Mathematical Modeling of a Bubbling Fluidized Bed Combustor Cofired with Lignite and Biomass

2010-01-01
A comprehensive system model of fluidized bed combustor, previously developed and tested for the prediction of combustion behavior of fluidized bed combustors fired with lignite was extended for the modeling of cofiring of lignite with biomass by incorporating volatile release, char combustion, and population balance for biomass. The model predictions were validated against measurements taken on a Middle East Technical University 0.3 MWt Atmospheric Bubbling Fluidized Bed Combustor fired with lignite only, lignite with limestone addition, and about 50/50 lignite-olive residue mixture with limestone addition. Predicted and measured temperatures and concentrations of gaseous species along the combustor were found to be in good agreement. Introduction of biomass to lignite was found to decrease SO2 emissions but did not affect NO emissions significantly. The system model proposed in this study proves to be a useful tool in qualitatively and quantitatively simulating the processes taking place in a bubbling fluidized bed combustor burning lignite with biomass.
COMBUSTION SCIENCE AND TECHNOLOGY

Suggestions

Modeling of NOx emissions from fluidized bed combustion of high volatile lignites
Afacan, Onur; Gogebakan, Yusuf; Selçuk, Nevin (2007-01-01)
A comprehensive model, previously developed and tested for prediction of behavior of continuous fluidized bed combustors is extended to incorporate NOx formation and reduction reactions and applied to the simulation of Middle East Technical University (METU) 0.3 MW Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) burning lignites with high Volatile Matter/Fixed Carbon (VM/FC) ratios in their own ashes. Favorable comparisons are obtained between the predicted and measured temperatures and concentrations ...
Assessment of a model with char attrition for a bubbling atmospheric fluidized-bed combustor
Gogebakan, Y; Selçuk, Nevin (2004-05-01)
A comprehensive model, previously developed and tested for prediction of behavior of continuous fluidized-bed combustors, is extended to incorporate char attrition and is applied to the simulation of a 0.3 MegaWatt (MW) atmospheric bubbling fluidized-bed combustor burning lignites with high Volatile Matter/Fixed Carbon (VM/FC) ratios in their own ashes. The effect of this incorporation is assessed by comparing the predictions of the model with and without attrition with measurements. Favorable comparisons o...
Simulation of circulating fluidized bed combustors firing indigenous lignite
Özkan, Mert; Selçuk, Nevin; Department of Chemical Engineering (2010)
A comprehensive model, previously developed for a rectangular parallelepiped shaped 0.3 MWt circulating fluidized bed combustor (CFBC) fired with high calorific value coal burning in sand and validated against experimental data is adapted to cylindrical configuration and is extended to incorporate NOx formation and reduction reactions and pressure drops around cyclone, downcomer and loop seal. Its predictive accuracy is tested by applying it to the simulation of Middle East Technical University (METU) 150 k...
Mathematical modeling of a bubbling fluidized bed combustor co-fired with cotton residue and lignite
Yaşar, Mehmet Soner; Külah, Görkem; Selçuk, Nevin; Department of Chemical Engineering (2018)
A comprehensive system model, previously developed for prediction of combustion behaviors of Turkish lignites, lignite/hazelnut shell and lignite/olive residue blends in fluidized bed combustors, is extended for modeling of co-combustion of Turkish lignite and cotton residue in a bubbling fluidized bed combustor. Cotton residue has high nitrogen content (~ 4.1 wt. % a.r.) unlike lignite (~ 0.9 wt. % a.r.), olive residue (~ 1.6 wt. % a.r.) and hazelnut shell (~ 0.5 wt. % a.r.), which leads to relatively high...
Investigation of combustion characteristics of biomass and coal mixtures in a circulating fluidized bed combustor
Varol, Murat; Atımtay, Ayse; Department of Environmental Engineering (2013)
In this study, combustion and co-combustion tests of Bursa/Orhaneli lignite with two biomass fuels (olive cake and woodchips) were carried out in a laboratory scale Circulating Fluidized Bed (CFB) combustor, 6 m high and 108 mm inside diameter, in order to investigate the effect of excess air ratio (l), secondary air ratio (SAR) and location of secondary air injection along the combustor wall on the emissions. Optimum l and SAR was determined for each test. The flue gas emissions were compared with limits i...
Citation Formats
G. Külah and N. Selçuk, “Mathematical Modeling of a Bubbling Fluidized Bed Combustor Cofired with Lignite and Biomass,” COMBUSTION SCIENCE AND TECHNOLOGY, pp. 600–612, 2010, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/32684.