Computing equations of water hammer in pseudo-homogeneous solid-liquid flow and their verification

In engineering practice, single-phase water hammer models are still employed to analyze the water hammer of solid-liquid flow. According to the characteristics of solid-liquid flow, continuity equations and momentum equations of pseudo-homogeneous flows are deduced, and a pseudo-homogeneous water hammer model is thus built and verified with experiment results. The characteristics of solid-liquid flow’s viscosity, resistance and wave velocity are considered in the model. Therefore, it has higher precision than a single-phase model.

Kinetics of Esterification of 2-Keto-L-Gulonic Acid with Methanol Catalyzed by Cation Exchange Resin

The kinetics of esterification of 2-keto-L-gulonic acid with methanol in the liquid phase catalyzed by cation exchange resin, D001, was studied. The experiments were carried out in a stirred batch reactor at 318, 323, 328, 333, 338, 341 K under atmospheric pressure. It is found that the speed of rotating rate has no effect on the esterification rate in the range of 300-500 r/min and the effect of internal mass transfer resistance is not obvious. The effects of temperature and catalyst loading on the reaction rate were researched under the condition of eliminating the effect of diffusion. The rate was found to increase with the increase of the temperature and catalyst loading. The experimental data were correlated with a kinetic model based on the pseudo-homogeneous catalysis. The kinetic equation for describing the reaction catalyzed by cation exchange resin was developed. The experimental data are in good agreement with the model.

Kinetic and thermodynamic studies of the esterification of acidified oil catalyzed by sulfonated cation exchange resin

This study describes the kinetics and thermodynamics of the esterification of acidified oil with methanol catalyzed by sulfonated cation exchange resins（SCER）. The effects of the mass ratio of methanol to acidified oil,reaction temperature,and catalyst loading were studied to optimize the conditions for maximum conversion of free fatty acids（FFAs）. The results showed that the optimal conversion rate of FFAs was 91.87% at the mass ratio of methanol to acidified oil of 2.5：1.0,reaction temperature of 65.0 °C,catalyst loading of 5.0 g and reaction time of 8.0 h. The external and internal mass transfer resistances were negligible based on the experimental results and a pseudo-homogeneous kinetic model was proposed for the esterification. The activation energy and thermodynamic parameters including G,S and H were determined. The conversion rates of FFAs obtained from the established model were in good agreement with the experimental data.

Reactive extraction for synthesizing long chain ester butyl hexanoate intensified by deep eutectic solvent

Butyl hexanoate(BuHE)is an important long-chain ester that is widely used in the food,beverage and cosmetic industries.In this work,reactive extraction concept was proposed to intensify the BuHE formation in a biphasic system,in which deep eutectic solvent(DES)comprising 2-methylimidazole(2-MIm)and p-toluenesulfonic acid(PTSA)was used as dual solvent-catalyst.First,the effect of 2-MIm to PTSA molar ratio on esterification was investigated to determine the optimum DES of[2-MIm:2PTSA],which was characterized by FT-IR and TGA.Then,the liquid–liquid equilibrium(LLE)and esterification experiments were carried out to confirm the extraction and catalytic effect of[2-MIm:2PTSA],respectively.Afterwards,the pseudo-homogeneous kinetic model was employed to describe the esterification kinetics.Finally,the intensification mechanism of reactive extraction for BuHE formation was proposed according to the experiments and interaction effect analysis.

Radial heat transport in packed beds-I： Experimental investigation of heat transfer coefficients of pellets and monolith catalysts at atmospheric and high pressures

The effect of operating pressure on the radial heat transfer coefficients, in a non-adiabatic fixed packed bed was studied at atmospheric and higher pressures, The study was concerned with investigating the effect of the pressure on the radial thermal conductivity （K^r） and wall heat transfer coefficient （h~） for both pellets and monolith catalysts. The study included beds that were packed with pellets and monoliths, separately. The radial temperature distribution was measured at different beds heights and feed flow rates for both types of packing. Steady-state temperatures were measured using nine chromel-alumel thermocouples arranged on a stainless steel-cross. After temperatures were collected, the radial thermal conductivity and wall heat transfer coefficient were calculated using a two-dimensional pseudo-homogeneous model. The results showed that, the radial temperature profile at the entrance of the heating section was nearly even, and a constant temperature along the radius （0F/0r=0） taken as a boundary condition to solve the partial differential equation controlling the heat transfer. Temperature profiles obtained at elevated pressures were smoother at the center of the reactor and increased sharply near the wall, than profiles at atmospheric pressure. It could also be observed, that the radial temperature profiles in the center of the reactor using a monolith catalyst at elevated pressure were more even and smoother than those of pellets. Temperature profiles in fixed beds were found to be very sensitive to Ker and hw. In pressures between atmospheric and 10 bars, there was no change in the effective heat transport parameters （i.e. they are independent of pressure in this range）. Both parameters were strongly affected by the pressure changes, above 10 bars. For the same Reynolds number （Ker） increased by 27% and 53% at 11 and 20 bars, respectively, in pellets catalyst. And they increased by factors of 2.3 and 4, when the pressure increased to the same pressures, in monolith catalyst. On the other hand, the effect of pressure on （hw） was completely the opposite, h,~ for pellets and monolith catalysts were found to be decreasing with increasing the pressure. Moreover, both coefficients increased with the Reynolds number at all applied pressures. This increase was higher for pellets than it for monoliths.

Water hammer in pipelines with hyperconcentrated slurry flows carrying solid particles

Water hammers in pseudo-homogeneous flows and heterogeneous flows have been investigated, and equations for the wave propagation speed and the additional pressure due to water hammer in both flows have been developed. These equations have been tested against available experimental data.