Effects of Reduced Bed Temperature in Laboratory- and Full-Scale Fluidized-Bed Boilers: Particle, Deposit, and Ash Chemistry

2013 ◽  
Vol 27 (8) ◽  
pp. 4999-5007 ◽  
Author(s):  
Frida Jones ◽  
Fredrik Niklasson ◽  
Daniel Lindberg ◽  
Mikko Hupa
Keyword(s):  
Fluidized Bed ◽  
Full Scale ◽  
Bed Temperature ◽  
Fluidized Bed Boilers

Fireside Deposit Formation in Biomass Fired FBC: A Comparison Between Tests Performed in Three Significantly Different Sized Combustors

2003 ◽  
Author(s):  
Bengt-Johan Skrifvars ◽  
Patrik Yrjas ◽  
Mikko Hupa ◽  
Martti Aho ◽  
Jaani Silvennoinen ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Flue Gas ◽  
Pilot Scale ◽  
Full Scale ◽  
Small Scale ◽  
Deposition Rates ◽  
Stable Conditions ◽  
Bubbling Fluidized Bed ◽  
Main Components ◽  
Fluidized Bed Boilers

This paper deals with the prediction of ash related problems in fluidized bed boilers during co-firing of various bio-fuels. A study was performed where the slagging and fouling behavior was monitored in three different sized bubbling fluidized bed combustors, a 20 kW semi-pilot reactor, a 2 MW pilot-scale device and a 105 MW full-scale boiler. The aim of the study was to learn about how well slagging and fouling in a small-scale device compares to a full-scale boiler and to see how well the slagging and fouling can be predicted with a small-scale device. Various types of Scandinavian bio-fuels as well as peat were used both separately and mixed. From all three devices ash and deposit samples were collected during as uniform and stable conditions as possible. The fuels used in the three devices during the test campaigns were carefully chosen so that they would be as similar as possible. Bed, furnace and flue gas temperatures were monitored as well as flue gas emissions. The fuels, ashes and deposits were analyzed on their main components and deposition rates were calculated based on the deposit measurements. These data were finally used for assessing the slagging and fouling propensity of the fired fuel. The paper compares and discusses the results from the three different size classes.

The A˚bo Akademi Database: Ash Behavior Measurements in Full-Scale Boilers

2005 ◽  
Author(s):  
Bengt-Johan Skrifvars ◽  
Patrik Yrjas ◽  
Tor Laure´n ◽  
Mikko Hupa ◽  
Martin Dittrich
Keyword(s):  
Fluidized Bed ◽  
Compositional Data ◽  
Full Scale ◽  
Back Side ◽  
Ash Deposition ◽  
Chemical Analyses ◽  
Boiler Load ◽  
Probe Surface ◽  
Poster Paper ◽  
Fluidized Bed Boilers

This poster paper presents an overview of the A˚bo Akademi full-scale boiler ash behavior measurement database. The database contains data from some 20 full-scale boiler measurement campaigns during which the ash behavior in the boiler has been monitored identically. The measurements have been done in 3 different bubbling fluidized bed boilers and 2 circulating fluidized bed boilers during 11 different campaigns. For comparison data from 2 pulverized fuel fired boilers as well as from 2 grate fired boilers have also been included. The data collection includes conventional analyses of the fuels or fuel mixes used during the measurements, ash deposition measurements performed with the air-cooled probe technique, chemical analyses of the collected deposits (front and back side separately, chemical analyses of the boiler fly ashes, and recordings of chosen relevant boiler operation parameters such as boiler load, air-distribution, and flue gas temperatures. The poster paper presents ash deposition data, so called Rate-of-build-up values (RBU, g/m2h) as a function of fuel mixes, probe surface temperatures and boiler type. The poster also presents compositional data of the collected deposits such as the chlorine content as a function of fuel mix and probe surface temperature.

scholarly journals Study on the possibilities of treatment of combustion by-products from fluidized bed boilers into a product devoid of free calcium oxide

2015 ◽  
Vol 14 (4) ◽  
pp. 164-172 ◽  
Author(s):  
Jacek M. Łączny ◽  
Sebastian Iwaszenko ◽  
Krzysztof Gogola ◽  
Andrzej Bajerski ◽  
Tomasz Janoszek ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Calcium Oxide ◽  
Free Calcium ◽  
Fluidized Bed Boilers ◽  
By Products

The Local Heat Balance in a Stationary Fluidized-Bed Furnace Burning Biomass Fuels

2003 ◽  
Author(s):  
Fredrik Niklasson ◽  
Filip Johnsson
Keyword(s):  
Fluidized Bed ◽  
Combustion Rate ◽  
Heat Balance ◽  
Circulating Fluidized Bed ◽  
Local Heat ◽  
Splash Zone ◽  
Two Phase ◽  
Bed Temperature ◽  
Temperature Constant ◽  
The Vertical Distribution

This work investigates the influence of biomass fuel properties on the local heat balance in a commercial-scale fluidized bed furnace. Experiments with different wood based fuels were performed in the Chalmers 12 MWth circulating fluidized bed boiler, temporarily modified to run under stationary conditions. A two-phase flow model of the bed and splash zone is applied, where the combustion rate in the bed is estimated by global kinetic expressions, limited by gas exchange between oxygen-rich bubbles and a fuel-rich emulsion phase. The outflow of bubbles from the bed is treated as “ghost bubbles” in the splash zone, where the combustion rate is determined from turbulent properties. It is found that a large amount of heat is required for the fuel and air to reach the temperature of the bed, in which the heat from combustion is limited by a low char content of the fuel. This implies that a substantial fraction of the heat from combustion of volatiles in the splash zone has to be transferred back to the bed to keep the bed temperature constant. It is concluded that the moisture content of the fuel does not considerably alter the vertical distribution of heat emitted, as long as the bed temperature is kept constant by means of flue gas recycling.

The Pyrocarbon Deposition Techniques of Mechanical Heart Valve Prostheses

2011 ◽  
Vol 464 ◽  
pp. 749-752 ◽  
Author(s):  
Jian Hui Zhang ◽  
Xin Chen
Keyword(s):  
Fluidized Bed ◽  
Heart Valve ◽  
Gas Flow ◽  
Mechanical Heart Valve ◽  
Carbon Matrix ◽  
Artificial Heart Valve ◽  
Bed Temperature ◽  
Wide Range ◽  
Isotropic Carbon ◽  
Deposition Conditions

The structure and property of pyrocarbon varies widely with different deposition conditions. The isotropic carbon which can only been deposited in the bed of fluidized particles is very important in biomedical fields, for instance, it is often used as the coating of artificial heart valve components. The deposition of isotropic pyrocarbon containing silicon is experimented in fluidized bed over a wide range of deposition conditions. The results show that bed temperature influences strongly average coating rate, coating density, silicon content and coating micro-hardness. Propane concentration has a much effect on coating density, carbon matrix density and isotropic characteristics. Total gas flow rate and inlet dimension of fluidized bed affect the formation of fluidized bed.

Effect of bed temperature on bubble size and bubble rising velocity in a semi-cylindrical slugging fluidized bed.

1990 ◽  
Vol 23 (6) ◽  
pp. 765-767 ◽  
Author(s):  
Yasuo Hatate ◽  
Kazuya Ijichi ◽  
Yoshimitsu Uemura ◽  
Mitsunobu Migita ◽  
Desmond F. King
Keyword(s):  
Fluidized Bed ◽  
Bubble Size ◽  
Bed Temperature ◽  
Bubble Rising ◽  
Bubble Rising Velocity

scholarly journals Experimental study on production and emission characteristics of PM2.5 from industrial fluidized bed boilers

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2665-2675
Author(s):  
Songsong Zhang ◽  
Qian Du ◽  
Guoli Qi
Keyword(s):  
Fluidized Bed ◽  
Removal Efficiency ◽  
Mass Concentration ◽  
Great Influence ◽  
Chemical Properties ◽  
Dust Removal ◽  
Dust Collector ◽  
Bag Filter ◽  
Physical And Chemical ◽  
Fluidized Bed Boilers

Particle size distributions, concentrations, morphological characteristics, and elemental compositions of eight fluidized bed boilers with different capacities and different dust collectors were determined experimentally. The PM2.5 particle concentration and mass concentration were monitored in real-time before and after the boiler dust collector by electric low pressure impactor, and the physical and chemical properties of PM2.5 were analyzed by membrane sampling. We found that the PM2.5 particle concentration produced by industrial fluidized bed boilers displayed bimodal distributions, peaking at 0.2 ?m and 0.76 ?m, the formed mechanism of these two parts particles is vaporization-condensation of mineral matter and residual ash particles and the adsorbent wear or tear. Mass concentration exhibits a single peak characteristic with a peak at 0.12 ?m. The removal efficiency for PM2.5 of dust collectors varies with different dust removal mechanisms. The electrostatic precipitator and bag filter have high dust removal efficiency, and the water film dust collector has low dust removal efficiency. The normal operation of the bag filter has a great influence on the dust removal efficiency. The physical and chemical properties of PM2.5 showed that the single-particle morphology was mainly composed of irregular particles, containing a small amount of solid spherical particles and more agglomerates. The content of Si and Al in PM2.5 elemental analysis is the highest, which decreases after a dust collector. Some fluidized bed boilers use desulfurization in the furnace, which has great influence on the mass concentration of Ca and S elements, and the lowest Hg content in trace elements, about a few ppm. <br><br><font color="red"><b> This article has been corrected. Link to the correction <u><a href="http://dx.doi.org/10.2298/TSCI200901242E">10.2298/TSCI200901242E</a><u></b></font>

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