煤粉等温燃烧挥发分、焦炭分阶段SO_2释放规律研究

Experimental Study on the SO_2 Emission of Volatile and Char During the Isothermal Combustion of Pulverized Coal

利用自制SO_2测量系统,对煤粉及煤焦进行了等温燃烧实验,针对挥发分与焦炭分阶段SO_2释放规律研究了温度、煤质、氧浓度对SO_2释放的影响。结果表明:煤粉等温燃烧过程中,经历了挥发分SO_2的快速释放和焦炭SO_2的缓慢释放,挥发分SO_2和焦炭SO_2的释放存在一定的重叠时间。随着温度升高,焦炭SO_2转化率显著增大,挥发分SO_2转化率变化不大。不同煤种SO_2转化率差异明显,低阶煤挥发分S0_2的转化率较低,塔山煤和印尼煤的焦炭SO_2转化率显著低于阳泉煤。随着氧浓度升高,挥发分和焦炭SO_2释放速率加快,挥发分SO_2和焦炭SO_2转化率均升高,挥发分SO_2的释放对氧浓度的变化更为敏感。

By means of a self-designed SO2 measure system, the emission characteristics of SO2 in the two stages of devolatilization and char combustion were investigated via isothermal combustion of pulverized coal and char and considering the influence of temperature, coal quality and oxygen concentration on SO2 emission. The results indicated that there were a quick emission of volatile SOz and a slow emission of char SO2, and the emissions of volatile SO2 and char SO2 were simultaneous at some time. With the rise of temperature, the emission rates of char SO2 increased significantly, however not remarkably for the volatile SO2. There were distinctly differences of sulfur conversion between different kinds of coal. Low-rank coals have a low conversion of volatile sulfur, and the conversions of char sulfur of Tashan coal and Yinni coal were lower than that of Yangquan coal, significantly. With the increase of O2 concentration, the emission rates of volatile SO2 and char SO2 increased, and the conversions of volatile SO2 and char SO2 raised, too. And the emission of volatile SO2 was more sensitive to the change of O2 concentration.