The film thickness distribution outside a horizontal test tube was measured with a film-thickness meter,to obtain the average thickness.The average film thickness increased with irrigation density of water.It was also relative to θ ,and the waving intensity was controlled by both irrigation density and tube radius.Dimensionless wave amplitude was defined and correlated in terms of Reynolds number and tube diameter,by regression of experimental data.Experiments of the evaporation heat-transfer coefficient on a horizontal-tube were conducted with various irrigation density,boiling point,temperature difference, heat flux and tube diameter.The influences of dimensionless film thickness and dimensionless wave amplitude on heat- transfer coefficients were obtained.These would provide a basis for further developing high efficiency heat- transfer process and evaporator.

Based on the optimum numerical geometry of a sphere,a new angular quadrature scheme named Spherical surface Symmetrical equal Dividing(abbreviated to SSD _N ) was presented.The evaluations of double moment by SSD _N and other traditional quadrature sets showed that the new SSD _N could provide good accuracy and compared well with others such as the S _N with the highest accuracy.Radiative heat transfer predictions in a black-walled rectangular enclosure containing absorbing-emitting medium indicated that,compared with S _N ,T _N and SRAP _N ,the SSD _N could give almost as high or even accuracy as the S _N does under some order numbers N .The numerical experiments of iteration comparison higs lighted the feature of SSD _N of computational economy.

This paper presents a novel adsorption-absorption cascading triple-effect refrigeration cycle, which consists of a high-temperature stage of single-effect solid adsorption unit working with zeolite-water and a low-temperature stage of double-effect liquid absorption unit working with LiBr-water.High-temperature heat source is added into adsorption unit first,and its adsorption heat is then transferred to the high-pressure generator of absorption unit.The COP of the cycle can be greatly improved by the efficient utilization of energy in the system.Compared with the traditional LiBr/water triple-effect absorption system, there is no corrosive problem though the temperature of working pair could be higher than 200℃ in the adsorption unit.This new cascading refrigeration cycle is feasible in engineering.The thermodynamic characteristics of this cycle are discussed.Some simulation results are presented as well.

In this paper the Concentrations of fluorine in typical Chinese coals are determined by the pyrohydrolysis/FISE method.The distribution characteristics of fluorine in coal are obtained.The correlation between fluorine and ash,the probable mode of occurrence of fluorine in coal are discussed.Fluorine concentration ranges between 17-3145μg·g ^-1 and the mean value is close to 200μg·g ^-1 .Good correlation between fluorine and ash content suggested that fluorine is present in these coals in inorganic mineral species.Fluorine emission characteristics during coal combustion are studied systemically in tube furnaces for the first time.The influence factors on fluorine emission and the relationship of fluorine emission with coal type,combustion temperature,retention period and combustion atmosphere are obtained and the production mechanism of gaseous fluorine during coal combustion are proposed.Experimental results indicate that fluorine emission appears to begin at 573-673K and emission rates reaches about 96% at above 1473K.Gaseous fluorine is probably originated from fluorine occurring as organic forms or adsorbed inorganic form in coals at low temperatures,and appears to come mainly from fluorine occurring as inorganic salt forms in coal at high temperatures.

The photocatalytic oxidation of organic compounds using ultrafine semiconductor powder has been one of the most active areas for environmental problems.It is important from the viewpoint of practical applications to develop a simplified kinetic model suitable of representing the very complex mechanisms of photocatalytic oxidation.In the present paper,kinetic analysis is carried out for gas-solid photocatalytic reaction,and a kinetic model is developed.The theoretical results show that the rate of gas-solid photocatalytic reaction is proportional to the light intensity ( I ₀) under low UV light intensity, proportional to the square root of the light intensity under medium UV light intensity,and independent of I ₀ under extremely high UV light intensity.Photocatalytic reaction could be simply decomposed as three continuous processes as follows:photon transfer step, surface action step,and diffusion step.A novel gas-solid photocatalytic reactor is designed,and trichloroethylene is selected as the testing substance.The experimental results show that photon transfer step and surface action step are verified for gas-solid photocatalytic oxidation on nano-TiO₂ powder.

A kinetic model of two-step of methanol synthesis at lower temperature and pressure was derived on the basis of reaction mechanism in which different functions of two catalysts and adsorption methods were taken into account.Two reactions was concurrently analyzed for reaction mechanism,hence this kinetic model is useful in scale up.Model discrimination and parameter estimation were performed for the kinetics models of low temperature methanol synthesis on the basis of kinetic data measured in a stirred reactor.The results showed that the best model for fitting the experimental data is the model of 5-10 which takes into account that H ₂ is molecular adsorption,reaction is two-site adsorption reaction,and methanol desorption step is the rate determining step.The final model for methanol synthesis meets the requirement of statistic test(F-test) at 95% confidence level.The kinetic parameters for the final model agreed well with physical meaning.

The effect of guanidine hydrochloride (GuHCl) concentration on the oxidative refolding of denatured-reduced lysozyme of high concentration in the presence of artificial chaperone, that is, cetyl trimethyl ammonium bromide (CTAB) and β -cyclodextrin ( β -CD),was studied.A two-state refolding model was used to analyze the refolding kinetics.It was shown that there existed an optimum GuHCl concentration that gave maximum refolding yield of lysozyme.At this GuHCl concentration,the refolding rate constant increased, while the reverse refolding-rate constant decreased, with increasing artificial chaperone concentration,which led to the increase of refolding yield.The results indicated that the effect of artificial chaperone and GuHCl was cooperative in facilitating the refolding of denatured-reduced lysozyme.At the optimum GuHCl concentration,the spontaneous refolding yield of 1.05mg·ml ^-1 lysozyme in 60min was only 49%.In contrast, cooperated with artificial chaperone-facilitated refolding the recovery yield reached as high as 81%.

A model is derived for describing the capillary filtration process of asymmetrical tubular ceramic ultrafiltration membranes from the filtration and capillary function theory.Methods for measuring parameters in this model are proposed and used.The good consistency between simulated results and measured ones showes that the model has a high reliability and practical values.

To investigate the influence of Marangoni effect on liquid flow and its distribution as well as separation efficiency of structured packing, binary distillation experiments were carried out at total reflux using six typical systems for ceramic corrugated sheet and stainless steel gauze structured packing.It was shown that the influence of Marangoni effect was small for pure organic systems.However,for aqueous organic systems,hydraulics and mass transfer of structured packing were both strongly influenced by Marangoni effect.

The selective hydrogenation of the C C bonds in acrylonitrile-butadiene rubber(NBR),using a new Rh-Ru based bimetallic single ligand catalyst(BMSC),was examined.Gel free products with a high degree of hydrogenation were obtained,indicating a degree of activity and selectivity equal to RhCl(PPh 3) 3 for this new less expensive catalyst.The concentration of NBR solution and the amount of the second-ligand L 2 could affect the degree of hydrogenation.It was found that 7.0×10 ^-2 g·ml ^-1 NBR solution and 1.5% second-ligant L 2 based on the amount of NBR were appropriate.An experimental design to study the effect of temperature,hydrogen pressure,catalyst concentration and reaction time on the degree of hydrogenation was developed and subsequently carried out.The resulting optimum technological parameters were defined.When the catalyst concentration was 0.25%,temperture 145℃,hydrogen pressure 1.2MPa,reaction time 4h,the degree of hydrogenation reached over 98%.

The diffusion characteristics of spherical solute in the network of polymer gel were studied based on the three-dimension network model of gel,in which the effect of the interaction between the solute and fibers of gel was taken into account.It was found that the movement of solute in gel is quite different from the Brownian movement in free solution.The difference increased with the solute size.A Significaut effect of the interaction between solute and gel fiber on the movement of solute molecule was also observed.Attraction and repulse both hindered the diffusion obviously.Decreasing the size of the solute and increasing the interaction would enhance the hindering effect markedly.

A computation algorithm for simultaneous chemical and phase equilibrium is proposed based on minimization of Gibbs free energy. By using the extent of reaction and the yield factor of phase, the computation of simultaneous chemical and phase equilibrium is transformed as into unconstrained nonlinear minimization problem, and is solved by Genetic Algorithm. The proposed algorithm has a wide application prospect because in this algorithm the variables are less,and negative mole-fraction, which usually appears in conventional algorithms,will not occur,and it can obtain a global optimization solution. The formaldehyde-water system is taken as an example.It is found that the computation results are just the same as those reported in the literature, which shows that the presented algorithm is robust and efficient.

The characteristic of the concentration wave in the RTD of out-circular reactor,which is a nonstationary quasi-periodic signal,has been investigated with wavelet analysis.At first,the characteristic scale of concentration wave was determined with an energy maxima criterion based on wavelet analysis.And we found that the characteristic scale of concentration wave is about directly proportional to the average once through time of the reactor.Then,a reconstruction formula based on wavelet analysis is strictly proved to be capable of reconstructing the concentration wave shape.At last,the local singularity exponents of concentration wave crests are calculated with wavelet analysis.The results show that the local singularity exponents of crest increase with time,and runs to about 2 0,which agree very well with theoretical result.

This paper has induced the algorithm of Multi-dimension Cyclic Subspace Regression (MCSR), an approach as linear regression which can deal with multi-dimension dependent variables. By combining the Radial Basis Functions (RBF) with MCSR, it provides a better approach of modeling non-linear systems in chemical engineering process in which its dependent variables are multi-dimensional. It adopts the frame of the RBFN, which can express a complicated non-linear relationship, and combines with the MCSR to avoid a variety of troubles of the design and training of the network. Thus, it can search the optimal model in an extensive solution space and the model has a briefly analytic form. Its good performance is demonstrated by an example of modeling the equipment of isomerization of xylene to paraxylene as compared with the RBF-PLSR.

Based on a reasonable hypothesis and according to the continuity equation, momentum equation, energy equation, boundary layer theory and relevant boundary condition, the mathematial model of heat transfer and fluid mechanics with fluid flowing through the heat pipe immersed in the packed bed is developed in this paper. After analogy transition and numerical calculation, the model is simplified and solved. In addition, convective heat transfer is measured experimentally with the fluid flowing through heat pipe immersed in the packed bed. After analyzing the experimental data, a heat transfer correlation is obtained. The experimental result is in agreement with the theoretical result while Re _d<500. The reason why there exists a great difference between the experimental result and theoretical result while Re _d>500 is discussed.

In order to overcome the many shortcomings of the traditional conversion system, this paper proposes a new kind of continued heat transfer conversion system.The new system is in accordance with the advances of contemporary chemical engineering because it makes the equipment smaller. In addition, an optimal research on this new system is made and the optimal results under the three kinds of different objective function are obtained. Three kinds of different objective functions are minimum catalyst amount( R ₁), minimum total equipment investment ( R ₂),minimum total equipment investment and operation expense per year ( R ₃).

The radiation effect of powdery HDPE was studied,and was shown to be different behavior from sheet or film HDPE.Some factors affecting radiation grafting in solid state powdery HDPE like dose,dose rate,monomer kinds,were investigated in detail.The characteristics of grafted HDPE such as melting temperature,crystallinity,decomposition temperature and decomposition activation energy were analyzed.Compared to the ungrafted HDPE, the grafted HDPE has better cohesive force and flexibility.The influence of various groups on cohesive force and flexibility was studied.

Membrane dispersion extraction is a process with a macroporous membrane as dispersion medium. In this paper, 30%TBP(in kerosene)/nitric acid/H ₂O is chosen as an experimental system. The mass transfer characteristics are studied in two kinds of membrane dispersion modules.In order to improve mass transfer performance, a concentric inner element is designed. The effects of transmembrane pressure and the flux of continuous phase on efficiency, as well as on the flux of dispersion phase are investigated. The experimental results show that the flux of disperse phase is increased with an increase of the transmembrane pressure. However, it could hardly be influenced by the flux of continuous phase. mass transfer efficiency decreases slightly when the pressure or the flux of continuous phase is increased. The concentric inner element can improve the mass transfer performance greatly. Membrane dispersion extraction can be carried out with a higher mass transfer efficiency.

The isoplethic vapor-liquid equilibria(VLE)for N,N -dimethylformamide +2-propanol+1-propanol and their binary constituent mixtures were measured by using an inclined ebulliometer with a pump-like stirrer. The comparison between the experimental results and literature for binary systems was given. The ternary VLE were predicted by using modified UNIQUAC model with temperature-dependence binary parameters.

The effects of superficial gas velocity, catalyst loading, liquid properties and internal fitting on gas holdup of air/water, air/paraffin oil and air/catalyst/paraffin oil were investigated in a 0 2 m diameter, 4 2 m height slurry bubble column reactor operating with methanol synthesis copper-based catalyst and methanol dehydration catalyst. The experimental data showed that gas holdup increased with superficial gas velocity no matter whether there was a heat exchanger. However, no matter whether there was a heat exchanger, gas holdup decreased with the increase of catalyst loading. The existence of heat exchanger favored the increase of gas holdup. The gas holdup in the air-water system was slightly higher than in the air-paraffin system. Empirical correlations for gas holdup data were proposed.

Intermittency means the occurrence of a signal that alternates randomly between long regular phases and relatively short irregular bursts.In this paper,we simplify the mathematical analysis of pressure signal by idealizing it as a train of signals of zero duration and of size unity in a bubbling fluidized bed,0.30m in diameter and 3.8m in height.Therefore,the simplified signals are zero corresponding to the laminar signals and unity corresponding to irregular bursts.Statistics show that mean laminar length decays with excess gas flow above u mf ,obeying a power law < l > ∝(u-u _mf ) ^-0.55 .Similar results were obtained by Daw et al (1995) .These results suggest that laminar motion is disturbal more frequently and chaotic burst occurs more frequently as gas velocity increases,and chaotic nature of Type-Ⅰ intermittency of fluidizing systems is confirmed further.The chaotic irregular bursts can be considered as the result of intermittent gas bubbles in fluidized beds.

Most previous studies about chaotic mixing focused on time-periodic or spatialy-periodic flows.In contrary,fewer studies have been done in aperiodic flows.In this paper,the chaotic mixing generated by periodic and aperiodic flows is investigated through visible experiments and numerical simulations.The distribution of stretching is found to be much more uniform for apeiodic flows and mixing efficiency of aperiodic flows is higher than periodic flows.Among the several aperiodic sequences,the SB sequence is the best one.