METHOD AND DEVICE FOR DENITRATING PRESSURE FLUIDIZED BED BOILER

摘要

PROBLEM TO BE SOLVED: To ensure high denitration efficiency even in the case when waste gas temp. is low by dedusting the waste gas subjected to desalting and desulfurizing treatment by a ceramic filter, selectively subjecting nitrogen oxides in the waste gas to non- catalyzed reduction with a denitrating and reducing agent and also by allowing the waste gas to contact with denitrating and reducing catalyst. SOLUTION: The fuel such as coal is burned together with a desalting agent and a desulfurizing agent at a pressure fluidized bed boiler 1. Then the waste gas generated in accordance with the combustion is fed into a cyclone 2 to separate coarse particle ash and the dedusted high temp. waste gas is fed into a ceramic tube filter 4 at the outside of a pressure vessel 3 to remove ash dust. Then, the dedusted waste gas is sent to a post flow waste gas flow passage 5 and a denitrating and reducing agent soln. is jetted and injected from a denitrating and reducing agent soln. injection pipe 11. At this time, the temp. of waste gas flow passage 5 is kept appropriately in 450-900 deg.C. Moreover, the waste gas is fed to a denitrating reaction column 7 at 150-500 deg.C to subject residual NOx to catalytic reduction by using active ammonia as the denitrating and reducing agent.