Study On The Preparation Of Activated Carbon For Pollutant Treatment From Coal Poly-generation Semi-coke

The coal poly-generation technology based on pyrolysis is a clean and efficient coal utilization technology.In the production process of coal poly-generation system,coal semi-coke is one of the important intermediate products,coal semi-coke is one of the most important intermediate products,which has a certain pore structure and can be converted into activated carbon.In order to increase the added value of the by-product coal semi-coke from poly-generation,this work uses coal semi-coke as a raw material to prepare granular activated carbon for pollutant treatment,and studies on flue gas desulfurization,the adsorption performance of phenol and heavy metal ions in water.The main work and research results are as follows:（1）Activated carbon was prepared from coal poly-generation pyrolysis semi-coke by 4activation methods:steam activation,CO₂ activation,K₂CO₃/steam combined activation,and flue gas activation.The factors of activation dose,activation temperature,and activation time were analyzed by orthogonal test method,and the optimal preparation conditions were obtained.Activated carbon with different pore size distributions were prepared.Steam activation tends to produce mesopores,and activated carbon with a mesoporosity of 63%can be obtained;K₂CO₃/steam activation tends to produce micropores,and an activated carbon with a microporosity of up to 83%can be obtained.This work also analyzed the reaction mechanism of combined activation.The introduction of water vapor can promote the activation of K₂CO₃,so that combined activated activated carbon has a developed microporous structure;and K₂CO₃ has a certain inhibitory effect on the ability of steam activation to produce mesopores.As a result,the mesopore and total pore volume are lower than that of single steam activation.（2）The activated carbon prepared by different activation methods was tested for SO₂adsorption and desorption.SO₂ adsorption mainly occurs in the micropore structure of the activated carbon.Therefore,the combined activated activated carbon with developed micropores has the highest desulfurization value,reaching 31.24mg/g.The desulfurization capacity of activated carbon made by flue gas is slightly second,with a desulfurization value of 27.48 mg/g.However,this preparation method is based on local materials,simple operation,which has huge industrial application potential.The desulfurization effect of steam activated carbon and CO₂activated carbon are similar,and they all reach the national standard of activated carbon for desulfurization and denitration.（3）The activated carbon prepared by different activation methods has been tested for the adsorption of Cd²⁺and phenol in water.The results show that the micropores with a pore diameter of 1-2 nm play a major role in the adsorption of phenol,so the combined activated activated carbon with developed micropores has the best adsorption effect on phenol,reaching 105.2 mg/g.Cd²⁺in water is easy to form hydrated ions,and activated carbon materials with a larger pore structure are required.Water vapor activated carbon with developed mesopores has the largest adsorption capacity for Cd²⁺,reaching 22.54 mg/g.