国内外聚烯烃流化床技术专利分析

采用流化床进行烯烃聚合是聚烯烃制备的核心技术之一,本文以全球聚烯烃流化床技术相关专利为研究对象,从全球专利申请趋势、专利技术来源与布局等角度,研究了全球聚烯烃流化床专利技术的分布情况,并采用文本聚类、技术功效矩阵、合作网络分析等方法,分析领域技术发展趋势、主要技术分布以及全球技术竞争格局,同时针对核心申请人进行重点技术分析,为我国聚烯烃流化床技术的发展提供参考依据。分析表明：聚烯烃流化床领域技术处于技术稳定期,且存在明显的技术垄断现象,美国技术实力最强,中国属于技术输入国,本土技术研发实力与美国存在较大差距;催化剂研究是领域研究的重点方向,围绕聚合反应器方面的研究逐步成为热点;针对冷凝工艺与回收分离工艺的改进探索相对较少,国内企业与研发机构可以作为技术突破的方向。     

Electrosynthesis of dimethylsulfone from dimethylsulfoxide at a dimensionally stable anode

Galvanostatic electrochemical oxidation of dimethylsulphoxide (DMSO) to dimethylsulfone (DMSO₂) has been effected at a dimensionally stable anode (DSA) under different conditions of current density and reaction media, in both a batch and a flow reactor (membrane cell with an ion-exchange membrane between the two working electrodes) functioning in batch recirculation mode. Excellent yields of the sulfone have been obtained under both conditions. The product has been characterized by various physicochemical techniques. The operational conditions giving maximum yield of the product have been established. The electrochemical oxidation of DMSO has also been studied by cyclic voltammetry at a glassy carbon (GC) electrode. The mechanism of electrochemical oxidation and the advantages of the present methods over existing ones, are discussed.     

甲醇制汽油工艺概述

介绍了固定床工艺、流化床工艺、多管式反应器以及一步法甲醇制汽油（MTG）的工艺特点及其流程,并对几种工艺进行了比较。     

Robust temperature control for batch chemical reactors

Since batch chemical reactors exhibit an integrating response, temperature control for these systems can be a real problem for conventional PID controllers. Tuning can be extremely difficult due to the reduced stability margins proved for this type of processes. In this work, a simple robust control strategy for temperature regulation in batch and semi-batch chemical reactors is proposed. The feedback controller is composed by an approximate I/O linearizing feedback equipped with a calorimetric balance estimator. Based on standard results from singular perturbations, it is proven that the proposed feedback controller (i) can track a bounded temperature trajectory as close as desired (i.e., practical stability) by adjusting a single estimation parameter, and (ii) after a short transient, the performance of the exact I/O linearizing feedback can be recovered as the calorimetric balance estimation rate is increased.     

Mass transfer studies at rotating cylinder electrodes of expanded metal

Mass transfer has been studied at rotating cylinder electrodes of expanded metal using the reduction of ferricyanide as test reaction. The experimental data are well correlated by an empirical expression between the Sherwood number and the Reynolds number, both in terms of the hydraulic diameter as characteristic length, and including two additional dimensionless parameters in order to characterize the geometry of the expanded metal. Comparisons of the mass-transfer performance of the expanded metal electrodes with other three-dimensional structures are made.     

Heterogeneous photocatalysis: state of the art and present applications In honor of Pr. R.L. Burwell Jr. (1912–2003), Former Head of Ipatieff Laboratories, Northwestern University, Evanston (Ill).

In the present paper, the basic fundamentals of photocatalysis are explained with the influence of the five main parameters which govern the kinetics: (i) mass of catalyst, (ii) wavelength, (iii) partial pression and/or concentrations of reactants, (iv) temperature (at a second degree) and (v) the radiant flux. The main types of photocatalytic reactions presently described (all performed at room temperature) concern (i) the selective mild oxidation of hydrocarbons, (ii) the hydrogen production and (iii) the total oxidation reactions of organics in presence of water. The last point constitutes the ensemble of the last recent developments in photocatalysis. Most of organic contaminants, including dangerous pesticides, can be easily totally degraded and mineralized.Dyes are also not only decolorized, but mineralized in colored aqueous effluents. The most abundant ones (the azo-dyes) have their azo-group(s) –N=N– decomposed into N2(g), which represents an ideal decontamination case.Photocatalytic engineering is under development, now using deposited titania in a fixed bed. Some (solar) photocatalytic pilot reactors and prototypes are described. The use of solar energy as a source of activating UV–A irradiation is described as a sub-discipline called helio-photocatalysis.     

Difference points in reactive and extractive cascades, V: Determining reaction distribution from separatrix manifolds

The effect of reaction distribution policy on a reactive column profiles is analyzed. We find that the extent reaction on a single reactive stage can greatly influence the feasibility and termination of subsequent non-reactive stages. We develop a method to quantitatively predict when perturbing the amount of reaction on a single stage will subsequently force the column profile to become infeasible or otherwise fail to meet global design targets. To predict such behavior we rely on the map of stable invariant manifolds over the saddle branch of an isoreflux pinch point curve. We show how this method can be used to select reactive stages and distribute reaction over a column section profile to meet certain design criteria. We also show how this method can be used to find limits on overall extent reaction within a column or extent reaction on a single stage.     

Flow and particle motion in scraped heat exchanger crystallizers

Turbulent fluid flow and related solid particle behaviour in the direct vicinity of the heat exchanging (HE) surface of a scraped heat exchanger crystallizer was studied. The liquid flow is visualized by dye injection and the particles are monitored directly for two types of commonly used scraper geometries. In conjunction with this experimental work, we performed direct numerical simulations of the two-phase (solid-liquid) flow system. Our main goal is the design of scraper geometries that enhance heat transfer by perturbing the thermal boundary layer, and effectively scrape off particles that nucleate, grow and adhere onto the HE surface. Also the turbulent flow generated by the moving scrapers should direct the particles into the bulk of the tank. The experiments and simulations show good qualitative resemblance which enables the design of scrapers based primarily on numerical predictions.     

Deposition and characterisation of TiO2 coatings on various supports for structured (photo)catalytic reactors

Different types of aqueous TiO₂–P25 suspensions were prepared and their properties, including rheological behaviour and zeta potential, were studied. Then, TiO₂ suspensions were used to elaborate TiO₂ coatings on various substrates (cordierite monolith, stainless steel plates and -SiC foam) using a dip-coating method. The relationship between the suspension stability and the coating adhesion has been considered. The structural and morphological characterisation of TiO₂ coatings has been performed using scanning electron microscopy, X-ray diffraction and other methods. Finally, the photocatalytic properties of the materials have been determined by studying the photooxidation of aqueous ammonia.     

Hollow fiber membrane contactor transient experiments for the characterization of gas/liquid thermodynamics and mass transfer properties

We present results from experiments and numerical simulations of contact between a non-reactive gas (N₂O and CO₂) and a physical solvent (H₂O) occurring in a polypropylene (PP) hollow fiber membrane contactor. The closed-loop liquid flow within the experimental setup provides transient curves representing the progressive saturation of the solvent by the gas. We develop an in-house numerical model to fully characterize the gas/liquid mass transfer both in the non-wetted and in the wetted modes, i.e., when the liquid starts partially wetting the pores of the membrane. Using experiments and numerical simulations, we show that the Henry constant (H) and the molecular diffusion coefficient of a non-reactive gas absorbing into a liquid solvent can be extracted by parameter estimation. Both parameters are obtained within a single experiment at a constant temperature and the comparison with temperature-dependant correlations yields excellent agreement over the whole range of temperature studied in this work. Simulations show a partial wetting of the membrane pore by the liquid meniscus during a contact between CO₂ and H₂O, possibly due to the plasticizer effect of CO₂ inside the membrane contactor fibers.