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摘要: 以遵义无烟煤煤焦为气化原料,以稻草灰和棉秆灰为生物质灰添加剂,基于热重分析仪开展焦样-CO2等温气化实验,以探究生物质灰添加对煤焦气化反应特性的影响,并基于气化过程焦样固体结构演变对其进行关联解释。研究表明,稻草灰和棉杆灰的添加有利于提高煤焦气化反应活性,这主要归因于生物质灰添加有利于气化过程煤焦活性矿物质含量增加和碳结构有序度降低。且稻草灰和棉秆灰的添加对焦样气化反应活性的增加幅度随气化温度升高而减小,这可解释为生物质灰添加对气化过程煤焦活性矿物质含量增加和碳结构有序度降低的幅度随气化温度升高而减小。此外,棉秆灰对煤焦气化反应活性的促进作用较稻草灰更为显著,这主要由于棉杆灰的添加对气化半焦中活性AAEM含量的增加作用以及碳结构石墨化进程的抑制作用更加明显。Abstract: Zunyi anthracite was used as the raw material of gasification and rice straw ash and cotton stalk ash were optioned as biomass ash additives. Char-CO2 isothermal gasification experiments were conducted using TGA to investigate the effect of biomass ash addition on coal char gasification characteristics. Furthermore, the relationship between char structure evolution during gasification and char gasification reactivity was investigated. The results indicate that the biomass ash addition has a promotion effect on coal char gasification, which is well related to the increase in active AAEM content and the decrease in the order degree of carbon structure of chars by the addition of biomass ash. However, the promotion effect of biomass ash additives on coal char gasification is weakened with increasing gasification temperature, mainly due to that the positive effect of biomass ash additive on the increase of active AAEM content in char and the inhibition effect of biomass ash additive on carbon structure order degree of coal char become weaker at higher gasification temperature. Additionally, it is found that cotton stalk ash has a more significant positive effect on coal char gasification than rice straw ash because cotton stalk ash has a more obvious effect on the increase in active AAEM content and the decrease in the carbon structure graphitization degree of coal char.
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Key words:
- biomass ash /
- coal char /
- gasification characteristic /
- structure evolution
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表 1 煤样的工业分析和元素分析
Table 1 Proximate and ultimate analyses of ZY sample
Sample Proximate analysis wd /% Ultimate analysis wd /% V FC A C H N O S ZY 7.59 73.46 18.95 76.57 2.13 1.10 0.83 0.42 表 2 煤灰和生物质灰化学组成
Table 2 Ash chemical composition of tested samples
Sample Ash composition /% SiO2 Al2O3 K2O Na2O CaO Fe2O3 MgO ZY 55.67 30.63 1.04 1.64 0.95 4.45 0.59 RS 58.88 0.18 21.97 1.13 4.20 0.26 2.73 CS 1.73 0.35 40.96 6.99 20.60 0.51 9.38 表 3 焦样气化反应活性指数
Table 3 Gasification reactivity index of coal char samples
Temperature t/℃ R0.9 ZY-800P ZY-800P-RSA ZY-800P-CSA 850 - 0.001 0.009 900 0.001 0.002 0.017 950 0.003 0.005 0.031 1000 0.007 0.009 0.057 表 4 气化半焦中活性AAEM含量
Table 4 Active AAEM contents in gasified semi-char of individual and blended chars
Sample Active AAEM content/(mg·g-1 semi-char) K Na Ca total ZY-800P-900G ~0 0.45 4.15 4.60 ZY-800P-1000G ~0 0.40 3.71 4.11 ZY-800P-RSA-900G 0.43 0.79 4.06 5.28 ZY-800P-RSA-1000G 0.24 0.57 3.61 4.42 ZY-800P-CSA-900G 3.94 1.07 8.40 13.41 ZY-800P-CSA-1000G 1.88 1.01 7.38 10.27 表 5 气化半焦拉曼光谱峰面积比
Table 5 Raman band area ratio of gasification semi-chars
Gasification temp. t/℃ ID1/IG ZY-800P ZY-800P-RSA ZY-800P-CSA 900 4.85 4.93 5.16 1000 4.62 4.66 4.78 -
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