Influence of calcination conditions on the performance of Ni-Al₂O₃ catalyst for CO methanation in slurry-bed reactor

Effects of calcination temperature and calcination time on the crystal structure, reduction characteristics, pore structure and CO methanation performance of Ni-Al₂O₃ catalyst were investigated by using a mechanical-chemical method to prepare Ni-Al₂O₃ catalyst. The catalysts were characterized by XRD, H₂-TPR, BET, XPS and TPH. The results showed that the calcination temperature increased from 350℃ to 700℃, NiO was still well dispersed on the surface of the carrier, and the reduction peak temperature decreased to high temperature. The specific surface area of the cat-450 sample obtained by calcination at 450℃ was 350 m²/g. The results showed that with the calcination temperature increased from 350℃ to 700℃, CO conversion, CH₄ selectivity and yield were increased first and then decreased, reaching the maximum at 450℃, with 97.8%, 88.2% and 86.2%, respectively. In addition, the calcination time has little effect on the reduction performance of the catalyst, and has small influence on the crystal structure of the carrier Al₂O₃. With the increase of calcination time, CO conversion decreased slightly and then increased with the better calcination time of 4 h.