A non-lumped dynamic simulation method of sorption compressor for sorption cryocooler

A dynamic analysis of sorption compressor is motivated by the design of a practical sorption compressor. In this paper a non-lumped dynamic simulation method based on a non-isothermal parameter has been developed. An algorithm for simulating the dynamic behaviors of sorption compressor involving mass and energy transport is described and is calculated using Computational Fluid Dynamics (CFD). The calculated time-dependent pressure and temperature across the sorption compressor are obtained and verified by experiments. Then, the effects of thermal gradient and non-equilibrium adsorption–desorption on the net gas outflow from the sorption compressor are also investigated. It is shown that thermal gradient and non-equilibrium adsorption–desorption can significantly affect the net gas outflow with the same total heat input.     

In-situ monitoring of lowermost amounts of hydrogen desorbed from materials

A recently developed thermal desorption spectrometry variant, Molecular Beam–Thermal Desorption Spectrometry (MB–TDS) is used, to monitor in real time and in-situ the dehydriding kinetics from hydrogen storage materials.     

Hydrogen storage in a Li–Al–N ternary system

Hydrogen-storage properties and mechanisms of a novel Li–Al–N ternary system were systematically investigated by a series of performance evaluation and structural examinations. It is found that ca. 5.2 wt% of hydrogen is reversibly stored in a Li₃N–AlN (1:1) system, and the hydrogenated product is composed of LiNH₂, LiH, and AlN. A stepwise reaction is ascertained for the dehydrogenation of the hydrogenated Li₃N–AlN sample, and AlN is found reacting only in the second step to form the final product Li₃AlN₂. The calculation of the reaction enthalpy change indicates that the two-step dehydrogenation reaction is more thermodynamically favorable than any one-step reaction. Further investigations exhibit that the presence of AlN in the LiNH₂–2LiH system enhances the kinetics of its first-step dehydrogenation with a 10% reduction in the activation energy due likely to the higher diffusivity of lithium and hydrogen within AlN.     

Numerical research for contaminant release from un-suspended bottom sediment under different hydrodynamic conditions

Contaminant release from bottom sediments in rivers is one of the main problems to study the environmental hydrodynamics. Contaminant will release into the overlying water column under different hydrodynamic conditions through pore-water in sediment, the release mechanism can be roughly divided into convection diffusion, molecular diffusion and adsorption/desorption. In this article, phosphorus was as a typical contaminant with sorption. Through theoretical analysis of the contaminant release, according to different particle-sized and hydraulic conditions, the mathematics model of contaminant release can be established by the coupled Navier-Stokes equation, Darcy equation, solute transport equation and adsorption/desorption equation. Then that model was verified by flume experiment. Numerical studies show that, under different velocity, the instantaneous concentration of convection diffusion is about 6 times to 50 times larger than that of molecular diffusion during initial stages. The concentration of molecular diffusion is about 1 times to 4 times larger than to that of convection diffusion during late stages. Through analysis, the diffusive boundary layer near the interface can be obtained. In addition, the release will increase with particle size decreasing, and the release will be influenced much more by the size change when the particle size is relatively big under different velocity.     

Desorption of Human Serum Albumin and Human Fibrinogen from the Poly(3-Hydroxybutyrate) Surface

Abstract

The protein desorption of human serum albumin and human fibrinogen from the surface of poly(3-hydroxybutyrate) films was studied with ATR-FTIR spectroscopy. The diffusion model for reversible and irreversible sandwiched layers was confirmed. The reversible ratio (ratio of reversible adsorbed concentration to irreversible one) registrated as a function of time allow us to propose the kinetic model of the initial stage of thromb formation. The parameters of adsorption/desorption for both proteins are compared. The reversible ratio of plasma protein adsorption is proposed as a quantitative criterion of thromb-resistance behavior for polymer in biomedicine, namely, controlled drug release vehicles, artificial vessels, magistrals, reservoirs for blood storage, and surgical threads especially. The mechanism of interaction of protein molecules with PHB macro-molecules is discussed.     

Analysis of CO2 sorption/desorption kinetic behaviors and reaction mechanisms on Li4SiO4

The CO₂ sorption/desorption kinetic behaviors on Li₄SiO₄ were analyzed. The theoretical compositions of the sorption/desorption reactions were calculated using FactSage. The sorption/desorption process on Li₄SiO₄ was investigated by comparing the shrinking core, double exponential, and Avrami–Erofeev models. The Avrami–Erofeev model fits the kinetic thermogravimetric experimental data well and, together with the double‐shell mechanism, clearly explains the sorption/desorption mechanism. The sorption process is limited by the rate of the formation and growth of the crystals with double‐shell structure consisting of Li₂CO₃ and Li₂SiO₃. The whole desorption process is found to be controlled by the rate of the formation and growth of the Li₄SiO₄ crystals. Furthermore, the influence of steam on the CO₂ sorption process was analyzed. It has been observed that the presence of steam enhance the mobility of Li⁺ and, therefore, the rate of diffusion control stage. © 2012 American Institute of Chemical Engineers AIChE J, 59: 901–911, 2013     

振荡时间、离子强度、温度和pH值对GMZ膨润土中Cr（Ⅲ解）吸特性的影响

对吸附在高庙子（GMZ）膨润土上的Cr（III）进行解吸实验，研究振荡时间、解吸溶液离子强度、温度和pH值等因素对解吸特性的影响规律。结果表明：高庙子膨润土上Cr（III）的解吸过程较易发生；Cr（III）的解吸动力学过程较吸附过程慢，实验条件下解吸过程在3 h后达到平衡；当使用0.1 mol/L HCl、1 mol/L NaCl和1 mol/L CaCl 2作为解吸液时，Cr（III）的最终解吸率分别达89.4%,56.5%和77.2%；增大解吸溶液的离子浓度能够促进解吸过程的发生；pH值对Cr（III）解吸过程有重要影响；吸附/解吸过程较符合Freundlich等温模型。GMZ膨润土在处理Cr（III）废水时具有较好的再生能力，可以多次重复利用。     

气相色谱分析中样品引进的新技术—柱上热解吸调制

本文简要介绍了气相色谱分析中常规的样品引进技术，了一种样品引进的新技术－柱上热解吸调制技术，该技术简单、再现性好、其“注射”适于任何大小直径的毛细管柱的进样并易于计算机自动化。     

程序控温吸附法对分子筛扩散性能的研究

提出了研究气体分子在沸石分子筛晶内孔中活化扩散的抛物线降温吸附法,经理论推导得到了计算晶内活化扩散动力学参数的基本公式,同时解决了降温过程中吸附动力学参数的计算问题。在前人工作的基础上,对研究多孔物质扩散性能的 TPD 公式加以改进,使其能够适于沸石分子筛的晶内活化扩散研究。对实际体系的研究结果表明:当采用抛物线降温吸附法对沸石分子筛进行研究时,可根据一次实验的数据,经一次回归计算得到气体分子在沸石分子筛晶内孔中的活化扩散动力学参数及吸附动力学参数,能够方便地进行活化扩散及吸附的研究,并可结合 TPD 数据进一步说明扩散和吸附所具有的特性。