| 1. |
- Johnsson, Filip, 1960, et al.
(author)
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Fluidization regimes in fluidized bed boilers
- 1992
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In: Proc of the 7th Engineering Foundation Conference on Fluidization. - 0939204479 ; 7, s. 471-478
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Conference paper (peer-reviewed)abstract
- The fluidization regime of the bottom bed has been investigated in a circulating fluidized bed at ambient temperature. A few measurements have also been made in a 12 MWth CFB boiler at normal operation temperature. It was found that the bottom bed was of a bubbling type for all conditions studied.
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| 2. |
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| 3. |
- Johnsson, Filip, 1960, et al.
(author)
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Expansion of a freely bubbling fluidized bed
- 1991
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In: Powder Technology. - 1873-328X .- 0032-5910. ; 68:2, s. 117-123
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Journal article (peer-reviewed)abstract
- The expansion of a freely bubbling fluidized bed is studied over a range of particle properties and gas velocitiesthat applies to fluidized bed boilers. A bed expansion model is derived from a modified two-phase flow model.The results from the model are compared with measurements in both a cold two-dimensional bed and a 16MW,, fluidized bed boiler, as well as with data found in the literature. The model represents experimentalresults for sand particles of a diameter ranging from 0.15 mm to 4.0 mm and with gas velocities up to 3 m s-‘.
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| 4. |
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| 5. |
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| 6. |
- Lyngfelt, Anders, 1955, et al.
(author)
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Dependence of Sulphur Capture Performance on Air Staging in a 12 MW Circulating Fluidised Bed Boiler
- 1993
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In: Gas Cleaning at High Temperatures, Eds. R. Clift and J.P.K. Seville, Blackie Academic & Professional, Glasgow, ISBN 0 7514 0178 1.. - 0751401781 ; , s. 470-491
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Book chapter (other academic/artistic)abstract
- Three cases of air staging were examined in a 12 MW circulating fluidised bed boiler: i) no staging, ii} normal staging and iii) intensified staging. The conditions inside the combustion chamber were investigated by zirconia cell measurements of the oxygen partial pressure, 0.35, 0.65 and 8 m above the bottom air distributor plate. A significant effect of the degree of staging was seen in the two lower locations: At 0.65 m height the fraction of time under substoichiometric conditions was low in the no-staging case (2-35%), at normal staging it was 70-90%, whereas at intensified staging it was 100Y.. At 0.35 m height, i.e. in the dense bed, a similar effect was seen, although the fraction of time under reducing conditions was lower. The fraction of time under reducing conditions was low in the top of the combustion chamber in all three cases . The increase in the fraction of time under reducing conditions with a higher degree of staging is associated with a decrease in sulphur capture. It is assumed that a release of SO2 from CaSO4 takes place during the transitions between oxidising and reducing conditions. Thus, the rapid alternations between oxidising and reducing conditions, as seen with the zirconia cell, offer an explanation of the reductive decomposition and, accordingly, of the dependence of sulphur capture on temperature and on the extent of staging.
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| 7. |
- Zhang, Wennan, 1962, et al.
(author)
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Characteristics of the Lateral Particle Distribution in Circulating Fluidized Red Boilers
- 1993
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In: Proc of the 4th International Conference on Circulating Fluidized Beds. ; , s. 266-273
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Conference paper (peer-reviewed)abstract
- The local time-averaged solids volume fraction was measured in the 12MW~1 Circulating Ruidized Bed (CFR) boiler at Chalmers University of Technology. It was found that the corelwall-layer structure of the flow pattern observed in small-scale beds also characterizes large-scale CFR boilers. The local solids volume fractions close to the wall and in the core region of the furnace were found to be directly proportional to the cross-sectional average solids volume fraetjon, c, as ohtained from pressure rneasurements. If the shape of the membrane-tube wall is taken into account, the relationship for the solids fraction close to the wall (related to a plane wall) is c~=3.6c, which is similar to that reported in literature for plain walls.
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