Lignite temperature distribution during low temperature carbonization process in an industrial width carbonization furnace

Abstract

Highly efficient industrial carbonization furnace with a width of 500mm was established in this study. The characteristics involving temperature increase, variation rules for the thermal conductivity of coal, and the temperature distribution model of the coking chamber in a low temperature carbonization process of lignite performed in the furnace were studied. The results showed that the temperature profile of coking chamber could be divided into three zones: the near, middle, and remote zones. The distinguishing index between near and middle zones was a low-temperature-constant (80–100°C) stage. ∂2T∂t2=0,∂T∂t=n were the distinguishing indices between the middle and remote zones. When the lignite was carbonized in a single heat source furnace wall coking chamber, the temperature distribution followed the Chen–Clayton equation. Moreover, the effective thermal conductivity coefficient of coal was affected by the carbonization time and heat transfer distance, which exhibited a unimodal distribution during the carbonization process. Furthermore, the classic one-dimensional unsteady temperature distribution model with heat resource factor and the correction equation of heat temperature thermal conductivity were established. After being corrected, the calculated temperature curve was consistent with the measured temperature curve. The model was confirmed by the residual analysis and the error points were in well agreement with the normal distribution.