Abstract:

Steam gasification of potassium-loaded semi-coke has been carried out with a fixed-bed laboratory gasifier at atmospheric pressure. With the K₂CO₃ loading increased the micropore area decreased. At a loading of 5% (mass), the K₂CO₃ mainly plays the role of filling pores. Above the loading of 10% (mass), the accumulation of catalyst will lead to more pores on the surface and interior of the particles. Increasing the gasification temperature could increase the carbon conversion rate, but above 750℃ the carbon conversion rate increased indistinctively. The loading values above which the effect was negligible were 10% (mass). High concentration of C(O) on the surface of particles and in open pores has a higher desorption rate and led to the generation rate of CO increase. Under non-catalytic conditions, CO/CO₂ decreased as gasification time increasing, while H₂/(2CO₂+CO) increased first and then decreased. Under catalytic conditions, H₂/(2CO₂+CO) was stable at 1.5－1.7. The active components, such as K₂Ca(CO₃)₂, K₂O, and KO₂, appeared in the catalyst semi-coke samples and increased with the catalyst loading increasing. Catalyst deactivation phenomenon was aggravated due to the loading increasing, but it was not completely inactivation under the condition of gasification 1 h at 750℃.

Key words: fixed-bed, catalyst, semi-coke, hydrogen production, gasification

摘要：

在固定床中考察了不同K₂CO₃植入浓度和不同温度条件下兰炭催化气化特性。结果表明，5%的催化剂植入浓度主要起到填充孔隙的作用，当植入浓度增加到10%以后，催化剂发生堆积会使颗粒表面及内部形成较多孔隙。提高气化温度可提高兰炭转化率，超过750℃之后碳转化率增幅减缓，催化剂饱和装载浓度为10%。在颗粒表面和开放孔隙中的高浓度C(O)才具有较高的脱附速率，并提高CO生成速率。在非催化条件下，随着气化的进行CO/CO₂下降，而H₂/(2CO₂+CO)先增后减。在催化条件下，H₂/(2CO₂+CO)稳定在1.5～1.7。催化剂兰炭样品中出现了K₂Ca(CO₃)₂双金属碳酸盐、K₂O、KO₂等活性组分，并随催化剂植入浓度的增加而增加。催化剂植入浓度的增加会导致失活现象加重，但兰炭在750℃条件下气化1 h 催化剂没有完全失活。

关键词: 固定床, 催化剂, 兰炭, 制氢, 气化