scholarly journals Influence of fuel properties on fluidized bed combustion

1988 ◽  
Author(s):  
I T Lau ◽  
F D Friedrich
Author(s):  
Sonja Enestam

When moving towards CO2 neutral biofuels, fluidized bed combustion represents a good and flexible combustion technique. Biofuels typically have a high volatile content and varying moisture content. Fluidized bed combustion can provide even combustion conditions regardless of big variations in the fuel quality and fuel properties. However, compared to conventional fuels, biofuels often contain high amounts of chlorine and alkali metals, which set certain challenges for the boiler design. The problems that might occur due to high alkali and chlorine levels in the fuels are mainly slagging, fouling, corrosion and bed sintering. Since the variations in fuel properties between different fuels are big, it is of outmost importance from the boiler manufacturer’s point of view, to be able to predict the behavior of a specific fuel or fuel mixture in a very early stage of boiler design. For this purpose different kinds of calculation and prediction tools are needed. For prediction of slagging and fouling an ash behavior prediction tool has been developed. The prediction routine is based on advanced multi-phase multi-component equilibrium calculations, using the fuel composition and combustion conditions as input. Based on the calculations, the rate of deposit formation, the composition of the deposits and the corrosivity of the deposits at different locations in the boiler can be estimated. The prediction tool can be used in boiler design for defining the optimum arrangement of the superheaters, maximum flue gas temperature in the superheater area and maximum steam temperature. It can also be used for specification of maximum limits of troublesome high alkali, high chlorine fuels in fuel mixtures. In this study the prediction routine has been performed for three biofuels / biofuel mixtures. The calculated results have been evaluated with full scale and pilot scale probe measurements as well as with full scale long term operational experience.


Author(s):  
Tânia Ferreira ◽  
Carlos Alberto Catorze Pereira ◽  
Carlos Pinho ◽  
JOÃO LUÍS MONNEY DE SÁ PAIVA ◽  
Edmundo Manuel Tavares Marques

Oil Shale ◽  
2020 ◽  
Vol 37 (2) ◽  
pp. 89 ◽  
Author(s):  
H Liu ◽  
S Feng ◽  
S Zhang ◽  
C Jia ◽  
H Xuan ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3106
Author(s):  
Tomasz Kalak ◽  
Kinga Marciszewicz ◽  
Joanna Piepiórka-Stepuk

Recently, more and more attention has been paid to the removal of nickel ions due to their negative effects on the environment and human health. In this research, fly ash obtained as a result of incineration of municipal sewage sludge with the use of circulating fluidized bed combustion (CFBC) technology was used to analyze the possibility of removing Ni(II) ions in adsorption processes. The properties of the material were determined using analytical methods, such as SEM-EDS, XRD, BET, BJH, thermogravimetry, zeta potential, SEM, and FT-IR. Several factors were analyzed, such as adsorbent dose, initial pH, initial concentration, and contact time. As a result of the conducted research, the maximum sorption efficiency was obtained at the level of 99.9%. The kinetics analysis and isotherms showed that the pseudo-second order equation model and the Freundlich isotherm model best suited this process. In conclusion, sewage sludge fly ash may be a suitable material for the effective removal of nickel from wastewater and the improvement of water quality. This research is in line with current trends in the concepts of circular economy and sustainable development.


2005 ◽  
Vol 128 (2) ◽  
pp. 99-103 ◽  
Author(s):  
Alberto Bahillo ◽  
Lourdes Armesto ◽  
Andrés Cabanillas ◽  
Juan Otero

Transformation of hide (animal skins) into leather is a complicated process during which significant amounts of wastes are generated. Fluidized bed combustion has been extended to burn different wastes that have problems with their disposal showing its technical feasibility. Considering the characteristics of the leather waste, especially the heating value (12.5-21MJ∕kg), it is a fairly good fuel. Moreover, leather waste has a high volatile matter, 65%, similar to other biomasses and unusual high nitrogen content, 14%. The aim of this work was to study leather wastes combustion in fluidized bed presenting experimental results regarding NOx and N2O emissions. A series of experiments were carried out in a fluidized bed pilot plant to understand the importance of operating parameters such as furnace temperature, oxygen content in gases, staged combustion and residence time on the NOx and N2O emission level. Despite having high nitrogen content, low conversion of N-fuel to NOx and N2O was measured during the combustion of leather waste in BFB. Bed temperature and oxygen content were found as the most important single parameters on N2O emission and only oxygen content has a significant influence on NOx emission. Leather waste exhibits a great NOx∕O2 trend; NOx emission decreases as the oxygen concentration decreases while the effect of combustion temperature on NOx is insignificant. Staged combustion does not give a reduction in NOx.


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