Model of estimating viscosity based on slag structure in entrained flow gasifier

doi:10.11949/j.issn.0438-1157.20170443

Abstract

Abstract:

The viscosity of molten slags is one of the most significant parameters to predict the flow properties of ash in coal gasification process.To estimate the viscosity of molten slags,a model based on the structure of slags was established.NBO/T (number of non-bridging oxygen/tetragonally-bonded oxygen) and P/M (polymer/modifier),as the structural parameters of slags,provide description of the polymerization and bond strengths of molten slags,respectively.The model presented the dependency on both temperature and structural parameters with the viscosity in the SiO₂-Al₂O₃-CaO-MgO-Fe₂O₃-K₂O-Na₂O-TiO₂ slag systems.The accuracy of the model was verified by the experimental data of literatures.The results indicate that the viscosity decreases with the increase of NBO/T due to the reduction of polymerization in the molten slags,whereas the viscosity rises with the increase of P/M because of the strength weaken of molten slags.A good agreement is obtained from the calculated and measured values of the viscosity within a certain range.The deviation between the prediction and experiment results is within 10% when NBO/T < 0.5 and 25% when NBO/T > 0.5.

Key words: slag structure, viscosity, gasification, model, NBO/T, P/M

摘要：

在煤气化工艺中，煤灰高温黏度特性是影响熔渣流动特性重要参数之一。以NBO/T、P/M为结构参数，建立熔渣高温黏度预测模型，对结构参数、熔渣黏度的关系进行了研究，并通过文献的实验数据验证了模型的准确性。研究发现随着NBO/T的增大，熔体聚合程度降低，熔体流动时内摩擦力减小，黏度降低；随着P/M增大，熔体结构强度减弱，熔体流动所需要克服的阻力增加，熔渣黏度逐渐升高。引入结构参数后的熔渣黏度预测模型对一定范围内的熔渣黏度具有良好的预测效果，在NBO/T < 0.5时，黏度预测值和实验值误差在10%以内，采用两种结构参数均可；在NBO/T > 0.5时，黏度预测值和实验值误差在25%以内，采用结构参数P/M更合适。

关键词: 熔渣结构, 黏度, 气化, 模型, NBO/T, P/M

CLC Number:

TQ546.4

WANG Qian, LI Qiang, ZHANG Jiansheng. Model of estimating viscosity based on slag structure in entrained flow gasifier[J]. CIESC Journal, 2017, 68(10): 3877-3883.

王倩, 李强, 张建胜. 基于气流床气化炉熔渣结构的黏度预测[J]. 化工学报, 2017, 68(10): 3877-3883.

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