| 1. |
- Andersson, Bengt-Åke, et al.
(author)
-
Fluidized bed combustion of coals and alternative fuels
- 1985
-
In: Proc of the 8th International Conference on Fluidized-Bed Combustion held in Houston Texas USA, March 18-21, 1985. ; 2, s. 1019-1029
-
Conference paper (peer-reviewed)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.
|
|
| 2. |
- Andersson, Sven B, 1952, et al.
(author)
-
N2O-Emissions from Fluidized Bed Combustion
- 1988
-
In: Proceedings of IEA AFBC Technical Meting held in November 1988 in Amsterdam, The Netherlands.
-
Conference paper (other academic/artistic)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.
|
|
| 3. |
- Leckner, Bo G, 1936, et al.
(author)
-
Emissions from a circulating and a stationary fluidized bed boiler: A comparison
- 1987
-
In: Proc of the 9th International Conference on Fluidized-Bed Combustion held in Boston Massachusetts, USA, May 3-7, 1987. ; 2, s. 891-897
-
Conference paper (peer-reviewed)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.
|
|
| 4. |
- Leckner, Bo G, 1936, et al.
(author)
-
Primary Measures to Reduce the Emissions of Nitrogen Oxide in Circulating Fluidized Bed Boilers
- 1987
-
In: In proceedings of the Swedish Flame Days held 8-9 September 1987 in Studsvik, Sweden.
-
Conference paper (other academic/artistic)abstract
- During the combustion of coal in a circulating fluidized bed boiler the conversion of the fuelbond nitrogen to either nitrogen oxides or nitrogen can be influenced by design and operational measures. The paper gives a summary of results obtained in a series of tests on a 40 MW circulating fluidized bed boiler in Nykoping, designed by Gotaverken Energy. In this commercial boiler it was not possible to study the influence of primary to secondary air addition independent of thebed temperature. For this reason, a smaller boiler designed by the same manufacturer was adapted to permit independent variations of the primary air ratio and the bed temperature. The results from the 40 MW and the 8 MW boilers are compared and the influence of the distribution of the air supply and of the bed temperature on the reduction of nitrogen oxide emissions are discussed.
|
|
| 5. |
|
|
| 6. |
- Åmand, Lars-Erik, 1957, et al.
(author)
-
Ammonia Addition for NOx Reduction in Fluidized Bed Boilers
- 1988
-
In: Proceedings from the 1st International Conference on Industrial Furnaces and Boilers.
-
Conference paper (other academic/artistic)abstract
- Ammonia is added to the gases in the combustion chamber of fluidized bed briilers in order to investigate its effect ori the emission of nitrogen oxides. A stationary and a circulating fluidized bed boiler are used. In the stationaryfluidized bed boiler an addition corresponding to a (NH3/NOexit-molar ratio of 3 gives a 50% reduction of the NO emission. Larger doses lead to escape of ammonia and other disadvantages. In the circulating fluidized bed boiler no effect from injection of ammonia into the combustion chamber is noted. The ammonia is decomposed. If NH3 is to be used in circulating fluidized bed boilers it should be introduced in the particle-free gas after the particle separator.
|
|
| 7. |
|
|
| 8. |
- Åmand, Lars-Erik, 1957, et al.
(author)
-
Emissions of nitrogen oxide from a circulating fluidized bed boiler--the influence of design parameters
- 1988
-
In: In Circulating Fluidized Bed Technology II, Proceedings of the Second International Conference on Circulating Fluidized Beds, Compiégne, France, 14-18 March 1988. - 0080362257 ; , s. 457-464
-
Conference paper (peer-reviewed)abstract
- In a circulating bed of silica sand, char is the principal agent for the reduction of nitrogen oxide. The role of volatiles is not significant. Most features observed can be qualitatively explained as a consequence of the presence of char.In a circulating bed with limestone addition, the oxidation of nitrogen containing volatiles causes an increased emission of nitrogen oxide. This effect can be mitigated by avoiding excess addition of limestone in relation to the sulphur content of the fuel or by arranging the air supply in a suitable way, thus decreasing the oxidation of ammonia.
|
|
| 9. |
- Åmand, Lars-Erik, 1957, et al.
(author)
-
EMISSIONS OF NITROUS OXIDE (N2O) FROM FLUIDIZED BED BOILERS
- 1989
-
In: Proceedings of the 1989 (10th) International Conference on Fluidized Bed Combustion. - 0791803082 ; 1, s. 49-56
-
Conference paper (peer-reviewed)abstract
- ABSTRACT Measurements of emissions of nitrous oxide (N20) have been carried out on two kind of fluidized bed boilers. One of them, a circulating fluidized bed boiler has been run with three kind of fuels at different operating conditions. The results of the measurements show that the emission of N20 depends on bed temperature and fuel. The temperature dependence is explained by the strong influence of temperature on the rate of destruction of nitrous oxide by radicals in the gas phase.
|
|
| 10. |
- Åmand, Lars-Erik, 1957, et al.
(author)
-
NOx Begränsning vid Förbränning i Fluidiserad Bädd
- 1988
-
In: Proceedings till Första Nordiska Konferensen om Svaveldioxid- och Kväveoxid- begränsning vid Förbränning av Fasta Bränslen som hölls vid Danmarks Tekniska Högskola i Lyngby, Danmark i oktober 1988.
-
Conference paper (other academic/artistic)abstract
- Sedan senaste Nordiska seminariet om NOx-begränsning i november 1986 har ett intensivt arbete bedrivits inom området NOx-begränsning i fluidiserad bädd vid institutionen för Energiteknik CTH. Totalt har tre eldningssäsonger ägnats åt omfattande mätprogram på storskaliga fluidbäddanläggningar. Nedan presenteras först en strategi för kväveoxidbegränsning som bygger på dagens kunskap om hur kväveoxider bildas och reduceras. Vidare ges ett försök att visa hur denna strategi tillämpats genom de olika mätprogrammen och slutligen redovisas mer ingående de viktigaste resultaten från senaste eldningssäsongen.
|
|
