Mathematical modelling of sulfur retention in fluidized bed combustors

Download
2003
Altındağ, Hakan
A considerable number of modeling studies for the investigation of sulfur retention in atmospheric bubbling fluidized bed combustors have been carried out and well documented in the literature. Despite 30 years of intensive study of sulfation process in fluidized bed combustors and numerous laboratory studies, there are still many uncertainties and disagreements on the subject. In addition, modeling sulfur retention performance of Turkish lignites with high sulfur, volatile matter and ash contents has not drawn much attention to date. Recent trend in utilization of indigenous lignites in fluidized bed boilers necessitated investigation of pollutant emissions and adaptation of fluidized bed combustion technology to these lignites. In an attempt to achieve this objective, a system model, previously developed and tested for the prediction of the combustion behavior of fluidized bed combustors was extended to incorporate sulfur retention. The predictive accuracy of the model was assessed by applying it to the prediction of the behavior of METU 0.3 MWt ABFBC test rig burning indigenous lignites in their own ashes, and comparing its predictions with measurements taken on the same rig. Sulfur dioxide concentration predictions throughout the combustor were found to be in good agreement with the experimental data except for the small discrepancy between predictions and measurements in the bed section. Measurements and model predictions revealed that recyling enhances calcium utilization significantly by increasing the sorbent residence time leading to higher sulfur retention efficiencies. The system model proposed in this study proves to be a useful tool in qualitatively and quantitatively simulating the processes taking place in an atmospheric fluidized bed combustor.

Suggestions

Simultaneous detection of surface coverage and structure of krypton films on gold by helium atom diffraction and quartz crystal microbalance techniques
Danışman, Mehmet Fatih (2011-11-01)
We describe a quartz crystal microbalance setup that can be operated at low temperatures in ultra high vacuum with gold electrode surfaces acting as substrate surface for helium diffraction measurements. By simultaneous measurement of helium specular reflection intensity from the electrode surface and resonance frequency shift of the crystal during film adsorption, helium diffraction data can be correlated to film thickness. In addition, effects of interfacial viscosity on the helium diffraction pattern cou...
Characterization of gas-solid flow in conical spouted beds operating with heavy particles
Sari, Salih; Külah, Görkem; KÖKSAL, MURAT (2012-07-01)
This study presents the results of an experimental investigation of the hydrodynamics of conical spouted beds operating with high density particles. This type of spouted beds is frequently encountered in chemical vapor deposition coating of nuclear fuel elements. Measurements were performed in three 15 cm ID full circular (gamma = 30 degrees, 45 degrees, 60 degrees) and one half circular conical spouted (gamma = 30 degrees) bed with yttria-stabilized zirconia particles (d(p) = 0.5, 1 mm; rho(p) = 6050 kg/m(...
Dynamic mechanical analysis of provisional resin materials reinforced by metal oxides
Korkmaz, T; Doan, A; Usanmaz, Ali (2005-01-01)
In this study, several provisional resin materials were investigated by dynamic mechanical analysis (DMA). The materials were autopolymerized PMMA and PEMA, light cured PMMA. Autopolymerized PMMA has the highest T-g (131 degrees C) compared to that of the autopolymerized PEMA (102 degrees C) and light cured PMMA (120 degrees C). The storage moduli for autopolymerized PMMA, autopolymerized PEMA and light cured PMMA are 2.9, 1.8 and 2.3 GPa, respectively. The loss moduli of the same resins are 330, 300 and 35...
Evaluation of novel thermo-resistant Micractinium and Scenedesmus sp for efficient biomass and lipid production under different temperature and nutrient regimes
Sonmez, Cagla; ELÇİN, EVRİM; Akin, Dilan; Öktem, Hüseyin Avni; Yücel, Ayşe Meral (2016-07-01)
Despite the vast interest in microalgae as feedstock for biodiesel production, relatively few studies examined their response to diurnal temperature fluctuation. Here, we describe biomass and lipid productivities and fatty acid profiles of thermo-resistant Micractinium sp. and Scenedesmus sp. grown in batch cultures in a laboratory set-up that mimics a typically warm summer day in Central Anatolia with a 16-h light temperature of 30 degrees C and 8-h dark temperature of 16 degrees C (30 degrees C (day)/16 d...
Mathematical modeling of nox emissions in bubbling fluidized bed combustors
Afacan, M. Onur; Selçuk, Nevin; Department of Chemical Engineering (2005)
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 METU 0.3 MWt Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) burning lignites with high volatile matter in their own ashes. The predictive accuracy of the model was assessed by comparing its predictions with measurements taken previously on the same rig. Favorable comparisons are obtaine...
Citation Formats
H. Altındağ, “Mathematical modelling of sulfur retention in fluidized bed combustors,” M.S. - Master of Science, Middle East Technical University, 2003.