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

摘要

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 Nm(3)/h fly ash entrained-flow gasifier, air/particle flow characteristics under various burner centerline angles (75 degrees, 72 degrees, and 69 degrees) are obtained by a particle dynamics anemometer. The results show that when the burner centerline angles are 75 degrees, 72 degrees, and 69 degrees, 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 degrees to 69 degrees, 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 degrees is recommended. (C) 2021 Elsevier Ltd. All rights reserved.