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

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.

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 785
Author(s):  
Zdzisław Adamczyk ◽  
Magdalena Cempa ◽  
Barbara Białecka

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.


2018 ◽  
Vol 12 (5) ◽  
pp. 735-748 ◽  
Author(s):  
Zakir Khan ◽  
Suzana Yusup ◽  
Murni M Ahmad ◽  
Abrar Inayat ◽  
Muhammad Naqvi ◽  
...  

2016 ◽  
Vol 86 ◽  
pp. 116-123 ◽  
Author(s):  
Jan Hrdlicka ◽  
Pavel Skopec ◽  
Jan Opatril ◽  
Tomas Dlouhy

Author(s):  
Christian Mueller ◽  
Anders Brink ◽  
Mikko Hupa

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.


2014 ◽  
Vol 16 (2) ◽  
pp. 74-76 ◽  
Author(s):  
Małgorzata Olek ◽  
Stanisław Kandefer ◽  
Wiesław Kaniowski ◽  
Witold Żukowski ◽  
Jerzy Baron

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.


2019 ◽  
Vol 23 (Suppl. 5) ◽  
pp. 1627-1636
Author(s):  
Milica Mladenovic ◽  
Stevan Nemoda ◽  
Milijana Paprika ◽  
Ana Marinkovic

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.


2015 ◽  
Vol 786 ◽  
pp. 232-237 ◽  
Author(s):  
Iman Eslami Afrooz ◽  
Chandra Mohan Sinnathambi ◽  
Saravanan Karuppanan ◽  
Dennis Ling Chuan Ching

Bubbling fluidized bed (BFB) is a vital equipment in many applications in the energy, pharmaceuticals, and chemicals process industries due to its numerous advantages such as large heat capacity inside a bed, and rapid heat and mass transfer rate. In spite of numerous research activities, achieving high fluidization performances in BFB process is still a challenge of science. This research is being conducted to study the hydrodynamic regime of a BFB pilot plant gasifier. To this end, a lab-scale cold model was first designed based on the empirical equations and scaling laws. The scaling laws was used to scale down the Tenaga Nasional Berhad-PETRONAS (TNBR-PETRONAS) pilot plant gasifier into a small scale laboratory model. Moreover, the empirical equations were utilized to determine the critical parameters such as bed pressure drop, height of the bed, number of orifices of the distributor plate and the pitch size. Finally a lab-scale hot flow model will be designed based on the cold model geometric dimensions but under a real operating conditions as that of a pilot plant.


Sign in / Sign up

Export Citation Format

Share Document