Micronization of Hard Coal with the Use of a High-Pressure Water Jet

Przemysław J Borkowski,Wiesław Szada-Borzyszkowski

doi:10.3390/en14164745

Przemysław J Borkowski, Wiesław Szada-Borzyszkowski

Open Access

https://doi.org/10.3390/en14164745

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Abstract

This paper presents an original method for the micronization of coal particles in a hydro-jet mill, which allows effective comminuting of coal in the pressure range of 100–250 MPa, at a variable water flow rate of 0.2–0.5 dm3/s. The discussed high-pressure water jet mill (HPWJM) allows the comminution of standard fines, with a grain size up to 2 mm, and at a relatively high comminuting efficiency of 8 to 55 g/s. In addition, the paper presents energy-consumption ratios, and indicates the advantage of this method over mechanical grinding in a planetary ball-mill. At optimum conditions, coal comminution at an efficiency of Qc = 38.4 g/s and at an energy input of EH = 1.1 MJ/kg provides an average particle size of about 40 µm. The degree of comminution was further improved by applying roto-turbulent micronization, which resulted in an average size of comminuted coal particles of only 17 µm. As an additional result, the actual surface area of the particles increased by 10–30 thousand times when compared to ground fines—this fact is of significance for the application of micronized particles in quasi-liquid coal-water fuel.

Highlights

Koszalin University of Technology, Branch of the KUT in Szczecinek, Waryńskiego 1, Abstract: This paper presents an original method for the micronization of coal particles in a hydro-jet mill, which allows effective comminuting of coal in the pressure range of 100–250 MPa, at a variable water flow rate of 0.2–0.5 dm3 /s
Sults teststechnological on how the efficiency of hard coal comminution is i. An example of such results can be presented in diagrams of averaged size distributions from homogenizing outlet to the of hardthe coal particles comminuted in anozzle hydro-jet mill equipped with acomminuting homogenizing nozzle,disk
The device allows the comminution of standard fines, with a grain size up to 2

Summary

Mineralogical

Characteristics of Hard Coal coal [31] were analyzed carefully, which has indicated a need for implementing an alternative, original technology based on a high-pressure water jet One of future directions of its mogeneous water suspension Such a fuel betheecologically combusted, application is the production of coal-water slurry (CWS)-type fuels [5,6]. This application power boilers [5] and in experimental combustion engines [6], while ensu requires hard coal particles to be comminuted to a substantial degree and transformed into times lower emission levels of Such sucha fuel harmful compounds as SOnot.

Equipment and Research Methodology

Roto-turbulent micronizer:

Illustrative distributions of of hard comminutedatatwater water pressure

Results and Discussion

Roto-Turbulent Micronization of Hard Coal

Conclusions