Experimental study on co-gasification reactivity of Shenfu bituminous coal char and MSW-based hydrochar
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摘要: 基于常压热重分析仪(TG)开展了神府烟煤焦(SF char)、水热炭焦(HTC char)及其混合物等温CO2气化实验以研究气化温度(800-950℃)、掺混比(3:1、1:1、1:3)对共气化特性的影响,并探讨了气化反应活化能及其影响因素。结果表明,HTC因其较大的比表面积和较多的灰分而具有较强的气化活性。低HTC掺混比的混合物气化活性对温度变化敏感。低温下混合物的气化活性受HTC掺混影响显著。反应活化能随着反应转化率的增大而逐渐增大并趋于稳定。进一步研究表明,混合物的活化能与其掺混比以及活性矿物(K+Na)/Ca的物质的量比均存在近似线性关系。Abstract: The influences of gasification temperature (800-950℃) and blending ratio (3:1, 1:1, 1:3) on the isothermal CO2 co-gasification reactivities of Shenfu bituminous coal char (SF char) and HTC char were investigated using an atmospheric thermogravimetric analyzer (TGA). Moreover, the activation energy of char gasification and its influence factors were explored. The results show that the greater surface area and the higher ash content are the main reasons for the high gasification reactivity of HTC char. The reactivities of mixtures with low HTC char proportion are more sensitive to temperature at low temperature range. The activation energy increases with the increase of carbon conversion, and the activation energy correlates well with the blending ratio and the molar ratio of active (K+Na)/Ca in the char.
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Key words:
- co-gasification /
- coal /
- hydrochar /
- reactivity /
- activation energy
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表 1 样品的工业分析和元素分析
Table 1 Proximate analysis, ultimate analysis and ash fusion temperature of the samples tested
Sample Proximate analysis wd/% Ultimate analysis wd/% V FC A C H N O* St SF 35.42 58.29 6.29 79.14 2.32 1.12 10.36 0.77 SF char 6.48 82.255 10.27 87.17 0.91 0.54 1.01 0.10 HTC 69.71 11.38 18.91 47.36 8.56 1.78 23.01 0.38 HTC char 8.65 54.99 36.36 56.71 0.77 1.03 4.98 0.15 d:dry basis;*:by difference 表 2 样品的灰成分分析
Table 2 Ash composition of samples
Sample Ash composition w/% SiO2 Al2O3 K2O Na2O CaO Fe2O3 MgO SF 33.36 12.44 0.67 1.73 27.78 9.11 1.34 HTC 20.22 8.07 3.58 4.40 37.43 5.14 2.06 表 3 热解前后样品质量及混合比例变化
Table 3 Quality and blending ratio change of samples during pyrolysis
SF m/g HTC m/g Mixing ratio (SF:HTC) Raw material 20.00 20.00 3:1 1:1 1:3 Char 13.44 7.17 0.85:0.15 0.65:0.35 0.38:0.62 表 4 SF半焦表面的元素组成
Table 4 Element composition on the surface of AF semi-char
Content w /% Na Mg Al Si K Ca Fe Co-gasificationa, b 5.66 0.99 2.08 3.70 2.64 2.36 0.83 Individual gasification 1.33 0.49 1.62 2.24 0.32 1.84 0.83 a:SF semi-char was obtained from the mixture SF:HTC-1:1-800P
b:At the same gasification time, the conversions were xSF:HTC-1:1-800P=0.9 and xSF-800P=0.67 respectively表 5 不同转化率活化能拟合的校正决定系数
Table 5 The Adj. R. Square (R2) of activation energy under different conversion
Sample R2 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 SF-800P 0.978 0.983 0.986 0.989 0.993 0.995 0.997 0.998 0.999 SF:HTC-3:1-800P 0.979 0.987 0.991 0.993 0.994 0.994 0.995 0.995 0.996 SF:HTC-1:1-800P 0.970 0.986 0.992 0.995 0.995 0.996 0.996 0.996 0.996 SF:HTC-1:3-800P 0.960 0.981 0.988 0.991 0.993 0.995 0.994 0.994 0.994 HTC-800P 0.986 0.982 0.985 0.987 0.988 0.990 0.991 0.990 0.989 表 6 气化反应的活化能
Table 6 Gasification activation energy
Conversion Gasification activation energy EA/(kJ·mol-1) SF-800P SF-HTC-3:1-800P SF-HTC-1:1-800P SF-HTC-1:3-800P HTC-800P 0.1 192.34 176.16 149.62 133.11 114.43 0.2 201.85 187.42 163.05 142.04 126.83 0.3 207.31 195.00 169.71 147.46 133.91 0.4 210.08 199.28 177.10 150.39 137.06 0.5 211.30 201.22 182.80 152.48 139.89 0.6 211.73 201.95 185.28 158.17 141.48 0.7 211.85 202.31 186.04 163.59 140.86 0.8 211.63 203.10 186.07 164.66 139.94 0.9 211.15 204.30 185.35 162.75 139.80 Average value 207.69 196.75 176.11 152.74 134.91 表 7 焦活性AAEM含量
Table 7 Content of active AAEM in char
AAEM w/(mmol·g-1) SF-800P SF-HTC-3:1-800P* SF-HTC-1:1-800P* SF-HTC-1:3-800P* HTC-800P K 0.0015 0.0472 0.1082 0.1904 0.3062 Na 0.0061 0.0441 0.0948 0.1632 0.2596 Ca 0.5000 0.5705 0.6646 0.7916 0.9703 -
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