数据还比较欠缺；在物性估算方面，面向CCS的物性估算模型研究自2008年开始活跃，基于不同理论构架，目前已逐步形成面向CCS的多元化的物性估算体系。物性研究在CCS中的应用主要体现在物性是支撑CCS过程研究的基础，其不准确性在过程模拟或计算中会被“放大”，从而影响过程评估的准确性，本文从物性在循环构建和能效分析中的作用以及CO₂水合物的形成3个方面入手做了说明。文章最后对面向CCS的物性研究趋势进行了梳理，对分子模拟技术、通用性强的物性估算模型和物性在过程设计和循环分析中的角色进行了展望。     

高温固硫矿物3CaO·3A12O3·CaSO4的热力学数据的计算与验证

Calcium sulfoaluminate,3CaO·3Al2O3·CaSO4,has been widely recognized in the realms of high-temperature combustion and cement chemistry.However,the lack of relevant thermodynamic data limits the progress of its research and development.Through comparative calculations using several different approaches,we obtain the thermochemical properties of 3CaO·3Al2O3·CaSO4 in this work,such as its standard formation enthalpy,Gibbs free en- ergy of formation,entropy,and molar heat capacity.With these fundamental data,thermodynamic calculations become possible for reactions involving this mineral.It is found that some reactions proposed in literature to generate this mineral may not proceed thermodynamically.     

火用函数热力学一致性基础

近年来 ,随着国家能源利用技术、环境保护技术水平的提高 ,作为一个重要而有效的理论工具 ,火用分析方法已经从一般的过程能量分析发展到过程经济评价甚至过程的环境影响评价 ,即所谓过程可持续性评价的定量化分析 .给出了体现热力学一致性的火用函数普遍化基础表述及计算原理 ,强调火用分析采用合理的环境参考态模型、统一的热力学标准性质数据以及适宜的热力学模型的重要性 .基于ISO 136 0 0系列能源系统标准(1999～ )的概念和IUPAC的化学热力学标准压力的规定 ,基于国际上具有权威性的最新化合物标准生成Gibbs函数数据等修正了龟山等人提出的热力学平衡环境参考态模型 .修正模型由 2 98.15K和 1bar下的大气圈、水圈和地壳岩石圈中的选定基准物体系所组成 .提出了一个包含 80种常见化学元素标准火用数据体系 .另外 ,给出的氨水均相混合物计算实例表明 ,物质标准火用的数值是混合物火用函数的最主要构成 ,其数值处理中的微小偏差都会对火用函数计算结果产生很大影响.     

基于1H NMR测定和基团贡献法预测石油馏分的热化学性质

测定了两种原油 2 0个石油馏分的¹H NMR谱和氢、碳元素含量等结构参数 ,以及馏分的燃烧焓、蒸发焓等热化学性质 .假设每个石油馏分仅由CH₃ 、CH₂ 、CH、ACH和C这 5种简单基团构成 ,基于¹H NMR测定和元素分析结果解出石油馏分平均分子结构中的基团数目 ,再用纯有机物的基团贡献法预测石油馏分的燃烧焓、蒸发焓 ,预测值与实验数据吻合良好     

生物质与煤（共）热解/气化过程中挥发分-半焦交互作用研究与进展

生物质和煤协同热化学转化是实现非化石能源和化石能源耦合高效利用的技术手段,对实现“双碳”目标具有重要现实意义。基于生物质等含碳燃料高挥发分组成和富氧特性,热化学转化过程不可避免地发生挥发分-半焦交互作用并影响原料性质和设备过程参数。综述了生物质与煤（共）热解/气化过程中挥发分-半焦交互作用的研究进展,总结了交互作用对挥发分的催化裂解规律、对半焦结构与性质的影响及生物质和煤协同热化学转化下的解耦研究思路三方面具体内容。针对目前挥发分-半焦交互作用机制解析过程所采用的研究方法及思路,提出了新的见解并对未来交互作用的重点研究方向进行了展望,以期为进一步认识交互作用的物理化学本质提供理论指导。     

Determination and correlation of temperature and pH value dependent solubility of dl-methionine

In order to provide basic data for the crystallization of dl -methionine and understand the thermodynamic properties of dissolution, the solubility of dl -methionine in water was measured by gravimetric method from 294.05 to 347.05 K and the solubility at different pH values under temperature 302.95 to 342.05 K was determined by elemental analysis in this work. The experimental data show that the solubility of dl -methionine increases with increasing temperature as well as more acidic or basic pH values. The van't Hoff equation, modified Apelblat equation, λh equation, Wilson model, NRTL model, and UNIQUAC model were used to correlate the solubility data versus temperature. The melting temperature, enthalpy of fusion, enthalpy and entropy of dissolution were estimated from solubility data and it shows that the expression of solubility by enthalpy and entropy of dissolution gives more reasonable estimation and Wilson model gives a better correlation for these thermodynamic properties.     

Thermodynamics of the Y-Ba-Cu-C-O-H System: Application to the Organometallic Chemical Vapor Deposition of the YBa2Cu3O7−x Phase

A calculational thermodynamic investigation of the chemical vapor deposition (CVD) of YBa₂Cu₃O_{7− x} from organometallic precursors has been performed, based on the minimization of the Gibbs energy of the Y-Ba-Cu-C-O-H chemical system. Thermodynamic data for the participating compounds were selected after a critical assessment of the available thermochemical information and are self-consistent with an accepted phase diagram. The results are presented in CVD diagrams which illustrate the influence of the most commonly used operating conditions of temperature, pressure, and initial gas composition on the formation of stable phases.