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摘要: 利用程序升温热天平研究了神木煤(SMC)分别与气煤(QM)、肥煤(FM)、焦煤(JM)不同比例配合后的共热解交互作用规律,通过分布活化能模型(DAEM)对配合煤的热解动力学进行了考察。结果表明,随着SMC配入比例的增加,配合煤水分集中释放的速率增大,挥发分释放速率峰对应的温度tmax降低,配合煤在塑性固化温度后(>460-480 ℃)的热解过程中抑制作用减弱,表明配合煤黏结性降低。随着升温速率增加,配合煤热解抑制作用增强,表明配合煤黏结性提高。随着黏结煤变质程度加深(QM、FM、JM),配合煤共热解发生促进作用(促进挥发分释放)的温度分别低于、介于、高于黏结煤塑性温度区间,因此,对缓解胶质体膨胀压力及改善胶质体分散性的作用逐渐降低。通过分布热解活化能实验值与理论值的比较,证实了配煤共热解过程中的交互作用规律。Abstract: The pyrolysis characteristic of blended coal and the interaction between Shenmu coal (SMC) and caking coals(Fat coal-FM, gas coal-QM, coking coal-JM) were studied by temperature-programmed thermobalance. The pyrolysis kinetics were analyzed using distributed activation energy model (DAEM). The results indicate that the concentrated release rate of moisture increases and temperature corresponding to the release peak of volatile matter(tmax) for coal blends decreases as increasing SMC blending ratio. The inhibition of blended coal is reduced as increasing SMC blending ratio when pyrolysis temperature surpasses the solidified temperature of metaplast (>460-480 ℃), indicating a poor bonding behavior of metaplast. In addition, the inhibition of blended coal is enhanced and its bonding behavior is improved with increasing heating rate. The effects of relieving swelling pressure and improving dispersity of metaplast gradually reduce as deepening the metamorphic degree of caking coal from QM, FM to JM, since the corresponding temperature for promoting interaction (release of volatile) is below, within, above the plastic temperature range of caking coals, respectively. A comparison of experimental and calculated distributed activation energy model confirms the interaction mechanism of blended coal during co-pyrolysis.
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Key words:
- Shenmu coal /
- caking coals /
- co-pyrolysis /
- interaction /
- distributed activation energy
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图 7 热解活化能Ea随煤热解转化率x的变化关系及配煤热解活化能实验值与计算值差值曲线
Figure 7 Relationship between Ea and x and the difference between experimental and calculated value of Ea
(a), (b): blends of SMC and QM; (c), (d): blends of SMC and FM; (e), (f): blends of SMC and JM
■: SMC; ●: caking coal; ▲: 40SMC:60 caking coal (exp); ▼: 40SMC:60 caking coal (cal)表 1 原料煤样的工业分析和元素分析
Table 1 Proximate and ultimate analyses of coals
Sample Proximate analysis w/% Ultimate analysis wdaf/% Mad Aad Vdaf C H O* N S SMC 10.52 4.40 34.02 82.98 4.70 11.10 1.02 0.20 QM 2.24 7.88 34.90 86.37 5.35 6.22 1.18 0.88 FM 0.80 20.74 32.03 87.06 5.39 2.55 1.33 3.67 JM 0.84 13.17 26.72 89.10 4.99 2.28 1.47 2.16 *:by difference -
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