在非等温条件下石膏和硼石膏的加热脱水动力学研究

Thermal dehydration of gypsum and borogypsum was investigated under nonisothermal conditions in air by using simultaneous thermogravimetric-differential thermal analyzer. Nonisothermal experiments were carried out at various linear heating rates. Kinetics of dehydration in the temperature range of 373-503 K were evaluated from the DTA (differential thermal analysis)-TGA (thermogravimetric analysis) data by means of Coats-Redfern,Kissinger and Doyle Equations. Values of the activation energy and the pre-exponential factor of the dehydration were calculated. The results of thermal experiments and kinetic parameters indicated that borogypsum is similar to gypsum from dehydration mechanism point of view although it consists of boron and small amount of alkali metal oxides.     

Gas-phase dehydration of glycerol over commercial Pt/γ-Al2O3 catalysts

Gas-phase dehydration of glycerol to produce acrolein was investigated over commercial catalysts based onγ-Al2O3, viz. A-64, A-56, I-62, AP-10, AP-56, AP-64 and KR-104. To understand the effect of Cl?anions, HCl-impregnated sup-ports have been investigated in the dehydration reaction of glycerol at 375 °C. For comparison, various H-zeolites were also examined. It was found that the glycerol conversion over the solid acid catalysts was strongly dependent on their acidity and surface area. And the relationship between the catalytic activity and the acidity of the catalysts was discussed. The outstanding properties of Pt/γ-Al2O3 catalyst systems for the dehydration of glycerol were revealed. Pt/γ-Al2O3 catalyst (AP-64) showed the highest catalytic activity after 50 h of reaction with an acrolein selectivity of 65%at a conversion of glycerol of 90%. Based on these results, catalysts based onγ-Al2O3 appear to be most promising for gas phase dehydration of glycerol.     

Structural evolution of chars from biomass components pyrolysis in a xenon lamp radiation reactor

The structural evolution of the chars from pyrolysis of biomass components(cellulose, hemicellulose and lignin)in a xenon lamp radiation reactor was investigated. The elemental composition analysis showed that the C content increased at the expense of H and O contents during the chars formation. The values of ΔH/C/ΔO/Cfor the formation of cellulose and hemicellulose chars were close to 2, indicating that dehydration was the dominant reaction. Meanwhile, the value was more than 3 for lignin char formation, suggesting that the occurrence of demethoxylation was prevalent. FTIR and XRD analyses further disclosed that the cellulose pyrolysis needed to break down the stable crystal structure prior to the severe depolymerization. As for hemicellulose and lignin pyrolysis, the weak branches and linkages decomposed firstly, followed by the major decomposition. After the devolatilization at the main pyrolysis stage, the three components encountered a slow carbonization process to form condensed aromatic chars. The SEM results showed that the three components underwent different devolatilization behaviors, which induced various surface morphologies of the chars.     

介孔纳米氧化铝的制备、表征及其应用

Using aluminum isopropoxide as the aluminum source and O,O′-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol as the template,ordered worm-like mesoporous nano-alumina was prepared by sol-gel method.The characterization results showed that the surface area,average pore diameter and pore volume of the calcined mesoporous alumina were 341.1 m²·g^-1,17.4 nm and 1.54 cm³·g^-1,respectively.The catalytic properties of the mesoporous nano alumina for the dehydration of isopropanol to propylene was investigated.The results indicated that the as-prepared mesoporous nano-alumina exhibited high catalytic activity.The conversion of isopropanol and the selectivity to propylene were more than 99.0% and 98.5%,respectively,when isopropanol WHSV was 0.5 h^-1,1.0 h^-1 and 2.0 h^-1 and the corresponding reaction temperature was controlled at the range of (230-320) ℃,(250-340) ℃ and (260-350) ℃,respectively.     

Preparation of Reference Samples for Refractoriness Under Load (Non-differential, with Rising Temperature) of Refractories

The preparation of reference samples for refractoriness under load < non-differential.with rising temperature) of refractories was discussed.According to features and application of reference samples.quartz glass was chosen as a stand-by reference material for uniformity and stability tests.Then.the true value was fixed by gathering the testing results from many labs with stable testing levels and reliable testing results in China.The testing results from these labs were used for normality test by Shapiro-wilk method:and for abnormality value test by Grubbs method.for equal observation test by Cochran method.After confirming no abnormality values among the testing results from the labs.the average values of reference samples were calculated and the uncertainty was appraised.The results show that the standard value of reference samples is 1 386℃and the expanded uncertainty is 12℃.     

交联壳聚糖磁性颗粒吸附去除水溶液中的铜

The performance of cross-linked magnetic chitosan, coated with magnetic fluids and cross-linked with epichlorohydrin, was investigated for the adsorption of copper (II) from aqueous solutions. Infrared spectra of chitosan before and after modification showed that the coating and cross-linking are effective. Experiments were performed at different pH of solution and contact time, and appropriate conditions for the adsorption of Cu(II) were determined. Experimental equilibrium data were correlated with Langmuir and Freundlich isotherms for determination of the adsorption potential. The results showed that the Langmuir isotherm was better compared with the Freundlich isotherm, and the uptake of Cu(II) was 78.13 mg&#8226;g－1. The kinetics of adsorption corresponded with the first-order Langergren rate equation, and Langergren rate constants were determined.     

椭球形颗粒动力效应模型(DEM)构建方法的比较(英文)

Discrete element model was developed to simulate the ellipsoidal particles moving in the moving bed.Multi-element model was used to describe a ellipsoidal particle,the contact detection algorithm of ellipsoidal particle was developed,and both contact force and gravity force were considered in the models.The simulation results were validated by our experiment.Three algorithms for representing an ellipsoidal particle were compared in macro and micro aspects.The results show that there exists big difference in the microscopic parameters such as kinetic energy,rotational kinetic energy,deformation,contact force and collision number which leads to the difference of macroscopic parameters.The relative error in the discharge rate and tracer particle position is the largest between 3-tangent-element representation and experimental results.The flow pattern is similar for the 5-element and 3-intersection representations.The only difference is the discharge rate of 5-element representation is larger than the experimental value and that of the 3-intersection representation has the contrary result.Finally the 3-intersectionelement representation is chosen in the simulation due to less computing time than that of the 5-element representation.     

搅拌槽中固体颗粒离底悬浮机理的研究

The minimum fluid velocity to maintain particles just suspended was deduced, and the theoretical analysis shows that the minimum velocity is influenced by the properties of the solid and liquid, not by the operational conditions. For justification, the local minimum velocity at the bottom of the tank was measured by a bi- electrode conductivity probe, in a square-sectioned stirred tank (0.75 m×0.75m×1.0m) with the glass beads-water system. The experiments showed that the fluid velocities for the same suspension state were identical despite that the power dissipated per unit mass was not the same under different configuration and operation. Both theoretical analysis and experimental results indicate that the off-bottom suspension is controlled by the local fluid flow over the bottom of the stirred tank.     

绝热固定床反应器甲醇脱水合成二甲醚的实验和模型研究

One-dimensional heterogeneous plug flow model was employed to model an adiabatic fixed-bed reactor for the catalytic dehydration of methanol to dimethyl ether. Longitudinal temperature and conversion profiles predicted by this model were compared to those experimentally measured in a bench scale reactor. The reactor was packed with 1.5 mm γ-Al2O3 pellets as dehydration catalyst and operated in a temperature range of 543-603 K at an atmospheric pressure. Also, the effects of weight hourly space velocity (WHSV) and temperature on methanol conversion were investigated. According to the results, the maximum conversion is obtained at 603.15 K with WHSV of 72.87 h－1.     

Synthesis of Chelating Resin PETU and Its Adsorption to Ag(I)

A novel chelating resin (PETU) with thiourea groups in its main chain was synthesized by the reaction of O,O'-butane-1,4-diyl dicarbonisothiocyanatidate and triethylene tetraamine. The adsorption of Ag(I) on PETU was investigated by batch tests. The results showed that adsorption data fitted Boyd's diffusion equation of liquid film and the adsorption was controlled by liquid film diffusion. Under the temperatures between 15～60 ℃, the adsorption capacity decreased with the increase of temperature, and increased with the increase of initial concentration of Ag(I). The experimental data fitted Langmuir and Freundlich equations, and the correlation coefficients for Langmuir equation were between 0.9965～0.9998, and those for Freundlich equation were between 0.8211～0.9810, and increased with the adsorption temperature. △H, △G and △S calculated by thermodynamic formulae were all negative, which meant that the adsorption process was exothermic and spontaneous, and the entropy decreased during the process. XPS results showed that N, S and O atoms were the electron donors to coordinate with Ag.     

REOx掺杂的ZrO2催化剂催化羟乙基吡咯烷酮脱水反应性能

Catalyst plays an important role in the dehydration of N-（hydroxylethyl）pyrrolidone （NHP） to prepare N-vinyl-pyrrolidone （NVP）. At present, NVP yield is only about 30% on commercial ZrO2 catalyst. A coupled precipitation and solid dispersion technique was designed to prepare the nano-ZrO2 catalyst, in which rare earth metal oxides （REOx） was used as electronic promoter. The results indicated that the catalyst doped REOx （S-1.0） exhibits the optimum performance of NHP dehydration at moderate conditions. NHP conversion and NVP selectivity are respectively 97.0%, 82.3%. Of special interest is that the indexes of the catalyst （S-1.0-1.0） are up to 98.4% and 89.2% respectively. Furthermore, this catalyst bears the good stability. It means that nano-ZrO2 doped REOx catalyst might be a potential commercial catalyst for the NHP dehydration.     

Mechanistic insights into aqueous phase propanol dehydration in H‐ZSM‐5 zeolite

Aqueous phase dehydration of 1‐propanol over H‐ZSM‐5 zeolite was investigated using density functional theory (DFT) calculations. The water molecules in the zeolite pores prefer to aggregate via the hydrogen bonding network and be protonated at the Brønsted acidic sites (BAS). Two typical configurations, i.e., dispersed and clustered, of water molecules were identified by ab initio molecular dynamics simulations of the mimicking aqueous phase H‐ZSM‐5 unit cell with 20 water molecules per unit cell. DFT calculated Gibbs free energies suggest that the dimeric propanol–propanol, the propanol–water, and the trimeric propanol–propanol–water complexes are formed at high propanol concentrations in aqueous phase, which provide a kinetically feasible dehydration reaction channel of 1‐propanol to propene. The calculation results indicate that the propanol dehydration via the unimolecular mechanism becomes kinetically discouraged due to the enhanced stability of the protonated dimeric propanol and the protonated water cluster acting as the BAS site for alcohol dehydration. © 2016 American Institute of Chemical Engineers AIChE J, 63: 172–184, 2017     

合成气制二甲醚三相淤浆床反应器的数学模型研究

A mathematical model for a bubble column slurry reactor is presented for dimethyl ether synthesis from syngas. Methanol synthesis from carbon monoxide and carbon dioxide by hydrogenation and the methanol dehydration are considered as independent reactions, in which methanol, dimethyl ether and carbon dioxide are the key components. In this model, the gas phase is considered to be in plug flow and the liquid phase to be in partly back mixing with axial distribution of solid catalyst. The simulation results show that the axial dispersion of solid catalysts, the operational height of the slurry phase in the bubble column slurry reactor, and the reaction results are influenced by the reaction temperature and pressure, which are the basic data for the scale-up of reactor.     

三甘醇脱水效果的影响因素分析

为了提高三甘醇脱水的脱水效果,有必要分析各种因素对脱水效果的影响。利用HYSYS软件对处理量为100×10^4Nm^3／d的三甘醇脱水装置进行模拟计算,分析结果显示吸收塔的吸收温度越低、三甘醇贫液浓度越高、三甘醇循环量越大、吸收塔塔板数越多,则脱水效果越好,外输干气水露点越低。‘     

甲乙酮成套技术开发及工业应用

A synthetic technology for the production of methyl-ethyl-ketone （MEK） is introduced, which makes use of butylene catalytic hydration to produce secondary butanol （SBA） and this is followed by dehydrogenation of SBA. By optimizing the operating conditions of a commercial unit, the running results showed that the recommended process was successful and that the catalysts had high activity, good selectivity, and long lifespan, which ensured long-term running in commercial units.     

Feasibility analysis and process simulation of CO2 dehydration using triethylene glycol for CO2 pipeline transportation

The operation of dehydration is very important in the process of gas transportation. This study aims to evaluate the application feasibility of CO₂ dehydration using triethylene glycol, which is also called TEG for short. Aspen Plus software was used to simulate the dehydration process system of CO₂ gas transportation using TEG dehydration. Parameter analysis and process improvement were carried out for the simulation of dehydration process. At first, a sensitivity analysis was conducted to analyze and optimize operating conditions of conventional CO₂-TEG dehydration process system. Subsequently, a recycle unit was introduced into the conventional CO₂-TEG dehydration process system, it can be found that the improved process system with the recycle unit has a higher CO₂ recovery rate which was about 9.8% than the conventional one. Moreover, the improved process system showed excellent operation stability through the comparison of simulation results of several processes with various water contents in their feed gases. Although the energy consumption is increased by about 2%, the improved process was economically and technically feasible for the long-term availability of CO₂ pipeline transportation. The simulated results showed that the improved CO₂-TEG process system has promising application prospects in CO₂ dehydration of CO₂ gas transportation with high stability.     

在高压下规整填料中的流动实验研究

Both distillation performance and hydrodynamic study for backmixing by tracer technique were carried out in a high-pressure packed column with 0.15 m inner diameter over a wide range of operating conditions. Isobutane and n-pentane are employed as test mixture in the distillation experiment and air/water is used for the hydrodynamic study. The column is installed with Mellapak 350Y structured packing and the total packing height is 2.0 m. With the increasing operating pressure, the separation efficiency increases slightly while the F-factor corresponding to the maximum efficiency at each pressure is descending. It is noted that, at all operating pressures, with the increase of F-factor, the packing efficiency is slightly higher up to the flooding point. The application of SRP model to high-pressure distillation gives much lower values of HTUOG than those obtained experimentally. An additional term, the height of mixing unit, is introduced to correct the SRP model and improve its accuracy at high pressure. From the tracer experiments, the height of mixing unit for gas phase was found to be larger than that for the liquid phase. From this viewpoint, it is believed that the gas phase backmixing gives more unfavorable influence on the separation efficiency in comparison with liquid phase.     

电化学还原硝基甲烷合成N-甲基羟胺盐酸盐的工业化试验

An industrial electrolytic cell was designed for the electrochemical synthesis of N-methylhydroxylamine hydrochloride （N-MHA）. Copper was used as the cathode, graphite as the anode, and a cation membrane as the separator. The results show that N-MHA with a high purity of 99% can be electrosynthesized directly from nitromethane in HC1 solution. Under a constant current of 1000-2500A.m^-2 in the temperature of 30-50℃, the average yield, current efficiency, and reaction selectivity were 65%, 70%, and 99%, respectively. Graphite electrode and membrane material can be used continuously in the preparative electrolysis for 5000h. Moreover, the effects of the electrode and membrane materials, current intensity, electrolyte temperature, and other associated parameters on the electrosynthesis results were investigated. The direct current power consumption was 8151.3kW-h-（1000kg N-MHA）^ -1. This method is a simple separation process with limited contamination and hence, is a new green synthesis method for the industrial production of N-MHA.     

成品油罐自动脱水装置数值模拟

成品油外输时对其含水率有严格要求,因此,成品油在储运过程中,尤其是在油罐储存过程中必须要进行脱水。成品油罐的脱水设备在运行过程中应尽量满足低能耗、低污染的要求。本文以成品油罐自动脱水装置为研究对象,建立了水力数学模型,对流经自动脱水装置的油水混合物进行了流动状态的数值模拟,进一步验证了自动脱水装置设计的合理l生,为成品油罐自动脱水装置的安装使用提供了经验。     

钛和沥青机械合金化合成纳米级碳化钛

Abstract TiC powder was synthesized by mechanical alloying of titanium and asphalt in this paper. Deoiled asphalt as a carbon source not only provided element C in the fabrication of TiC but also cracked itself by the mechanical alloying process. The results of X-ray diffraction demonstrated the synthesis of cubic TiC. Gas phase chromatography showed that the discharged gas was composed of low molecular weight hydrocarbons, including H2, CH4 and C2H6. The formation mechanism of titanium carbide by mechanical alloying, and the thermodynamic and kinetics were discussed. These results showed that mechanical alloying is a promising method to prepare TiC and to crack asphalt with some light fraction byproducts.