Mathematical modeling of ignition of coal-water slurries particles coated with water film

V.G Afanaseva,G.V Kuznetsov,D Feoktistov,E Bulba

doi:10.1051/matecconf/201819401001

Abstract

The results of the mathematical modeling of heat and mass transfer processes occurring jointly with ignition of coal-water slurries particles covered with a water film are presented. It is shown that water film thickness can have a significant effect on the ignition dynamics. In addition, it was found out that the main fuel layer is heated to the evaporation temperature during water film evaporation. As a result, following processes of thermal preparation (evaporation of moisture, thermal decomposition) occur faster.

Highlights

The large-scale inmplementation of coal water slurry (CWS) in the energy sector is hampered by many factors, one of which is insufficient study of the processes occurring during the CWS thermal preparation for ignition
The mathematical formulation of the problem, the corresponding stated higher of physical model is a non-stationary system of differential equations in partial derivatives: CWS particle has a polyhedral shape that depends on many factors and can vary randomly, the particle was observed in the spherical form for simplification [7]
It can be noted that the film evaporation time for almost the entire temperature range is up to 60% of the induction period, it is due to the fact that during the evaporation of the water film the main fuel layer is heated to the evaporation temperature

Summary

Introduction

Climate change problem is acute. The main cause of the current global warming trend is increasing concentration of carbon dioxide in the atmosphere, resulting in the greenhouse effect. The highest level of emissions is observed during coal combustion, the first thing we have to do is develop clean coal technologies to minimize the negative impact on the environment. One of such technological solutions that ensure safety and efficiency of coal use is the technology of combustion it in the form of coal water slurry (CWS) [1,2,3,4]. The ignition characteristics of the latter class are currently insufficiently studied, but it is clear that the presence of a water film can have an impact on the ignition of CWS particles due to the high endothermic evaporation and heat capacity of water [6].

Formulation of the problem

The results

Findings

Conclusion