Experimental Study on the Tangentially Fired System with the Reverse Tangential Rich Primary Air

摘要

The high combustion efficiency, low NO_x emission and stable ignition were the principal demands to the tangentially fired system. In order to burn the lean coal with high ash-content, high sulfur-content, low ash softening-temperature and near 20% V_(daf), a tangentially fired system with the reverse tangential rich primary-air as a novel tangentially fired system was presented and applied in a 300MW boiler. In comparison with the conventional tangentially fired system, there was the following characteristics: (1) improved horizontal bias burner; (2) the reverse tangential rich primary-air; (3) small diameter of imaginary-circle; (4) overture air. The results of the experiment and application of the new tangentially fired system in a 300MW boiler showed: slagging and high temperature corrosion could be avoided effectively; the superheater and reheater were in safe operation; unburned heat loss was less than 2% at ECR; the boiler could operate at 35-100% BMCR without oil support; the NO_x emission was low. The new tangentially fired system was one of the advanced high combustion efficiency, low NO_x emission and cyclic-load flexibility.