A 2000 t/day HNCERI
(Huaneng Clean Energy Research Institute) entrained-flow
pulverized coal gasifier suffers from the problem of a high ash–slag
ratio. An appropriate bias angle of the burners is the key to solve
this issue for the gasifier with a specific structure. A random pore
model considering bulk and pore diffusion effects was extended by
user-defined function to describe the gasification reactions. The
simulation of the gas flow and char gasification characteristics under
different bias angles (0, 1.5, 2.5, 3.5, and 4.5°) of the four
burners in the first stage was conducted. The simulation results showed
favorable agreement with the industrial data. The evaporation, devolatilization,
and char oxidation mainly occurred in the first-stage jet zone, and
the upflow and downflow zones are dominated by the gasification reactions.
The bias angles of the burners mainly affect the scale of gasification
reaction zones. As the bias angles increased from 0 to 4.5°,
the gas temperature at the slag tap hole decreased from 1880 to 1500
K. The carbon conversion efficiency of the first stage decreases and
that of the second stage increases with the bias angle increasing.
An optimal bias angle of 2.5° is recommended for the HNCERI gasifier
with a total carbon conversion efficiency of 98.16%.