METHOD OF OBTAINING WATER-COAL SUSPENSION AND HEAT AND MASS EXCHANGE EQUIPMENT FOR ITS APPLICATION

Abstract

The analysis of methods and equipment for obtaining water-coal suspensions was carried out. The purpose of the research is to improve the quality of the resulting suspension due to more effective grinding and increasing the amount of its solid component. Heat and mass exchange equipment has been developed, with the help of which it is possible to achieve an increase in the efficiency of hydraulic impact due to an increase in the frequency of pulsations when obtaining water-coal suspensions. The use of water-coal suspensions as an energy fuel makes it possible to improve the technical, economic and environmental performance of power plants. Thus, during the conversion of the boiler to water-coal fuel, it was possible to increase the thermal power of the boiler from 13,2 to 21,1 MW when replacing 70 % of coal with water-coal fuel. Currently, there are different methods and equipment for the preparation of water-coal suspension. However, they all have certain drawbacks. The main disadvantages of the method of obtaining water-coal suspensions are multi-stage, metal consumption, difficulty of installation and start-up, high energy costs, and the resulting suspension is of insufficiently high quality. Also, the disadvantages are the limited frequency of hydraulic shock pulses during processing in one cycle, which is insufficient for the preparation of highly concentrated suspensions that meet the requirements for liquid composite fuel intended for direct combustion. In order to improve the quality of the resulting suspension due to more effective grinding and increasing the amount of its solid component, heat and mass exchange equipment was developed, with the help of which it is possible to achieve an increase in the efficiency of the hydraulic impact action due to an increase in the frequency of pulsations during the production of water-coal suspensions. As heat and mass exchange equipment, rotary pulsation devices (RPD) operating according to the method of discrete-pulse energy input (DPEI) were used. The DPEI method involves the creation of a large number of working bodies or working elements evenly distributed in the water, which transform stationary thermal, mechanical or other types of energy into energetically powerful pulses, discrete in time and space.