松木粉气流床气化特性实验研究

在气流床气化实验装置上进行了松木粉气化特性的研究。考察了温度、氧当量比、水蒸气配比对气体产物的成分、气化特性和固体产物的微观形态及成分的影响,结果表明,随着温度的升高,CO与H₂浓度显著升高,CO₂与CH₄浓度明显下降,碳转化率、产气率、产气热值有所提高;氧当量比从0.2上升至0.5时,CO与H₂浓度降低超过10%,CO₂浓度则上升100%以上,碳转化率提高至92.9%,产气率有所上升,而产气热值则降低超过20%;水蒸气配比从0增大至0.58时,H₂/CO体积比由0.63提高为1.40,碳转化率、产气率和产气热值均呈现先增大后减小趋势。由SEM照片可以看出,固体残渣主要由类球状或块状结构与纤维团聚结构两部分组成。温度升高使残渣颗粒由呈现不规则形状逐渐向球形转化,氧当量比的增大使残渣中类球状颗粒表面孔洞与裂缝明显增多直至破碎。     

生物质空气-水蒸气气化制取合成气热力学分析

基于Gibbs自由能最小化原理,计算了包括H2O(l)和C(s)在内的,生物质空气 水蒸气气化体系热力学平衡,对比分析了常压气化和加压气化的特点,通过回归分析得到了不同压力下,气化产物中可燃气体分率最高时的水蒸气/生物质质量比（S/B,Steam to Biomass Ratio）与空气当量比（ER,Equivalence Ratio）的关系曲线,为探讨适于制取合成气的气化工艺和条件提供初步的理论指导。研究表明,相对于常压气化,加压气化体系的平衡温度较高,平衡状态下可燃气体分数较低,但CH4含量明显增加;一定温度和当量比下,加压气化使得气化产物中可燃气体分数达到最高所对应的S/B比增大,即需要消耗更多水蒸气;通过调节S/B比,可以比较方便地控制产物中H2和CO的比例。以常压为例,T=1173K,S/B=0.17时,气化产物中H2/CO约为1.1∶1,而S/B=1.02时,气化产物中H2/CO约为2∶1;不同压力下最佳S/B比和ER有很好的线性关系,温度为1173K时,最佳S/B比与压力及ER〖的关系为S/B=－1.48×ER－4.49 E×10－5×p2 + 5.83 E×10－3×p + 0.32。     

C_8芳烃异构体+异丙醇体系在333.15K时的过量摩尔Gibbs自由能

采用CP-I型汽液平衡双循环釜,测定了333.15 K时乙苯+异丙醇、邻二甲苯+异丙醇、间二甲苯+异丙醇、对二甲苯+异丙醇四个体系的汽液平衡数据,计算了该温度下四个体系的过量摩尔Gibbs自由能,并对所测数据进行了恒温下热力学一致性检验。用Wilson方程关联了实验数据,拟合精度令人满意。     

含醇溶液的热力学研究IV.超额Gibbs自由能

利用先前提出的含醇溶液形成的热力学模型，以及释放和充入组分间引力势能 的方法，建立了超额Bibbs自由能方程，它可以避开计及化学作用对超额Gibbs自由 能的贡献，使方程的推导大为简化。这个模型能够联立地用来关联各种含醇溶液， 包括含醇水溶液的超额焓、超额Gibbs自由能和超额熵。对17个有代表性的含醇溶 液关联结果表明，与实验值的一致性是很令人满意的。     

含醇溶液的热力学研究IV.超额Gibbs自由能

利用先前提出的含醇溶液形成的热力学模型，以及释放和充入组分间引力势能 的方法，建立了超额Bibbs自由能方程，它可以避开计及化学作用对超额Gibbs自由 能的贡献，使方程的推导大为简化。这个模型能够联立地用来关联各种含醇溶液， 包括含醇水溶液的超额焓、超额Gibbs自由能和超额熵。对17个有代表性的含醇溶 液关联结果表明，与实验值的一致性是很令人满意的。     

DMSO溶液中有机溶质与尿素、酰胺的Gibbs自由能相互作用参数

ＤＭＳＯ溶液中有机溶质与尿素、酰胺的Ｇｉｂｂｓ自由能相互作用参数张心宽白同春卢雁李强＊（河南新乡师专化学系４５３０００）（河南师范大学化学系新乡４５３００２）酰胺、尿素等模拟生物分子的溶液热力学性质是许多热力学工作者关心的重要课题［１］。一些作者［２...     

原煤可磨性对气流床粉煤气化混配煤煤粉均匀程度的影响

以气流床粉煤气化工业装置不同时期的两组进料煤粉为研究对象,在实验室按粒径对两组煤粉进行了筛分分组,对分组后子煤粉进行了煤质、煤灰特性及反应活性分析,研究了原煤可磨性差异对混配磨制后煤粉均匀程度的影响。结果表明,原煤可磨性对混煤煤粉的颗粒粒径分布及其均匀性均具有影响。混配磨制煤粉的粒径主要取决于原煤中可磨性指数较小的原煤,此原煤可磨性指数越小,煤粉颗粒粒径越大;可磨性相近的原煤混配制得的煤粉混合较均匀,可磨性差异较大的原煤混配煤粉混合不均,煤粉发生偏析,使得大颗粒煤粉中含有过多的难磨煤,导致煤粉的反应性能变差。     

盐-水体系溶解平衡计算的自由能最小化及溶度积方法

根据电解质溶液的基本物理化学原理和近代电解质溶液理论的Pitzer离子相互作用模型,通过计算浓电解质溶液的活度系数和水的活度,研究了盐-水体系溶解平衡的计算方法.结果表明,体系Gibbs自由能最小化方法是计算盐-水体系溶解平衡的一种有效方法,其计算结果与溶度积法一致.     

煤的模型化合物混合燃料气流床气化中N的迁移研究

将吡啶配入柴油中模拟煤中氮的存在形式,考察了混合燃料在四喷嘴对置式气化炉中,轴径向位置HCN、NH3、NO和N2的浓度分布。结果表明：氮污染物(HCN、NH3、NO)在喷嘴平面处即产生且浓度最高,远离喷嘴平面时其浓度大幅降低,N2也裂解参与了气化反应,且出口浓度N2>HCN>NH3>NO;氧燃料比增高,NO、N2增加;氧燃料比1.3时HCN、NH3浓度最高,0.9和1.7时浓度较低;流场的分布使靠近出口处径向浓度基本一致,而上部各平面位置浓度靠近炉壁处最低;水汽的加入使HCN、NH3浓度增高而NO浓度降低。     

基于支撑向量机方法的有机化合物的生成Gibbs自由能的预测

基于支撑向量机方法的有机化合物的生成Gibbs自由能的预测;支撑向量机;多元线形回归;吉布斯自由能     

煤与甲烷共转化制合成气过程的热力学分析

采用Gibbs自由能最小法,对流化床煤与甲烷共转化过程进行了热力学分析。在保持体系绝热温度为常压流化床煤气化的操作温度1 273 K下,将煤与甲烷共转化过程的冷煤气效率、产出合成气的单位有效能氧耗及H2/CO比等指标与单纯煤气化过程进行了比较。结果表明,在煤气化体系中增加甲烷进料,能使冷煤气效率提高,单位有效能氧耗降低,产出合成气的H2/CO比可调。此外,甲烷可作为部分氢源,降低过程水耗。从热力学角度证明了煤与甲烷共转化方法对于有效利用煤层气的优越性,所得出的操作线也为该过程的实际操作指出了方向。     

A Gibbs free energy correlation for automated docking of carbohydrates

Thermodynamic information can be inferred from static atomic configurations. To model the thermodynamics of carbohydrate binding to proteins accurately, a large binding data set has been assembled from the literature. The data set contains information from 262 unique protein-carbohydrate crystal structures for which experimental binding information is known. Hydrogen atoms were added to the structures and training conformations were generated with the automated docking program AutoDock 3.06, resulting in a training set of 225,920 all-atom conformations. In all, 288 formulations of the AutoDock 3.0 free energy model were trained against the data set, testing each of four alternate methods of computing the van der Waals, solvation, and hydrogen-bonding energetic components. The van der Waals parameters from AutoDock 1 produced the lowest errors, and an entropic model derived from statistical mechanics produced the only models with five physically and statistically significant coefficients. Eight models predict the Gibbs free energy of binding with an error of less than 40% of the error of any similar models previously published.     

用于煤制天然气的气化-热解耦合系统模拟研究及能量分析

大规模煤制天然气系统中气流床气化是一种重要且富吸引力的技术。对一种气流床气化-热解耦合系统进行了研究。该系统中气化炉分为两段:主要进行煤焦气化的气化段以及主要发生煤热解的热解段。采用流程模拟方法建立了耦合系统模型并与煤气化废锅系统进行了比较。同时,考察了操作条件对耦合系统气化性能的影响,提出了优化的操作条件。结果显示,气化温度1400 ℃时,耦合系统优化的蒸汽煤比为250~300 kg(steam)·t^-1(dry coal)。耦合系统的冷煤气效率为88.18%,高于气化废锅系统(84.14%),且其消耗指标均有所降低。但耦合系统的气化性能受到热解段焦油和CH₄产率很大的影响。耦合系统总体能量利用效率为92.26%,略低于气化废锅系统(93.39%),但其火用效率比气化废锅系统高2.2%。这说明通过热解-气化的耦合方式能够有效回收气化高温合成气中的显热并提高其能量品位。     

An algebraic method that includes Gibbs minimization for performing phase equilibrium calculations for any number of components or phases

The most widely used technique for performing phase equilibria calculations is the K-value method (equality of chemical potentials). This paper proposes a more efficient algorithm to achieve the results that includes Gibbs minimization when we know the number of phases. Using the orthogonal derivatives, the tangent plane equation and mass balances, it is possible to reduce the Gibbs minimization procedure to the task of finding the solution of a system of non-linear equations. Such an operation is easier and faster than finding tangents or areas, and appears to converge as fast as the K-value method. Examples illustrate application of the new technique to two and three phases in equilibrium for binary and ternary mixtures.     

Excess Gibbs free energy and kinetics of grain growth of nanostructured silver

Samples of nanostructured silver were prepared by a mechanochemical technique and by electrodeposition. In the former, the microstructure was stabilized by intergranular cosegregation of Mg and O atoms. The excess Gibbs free energy of these samples was investigated by e.m.f. measurements at 453 K in a solid state electrochemical cell with AgI as a solid electrolyte. Electrodeposited pure silver samples had a labile microstructure even at 298 K. Their structural relaxation process was monitored in situ by chronopotentiometric measurements in an aqueous iodoargentate electrolyte. The time dependence of the e.m.f. could be quantitatively described by a parabolic law of grain growth without any adjustable parameter. Received: 13 January 2000 / Accepted: 8 February 2000     

规范不同均相化学反应的热力学性质表示及其关系

尝试对均相化学反应的热力学性质表述进行规范,如浓度的表示形式、不同标准状态、B组分标准状态化学势μBo、标准吉布斯自由能变化量△rGm,ao、平衡常数Kao、反应的热效应△rHm,ao等。     

Oxidative reforming of methane for hydrogen and synthesis gas production:Thermodynamic equilibrium analysis

A thermodynamic analysis of methane oxidative reforming was carried out by Gibbs energy minimization (at constant pressure and temperature) and entropy maximization (at constant pressure and enthalpy) methods,to determine the equilibrium compositions and equilibrium temperatures,respectively.Both cases were treated as optimization problems (non-linear programming formulation).The GAMS 23.1 software and the CONOPT2 solver were used in the resolution of the proposed problems.The hydrogen and syngas production were favored at high temperatures and low pressures,and thus the oxygen to methane molar ratio (O 2 /CH 4) was the dominant factor to control the composition of the product formed.For O 2 /CH 4 molar ratios higher than 0.5,the oxidative reforming of methane presented autothermal behavior in the case of either utilizing O 2 or air as oxidant agent,but oxidation reaction with air possessed the advantage of avoiding peak temperatures in the system,due to change in the heat capacity of the system caused by the addition of nitrogen.The calculated results were compared with previously published experimental and simulated data with a good agreement between them.