Optimization of process parameters for preparation of powdered activated coke to achieve maximum SO 2 adsorption using response surface methodology

• Published in: Frontiers in Energy 2021, Vol.15 (1), p.159-169
• Main Authors: ZHOU, Binxuan, WANG, Tao, XU, Tianming, LI, Cheng, ZHAO, Yuan, FU, Jiapeng, ZHANG, Zhen, SONG, Zhanlong, MA, Chunyuan
• Format: Article
• Language: English
• Subjects: parameters optimization; powdered activated coke (PAC); response surface methodology; SO 2 adsorption capacity
• ISSN: 2095-1701; 2095-1698
• DOI: 10.1007/s11708-020-0719-7

Powdered activated coke (PAC) is a good adsorbent of SO 2, but its adsorption capacity is affected by many factors in the preparation process. To prepare the PAC with a high SO 2 adsorption capacity using JJ-coal under flue gas atmosphere, six parameters (oxygen-coal equivalent ratio, reaction temperature, reaction time, O 2 concentration, CO 2 concentration, and H 2O concentration) were screened and optimized using the response surface methodology (RSM). The results of factor screening experiment show that reaction temperature, O 2 concentration, and H 2O (g) concentration are the significant factors. Then, a quadratic polynomial regression model between the significant factors and SO 2 adsorption capacity was established using the central composite design (CCD). The model optimization results indicate that when reaction temperature is 904.74°C, O 2 concentration is 4.67%, H 2O concentration is 27.98%, the PAC (PAC-OP) prepared had a higher SO 2 adsorption capacity of 68.15 mg/g while its SO 2 adsorption capacity from a validation experiment is 68.82 mg/g, and the error with the optimal value is 0.98%. Compared to two typical commercial activated cokes (ACs), PAC-OP has relatively more developed pore structures, and its S BET and V tot are 349 m 2/g and 0.1475 cm 3/g, significantly higher than the 186 m 2/g and 0.1041 cm 3/g of AC1, and the 132 m 2/g and 0.0768 cm 3/g of AC2. Besides, it also has abundant oxygen-containing functional groups, its surface O content being 12.09%, higher than the 10.42% of AC1 and 10.49% of AC2. Inevitably, the SO 2 adsorption capacity of PAC-OP is also significantly higher than that of both AC1 and AC2, which is 68.82 mg/g versus 32.53 mg/g and 24.79 mg/g, respectively.