Dynamics of furnace processes in a CFB boiler
Journal article, 2007

With the aim of understanding the dynamics of combustion, this work examines simultaneous fluctuations in fluid dynamic parameters and gas composition measured in a CFB furnace operated with coal as a fuel. The fluid dynamic parameters investigated are pressure and air flow entering the furnace. Gas composition was recorded by a zirconia-cell probe and a gas suction probe connected to a mass spectrometer having a high time resolution (10 Hz). The principal fluctuations detected are around I Hz and below 0.3 Hz. The fluctuations below 0.3 Hz mostly originate from variations in the fuel-feed rate. These variations create periods of reducing conditions caused by a momentarily high fuel input accompanied by a pressure rise in the furnace and a reduction of the air feed, which occurs concurrent with the release of an enhanced quantity of volatiles. Modelled pressure fluctuations based on the relation between volatile release and pressure in the furnace give similar pressure fluctuations as the measured pressure fluctuations, with respect to amplitude and characteristic time scale of the fluctuations. There is also a correlation between reducing conditions and the concentration of hydrocarbons. (c) 2006 Elsevier Ltd. All rights reserved.

PRESSURE-FLUCTUATIONS

REGIMES

TIME

FLUIDIZED-BED

hydrodynamics

DEVOLATILISATION

combustion

fluidization

SYSTEM

circulating fluidized bed

gas composition

dynamics

BITUMINOUS COAL

Author

A. Johansson

University of Borås

Chalmers

Filip Johnsson

Chalmers, Energy and Environment

Fredrik Niklasson

Chalmers, Energy and Environment

Lars-Erik Åmand

Chalmers

Chemical Engineering Sciences

0009-2509 (ISSN)

Vol. 62 1-2 550-560

Subject Categories

Other Engineering and Technologies not elsewhere specified

DOI

10.1016/j.ces.2006.09.020

More information

Latest update

9/10/2018