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首页> 外文期刊>Fuel >Crystallization kinetics and T_(Cv) prediction of coal ash slag under slag tapping conditions in an entrained flow gasifier
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Crystallization kinetics and T_(Cv) prediction of coal ash slag under slag tapping conditions in an entrained flow gasifier

机译：夹带流化炉中出渣条件下煤灰渣的结晶动力学和T_（Cv）预测

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摘要

Slag blockages in the bottom of gasifiers cause unplanned shutdowns and huge losses for syngas utilization downstream of gasification. The sudden viscosity increase by crystal precipitation leads to slag blockage during slag tapping in entrained flow gasifiers. The temperature at which the viscosity abruptly increases is the tem-perature of critical viscosity (T-CV), which is the strict low limit temperature for slag tapping. A comprehensive investigation of slag crystallization kinetics was performed to illustrate T-CV in this work. Five slag samples with three different dominant mineral phases that commonly appear in coal ash slag were selected by thermodynamic calculations. The single hot thermocouple technique (SHTT) was applied to analyze the crystallization kinetics based on Avrami and JMA theory. The kinetic analysis indicated that anorthite showed heterogeneous nu-cleation and grew with a two-dimensional crystalline pattern. The temperature range for anorthite crystal-lization was approximately 150 degrees C. Corundum exhibited heterogeneous nucleation and one-dimensional growth pattern. The maximum crystal ratio was 52% for corundum at the temperature of 98 degrees C. Mullite showed a low E, value, resulting in a high T-on. Rapid crystallization of mullite was observed at 60 degrees C due to homogeneous nucleation and two-dimensional crystallization. In this work, T-CV was revealed by crystallization kinetics for the first time. The relationship between T-CV and the activation energy, maximum crystalline rate, and initial crys-tallization temperature was built to illustrate the influence of crystallization on T-CV. Three equations were used for Tcv prediction to guide coal selection and slag tapping in entrained flow gasifiers.
机译：气化炉底部的炉渣堵塞会导致计划外停车，并给气化下游的合成气利用带来巨大损失。晶体沉淀引起的粘度突然增加导致夹带流化气化炉出渣过程中堵塞了渣。粘度突然升高的温度是临界粘度（T-CV）的温度，该温度是排渣的严格下限温度。进行了矿渣结晶动力学的全面研究，以说明这项工作中的T-CV。通过热力学计算，选择了煤灰渣中常见的三种具有三种不同主要矿物相的矿渣样品。应用单热热电偶技术（SHTT）基于Avrami和JMA理论分析结晶动力学。动力学分析表明，钙长石显示出异相形核，并以二维晶体模式生长。钙长石结晶化的温度范围约为150摄氏度。刚玉表现出异相形核和一维生长模式。在98摄氏度的温度下，刚玉的最大结晶率为52％。莫来石显示出较低的E，值，从而导致较高的T-on。由于均相成核和二维结晶，在60℃观察到莫来石的快速结晶。在这项工作中，首次通过结晶动力学揭示了T-CV。建立了T-CV与活化能，最大结晶速率和初始结晶度之间的关系，以说明结晶对T-CV的影响。 Tcv预测使用三个方程式来指导气流床气化炉中的选煤和排渣。

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  • 来源
    《Fuel》 |2020年第jul15期|117723.1-117723.10|共10页
  • 作者

  • 作者单位

    Chinese Acad Sci Inst Coal Chem State Key Lab Coal Convers Taiyuan 030001 Peoples R China|Univ Chinese Acad Sci Beijing 100049 Peoples R China;

    Chinese Acad Sci Inst Coal Chem State Key Lab Coal Convers Taiyuan 030001 Peoples R China;

    Tech Univ Bergakad Freiberg Inst Energy Proc Engn & Chem Engn D-09599 Freiberg Germany;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Entrained flow gasifier; Coal ash slag; Cooling process; Crystallization kinetics; T-CV prediction;

    机译：气流床气化炉粉煤灰渣;冷却过程结晶动力学;T-CV预测;

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