碱金属钾对Ni基催化剂纤维素水蒸气气化活性的影响

采用两段式催化气化方式研究了生物质热解气化过程中碱金属的挥发对Ni基催化剂活性的影响。实验结果表明,负载K盐的纤维素水蒸气催化气化过程中,K挥发后会在催化剂表面沉积,而少量K的存在和表面沉积不但能够提高镍基催化剂的抗积炭能力,而且有助于提高其催化活性,产生更多的氢气。然而纤维素中K的浓度过大,将会抑制Ni基催化剂的效果;K在催化剂上的沉积随催化剂循环次数的增加而增加,K的含量愈高,对催化剂的抑制效果愈明显,从而缩短了催化剂的使用寿命。

Influence of potassium on the performance of nickel-based catalyst in the steam gasification of cellulose

The influence of alkali metal volatilization on the performance of nickel-based catalyst in the steam gasification of cellulose biomass was investigated in a two-stage fixed bed reactor. The results show that potassium is deposited on the catalyst surface with the volatilization of potassium salt during the catalytic steam reforming of potassium-loaded cellulose. The existence and deposition of proper amount of potassium may suppress the coke deposition and enhance the activity of nickel-based catalyst, which is of benefit to producing more hydrogen in the steam gasification of biomass. However, excessive amount of potassium loaded in cellulose may reduce the activity of nickel-based catalyst; moreover, with the repetitious operations, potassium is accumulated on the catalyst surface, which may lead to an obvious inhibitory effect on the activity and stability of nickel-based catalyst in the steam gasification of biomass.