| 1. |
- Andersson, Bengt-Åke, et al.
(författare)
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Fluidized bed combustion of coals and alternative fuels
- 1985
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Ingår i: Proc of the 8th International Conference on Fluidized-Bed Combustion held in Houston Texas USA, March 18-21, 1985. ; 2, s. 1019-1029
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Konferensbidrag (refereegranskat)abstract
- The 16 MW demonstration plant at Chalmers University of Technology was designed to burn coal but measures were taken also to allow the use of alternative fuels. Results of comparative tests, with bituminous coal and alternative fuels, brown coal, peat, and wood chips, are presented. The combustion characteristics of the various fuels are illustrated with temperature and heat flux profiles in the freeboard. It is found that the volatile fuels tend to burn to a large extent above the bed and secondary air is necessary to complete the combustion. However, -if secondary air is used, a combustion efficiency close to 100% is easily obtained. Bituminous coal, on the other hand, does not readily burn with a high combustion efficiency in the boiler used.
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| 2. |
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| 3. |
- Andersson, Bengt-Åke, et al.
(författare)
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Particle mass flux in the freeboard of a fluidized bed boiler
- 1989
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Ingår i: Powder Technology. - 1873-328X .- 0032-5910. ; 58:1, s. 25-37
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Tidskriftsartikel (refereegranskat)abstract
- The flux of descending particles has beenmeasured in the freeboard of a fluidized bedboiler. The lateral and vertical distributionsof the flux were studied and the influence ofthe superficial gas velocity and the static bedheight analyzed. A tube bundle located in thebed surface region made it possible to investigatethe effects of tubes on the entrainmentof particles from the surface of the bed.The particle flux was relatively constantacross the freeboard except near the wall,where it was about twice as large as the average.In the vertical direction, the flux decreasedexponentially with height exceptclose to the bed, where the rate of decay wasless than at higher elevations. The tube bundlewas found to inhibit the splashing of bedparticles when the bed is below the tubes.A model is used for the estimation of thevertical particle flux and concentrationprofiles in the freeboard. It is based on separatetreatment of small and coarse particlesand calculation of trajectories of ejected bedparticles. The calculated freeboard valuesdescribe the experimental data satisfactorilyexcept close to the bed, where a considerablediscrepancy is observed.
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| 4. |
- Andersson, Bengt-Åke, et al.
(författare)
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Use of a conductivity heat-flow meter in fluidised-bed boilers
- 1989
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Ingår i: Transactions of the Institute of Measurement and Control. - : SAGE Publications. - 1477-0369 .- 0142-3312. ; 11:2, s. 108-112
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Tidskriftsartikel (refereegranskat)abstract
- The usefulness of a conductivity type of heat-flow meter for measurements in fluidised-bed boilers is investigated. The design and the calibration of the meter are described. Results from measurements of the local heat tranfer at the walls of fluidised-bed boilers are presented. An error analysis shows that the accuracy of the heat-flow meter is +-9%.
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| 5. |
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| 6. |
- Andersson, Sven B, 1952, et al.
(författare)
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N2O-Emissions from Fluidized Bed Combustion
- 1988
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Ingår i: Proceedings of IEA AFBC Technical Meting held in November 1988 in Amsterdam, The Netherlands.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Nitrous oxide, N20, is formed during combustion. In flames the N20 is removed because of the fast destruction at high temperatures. At the temperatures of fluidized bed combustion the destruction is much slower and N20 will leave the system, normally at a concentration of 50-200 ppm when burning coal. Using the results of the preliminary model in a CFB, it can be assumed that:- N20 is formed from char nitrogen in the bottom bed because of reactions in the pores of the particle. - Only some N20 is formed when NO is reduced during its journey up through the combustion chamber. - N20 is formed from HCN. This is a slow process (taking seconds) and it therefore takes place principally above the bottom bed.
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| 7. |
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| 8. |
- Johnsson, Filip, 1960, et al.
(författare)
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Pressure distribution and particle concentration in bubbling fluidized beds
- 1989
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Ingår i: Proc of the 6th International Conference on Fluidization. - 0816904596 ; 6, s. 419-426
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Konferensbidrag (refereegranskat)abstract
- The expansion of and particle concentration in large-particle (>0.5 mm) bubbling beds, fluidized at high gas velocities (U-Umf>1 m/s) have been studied in a boiler with 10 m2 hot bed and in a cold two-dimensional bed. The significantly different behaviour of a freely bubbling versus a tube-filled bed at high gas velocity is demonstrated.
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| 9. |
- Leckner, Bo G, 1936, et al.
(författare)
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Emissions from a 16 MWth FBC boiler
- 1982
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Ingår i: The 7th International Conference on Fluidized Bed Combustion. ; 1, s. 514-524
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Konferensbidrag (refereegranskat)
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| 10. |
- Leckner, Bo G, 1936, et al.
(författare)
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Emissions from a circulating and a stationary fluidized bed boiler: A comparison
- 1987
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Ingår i: Proc of the 9th International Conference on Fluidized-Bed Combustion held in Boston Massachusetts, USA, May 3-7, 1987. ; 2, s. 891-897
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Konferensbidrag (refereegranskat)abstract
- A comparison is presented of the emissions of sulphur dioxide and nitrogen oxide from a stationary fluidized bed boiler and a circulating fluidized bed boiler. The boilers used for the comparison were the 16 MW stationary bed boiler at Chalmers University and the 40 MW circulating bed boiler at Nyköping (Sweden). In order to focus the comparison on the design of the boilers and to eliminate differences caused by fuel and sorbent, both boilers were run with the same coal and limestone. The influence of the operating conditions on the emissions is studied. The main influencing parameters are: Limestone feed rate, bed temperature, and excess air ratio, One of these parameters was varied at a time while the others were kept constant. The results show that both types of boiler can be run conveniently with low emissions of sulphur and nitrogen oxides. The sulphur absorption is superior in the circulating bed boiler, where an almost complete absorption is attained at a calcium-to-sulphur molar ratio of 2 , Without limestone addition, and at bed temperatures below 850°C, the nitrogen oxide emission from the circulating bed boiler is as low as is reasonable, achieving the equilibrium value of nitrogen oxide in oxygen and nitrogen. With limestone addition, however, considerably higher emission values are obtained in the circulating bed boiler, whereas the corresponding emission from the stationary bed boiler is not affected by limestone. In addition to the studies of sulphur and nitrogen oxide emissions, the influence of limestone on the emissions of mercury, chloride, and fluoride was investigated.
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