Influence of the multi-burner bias angle on the air/particle flow characteristics in an improved fly ash entrained-flow gasifier

The counter-biased burner arrangement has been confirmed to strengthen mixing between burner jets and reduce the risks of firebrick burning in the fly ash entrained-flow gasifier. The burner centerline angle, which represents the bias angle combination of multiple burners, is a critical factor that requires further experimental investigation to boost the air/particle mixture extent in the improved gasifier. In a 1:8-scale model of the 80,000 Nm³/h fly ash entrained-flow gasifier, air/particle flow characteristics under various burner centerline angles (75°, 72°, and 69°) are obtained by a particle dynamics anemometer. The results show that when the burner centerline angles are 75°, 72°, and 69°, the ratio of total particle volume flux in the near-wall region to the total particle volume flux in the measurement zone is 45.9%, 65.3%, and 57.8%; the ratio of the reflux particle quantity in the mixing zone is 0.88:1.27:1. As the burner centerline angle drops from 75° to 69°, the mixing zone radius decreases from 0.275 to 0.174. Simultaneously, the dimensionless difference of particle volume concentration gradually decreases, indicating that lowering burner centerline angle effectively improves the air-particle mixture extent between the burner jets. An optimal burner centerline angle of 69° is recommended.