Study On Preparation Of Columnar Activated Carbon From Changji Bituminous Coal In Xinjiang

Xinjiang bituminous coal is rich in resources,and has complete types,low ash content and good reactivity.There is a great room for development of activated carbon from Xinjiang bituminous coal.In order to prepare columnar activated carbon with high hardness and high adsorption performance,the preparation of activated carbon from Xinjiang bituminous coal was studied in this paper.The specific research contents are as follows:In this paper,the non-coked coal,weakly cohesive coal and gas fat coal in Changji area of Xinjiang were choosed.The D-optimal mixing design experiment method was used to perform multiple polynomial regression fitting on the hardness,iodine number and methylene blue adsorption of the active carbon.A regression model among the proportion of coal blending and three indicators was established.Using the model to optimize the three indexes simultaneously,the optimal proportion of coal blending was obtained,and the amount of asphalt added was optimized through experiments.The results show that the best proportion of ingredients is non-caking coal:weakly caking coal:gas fat coal=10:85:5,and asphalt added 5%.According to the best proportion of ingredients,the carbonization temperature,carbonization heating rate and activation temperature parameters were studied.The indexes are columnar activated carbon hardness,iodine number,methylene blue adsorption and pore distribution.The optimum conditions were:carbonization temperature 600°C,carbonization heating rate 12°C/min,activation temperature 900°C.The performance of the columnar activated carbon is:when the burn-off is 65.3%,the hardness is 96.3%,the iodine number is 1097.6 mg/g,the methylene blue adsorption is 304.4 mg/g,the specific surface area is 1321.1 m~2/g,the pore volume is0.7756 cm~3/g,and the average pore diameter is 2.3484 nm.According to the experimental data,for the Xinjiang Changji bituminous coal used in the experiment,in order to meet the 95%hardness requirement,the caking index of the raw material must reach 5%or more,and the increase of the ingredient caking index will cause the iodine number and methylene blue adsorption of the activated carbon to decrease.In this paper,the method of using the ingredient caking index to predict the performance of activated carbon is proposed.To a certain extent,the test range of the ratio of activated carbon raw materials can be quickly determined,which can greatly improve the efficiency of researching the ratio of activated carbon raw materials.The activated carbon of Xinjiang bituminous coal obtained in this study has an acetone adsorption capacity of 82.3 mg/g at an acetone concentration of 1000 mg/m~3 and a constant temperature of 30°C,and the desorption rate reaches 74.96%at 30°C and a pressure of 6 kPa,that lead to a good acetone working capacity.In general,the pores below 1.10 nm of activated carbon are favorable for the adsorption of low concentration acetone,while the pores above1.10 nm facilitate the desorption of acetone,which is not favorable for adsorption,but at the low acetone concentration selected herein,the pore size of activated carbon,the linear relationship of suction and desorption is not very significant and has certain randomness.The Langmuir adsorption isotherm model can well describe the adsorption behavior of acetone on activated carbon in the range of 200~1000 mg/m~3.It shows that the adsorption behavior of activated carbon on acetone is dominated by monolayer adsorption.The R~2 fitted by pseudo-first-order equation,pseudo-second-order equation,Bangham equation and acetone adsorption experiment data of activated carbon are above 0.97,and the Bangham equation has the best fitting effect.There are 37 figures,26 tables and 96 references in this thesis.