Quasi-hot spraying of coal-water slurries with pyrogenetic water additives

Abstract

The relevance of the work is explained by the absence of the results of the heating effect of multicomponent coal-water slurries on rheological properties and characteristics of spraying in the literature.PURPOSE. Efficiency substantiation of thermal preparation of coal-water slurries based on pyrogenetic liquid by the results of experimental studies.METHODS. When solving this problem, the Brookfield RVDV-II+Pro rotary viscometer, general-purpose hydrometers, and the Interferometric Particle Imaging method were used.RESULTS. It was found that when water in coal-water fuel is replaced by a similar amount of pyrogenetic liquid (no more than 25%), the density of the slurry increases by 14% at a temperature of 293 K. Preheating of coal-water slurries to 363 K reduces the increase in the density value to 7%. The experimental results showed that the greatest influence of the thermal preparation of the studied slurries on their dynamic viscosity is characteristic of the temperature range from 293 to 333 K. At such temperatures, a decrease in the viscosity of the fuel is possible by 17-20%. Preheating of slurries before spraying in the temperature range from 293 to 333 K makes it possible to increase jet spraying angle by 21-29% in comparison with two-component coal-water fuel at a temperature of 293 K. Substitution of more than 25% by weight of water with pyrogenetic liquid in coal-water fuel is impractical for the studied grade of coal from the point of view of a significant increase in viscosity. Preheating coal-water fuel before spraying reduces the average droplet size by 5-9%.CONCLUSION. The efficiency of thermal preparation of coal-water slurries based on pyrogenetic liquid by the results of experimental studies of rheological properties and spraying characteristics was substantiated.

Keywords

• lignite
• pyrogenetic liquid
• coal-water fuel
• thermal preparation
• viscosity
• spraying