scholarly journals Phosphorus-Rich Ash from Poultry Manure Combustion in a Fluidized Bed Reactor

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 785
Author(s):  
Zdzisław Adamczyk ◽  
Magdalena Cempa ◽  
Barbara Białecka
Keyword(s):  
Phase Composition ◽  
Fluidized Bed ◽  
Combustion Process ◽  
Poultry Manure ◽  
Raw Material ◽  
Process Efficiency ◽  
Chemical Components ◽  
Bubbling Fluidized Bed ◽  
Laboratory Reactor ◽  
Size And Morphology

The aim of this study was to examine the physico-chemical and phase characteristics of ash obtained in the process of the combustion of Polish poultry manure in a laboratory reactor with a bubbling fluidized bed. Three experiments, differing in the grain size and morphology of the raw material, the method of its dosing and the type of fluidized bed, were carried out. The contents of the main chemical components and trace elements in the obtained ash samples were determined using WDXRF, and the phase composition was examined through the XRD method. The morphology and the chemical composition of grains in a given micro-area using the SEM/EDS method were also investigated. The highest concentration of phosphorus (from 28.07% wt. to 29.71% wt. as P2O5 equivalent), the highest proportion of amorphous substance (from 56.7% wt. to 59.0% wt.) and the lowest content of unburned organic substance (LOI from 6.42% to 9.16%) (i.e., the best process efficiency), was obtained for the experiment in which the starting bed was quartz sand and poultry manure was fed to the reactor in the form of pellets. It has been calculated that in this case, the amorphous phase contains more than half of the phosphorus. The method of carrying out the combustion process has a significant impact on the phase composition and, consequently, on the availability of phosphorus.

Numerical Simulation of the Combustion Behavior of Different Biomasses in a Bubbling Fluidized Bed Boiler

2005 ◽  
Author(s):  
Christian Mueller ◽  
Anders Brink ◽  
Mikko Hupa
Keyword(s):  
Fluidized Bed ◽  
Power Plants ◽  
Thermal Power ◽  
Combustion Process ◽  
Fluidised Bed ◽  
Simplified Approach ◽  
Combustion Behavior ◽  
Bubbling Bed ◽  
Bubbling Fluidized Bed ◽  
Fuel Mixtures

Solid fuels currently used for energy production in thermal power plants are characterized by a large variety ranging from different coals to biomasses and wastes. This manifold of fuels offers opportunities to the energy producers and nowadays many power plants do not fire single fuels but fuel mixtures. While this procedure may lead to overall economic and environmental advantages it is very demanding for the boiler operators to maintain boiler performance and availability and to meet emission limits. The development of mathematical models that are capable of predicting the combustion behavior of fuel mixtures and provide guidelines for operators and manufacturers has been a challenge over the last years. Since bubbling fluidized beds are frequently used for firing fuel mixtures and especially biomass mixtures, current CFD based BFB models, such as the A˚bo Akademi Furnace Model, have been used widely over the last years to predict emission tendencies and ash deposition behavior. However, due to the complexity of the processes during combustion of fuel mixtures and the combustion process in the bubbling fluidised bed itself, the models are characterized by strong simplifications. This is especially true for the description of the lower part of the furnace, the region of fuel intake and bubbling bed. Recently, the A˚bo Akademi Furnace Model has been extended by a more detailed description of the fuel conversion by considering the combustion of individual biomass particles and a first simplified approach describing heat and mass transfer processes between the bubbling bed and the freeboard. Both submodels guarantee a closed mass and energy balance over the bed-freeboard region. In the current study the new submodels have been used to investigate the combustion conditions in a 290 MW bubbling fluidized bed boiler firing peat and forest residue. Clear differences in the simulation results for the both fuels can be found with regard to the specific combustion characteristics, the location of the main combustion zone and the total heat generated during combustion.

scholarly journals Carbon Shale Combustion in the Fluidized Bed Reactor

2014 ◽  
Vol 16 (2) ◽  
pp. 74-76 ◽  
Author(s):  
Małgorzata Olek ◽  
Stanisław Kandefer ◽  
Wiesław Kaniowski ◽  
Witold Żukowski ◽  
Jerzy Baron
Keyword(s):  
Fluidized Bed ◽  
Flue Gas ◽  
Combustion Process ◽  
Fluidized Bed Reactor ◽  
Ash Content ◽  
Conversion Degree ◽  
Hard Coal ◽  
Combustible Material ◽  
High Quality ◽  
Bubbling Fluidized Bed

Abstract The purpose of this article is to present the possibilities of coal shale combustion in furnaces with bubbling fluidized bed. Coal shale can be autothermally combusted in the fluidized bed, despite the low calorie value and high ash content of fuel. Established concentrations of CO (500 ppm) and VOC (30 mg/m3) have indicated a high conversion degree of combustible material during combustion process. Average concentrations of SO2 and NOx in the flue gas were higher than this received from the combustion of high quality hard coal, 600 ppm and 500 ppm, respectively. Optional reduction of SO2 and NOx emission may require the installation of flue gas desulphurization and de-NOx systems.

Retrofit of a Bubbling Fluidized Bed Pilot Plant From Air Combustion to Oxyfuel Combustion

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Gabriel M. Faé Gomes ◽  
Antônio C. F. Vilela ◽  
Guilherme P. da Silva Priebe ◽  
Leandro Dalla Zen
Keyword(s):  
Fluidized Bed ◽  
Process Parameters ◽  
Pilot Plant ◽  
Combustion Process ◽  
Air Leakage ◽  
Radiation Mechanism ◽  
Oxyfuel Combustion ◽  
Bubbling Fluidized Bed ◽  
And Control ◽  
Energy Balances

When using fluidized bed in oxyfuel combustion, process parameters must be adjusted to maintain combustion and control air leakage into the system as there are important changes in gases properties, flow, and temperature. In this sense, this work makes a description of the retrofit of air combustion to oxyfuel combustion in a 0.25 MWth bubbling fluidized pilot plant. Process parameters were analyzed and mass and energy balances were developed to compare air and oxyfuel combustion. Air leakage and fluidization showed to be important to control when proceeding transition to oxyfuel combustion and temperature increase was consequence of radiation mechanism changes.

scholarly journals Application of analytical and CFD models of liquid fuels combustion in a fluidized bed

2019 ◽  
Vol 23 (Suppl. 5) ◽  
pp. 1627-1636
Author(s):  
Milica Mladenovic ◽  
Stevan Nemoda ◽  
Milijana Paprika ◽  
Ana Marinkovic
Keyword(s):  
Fluidized Bed ◽  
Liquid Fuel ◽  
Combustion Process ◽  
Vertical Direction ◽  
Unsteady Motion ◽  
Cfd Modeling ◽  
Thermal Engineering ◽  
Two Phase ◽  
Bubbling Fluidized Bed ◽  
Two Fluid

In Laboratory for Thermal Engineering and Energy of Institute Vinca, University of Belgrade, a 2-D CFD modeling procedure of numerical simulation of unconventional liquid fuel combustion in bubbling fluidized bed has been developed. This procedure is based on a two-fluid Euler-Euler approach modeling a fluidized bed with the determination of the velocities field of gas and particulates in two-phase, granular flows, analog to the kinetic theory of gases. This model describes in detail the unsteady motion of gas and solid phases, the formation and movement of bubbles with the combustion process in the fluidized bed, but temperature profiles calculated by the bed height differ to some extent from the experimentally obtained profiles. This discrepancy is probably due to the inability of a two-fluid CFD model to give a realistic simulation of the liquid fuel mixing in a fluidized bed. Therefore, an analytical model has been developed, where one of the basic assumptions is that the particles are mixed in the vertical direction of fluidized bed mainly by the bubble wakes. The proposed zonal type of calculating procedure is based on Davidson and Harrison two-phase model of the bubbling fluidized bed, where fluidized bed is divided into zones within which material and energy balances are set.

scholarly journals Three phase Eulerian-granular model applied on numerical simulation of non-conventional liquid fuels combustion in a bubbling fluidized bed

2016 ◽  
Vol 20 (suppl. 1) ◽  
pp. 133-149
Author(s):  
Stevan Nemoda ◽  
Milica Mladenovic ◽  
Milijana Paprika ◽  
Aleksandar Eric ◽  
Borislav Grubor
Keyword(s):  
Fluidized Bed ◽  
Fluid Dynamic ◽  
Numerical Procedure ◽  
Combustion Efficiency ◽  
Liquid Fuels ◽  
Chemical Components ◽  
Fluidized Bed Combustion ◽  
Bubbling Fluidized Bed ◽  
Energy Equations ◽  
Kinetic Gas Theory

The paper presents a two-dimensional CFD model of liquid fuel combustion in bubbling fluidized bed. The numerical procedure is based on the two-fluid Euler-Euler approach, where the velocity field of the gas and particles are modeled in analogy to the kinetic gas theory. The model is taking into account also the third - liquid phase, as well as its interaction with the solid and gas phase. The proposed numerical model comprise energy equations for all three phases, as well as the transport equations of chemical components with source terms originated from the component conversion. In the frame of the proposed model, user sub-models were developed for heterogenic fluidized bed combustion of liquid fuels, with or without water. The results of the calculation were compared with experiments on a pilot-facility (power up to 100 kW), combusting, among other fuels, oil. The temperature profiles along the combustion chamber were compared for the two basic cases: combustion with or without water. On the basis of numerical experiments, influence of the fluid-dynamic characteristics of the fluidized bed on the combustion efficiency was analyzed, as well as the influence of the fuel characteristics (reactivity, water content) on the intensive combustion zone.

Experimental Evaluation of Biomass Medium-Temperature Gasification with Rice Straw as the Fuel in a Bubbling Fluidized Bed Gasifier

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiaojia Wang ◽  
Zhenyu Zhong ◽  
Baosheng Jin
Keyword(s):  
Moisture Content ◽  
Fluidized Bed ◽  
Rice Straw ◽  
Operating Conditions ◽  
Raw Material ◽  
Carbon Conversion ◽  
Medium Temperature ◽  
Positive Effects ◽  
Bubbling Fluidized Bed ◽  
Gasification Efficiency

Abstract Our previous pilot-scale studies (Bioresource Technology 2018, 267: 102–109) preliminarily demonstrated the feasibility of performing air gasification with a novel two-stage system, including a medium-temperature bubbling fluidized bed (BFB) reactor and a high-temperature swirl-flow furnace reactor, using rice husk as the fuel. As an extension of that work, this study aims to further investigate the reaction mechanism and application prospect of this technology in the use of a more representative biomass fuel, i. e. rice straw. The operation stability, flow behaviors and reaction characteristics in the first-stage medium-temperature gasification reactor are studied in a lab-scale BFB gasifier. The effects of important operating conditions on the syngas quality, tar yield, compositions of carbon residue, and risk of agglomeration are elucidated in depth. The results have shown that an increase in the gasification temperature can promote syngas quality, gasification efficiency, and carbon conversion, but also increases the risk of agglomeration. An increase in the gasification equivalent ratio leads to positive effects on the syngas yield, carbon conversion, and tar concentration, but also has negative effects on the syngas heating value, tar yield, and especially the restrain of agglomeration. An increase in the raw material moisture content has negative influence on the gasification performance of rice straw, in terms of the gasification efficiency, carbon conversion, tar yield, and so on. However, the increase of moisture content can reduce the cost of raw material drying, and avoid the fluctuation of bed temperature, and therefore, a practical gasification system is recommended to be designed and operated under a certain conditions with moderate moisture contents.

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