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摘要: 利用热重法和X射线衍射法,研究了神府煤热解焦CO2气化过程中,碱金属碱土金属(AAEM)催化剂对气化活性和微晶结构的影响。比较了负载方式(先热解后负载和先负载后热解)、催化剂种类(Na、K、Ca)以及催化剂添加量(金属原子质量分数1%、3%、5%)的影响。结果表明,对碱金属催化剂,先热解后负载焦样的反应活性比先负载后热解的更好,而碱土金属负载方式对活性的影响则相反;Na和K的催化能力相接近,且两者都比Ca强;煤焦气化活性随AAEM负载量的增加而增强。负载AAEM催化剂均能抑制煤焦石墨化进程,其中,K的抑制作用最强,Ca的抑制作用最弱;抑制作用随添加量增加而增强。Abstract: The gasification reactivity and crystallite structure of Shenfu char were measured via thermogravimetric analysis (TGA) and X-ray diffraction technology (XRD) to investigate the catalytic effect of AAEM during CO2 gasification. The interest was focused on effects of loading method (pyrolysis before loading or pyrolysis after loading), catalyst species (Na, K, Ca) and loading amount (1%, 3%, 5% on metal atom). For Na and K, the reactivity of char pyrolyzed before loading catalyst is better than that pyrolyzed after loading. The order of catalytic efficiency is Na~K >Ca. In addition, catalytic efficiency of AAEM catalyst increases with the increasing of loading amount. Catalyst addition inhibits the progress of char graphitizing during pyrolysis. The order of inhibition is K > Na > Ca, and the inhibition is enhanced with the increase of loading amount.
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Key words:
- catalytic gasification /
- AAEM /
- loading method /
- gasification reactivity /
- crystallite structure
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表 1 实验煤样的工业分析和元素分析
Table 1 Proximate and ultimate analysis of coal samples
Coal Proximate analysis wd/% Ultimate analysis wd/% V FC A C H S N O* SF 34.50 57.76 7.74 72.36 3.87 0.56 0.99 14.48 SF AC 34.21 61.81 3.98 71.17 3.60 0.34 0.96 19.95 *:by difference 表 2 煤中矿物质的元素分析
Table 2 Mineral element content of coal
Coal ASH
w/%Element content w/% Si Al Fe Ca Mg Ti Na K S SF 7.74 1.69 0.57 0.49 0.88 0.069 0.031 0.12 0.058 0.26 SF AC 3.98 1.25 0.33 0.18 0.090 0.023 0.018 0.016 0.041 0.056 表 3 干燥无灰基失重率L0
Table 3 Mass loss L0 on dry-ash-free base
Sample AC 0.01Na 0.03Na 0.05Na 0.01K 0.03K 0.05K 0.01Ca 0.03Ca 0.05Ca L0 w/% 35.96 34.89 35.69 38.11 36.30 35.15 36.20 40.17 40.06 46.51 表 4 900 ℃下煤焦气化反应性指数R0.5
Table 4 Gasification reactivity index R0.5 of chars at 900 ℃
Sample R0.5/min-1 Rchar 0.046 4 AC char 0.011 8 Pyrolysis before
loading catalystR0.5
/min-1pyrolysis after
loading catalystR0.5
/min-1AC char 0.01Na 0.055 8 AC 0.01Na char 0.045 6 AC char 0.03Na 0.145 7 AC 0.03Na char 0.134 8 AC char 0.05Na 0.207 1 AC 0.05Na char 0.151 8 AC char 0.01K 0.035 3 AC 0.01K char 0.033 4 AC char 0.03K 0.115 4 AC 0.03K char 0.086 5 AC char 0.05K 0.187 9 AC 0.05K char 0.177 8 AC char 0.01Ca 0.025 5 AC 0.01Ca char 0.019 7 AC char 0.03Ca 0.030 9 AC 0.03Ca char 0.092 0 AC char 0.05Ca 0.034 1 AC 0.05Ca char 0.147 8 表 5 焦样的XRD微晶参数
Table 5 XRD parameters of chars
Sample 2θ002/(°) 2θ100/(°) d002/nm Lc/nm La/nm AC char 24.15 43.55 0.368 0.946 3.646 AC 0.01Na char 23.79 43.45 0.374 0.916 3.573 AC 0.03Na char 23.70 43.40 0.375 0.944 3.248 AC 0.05Na char 23.10 43.35 0.385 1.018 3.108 AC 0.01K char 24.00 43.71 0.370 0.881 3.753 AC 0.03K char 23.66 43.20 0.376 0.859 3.464 AC 0.05K char 22.50 43.06 0.395 0.816 3.073 AC 0.01Ca char 23.26 43.71 0.382 0.913 4.123 AC 0.03Ca char 25.70 43.81 0.346 3.007 3.914 AC 0.05Ca char 25.64 43.99 0.347 2.933 3.518 -
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