Patent EA-004854-B1 (EA)
Title: Arrangement and method for heating gas in a gas duct in connection with continuously operated sintering
Inventor: NIEMELA PEKKA
IPC: F27D99/00
Filed: 2001-09-05
Abstract: 1. An arrangement for heating gas in a gas circulation duct (4,5) in connection with continuously operated sintering, characterized in that a part of the gas circulation duct (4,5), placed above a sintering belt (1), is formed as a burner ring (16,17) comprising at least one burner unit (21) directed inwardly from the circumference of the gas circulation duct. 2. An arrangement according to claim 1, characterized in that the burner ring (16,17) is formed on the horizontal part of the gas duct (4,5). 3. An arrangement according to claim 1, characterized in that above the sintering belt (1), there are placed several gas circulation ducts (3,4,5), among which at least one (4,5) is provided with a burner ring. 4. An arrangement according to claim 1, characterized in that the burner unit (21) comprises a feed duct (23,24) for at least one fuel. 5. An arrangement according to claim 1, characterized in that the burner unit (21) comprises feed ducts (23,24) for at least two different fuels. 6. An arrangement according to claim 1, characterized in that the feed ducts (23,24) are mainly placed inside the burner ring (16,17). 7. An arrangement according to claim 1, characterized in that the burner units (21) of the burner ring comprise at least one ignition burner (22). 8. An arrangement according to claim 1, characterized in that the ignition burner (22) is provided with hydraulic control which can be drawn in, to the protection of the masonry. 9. An arrangement according to claim 1, characterized in that the burner units (21) of the burner ring comprise at least one flame guard (25). 10. An arrangement according to claim 1, characterized in that the burner ring (4,5) comprises 2-6 burner units (21). 11. An arrangement according to claim 1, characterized in that the burner units (21) are placed in the burner ring (16,17) at an angle of 45-100 with respect to each other. 12. An arrangement according to claim 1, characterized in that the burner ring (16,17) is provided with a protuberance (27) that is directed inwardly from the inner edge of the ring. 13. An arrangement according to claim 12, characterized in that at the protuberance (27), the inner diameter of the burner ring (16,17) is 10-40% smaller than the inner diameter of the straight part of the gas duct (4,5). 14. A method for heating gas in a gas circulation duct (4,5) in connection with continuously operated sintering, characterized in that gas is heated in a burning zone (16,17) of a gas circulation duct (4,5), placed above a sintering belt (1), up to a temperature of 1,000-1,600 degree C; when the fuel used for heating is ignited, the combustion air needed for burning is obtained from the gas flowing in the gas circulation duct, and fuel is fed in the burning zone at least from one burner unit (21) directed inwardly from the inner edge of the gas circulation duct. 15. A method according to claim 14, characterized in that the burner ring (16,17) is located in the horizontal part of the gas circulation duct (4,5). 16. A method according to claim 14, characterized in that in each unit (21) of the burner ring (16,17), there is provided a feed duct (23,24) for at least one fuel. 17. A method according to claim 14, characterized in that in each unit (21) of the burner ring (16,17), there are provided feed ducts (23,24) for at least two different fuels. 18. A method according to claim 14, characterized in that the feed ducts (23,24) of the burner unit (21) are mainly protected by the burner ring (16,17) design. 19. A method according to claim 14, characterized in that the gases in the circulation duct are made turbulent and mixed with the fuel by means of a constriction spot (27) arranged in the burner ring (16,17).