Mathematical calculations for determining the hydrodynamic characteristics of granules movement in the workspace of the vortex granulator, which is the main ultimate process of chemical technology and forms properties of ordinary and porous ammonium nitrate and carbamide, are presented in this paper. Components of a granule velocity and the granulator design impact on them are analytically determined. Comparison of theoretical and experimental studies is performed.

Abstract. This paper presents the prospective line of studying such chemical process as granulation and the advantages of small universal vortex granulators usage in chemical processes, for example, for the production of nitrogen mineral fertilizers, complex mineral fertilizers and porous ammonium nitrate (PAN). The mathematical calculations for determining the hydrodynamic characteristics of gas flow movement, which ultimately affect the crystallization process in the workspace of the vortex granulator, are described. Components of a gas flow velocity and the granulator design impact on them are analytically determined. A comparison of theoretical and experimental studies is given.

No abstract

No abstract

Abstract:Prilling is a common process in the fertilizer industry, where the fertilizer melt is converted to droplets that fall, cool down and solidify in a countercurrent flow of air in a prilling tower. A vibratory granulator was used to investigate liquid jet breakup into droplets. The breakup of liquid jets subjected to a forced perturbation was investigated in the Rayleigh regime, where a mechanical vibration was applied in order to achieve the production of monodispersed particles. Images of the jet trajectory, breakup, and the formed drops were captured using a high-speed camera. A mathematical model for the liquid outflow conditions based on a transient two-dimensional Navier-Stokes equation was developed and solved analytically, and the correlations between the process parameters of the vibrator and the jet pressure that characterize their disintegration mode were identified. The theoretical predications obtained from the correlations showed a good agreement with the experimental results. Results of the experiments were used to specify the values of the process parameters of the vibration system, and to test them in the production environment in a mode of monodispersed jet disintegration. The vibration frequency was found to have a profound effect on the production of monodispersed particles. The results of experiments in a commercially-sized plant showed that the granulator design based on this study provided prills with a narrower size range compared to the conventional granulators, which resulted in a substantial reduction in dust emission.

The paper deals with the influence of humidifier type and humidification method on structure and quality of porous surface layer of ammonium nitrate granules. Different types of humidifiers are propose and the qualitative characteristics of porous ammonium nitrate for each of them are shown. The structure and quality parameters of porous ammonium nitrate with different mutual direction of movement of granules and humidifier. A method for granules pre-wetting with its heat treatment in vortex granulator is proposed. Obtained data are basis for technique of vortex granulators engineering calculation consisting units of 3-D nanostructured porous surface layer on granule ammonium nitrate obtaining.

This article was aimed to solve an urgent problem of ensuring quality for prilling processes in vibrational prilling equipment. During the research, the need for the application of vibrational prilling to create a controlled impact on the process of jet decay on droplets with the proper characteristics was substantiated. Based on the experimental and theoretical studies of the process of decay of a liquid jet into drops, axisymmetric droplet oscillation modes for the different frequencies were observed. Frequency ranges of transition between modes of decay of a jet into drops were obtained. As a result, the mathematical model of the droplet deformation was refined. The experimental research data substantiated this model, and its implementation allowed determining the analytical dependencies for the components of the droplet deformation velocity. The proposed model explains the existence of different droplet oscillation modes depending on the frequency characteristics of the superimposed vibrational impact. Based on an analytical study of the droplet deformation velocity components, the limit values of the characteristics defining the transition between the different droplet oscillation modes were discovered. Analytical dependencies were also obtained to determine the diameter of the satellites and their total number.

No abstract