| 煤粉高温快速裂解过程的颗粒内部传递行为 |
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| 引用本文： | 双玥,吴昌宁,颜彬航,程易.煤粉高温快速裂解过程的颗粒内部传递行为[J].化工学报,2010,61(12):3072-3079. |
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| 作者姓名： | 双玥 吴昌宁 颜彬航 程易 |
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| 作者单位： | 清华大学化学工程系，北京100084 |
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| 基金项目： | 国家自然科学基金，国家高技术研究发展计划重点项目 |
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| 摘 要： | 热等离子体裂解煤制乙炔为超高温毫秒级反应过程,煤粉升温及脱挥发分过程直接决定了反应器的乙炔产率和经济性。建立了描述单颗粒煤粉高温快速裂解过程的机理模型,综合考虑了颗粒自身导热阻力及挥发分逸出煤粉所伴生的热阻效应。模型预测表明颗粒内部传热阻力显著影响煤粉的热裂解过程,与忽略颗粒内部传热阻力相比,脱挥发分时间减慢30%～40%,且颗粒粒径增大该影响越加明显;提高供热流体温度可加速、加强煤裂解反应深度。针对毫秒级煤裂解过程,大于100μm的煤粉或者低于2000K的热流体温度均难于实现满意的脱挥发分行为,所得结果为反应器的设计和操作提供了重要的指导。
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| 关 键 词： | 煤裂解 乙炔 传热模型 脱挥发分 超高温 |
Influence of heat transfer inside particles on coal pyrolysis at ultra-high temperature |
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| SHUANG Yue,WU Changning,YAN Binhang,CHENG Yi.Influence of heat transfer inside particles on coal pyrolysis at ultra-high temperature[J].Journal of Chemical Industry and Engineering(China),2010,61(12):3072-3079. |
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| Authors: | SHUANG Yue WU Changning YAN Binhang CHENG Yi |
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| Abstract: | Coal pyrolysis in thermal plasma opens up a direct means for producing acetylene.This process is operated under ultra-high temperature conditions with the reaction time in milliseconds, where the rapid heating of coal particles and the release of volatile matters from coal particles play the dominant role in the overall reactor performance.A mechanism model was proposed for a deep understanding of the heat transport inside a coal particle under extreme environmental conditions, which incorporated the heat conduction in solid materials and heat resistance due to the outward diffusion of released volatile gases.The predicted yield of volatiles considering the heat transfer inside the particle agreed reasonably with the reported experimental data under different operating conditions, indicating 30%—40% time delay compared with the case without consideration of the heat resistance inside a particle.This effect became more evident for larger particles.Meanwhile, the heating fluid at a higher temperature could speed up and intensify the devolatilization of coal particles.Limited to the milliseconds process of coal pyrolysis, particle size greater than 100 μm or the heating fluid temperature lower than 2000 K is not recommended in the practical application because of the slow release of volatiles in coals. |
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