THERMAL SCIENCE

International Scientific Journal

Andriy Redko

,

Yurii Burda

,

Rafael Dzhyoiev

,

Igor Redko

,

Volodymyr Norchak

,

Serhii Pavlovskiiy

,

Oleksandr Redko

NUMERICAL MODELING OF PEAT BURNING PROCESSES IN A VORTEX FURNACE WITH COUNTERCURRENT SWIRL FLOWS

ABSTRACT
The paper presents the process of peat burning in a swirl furnace with counter-current swirl flows and the results of a numerical study. The cyclone-vortex technology of solid fuel combustion allows the furnace volume of a boiler unit, its dimensions and weight to be reduced. The aim of the work is a numerical study of the combustion of pulverized peat in a cylindrical vortex furnace with counter-current swirl flows. The results of computer simulation of the combustion of pulverized peat with a moisture content of 40%, an ash content of 6%, and a higher heat of combustion QpH = 12.3 MJ/kg are presented. The results of the influence of the design parameters of the furnace and heat load (from 100-15%) are given as well. When the heat load is reduced to 15%, the entrainment of unburnt particles increases. The cooled and adiabatic furnace is studied. A significant entrainment of unburned particles is observed in a cooled furnace. The fields of temperature distribution, gas velocity, and particle trajectory in the volume and at the outlet of the furnace are determined. The 3-D temperature distribution in the furnace volume indicates the combustion of peat particles at temperatures (1300-1450°C). Values of the tangential velocity of a swirl flow near the furnace outlet reach 150-370 m/s, which ensures the efficiency of separation of fuel particles and a reduction in heat loss due to mechanical underburning (up to 0.06%). The results of a numerical study show that the diameter of peat particles affects the combustion process, namely coke of particles with an initial diameter from 25-250 μm burns out by 96%, and particles with a diameter of about 1000 μm are carried away from the furnace and do not burn. The furnace provides a complete combustion of dust particles of peat by 99.8% and volatiles by 100%.
KEYWORDS
combustion processes, numerical modeling, peat, vortex furnace, countercurrent swirl flows
PAPER SUBMITTED: 2019-03-05
PAPER REVISED: 2020-03-16
PAPER ACCEPTED: 2020-04-07
PUBLISHED ONLINE: 2020-05-02
DOI REFERENCE: https://doi.org/10.2298/TSCI190305158R
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2021, VOLUME 25, ISSUE Issue 3, PAGES [1905 - 1919]
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Numerical modeling of peat burning processes in a vortex furnace with countercurrent swirl flows

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