Study On Methanation Reaction From Syngas Over Ni Based Catalyst

Coal to nature gas is one of the most efficient ways to produce products with high added value by coal,and the syngas methanantion reaction is one of the key technologies of coal to nature gas.In order to reduce costs,the technologies of coal to nature gas are used under high temperature and high pressure.Under this condition,the catalyst is easy to sinter and coke.The catalysts with high stability,anti-sintering and anti-carbon deposition was very important for the application of catalysts.The catalytic performances of Ni-based catalysts were studied in this paper,the stability of catalysts was also tested.The catalytic test was carried out in a fixed-bed reactor under T=200⁶50 oC,P=1.5 MPa?gauge pressure?,GHSV=10000 h-1 and H₂/CO= 3.The catalysts were characterized by N₂ adsorption-desorption,X ray diffraction?XRD?,H₂ temperature programmed reduction?H₂-TPR?and thermogravimetry?TG?.The results are showed as follows.1.The catalytic performance of catalysts with different TiO₂ contents was investigated.The results showed that the catalytic performance improved as the TiO₂ contents increased,and the Ni/20 TA exhibits the best catalytic performance at 200 °C-650 °C.The Ni/Al₂O₃ and Ni/20 TA catalysts were prepared and tested under different calcination temperature,and the results showed that catalytic performance decreased with the increasing calcination temperature.The reasons founded by characterization were that the formation of NiAl₂O₄ in high temperature reduces the amount of active nickel species and leads to a low activity for the reforming reactions2.The test for 100 h was investigared for Ni/20 TA and Ni/Al₂O₃ catakysts.The results showed that the catalytic performance of both catalysts decreased in 100 h reacrion,but Ni/20 TA performed better thermal stability in the reaction temperature of 600 ? than Ni/Al₂O₃.The results of TG showed that adding TiO₂ into Ni/Al₂O₃ catalyst can remarkably suppress carbon deposition.3.The Ni/TiO₂-Al₂O₃ catalysts were promoted by different promoters?La₂O₃,MoO₃,CoO?.The results revealed that the addition of La₂O₃ and MoO₃ significantly improved the performance of catalysts.The lifetime test for 100 h was investigared for Ni/20 TA and 4Mo-Ni/20 TA catalysts.The catalyst 4Mo-Ni/20 TA displays the better catalytic performance with excellent stability.The characterization results showed that the catalyst contains less carbon deposition.