COMBUSTION SYSTEM AND METHOD FOR COOPERATIVE CONTROL OF IN-FURNACE DESULPHURIZATION AND DENITRATION IN CFB BOILER

摘要

Provided are a combustion system and method for cooperative control of in-furnace desulphurization and denitration in a CFB boiler. The combustion system comprises a hearth (1), a coal feeding port (3), a primary air chamber (5), a secondary air box (4), a secondary air pipe (8), a cyclone separator (2), a material returning mechanism (13) and material returning pipes (6, 7) for connecting the material returning mechanism (13) with the hearth (1). The material returning pipes (6, 7) include an upper-layer material returning pipe (7) and a lower-layer material returning pipe (6), the tail end of the upper-layer material returning pipe (7) is higher than that of the lower-layer material returning pipe (6); the upper-layer material returning pipe (7) is connected with the material returning mechanism (13) and the dilute phase zone of the hearth (1), and the lower-layer material returning pipe (6) is connected with the material returning mechanism (13) and the dense phase zone of the hearth (1); and a charging port (12) is provided on the upper-layer material returning pipe (7). The method comprises: a desulphurizing agent is introduced from the charging port (12) on the upper-layer material returning pipe (7), and the cyclone separator (2) separates high-temperature solid materials in the hearth (1) from the flue gas, wherein a part of the high-temperature solid materials are sent into the dilute phase zone of the hearth (1) via the upper-layer material returning pipe (7); and a part of the high-temperature solid materials are sent into the dense phase zone of the hearth (1) via the lower-layer material returning pipe (6).