Analysis of Combustion of Coal-Water Fuel in Low-Power Hot-Water Boiler via Numerical Modeling and Experiments

Abstract

The paper presents an experimental and computational study of various regimes of firing coal-water fuel in a low-power hot-water boiler that enable both dry and liquid slag removal. The experimental studies were carried out on a pilot industrial boiler adapted for firing coal-water fuel. The fuel was prepared using flotation products of beneficiation of K grade hard coal. The experiments were accompanied by numerical modeling of combustion processes. The mathematical model includes description of the carrier phase motion (based on the RANS approach with the two-parameter Menter SST k-ω turbulence model), radiation transfer (based on the P1 approximation of the spherical harmonics method for a two-phase two-temperature gray medium), particle motion (based on the Lagrange approach), and gas phase combustion (based on a combination of the kinetic model of combustion of gas components with the vortex break model). The physico-mathematical model was tested on the problem of combustion of coal-water fuel (CWF). One of the goals of the work was verification of a complex mathematical model. A comparative analysis of the results of the numerical modeling and experimental data showed that the model reliably described the process of burning in a combustion chamber. An advanced design of hot-water boiler enabling regimes of both dry and liquid slag removal was investigated. The chamber was shown to provide the necessary conditions for firing CWF in terms of reliability and economy.