【摘要】 在常压、823～873K、流化床反应条件下,用自行研制的Ni0.5Mg0.5O催化剂,催化甲烷分解生长碳纳 米管(CNTs),考察催化剂床层由固定床过渡到流化床状态的条件及其对制管过程的影响。结果表明,在 Φ32mm管式反应器及相应供热工况条件下,其流化床操作条件以管壁温度控制在约853K、原料气CH4线速 v为18～22cm/s、空速GHSV为3×104～6×104mL(STP) CH4/(h·g)为宜;反应1.0h,最高产率达 10g CNTs/g,这相当于固定床将制管反应时间延长至4～5h的产率水平。所得CNTs产物经TEM、SEM、 TPH、XRD和LRS等测试技术表征。结果表明,其为多壁碳纳米管(MWCNTs),外管径在10～50nm范围;纯 化后的CNTs产物含碳量≥99.5%,石墨状碳含量≥90%。更多还原

【Abstract】 With home-made Ni 0.5Mg 0.5O as the catalyst, canbon nanotubes(CNTs) were synthesized from the catalytic pyrolysis of methane in a Φ 32 mm fluidized-bed reactor. The operation conditions for the transition of fixed catalyst-bed and fluidized catalyst-bed and their influence on the growth of CNTs were investigated. The optimized conditions in the Φ 32 mm fluidized-bed reactor are as follows, i.e., the temperature of reactor is ca. 853 K, the linear velocity of feed-gas CH 4 18~22 cm/s and the GHSV of CH 4 3×10 4~6×10 4 mL(STP)/(h·g)-catal. The maximum yield of reaction for 1 h is 10 g-CNTs/g-catal. The obtained CNT products were confirmed by means of TEM, SEM, TPH, XRD and LRS to be multi-walled carbon nanotubes( MWCNTs) with an outer diameter of 10~50 nm, and the contents of carbon and graphitic-carbon in the purified CNT products were found to be ≥99.5% and ≥90%, respectively.更多还原