кінетика

The article describes the results of experimental studies of the kinetic regularities of beet pulp drying by the filtration method. The influence of the main process parameters on the rate of moisture removal, including the height of the wet layer of material H (0,04 m, 0,08 m, 0,12 m, 0,16 m), temperature T (60 °C, 70 °C, 80 °C, 90 °C) and the velocity of the thermal agent v0 (1.24 m/sec, 1.76 m/sec, 2.29 m/sec, 2.82 m/sec), was investigated. The kinetic dependencies for the periods of complete and partial saturation of the thermal flow with moisture were derived.

The paper describes the study of the kinetics of filtration drying of barley brewer’s spent grain. The dependencies of the process at different parameters of the stationary layer and the heating agent are presented: different heights of the wet material H (40 mm, 80 mm, 120 mm, and 160 mm), different temperatures of the heating agent T (50 °C, 70 °C, 80 °C, and 90 °C), and the velocities of the heating agent through the stationary layer of material v0 (1.26 m/s, 1.55 m/s, 1.81 m/s, 2.31 m/s, and 2.82 m/s).

A conversion scheme for pentyl acetate, ethanolamine, and the products resulting from their interaction through aminolysis, transesterification, and O-N-acyl migration reactions catalyzed by homogeneous and heterogeneous Brønsted-Lowry bases and acids is proposed. It has been determined that acid and base catalysts significantly enhance the aminolysis reaction of esters with amino alcohols when compared to the non-catalytic process. The impact of the catalyst on each reaction has been assessed.

Phenolformaldehyde resins were obtained by polycondensation of concentrated phenols with formaldehyde in the presence of hydrochloric acid. Concentration of phenols is carried out by treating the phenolic fraction of coal tar with an aqueous solution of sodium hydroxide followed by neutralization of water-soluble phenolates with hydrochloric acid. The kinetic dependences of resin yield and softening temperature on the duration of the process at 333, 353, and 373 K were obtained.

The kinetics of the process of drying hot (80°C) and cold (20°C) candied pears were studied. The drying coefficient is found and an analytical dependence is derived for the drying time calculation. Experimental data of the change in the temperature of the thermal agent along with the height of the candied fruit layer was obtained.

In this paper, the dissolution kinetics of cement copper powder in sulfuric acid solutions containing cupric ions was examined. It was observed that the dissolution rate of copper increased with increasing the acid concentration, temperature, and stirring speed. It was determined that the dissolution rate of copper enhanced with increasing the cupric ion concentration up to 0.025 M. It was found that the temperature and concentration of cupric ion had more considerable effects on the dissolution of copper powder.

The kinetics of adsorption of ammonium ions under dynamic conditions has been studied. A mathematical model of the process was built. The mass transfer coefficient was calculated depending on the intensity of the change of location. It was established that ion exchange occurs in external and internal diffusion regions. The rate constants of ion exchange for the region of external and internal diffusion were calculated.