摘要:

The present work reports the results of so called “impact experiments” on nine different kinds of crystals, five inorganic salts and four organic acids, performed by letting ten crystals fall through an evacuated tube onto a glass plate. The ratio between the abraded volume of a crystal and the volume of the crystal itself is inversely proportional to the plasticity index of the material. The size distribution of the fragments, in terms of number density function vs. size, is well fitted for all the systems by a power law equation with an order equal to - 2.82

ISSN:0098-6445    

DOI:10.1080/00986449608936478

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Density and viscosity of the coexisting phases and interfacial tension of the following binary systems were measured: pelargonic acid, linoleic acid, oleic acid or stearic acid as subcritical and carbon dioxide as superecritical components. Also the corresponding phase equilibria were investigated at pressures ranging from 2 to 20 MPa and temperatures from 313 K to 393 K. With increasing pressure the concentration of the supercritical component in the liquid phase increases and viscosity and liquid interfacial tension decreases. At greater activities of the dense gases the interfacial tension decreases dramatically to values less than 2 mN/m. If the pressure exceeds a certain limit, a falling film disintegrates into small droplets. The surface excess passes through a maximum at these conditions. At first appearance of instabilities on a falling film, the logarithm of the Reynolds number is a linear function of the logarithm of the film number. Independent of the type of the investigated packings, the number of theoretical stages per meter versus Hodenstein number fall all on the same curve when an extraction is carried out in the droplet regime. Also the logarithm of the capacity of a column al the flooding point versus the logarithm of the density difference between the coexisting phases is a linear function when an extraction is carried out in the droplet regime.

ISSN:0098-6445    

DOI:10.1080/00986449608936479

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The Effects of non-ideal and nonhomogeneous mixing on barium sulfate precipitation in an MSMPR reactor were observed experimentally and analyzed theoretically. To generate nonhomogeneous mixing the unmixed feed streams were fed to the reactor at the same location (joint feeding mode) or a plug flow reactor was connected to the MSMPR reactor. These nonhomogeneous mixing conditions resulted in significant reductions in particle size and increases in particle numbers. These non ideal mixing effects were dependent on the impeller speed, feed stream velocity and residence time in the connected plug flow reactor and are believed to result from elevated supersaturation levels in a premixing zone which are controlled by turbulent micromixing

ISSN:0098-6445    

DOI:10.1080/00986449608936480

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Using the total pressure method, phase equilibria for then-Pentane-βmetoxipropionitrile system has been measured at temperatures of 37.8 and 43.3 °C. Data has been correlated with NRTL and Modified Wilson solution models. Coefficients for both models were obtained using the Barker method and are reported for both temperatures.

ISSN:0098-6445    

DOI:10.1080/00986449608936481

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The mass transfer coefficient between solid particle and liquid has been measured in high aspect ratio multiimpeller agitated three phase (gas-liquid-solid) reactors. Experiments were conducted in 0.15 and 0.30 m id acrylic columns of lm length each. Two types of impeller were used: disk turbine (DT) and pitched turbine downflow (PTD). Air used as the gas phase was introduced through a ring sparger of 0.8 D size located 0.1 T distance above the bottom. The interimpeller spacing was maintained at the tank diameter. The range of gas velocity used was 0-15 mm/s. A unique correlation between particle-liquid mass transfer coefficient and critical impeller speed for solid suspension has been presented.

ISSN:0098-6445    

DOI:10.1080/00986449608936482

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A novel method was provided to synthesize unsymmetric formaldehyde acetal by reacting two mixed alcohols (e.g., 1-butanol and 1-octanol) and dibromomethane via phase transfer catalysis. Only three final unique products with two alkoxide substituents (one unsymmetric and two symmetric acetals) were observed during the reaction for using higher reactivities of alcohols as the reactants for using higher reactivities of alcohols as the reactants. This result indicated that the rates of the four second reactions in the organic phase are larger than those of the two first reactions in the organic phase. Mass transfer of the catalyst and the active catalyst are very rapid, compared to the reaction in the organic phase. The reaction in the organic phase is a rate-determining step. Based on the fact that the intermediate products were not observed, a kinetic model was developed and simplified. A pseudo-first-order rate law was sufficient to describe the kinetics of reaction. High yields of the two symmteric acetals and the one unsymmetric acetal were produced by employing tetrabutylammonium bromide (TBAB) as a phase transfer catalyst in a high alkaline concentration of KOH/chlorobenzene two-phase medium.

ISSN:0098-6445    

DOI:10.1080/00986449608936483

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

While nucleation and crystal growth are normally considered to be the primary particle formation processes during industrial crystallization, secondary processes including crystal agglomeration and breakage can have a determining effect on product form, especially of precipitates. In addition to the usual overall size distribution, primary and secondary particle size, particle structure and morphology then become important characteristics affecting both product quality and downstream processing performanc

ISSN:0098-6445    

DOI:10.1080/00986449608936484

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper introduces a family of wavelet transforms based on the Poisson Transform. The wavelet transform maps L2(ℛ)functions to a space described by two continuous variables, scale and translation, as well as a discrete index. Reconstruction in the wavelet domain can be done for each of the discrete indices. Additionally, a different reconstruction formula exists for the Poisson Transform domain. We develop the Poisson Wavelet Transform, present an example relevant to stable, over-damped, linear, time-invariant systems, and show the relationship between the Poisson Transform and the Poisson Wavelet Transform.

ISSN:0098-6445    

DOI:10.1080/00986449608936485

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Excess enthalpiesHEfor two ternary systems, phenol-3-methylphenol-l-hexanol and 3-methylphenol-l-hexanol-cyclohexanol and four constituent binaries have been measured with Calvet-type micro-calorimeter at 318.15 K. The UNIFAC group contribution method and a version, the UNIFAC(3Q), as well as the Redlich-Kister equation have been applied in predicting ternary excess enthalpies. Based on the binaryHEdata, new interaction parameters have been determined.

ISSN:0098-6445    

DOI:10.1080/00986449608936486

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The noncatalytic gas-solid reaction between calcined dolomite and CO2(g) has been studied in an electrobalance reactor as a function of temperature, pressure, and reactive gas composition. Multicycle tests consisting of as many as ten complete calcination-carbonation cycles were carried out to obtain information on sorbent durability. Surface area, pore volume, and pore size distribution measurements were made to supplement the reaction studies. This reaction is of interest both as a model for studying (he importance of structural property changes in gas-solid reactions, and as the basis for a possible process for the high temperature separation of CO2from gas streams.

ISSN:0098-6445    

DOI:10.1080/00986449608936487

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor