加压条件下两段法天然气催化氧化制合成气催化剂的改进

Improvement of catalysts for synthetic gas with catalytic oxidation of methane technology using two-stage process under high pressure

以α Al2O3为载体,在加压条件下,采用初湿浸渍法制备了镧助Ni/α Al2O3部分氧化重整催化剂和负载型钙钛矿型LCFM/α Al2O3燃烧催化剂,考察了反应温度、压力、CH4与氧配比等因素对两段法甲烷催化氧化制合成气性能的影响。结果表明,在两段法催化氧化制合成气工艺中采用LCFM/α Al2O3燃烧催化剂和镧助Ni/α Al2O3部分氧化/重整催化剂,能够消除反应热点,降低反应的危险性。当温度为1000℃及体系压力为2MPa时,甲烷转化率约为85%,CO和H2的选择性接近90%,与热力学平衡值十分接近;增加原料气中的氧含量,可以提高甲烷的转化率,但CO和H2选择性随之降低。

La_xCa_(1-x)Fe_(1-x)Mn_xO_3/α-Al_2O_3 perofskite catalyst for methane combustion and La promoted Ni/α-Al_2O_3 catalyst in partial oxidation and reformation of methane were prepared under pressure action by using impregnation wetness method. The effects of reaction temperature, pressure and feedstock composition on the performance of catalytic oxidation of methane to synthesize gas with the two-stage process were investigated. The results show that the application of improved catalysts in the novel two-stage process can reduce the explosion danger in the operation and avoid the appearance of hot spots in the catalyst bed. The conversion rate of 85% for CH\-4 and the selectivity of 90% for CO and H\-2 can be achieved at 1?000 ℃ and 2.0 MPa. It is shown that under high pressure and temperature, the conversion rate of CH_4 and the selectivity of H_2 and CO are close to the values predicted at the thermal equilibrium. Increasing oxygen content in the feedstock can enhance the conversion rate of CH_4 and decrease the selectivity of CO and H_2.