活性焦烟气脱汞的试验研究与数值模拟

Experimental research and mathematics models of removing mercury in flue gas by activated coke

采用固定床吸附系统,对自制褐煤活性焦的脱汞性能进行了试验研究,研究发现自制活性焦对烟气中Hg0有一定的吸附能力,随着Hg0的入口浓度的增加,活性焦质量的增加,活性焦的吸附量也在增加。40mg时3号活性焦由10ng/min汞入口浓度时26.68%的最大吸附效率提高到40ng/min汞入口浓度时的53.12%。10ng/min汞入口浓度时3号活性焦在40mg时的最大吸附效率为26.68%,而在80mg时吸附效率提高到43.2%。烟气中的SO2、NO气体对活性焦吸附汞有一定的促进作用。在试验的基础上建立了固定床吸附系统的数学模型,基于Lanmguir吸附系数,考虑吸附过程中颗粒内、外的传质控制过程,建立质量平衡方程。通过Matlab模型计算,计算结果与试验结果基本吻合,计算的活性焦脱汞效率要优于试验数值,计算的是理想情况下活性焦对汞的吸附效率,实际情况会有所降低。

An experiment was conducted to study the effects of lignite activated coke on mercury adsorption by u- sing a bench - scale fixed bed, The results show that the lignite activated coke has some adsorption capacity for mercury in flue gas, the activated coke adsorption rate increases with increasing of entrance mercury concentra- tion and the quality of activated coke. The maximum adsorption efficiency of No. 3 activated coke is 26.68% at 10ng/min entrance mercury concentration and increased to 63. ]2% at 40 ng/min entrance mercury concentra- tion. When the entrance mercury concentration is 10 ng/min,the maximum adsorption efficiency of No. ,~ activa- ted coke is 26.68% at 40 mg quality of activated coke enhanced to 43.2% at 80mg quality of activated coke. The SO3 ,NO in flue gas can improve mercury adsorption capacity of activated coke. A theoretical model was devel- oped to predict mercury removal in bench - scale fixed bed adsorption system at different conditions. Base on the Lanmguir adsorption coefficient,considering the mass transfer control process in and outside the particles of the absorption process,established the mass balance equation. The simulation results by Matlab indicated that the model is capable of describing the test data. The simulation results is superior to the test data,for the simula- tion is the ideal circumstances,the actual situation of the adsorption efficiency will be reduced.