scholarly journals Agglomeration of bed material: Influence on efficiency of biofuel fluidized bed boiler

2003 ◽  
Vol 7 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Georgy Ryabov ◽  
Dmitry Litoun ◽  
Eduard Dik
Keyword(s):  
Fluidized Bed ◽  
Chemical Compositions ◽  
Air Supply ◽  
Drain Flow ◽  
Boiler Efficiency ◽  
Successful Design ◽  
The Common ◽  
Bed Material ◽  
Fluidized Bed Combustor ◽  
Steam Drum

The successful design and operation of a fluidized bed combustor requires the ability to control and mitigate ash-related problems. The main ash-related problem of biomass filing boiler is agglomeration. The fluidized bed boiler with steam capacity of 66 t/h (4 MPa, 440 ?C) was started up at the Arkhangelsk Paper-Pi dp-Plant in 2001. This boiler was manufactured by the Russian companies "Energosofin" and "Belenergomash" and installed instead of the existing boiler with mechanical grate. Some constructional elements and steam drum of existing boiler remained unchanged. The primary air fan was installed past the common air fan, which supply part of the air into 24 secondary airports. First operating period shows that the bed material is expanded and then operator should increase the primary air rate, and the boiler efficiency dramatically decreases. Tills paper presents some results of our investigations of fuel, bed and fly ash chemical compositions and other characteristics. Special experiments were carried out to optimize the bed drain flow rate. The influence of secondly air supply improvement on mixing with the main flow and boiler efficiency are given.

scholarly journals Agglomeration of Bed Material: Influence on Efficiency of Biofuel Fluidized Bed Boiler

2003 ◽  
Author(s):  
Georgy A. Ryabov ◽  
Dmitry S. Litoun ◽  
Eduard P. Dik
Keyword(s):  
Fluidized Bed ◽  
Chemical Compositions ◽  
Air Supply ◽  
Drain Flow ◽  
Boiler Efficiency ◽  
Successful Design ◽  
The Common ◽  
Secondary Air ◽  
Bed Material ◽  
Fluidized Bed Combustor

The successful design and operation of a fluidized bed combustor requires the ability to control and mitigate ash-related problems. The main ash-related problem of biomass firing boiler is agglomeration. The fluidized bed boiler with steam capacity of 66 t/h (4 MPa, 440 °C) was started up at the Archangelsk Paper-Pulp-Plant in 2001. This boiler was manufactured by the Russian companies “Energosofin” and “Belenergomash” and installed instead of the existing boiler with mechanical grate. Some constructional elements and steam drum of existing boiler remained unchanged. The primary air fan was installed past the common air fan, which supply part of the air into 24 secondary air ports. First operating period shows that the bed material is expanded and then operator should increase the primary air rate, and the boiler efficiency dramatically decreases. This paper presents some results of our investigations of fuel, bed and fly ash chemical compositions and other characteristics. Special experiments were carried out to optimize the bed drain flow rate. The influence of secondary air supply improvement on mixing with the main flow and boiler efficiency are given.

The Study of Combustion of Municipal Waste in a Fluidized Bed Combustor

2006 ◽  
Vol 128 (2) ◽  
pp. 123-128 ◽  
Author(s):  
I. Gulyurtlu ◽  
T. Crujeira ◽  
M. H. Lopes ◽  
P. Abelha ◽  
D. Boavida ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Fluidized Bed ◽  
Combustion Efficiency ◽  
Solid Particles ◽  
Combustion Gases ◽  
Air Supply ◽  
Refuse Derived Fuel ◽  
Emission Limits ◽  
Bed Material ◽  
Fluidized Bed Combustor

The combustion behavior of municipal solid waste was studied in a pilot fluidized bed combustor. The waste was pelletized prior to its use. Both co-firing with coal and combustion of waste alone were under taken. The combustion studies were carried out on the pilot installation of INETI. The fluidized bed combustor is square in cross section with each side being 300mm long. Its height is 5000mm. There is a second air supply to the freeboard at different heights to deal with high volatile fuels. There was a continuous monitoring of the temperatures in the bed, as well as the composition of the combustion gases. The combustion gases leaving the reactor were let go through the recycling cyclone first to capture most of particulates elutriated out of the combustor. There was a second cyclone, which was employed with the aim of increasing the overall efficiency of collecting solid particles. The gaseous pollutants leaving the stack were sampled under isokinetic conditions for particulate matter, chlorine compounds, and heavy metals. The ash streams were characterized for heavy metals. The results obtained were compared with national legislation. The results obtained suggest that (i) the combustion efficiency was very high, (ii) there was an enrichment of ashes with heavy metals in the cyclones compared to the bed material, (iii) in general, the flue gas emissions were below the permited limits, and (iv) for the compliance with the new European directive for stricter emission limits adequate control devices, like bag filters, should be integrated with refuse derived fuel (RDF) combustion.

scholarly journals A new design method for fluidized bed conversion of largely heterogeneous binary fuels

2017 ◽  
Vol 21 (2) ◽  
pp. 1105-1118
Author(s):  
Pal Szentannai ◽  
György Pláveczky ◽  
Csaba Sándor ◽  
Tibor Szűcs ◽  
János Ősz ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Design Method ◽  
Calculation Methods ◽  
Cold Model ◽  
Minimum Fluidization Velocity ◽  
Binary Character ◽  
The Common ◽  
Fuel Particles ◽  
Fluidized Bed Combustor ◽  
Novel Design

Binary fuels of a fluidized bed combustor or gasifier are solids composed of two groups of particles. Their optimal handling in the same bed becomes rather difficult if their hydrodynamic properties differ by two orders of magnitude or more. Both of these fuel classes are directly fed into the reactor in most cases but the rather homogeneous fuel originally fed switches into a binary character inside the reactor in some others. A typical example of the latter case is the thermal utilization of rubber wastes. A novel design is proposed in the present paper by setting up a non-mixing, non-elutriated binary bed. Design criteria and procedure are formulated as well. One of the known calculation methods is proposed to be applied for assuring a segregated bed by means of choosing the bed components, geometry, and gas velocity conveniently. Cold model experiments are proposed to be applied for assuring no elutriation of the fine fuel particles and no sinking of the coarse fuel particles in the same time. A simple experiment is proposed for determining the common minimum fluidization velocity of the binary bed because known calculation methods can not be applied here.

scholarly journals The Corrosive Environment in the Fluidized-Bed Heat-Exchanger for CCGT Service

1983 ◽  
Author(s):  
M. A. Rocazella ◽  
I. G. Wright ◽  
C. F. Holt
Keyword(s):  
Heat Exchanger ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Fluidized Bed ◽  
Mechanical Damage ◽  
Oxygen Probe ◽  
Erosion Process ◽  
Bed Material ◽  
Fluidized Bed Combustor

Corrosion and combustion diagnostic data were gathered in Battelle’s 0.6m diameter coal-fired atmospheric fluidized-bed combustor (AFBC). Corrosion probes, constructed from ring specimens of candidate heat-exchanger alloys, were exposed to the fluidized-bed environment during three different combustion experiments (50%, 20% and 0% excess air). An in-situ oxygen probe was used to monitor the oxygen partial pressure at the exposure locations. Two different mechanisms of material degradation were identified, i.e., both corrosion and erosion. An adherent deposit of bed material formed on all areas of the corrosion probes. The corrosion behavior of the alloys beneath the deposit, and the corresponding corrosion product morphologies, appeared to correlate well with predictions based on the oxygen partial pressure measurements from the exposure location. The results suggest the oxygen probe may be a useful diagnostic tool for locating regions with high corrosive potentials. However, the upstream faces of the corrosion probes were subjected to enhanced mechanical damage, and this periodic removal of both the deposit and corrosion products resulted in significantly more metal degradation. Also, this corrosion/erosion process may locally deplete the alloy in chromium, leaving it susceptible to severe sulfidation and/or accelerated oxidation. It was suggested that these locations would be the first to experience heat-exchanger tube failure, and the coupled corrosion/erosion process would be the failure mechanism.

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