Peat Pyrolysis and the Analytical Semi-empirical Model

Abstract

Pyrolysis of peat could convert this material into useful fuels and valuable hydrocarbons. A study of peat pyrolysis can also serve as a useful bridge between studies of coal pyrolysis and biomass pyrolysis. Using an analytical model of pyrolysis that has previously been applied to biomass and to coal, we present here the results of applications of this model to a representative peat. The analysis suggests means of organizing and processing rate and yield data that should be useful in applications of pyrolysis for the production of fuels and chemicals.     

On-line monitoring of vacuum drying of theophylline using NIR spectroscopy: solid-state transitions,water content and semi-empirical modeling

The aim of this work was to monitor in-line and at a real time, the solid-state forms during pharmaceuticals manufacturing. It concerns the dehydration behavior and the solid-state transitions of theophylline in an agitated vacuum contact dryer. First, a near infrared spectroscopy (NIRS) method was performed using a reflectance diffuse probe to measure the in-line and in-situ exact composition of the mixture of different forms of theophylline and water content during drying. A multivariate modeling has been investigated to build a robust model which can predict four components at the same time during drying process. The XRPD analysis was used as a reference method in the process of calibration of NIRS. The indicators of the accuracy in quantitative spectral analysis confirm the robustness of the model and the efficiency of the method of calibration. Second, the kinetics of solid state transformations were investigated. It was shown that the dehydration advanced first by the formation of the metastable anhydrate and after a lag time of the stable one. Once the stable form appeared, formation of the metastable form came to an end. The temperature was found out to be the main factor controlling the overall process rate but also the final contents of the stable and metastable anhydrates for the considered dryer and operating conditions range. Finally, a semi-empirical drying model was proposed and significant quantitative differences were found, particularly at the product temperature which was probably caused by the excessive simplicity of the model.     

基于半经验公式的风力机尾流模型研究

以瑞典航空研究院(FFA)、东京大学及荷兰能源研究中心(ECN)的风洞实验为参照,以探究半经验公式类型的风力机尾流模型为目的,验证了Jensen模型和改进Jens-en模型。采用上述两个半经验模型,编写计算程序,然后按照上述每个风洞实验的参数,设定计算条件,计算风力机下游的无量纲风速,再分别与相应的实验值进行比较。结果表明,在各自的适用条件下,上述两个模型都能比较精确地模拟风力机尾流特性。这证明上述两模型可以用于进一步研究风力机尾流效应,以进行风电场微观选址与布局优化。     

Rest masses of elementary particles as basic information of Gibbs–Falkian thermodynamics

As developed by G. Falk (following J.W. Gibbs), methods of modern thermodynamics allow by means of the Einstein mechanics to describe as well energy–momentum transports (EMT) which occur under vacuum conditions. Such EMT relations are proved to manifest a set of elementary particles which in its entirety determines real state changes of fluids on the macro-level. EMT differ from each other by their masses at rest ( m_# ) resulting as integration constant each. In order to identify m_# , Seelig has established a new theory whose physical background is de Broglie's mechanics of matter waves. Seelig's results stand out without exception by their excellent agreement with a lot of measured m_# values of elementary particles. Strikingly, the structure of the Seelig equation even permits for an extension upon particles hitherto outside Seelig's approach. This new semi-empirical mass formula agrees with the experimental m_# values of all known stabile elementary particles better than 0.085 % on weighted average. The formula has some outstanding properties leading to some remarkable conclusions on Higgs particles and allowing predictions of particles hitherto unknown. Thus, a new key to a uniform understanding of real processes in physics, e.g., in thermal sciences, is now at hand: matter is realized on the micro-level by a finite number of particle classes which are subject to well-posed constraints holding on macro-level for the physical system in question.     

Optimization of the mean radius flow path of a multi-stage steam turbine with evolution algorithms

A prototype model of the mean radius flow path of a four-stage, high speed 1 MWe axial steam turbine was optimized by using evolution algorithms, DE (differential evolution) algorithm in this case. Also the cost-benefits of the optimization were inspected. The optimization was successfully performed but the accuracy of the optimization was slightly less than hoped when compared to the control modeling executed with the CFD (computational fluid dynamics). The mentioned inaccuracy could have been hardly avoided because of problems with an initial presumption involving semi-empiric calculations and of the uncertainty concerning the absolute areas of qualification of the functions. This kind of algebraic modeling was essential for the success of the optimization because e.g. CFD-calculation could not have been done on each step of the optimization. During the optimization some problems occurred with the adequacy of the computer capacity and with finding a suitable solution that would keep the algorithms within mathematically allowable boundaries but would not restrict the progress of the optimization too much. The rest of the problems were due to the novelty of the application and problems with preciseness when handling the areas of qualification of the functions. Although the accuracy of the optimization results was not exactly in accordance with the objective, they did have a favorable effect on the designing of the turbine. The optimization executed with the help of the DE-algorithm got at least about 3.5 % more power out of the turbine which means about 150 000 € cost-benefit per turbine in the form of additional electricity capacity.     

甲叉膦酸型化合物阻垢机理的量子化学研究

运用密度泛函（DFT）理论,在B3LYP／6-31G水平下,系统研究了ATMP,EDTMP,HDTMP,GDMP,MADMP这5种甲叉膦酸类阻垢缓蚀剂分子结构与阻垢性能之间的构效关系。结果表明,5种膦酸分子中的氮原子及膦羧基团中的氧原子上负电荷密度较大,这使得氮原子及膦羧基易与垢晶体中的钙离子发生静电相互作用,如果氮原子与氧原子间距与方解石晶体生长面上的钙离子对间距匹配,将显著增强了阻垢剂分子与特定晶面的Coulomb吸附行为,诱导垢晶体发生畸变,有效地阻止其生长。本文还利用半经验（PM3）方法对分子势能面进行扫描,得出分子能量随二面角改变的变化率,初步探讨了分子柔性、刚性对其阻垢性能的影响。     

渗透性低温保护剂玻璃化转变临界降温速率的实验确定

从Boutron结晶动力学半经验公式出发，结合他人的修正结果，利用差示量热扫描仪(DSC)的实验数据，不必构造TTT和ccT曲线，获得了若干常用低温保护剂实现玻璃化转变的临界降温速率，测定了渗透性低温保护剂实现玻璃化转变的临界结晶率，修正了临界降温速率的计算公式，实验还说明了Bourton模型对非渗透性保护剂降温结晶过程的局限性。     

Schiff-base derivatives as corrosion inhibitors for carbon steel materials in acid media: quantum chemical calculations

Quantum chemical calculations based on Hartree–Fock, AM1 and B3LYP functions were performed on the three Schiff-base compounds used as corrosion inhibitors for carbon steels in acid media. The quantum chemical calculations were conducted to determine the relationship between inhibition efficiency (IE) and the molecular structure of inhibitors. Several quantum chemical parameters, such as charge distribution, energy and distribution of the highest occupied molecular orbital (E_HOMO) and lowest unoccupied molecular orbital (E_LUMO), absolute electronegativity (χ) and the fraction of electrons (ΔN) transferred from inhibitors to the steel surface, were calculated and correlated with inhibition efficiencies. The results showed that the IE of Schiff-base compounds enhanced with increasing E_HOMO or decreasing E_LUMO; meanwhile, N atoms on Schiff-base molecules were the most probable sites for adsorption of inhibitor molecules on the metal surface. The inhibition mechanisms of three Schiff-base compounds were obtained from different calculation methods, and the results from each method are consistent.     

The Activity and Theoretical Interpretation of Role of Trimethyl Phosphite Modified HZSM-5 Zeolite

The catalytic activity of trimethyl phosphite modified HZSM-5 zeolite and un-modified HZSM-5 zeolite treated with 100% steam at 673, 773,873,973 and 1073K, respectively, were investigated using heptane cracking as a probe reaction. The results showed that the heptane conversion of both trimethyl phosphite treated samples and un-phosphated samples decreased with an increase in treating temperature, but trimethyl phosphite modified samples showed higher activity in comparison with the un-modified samples, which were steam-treated at a higher temperature. The results were firstly elucidated by the model cluster method and computational quantum chemistry method. Full optimization and frequency analysis of all cluster model have been carried out using the Gaussian 94 software-package with the PM 3 semi-empirical method performed on small cluster models. The computational results showed that the dealumination of trimethyl phosphite modified zeolite model cluster was more difficult than that of un-modified zeolite model cluster when they were treated with steam while investigating the heat of reaction.     

Stability of the crystal structures of poly(vinyl alcohol) (PVA) by CNDO/2 calculations

CNDO/2 calculations using the tight-binding approximation for polymers was applied to poly(vinyl alcohol) (PVA). The calculations were performed assuming several crystal structures. The stability among the structures was explained by using the calculated results in connection with the hydrogen bonding involved.