Method and arrangement for optimising combustion conditions in a fluidised-bed boiler
AssigneeValmet Technologies Oy
InventorsMikko Varonen, Tero Luomaharju
Life of this patent
Estimating the term…
Abstract
A method and an arrangement for optimizing combustion conditions in a fluidized-bed boiler, in which combustion gas is fed at two or more height levels, the first of which is a primary level (P) which is located at the height of a furnace bottom and the second is a secondary level (S) which is located above fuel feed height (F), above which secondary level (S) there can be still other combustion gas feed levels (T, . . . ). At least one combustion gas feed level (P, S, T, . . . ) is fed at different points of the furnace (11) in its horizontal direction with combustion gases having different oxygen contents such that zones of different oxygen content can be formed in the horizontal direction of the furnace (11).
Claims8
A method for optimising combustion conditions in a fluidised-bed boiler where oxygenous combustion gas is fed at two or more height levels, the first of which is a primary level (P), which is located at the height of a furnace bottom, and the second is a secondary level (S), which is located close to fuel feed height (F), above which secondary level (S) there can be still other combustion gas feed levels (T, . . . ), characterised by producing combustion gases (15a, 15b;
- 16a, 16b;
- 28a, 28b) having different oxygen contents by mixing together air and pure oxygen or circulated flue gas at such a ratio that each combustion gas is provided with a desired oxygen content, and by feeding at least one of said combustion gas feed levels (P, S, T, . . . ) at different points in the horizontal direction of the furnace with combustion gases (15a, 15b;
- 16a, 16b;
- 28a, 28b) having different oxygen contents such that zones of different oxygen contents are formed in the horizontal direction of the furnace.
An arrangement for optimising combustion conditions in a fluidised-bed boiler, which arrangement comprises means for feeding oxygenous combustion gas at two or more height levels, the first of which height levels is a primary level (P), which is located at the height of a furnace bottom, and the second is a secondary level (S), which is located close to fuel feed height (F), above which secondary level (S) there can be still other combustion gas feed levels (T, . . . ), wherein the combustion gas feed arrangements comprise means for mixing air and pure oxygen or circulated flue gas together such that the combustion gas (15a, 15b;
- 16a, 16b;
- 28a, 28b) is provided with a desired oxygen content, and that at least one of said combustion gas feed levels (P, S, T, . . . ) is provided with combustion gas feed arrangements (26a, 26b, 31a, 31b;
- 32a, 32b) that are arranged to feed at different points in the horizontal direction of the furnace combustion gases (15a, 15b;
- 16a, 16b;
- 28a, 28b) having different oxygen contents such that zones of different oxygen contents can be formed in the horizontal direction of the furnace.
Dependencies are inferred from the claim text.