榆林长焰煤制备活性炭试验研究

Experimental research on preparation of active carbon using Yulin long flame coal

为优化煤基活性炭制备工艺参数,以陕北榆林原煤制备活性炭,设计搭建了制备活性炭的炭化、活化试验装置,开展了影响活性炭吸附性能的因素试验,采用正交试验方法分别对炭化过程和活化过程进行试验,以化工废水COD去除能力作为主要评价手段确定最优工艺参数,并对最优工艺参数制备的活性炭进行BET和SEM的表征分析,查找影响COD去除能力的主要因素。结果表明:以红柳林原煤为原料,通过炭化活化工序制备活性炭,原煤炭化工艺因素的影响程度依次为炭化温度、升温速率、炭化停留时间,最佳炭化工艺参数为炭化温度600℃、升温速率2℃/min、炭化时间30 min,该条件下炭化料的碘吸附值为135.66 mg/g;说明原煤经炭化后,炭化料有初步的吸附能力和孔隙结构,有利于进一步活化成活性炭;炭化料活化工艺因素的影响程度依次为活化温度、活化时间、蒸汽通入速率,最佳活化工艺参数为活化温度850℃、活化时间3 h、蒸汽通入速率15 L/min;所制备的活性炭COD去除率最高为70.97%,能有效处理某化工废水;活性炭的比表面积为671.50 m^2/g,同时存在数量相当的微孔和中孔,微孔孔径分布以0.7 nm为主,中孔孔径分布以5~20 nm为主。研究表明,通过优化工艺参数可以利用榆林当地煤加工生产中孔发达的活性炭,其对化工废水COD具有较强的去除能力。

In order to optimize preparation parameters of coal based activated carbon using Yulin coal as the raw material,the carbonization and activation test equipment for preparation of activated carbon was designed and built.The experiment factors influencing the activated carbon performance were carried out.The orthogonal test method was used to test the carbonization process and activation process.The COD removal capacity of chemical wastewater was used as the main evaluation method to determine the optimal process parameters.The structure characteristic of the activated carbon obtained under the optimal process parameters were analyzed by BET and SEM test to find out the main factors affecting the COD removal ability.The results show that activated carbon is prepared by using Hongliulin coal as raw material by the pyrolysis activation method.The influence degree of raw coal pyrolysis process factors are pyrolysis temperature,heating rate,and pyrolysis residence time,successively.The semi-coke iodine adsorption value is 135.66 mg/g in the best pyrolysis process parameters with 600℃,2℃/min,and 30 min.It shows that the semi-coke formed by the coal pyrolysis process has owing preliminary adsorption capacity and pore structure,which is conducive to further activation to turn into the activated carbon.The influence degree of the semi-coke activation process factors in order are activation temperature,activation time,and steam penetration rate.The best activation process parameters are activation temperature of 850℃,activation time of 3 h,and steam introduction rate of 15 L/min.The highest chemical wastewater COD removal rate of the activated carbon obtained in the best activation condition is 70.97%,which can be treat effectively.The specific surface area of the activated carbon is 671.50 m^2/g,and there are both micropores and mesopores in different quantity.The distribution of micropores is mainly 0.7 nm,and the distribution of mesopores is 5-20 nm.The research indicates that the Yulin coal can be processed to produce activated carbon with rich mesopores under optimizing process parameters,which can effectively remove chemical wastewater COD.