摘要:

AbstractThe photochemical reaction SiHCl3+Cl2→SiCl4+HCl is of industrial importance in the production of pure silicon for the semiconductor industry. The present paper deals with an experimental investigation of the kinetics of this purification step. The main reaction occurs in the liquid phase and is initiated by light. In this gas‐liquid reaction system, all components, which are present in both phases, were analyzed by gas chromatography. Reaction progress was monitored by recording the pressure rise. Apart from the influence of wavelength and radiation intensity on the above photoreaction, reactions in the absence of light and on the wall were also investiga

ISSN:0930-7516    

DOI:10.1002/ceat.270150202

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractChemical reaction fouling of heat exchangers involves deposition that is caused by chemical reactions which occur in the fluid, or on the surface itself. The factors which influence fouling of organic fluids via autoxidation and thermal decomposition processes are described and the dependence of the rate of thermal fouling on chemical effects and process variables demonstrated. Mitigation techniques are outlined in brief.

ISSN:0930-7516    

DOI:10.1002/ceat.270150203

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe transport of corrosive liquids containing solids, in conventional energy and process technology as, for example, in oil and gas production, places high demands on the selection of materials for plant construction. A discussion on the chemo‐mechanical load demonstrates the significance of hydrodynamics in selecting the test method. Choosing a pipe with an abrupt expansion of cross‐section as a flow model yields a new method of simulating operation conditions. By subjecting ferrous materials used for hydraulic machinery to representative media from three important industries, a broad spectrum of results can be obtained. Classification of the results leads to four basic types of mass loss behaviour in materials as functions of flow rate. These findings yield guidelines for the selection of materials and the dimensioning of flow equipm

ISSN:0930-7516    

DOI:10.1002/ceat.270150204

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractA method for the measurement of water content in a flowing gas has been developed. It consists in passing warm moist gas through a bed of CaC2where the water vapour is adsorbed and reacts directly with the carbide to form C2H2, which is then analyzed in a gas chromatograph. In this work, water vapour concentrations ranged from 1000 to 13000 ppm at a minimum pressure of 10 bar. The method has also been applied in a number of pyrolysis experiments.

ISSN:0930-7516    

DOI:10.1002/ceat.270150205

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractA new method for determining the efficiency of columns with sieve, sieve‐valve, valve, bubble cap and tunnel trays is introduced, taking into consideration entrainment, weeping and mixing of liquid on the tray. The presented calculation concept is valid for any stripping factors and any quality of liquid mixing on the tray. A comparison of the new calculation concept with experimental data from literature resulted in an average relative deviation of approx. 8% between the sieve tray efficiencies. The comparison of calculated values with experimental data for sieve‐valve, valve and tunnel trays also produced a satisfactory agreem

ISSN:0930-7516    

DOI:10.1002/ceat.270150206

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractA bubble column absorber was used to investigate kinetics of the reaction between carbon dioxide and aqueous solutions of diisopropanolamine (DIPA), by means of gas absorption experiments. These were conducted in the temperature range of 20 to 40°C, with DIPA concentrations from 5 to 500 mol/m3, and CO2partial pressures between 5 and 101 kPa. A model based on the Danckwerts' surface reneval theory was used to analyze the experimental results and to determine the rate constant. The obtained data support the assumption of a second‐order overall reaction, with the rate constants being well correlated by the Arrhenius equation:\documentclass{article}\pagestyle{empty}\begin{document}$$ k_2 = 1.112 \times 10^{10} \exp \left({ - {{4848} \mathord{\left/ {\vphantom {{4848} T}} \right. \kern-\nulldelimiterspace} T}} \right).$$\end{docume

ISSN:0930-7516    

DOI:10.1002/ceat.270150207

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe thermodynamic data bank system THERDAS [1, 2] has been used in conjunction with the program ChemSage [3]to calculate the conditions necessary for the formation of 2,3,7,8‐TCDD (tetrachlorodibenzodioxin). The stability ranges of both gaseous and condensed dioxin are presented as functions of the chlorine content, C/H mole ratio, oxygen partial pressure and temperature of the syste

ISSN:0930-7516    

DOI:10.1002/ceat.270150208

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe adsorption ofp‐nitrophenol (PNP) from an NaOH, H3PO4‐buffered, aqueous solution on activated carbon was studied at pH 2, 7, and 8.5. Comparative studies were then carried out on ozonized carbon and ozonized PNP solution. In the latter case, PNP adsorption was performed from an ozonized solution, and also after exposing the activated carbon to the ozonized PNP solution for 24 h. At acid pH, PNP adsorption was found to be markedly higher than at neutral and weakly basic pH's. Ozonization of carbon affects the results only at pH 7 and 8.5. Ozonization of PNP led to a small decrease in adsorption, irrespective of the method of contect between carbon and ozonization reaction products. The rate was faster at acid than at basic pH, and the ozonization speeded up the adsorption slightly but only at pH 8.5. Application of a mathematical model indicated that mass transfer in bulk solution controls the rate of adsorpt

ISSN:0930-7516    

DOI:10.1002/ceat.270150209

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper is devoted to the problem of determining intraparticle transport coefficients for multicomponent adsorption from experimental kinetic curves. Due to thermodynamic and kinetic interactions between the mixture's components, this task is more difficult than for single component systems. As an example, the kinetics of adsorption on activated carbon of binary mixtures of phenol and indole from aqueous solutions was studied in a continuous stirred tank adsorber (CSTA). To describe the intraparticle transport of this system, the surface diffusion model using a linear driving force (LDF) was applied. For determining the matrix of the unknown kinetic parameters of the LDF‐model, the application of three independent mathematical methods is discussed. Firstly, a semi‐analytical calculation (SA) of the intraparticle transport parameters by solving a system of linear equations on the basis of an empirical description of experimental kinetic curves is put forward. Secondly, a non‐linear regression (NR) method for parameter estimation was applied. The third method is a non‐linear regression which, in contrast to the SA and NR methods, guarantees the stability of the system of differential equations in the steady state of the proces

ISSN:0930-7516    

DOI:10.1002/ceat.270150210

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

ISSN:0930-7516    

DOI:10.1002/ceat.270150201

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY