A Novel Granulation Technology for Producing Spherical Wax Particles

Abstract

A novel granulation technology for producing spherical wax particles that makes use of the insolubility of wax and water is developed. The granulation is stably performed in a granulator with a water-cooling tower. The granulation process is analyzed and the influences of key factors on the process are studied. Experiments are carried out with 58 # semi-refined wax and 70 # crystallitic wax in an experimental granulator which has 118 nozzles (D i = 0.96 mm, D o = 1.28 mm). The process capacity and the corresponding particle diameter are 55±60 kg/h and 4±5 mm, respectively. Using the modified correlation of Scheele and Meister, suitable operation flow rates and the corresponding particle diameters for different nozzles can be predicted. This technology has the following advantages: good particle shape with excellent fluidity, high process capacity and heattransfer efficiency, and a small space for the granulator. It is also suitable for producing spherical particles of other materials, which have similar physical properties to wax.

Granulation Process for Producing Spherical Particles of a Rubber Antioxidant in a Water Cooling Tower

“…The current granulation technology for rubber antioxidants is wax-flake molding with a belt cooler [3]. In this technology, melted feed is dropped onto a moving belt of stainless steel from a rotating drum, and cooling water is sprayed onto the back surface of the belt.…”

Cooling and Solidification of Melted Drops in an Immiscible Cooling Medium

“…In the case of wax granulation, when a wax particle reaches its terminal velocity, the buoyancy, gravity, and drag forces acting on the particle reach equilibrium 1) :…”

“…In the case of 58 # wax granulation, particles with diameters of 4 mm and 5 mm are taken as calculation examples. It is assumed that the initial temperature of the drop is 70 C and the temperature of the cooling water is 43 C [1]. The related data on particle movement and heat transfer are listed in Tab.…”

“…The granulation method of drop formation and solidification of the melted material in an immiscible cooling medium is widely used in chemical engineering, e.g., urea granulation in an air-cooling tower (spraying tower), some fertilizer granulations in an oil-cooling tower, and spherical wax granulation in a water-cooling tower [1]. In the granulation process in air-cooling towers and oil-cooling towers the melted material is sprayed by a sprayer to form a series of drops in the tower.…”

“…The particles are discharged by the circulatory overflow at the top of the tower and re-cooled in a chute by spraying cool water. After dehydration, spherical wax particles are obtained [1].…”