Bed Agglomeration During the Fluidized Bed Combustion of Olive Husk

2005 ◽  
Author(s):  
Antonio Cammarota ◽  
Riccardo Chirone ◽  
Fabrizio Scala
Keyword(s):  
Fluidized Bed ◽  
Dynamic Pressure ◽  
Mediterranean Area ◽  
Operating Conditions ◽  
Pressure Gradients ◽  
Fluidized Bed Combustion ◽  
High Propensity ◽  
Olive Husk ◽  
Bed Agglomeration ◽  
High Alkali

The fluidized bed combustion of a biomass residue (olive husk) common in the Mediterranean area has been investigated in a bench scale reactor. The focus of the study was the high propensity of this fuel to give rise to bed agglomeration problems during combustion, as a consequence of the high alkali content of the ash. Bed agglomeration characteristic times as well as temperature and pressure gradients were measured at different operating conditions. In addition, a diagnostic tool based on the measurement of the dynamic pressure signal inside the bed was tested for its capability to predict the bed agglomeration onset.

A New Method to Inhibit Bed Agglomeration Problems in Fluidized Bed Boilers

2003 ◽  
Author(s):  
Jaani Silvennoinen
Keyword(s):  
Fluidized Bed ◽  
Industrial Scale ◽  
Fluidized Bed Combustion ◽  
Natural Sand ◽  
Worst Case ◽  
Free Quartz ◽  
Bed Materials ◽  
Bed Agglomeration ◽  
High Alkali ◽  
Bed Material

Fluidized bed combustion (FBC) technology was commercialized in the 70s. Both bubbling fluidized bed (BFB) and circulating fluidized bed (CFB) technology are capable of handling a wide variety of solid fuels. Natural sand is typically used as the fluidizing material. However, the properties and behavior of some solid fuel ash may limit the use of these fuels due to bed agglomeration problems. Natural sand contains several minerals, typically mainly consisting of 20–50 wt.-% of plagioclase (NaAlSi3O8 + CaAlSi3O8), 10–30 wt.-% of potash feldspar (KAlSi3O8), and 25–100 wt.-% of quartz (SiO2). Biomass based fuels contain high amounts of alkali. Ash high in alkali may react with the free quartz of the natural sand, producing an alkali silicate mixture with low melting point. This mixture may act as an adhesive between fluidized bed particles and may, in the worst-case, result in serious fluidization problems. This problem can be avoided by using AGGLOSTOP™ quartz-free bed material. Four different bed materials were tested in a 15 kW laboratory-scale FBC test rig with plywood residue, which is known to cause severe fluidization problems in FB boilers. Two of the tested bed materials were quartz-free. When quartz-free bed materials were used, no signs of bed agglomeration were observed. The other two bed materials containing free quartz caused total defluidization at a temperature of around 750°C after about half an hour of operation. The concept of using AGGLOSTOP™ quartz-free bed material with high alkali fuels has been successfully applied in two industrial scale BFB boilers (15 and 74 MWth). The use of AGGLOSTOP™ fluidized bed material enables energy production in FB boilers based on high alkali fuels, which were earlier impossible to utilize due severe bed agglomeration problems. This paper focuses on the bed agglomeration phenomenon by discussing the results from laboratory and industrial-scale boilers and presents a new solution to extend the use of high alkali fuels in FB boilers.

Bed Agglomeration Characteristics during Fluidized Bed Combustion of Biomass Fuels

2000 ◽  
Vol 14 (1) ◽  
pp. 169-178 ◽  
Author(s):  
Marcus Öhman ◽  
Anders Nordin ◽  
Bengt-Johan Skrifvars ◽  
Rainer Backman ◽  
Mikko Hupa
Keyword(s):  
Fluidized Bed ◽  
Fluidized Bed Combustion ◽  
Biomass Fuels ◽  
Bed Agglomeration

scholarly journals Research in the fluidized bed combustion in the Laboratory for thermal engineering and energy - Part B: Achievements in technology implementation

2019 ◽  
Vol 23 (Suppl. 5) ◽  
pp. 1655-1667
Author(s):  
Borislav Grubor ◽  
Dragoljub Dakic ◽  
Stevan Nemoda ◽  
Milica Mladenovic ◽  
Milijana Paprika ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Technology Implementation ◽  
Liquid Fuels ◽  
Thermal Engineering ◽  
Fluidized Bed Combustion ◽  
Biomass Waste ◽  
Technology Application ◽  
Wide Range ◽  
Combustion Technology ◽  
Bed Agglomeration

Paper gives a review of the most important results of extensive and wide-ranging research program on R&D of fluidized bed combustion technology in the Laboratory for Thermal Engineering and Energy of the VINCA Institute of Nuclear Sciences. Paper presents detailed overview of R&D activities from the beginning in the second half of the 1970's up to present days. These activities encompass applied research achievements in the field of characterization of limestones and bed agglomeration and sintering and modeling of overall processes during fluidized bed combustion, all of which have facilitated the R&D of the fluidized bed combustion technology. Attention is also given to steady-state combustion testing of a wide-range of fuels (coals, liquid fuels, biomass, waste solid and liquid materials, etc.) in our fluidized bed combustor and development of original methodology for testing the suitability of fuels for fluidized bed combustion, as well as specific achievements in the area of technology application in Serbia.

Release and migration characteristics of sodium and potassium in high alkali coal under oxy-fuel fluidized bed combustion condition

Fuel ◽  
2020 ◽  
Vol 262 ◽  
pp. 116413 ◽  
Author(s):  
Kaijun Yu ◽  
Xiaoping Chen ◽  
Tianyi Cai ◽  
Jiliang Ma ◽  
Daoyin Liu ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Fluidized Bed Combustion ◽  
Combustion Condition ◽  
And Migration ◽  
High Alkali ◽  
Sodium And Potassium

Attrition Behavior of Coal Ash Under Circulating Fluidized Bed Combustion Conditions

2003 ◽  
Author(s):  
Franz Winter ◽  
Xin Liu
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Coal Ash ◽  
Operating Conditions ◽  
Laboratory Scale ◽  
Silica Sand ◽  
Electrical Heating ◽  
Fluidized Bed Combustion ◽  
Bed Temperature ◽  
Wide Range

The attrition behavior of ash produced from two bituminous and one anthracite coal was studied under laboratory-scale circulating fluidized bed combustor (CFBC) conditions. After the ash was produced in the oven, the ash sample with a size range from 0.1 to 1 mm was fed into the hot CFBC, which was heated by electrical heating shells and fluidized by air. The laboratory-scale CFBC was operated with using fine silica sand (40 to 80 μm) as bed material. After a certain time the operation was stopped, all particles were collected and sieving analysis was performed to obtain the actual particle size distribution (PSD) of the coal ash. The operating conditions were changed in a wide range, i.e. the bed temperature from 600 to 850°C, the fluidizing velocity from 1.2 to 2 m/s, the residence time from 60 to 120 min and the design of the cyclone. The effects of operating conditions and coal type were studied and their relative importance is discussed. Elemental analysis of the coal ashes showed that Si and Ca may play an important role during attrition.

Simultaneous CO2 and SO2 Capture at Fluidized Bed Combustion Temperatures

2005 ◽  
Author(s):  
P. Sun ◽  
J. R. Grace ◽  
C. J. Lim ◽  
E. J. Anthony
Keyword(s):  
Particle Size ◽  
Reaction Time ◽  
Fluidized Bed ◽  
Co2 Capture ◽  
Atmospheric Pressure ◽  
Pressure Range ◽  
Operating Conditions ◽  
The Other ◽  
Fluidized Bed Combustion ◽  
So2 Capture

Simultaneous carbonation and sulphation have been investigated to simulate non-calcining conditions at FBC temperatures (750–850°C) using an atmospheric-pressure thermogravimetric reactor (TGR) with up to 80% CO2 in the gas stream to extend the pressure range of applicability of the results. This investigation was undertaken to provide insight on simultaneous carbonation and sulphation and to provide knowledge relevant to FBC, including PFBC, operations. Two calcium-based sorbents (one limestone and one dolomite) were tested with particles of diameter 212–250 μm and 500–600 to determine the effects of operating conditions such as temperature, CO2 and SO2 concentrations, particle size and reaction time on the sorbent performance. SO2 was found to impede CO2 capture; on the other hand, CO2 enhanced the capture of SO2. The calcination rate was also observed to decrease as a result of the presence of the sulphate layer.

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