富油煤热解产物分布的机器学习预测与实验验证

Machine learning-based prediction and experimental validation of the pyrolysis product distribution in tar-rich coals

  • 摘要:
    背景 富油煤作为我国重要的煤基油气资源,其热解产物分布受煤质属性与反应条件耦合作用控制,快速识别产物分布规律对资源评价与实验设计具有重要意义。
    方法 针对现有研究中富油煤专属数据整合不足、产物协同预测能力有限的问题,通过系统收集文献实验数据,构建包含工业分析、元素分析、元素摩尔比、显微组分及热解条件等信息的富油煤热解数据集,并建立多目标回归神经网络模型对热解产物产率进行基础预测。在此基础上,结合Van Krevelen图、Spearman相关分析及SHAP特征贡献分析,识别影响富油煤热解产物分布的主要控制因素。通过400~600 ℃热解实验,验证模型对主要温度响应规律的再现能力。
    结果和结论 所建模型能够较好再现富油煤热解过程中半焦产率下降、气体产率升高、水产率整体增加以及焦油产率先升后降的典型温度响应规律,测试集决定系数平均为0.89,均方根误差平均为1.53。煤质属性,尤其是碳含量、镜质组含量及挥发分含量,对产物分布的影响总体强于升温速率和粒径等外部操作参数。实验验证表明,模型对气体和半焦产率的预测一致性较好,对高温区焦油产率存在一定高估,说明高温二次裂解行为及样本覆盖范围仍是后续改进的重点。研究揭示了富油煤热解产物分布的基本规律,并通过实验验证了模型对主要温度响应趋势的再现能力,可为富油煤资源评价、热解实验设计及产物调控研究提供参考。

     

    Abstract:
    Background Tar-rich coals serve as an important coal-based oil and gas resource in China, while their pyrolysis product distribution is governed by the coupling effects of coal properties and reaction conditions. Therefore, rapidly identifying the pyrolysis product distribution patterns holds great significance for the resource evaluation and experimental design of tar-rich coals.
    Methods  Existing studies on tar-rich coals suffer from the insufficient integration of exclusive data and limited synergistic prediction capacities for multiple products. To address these issues, this study constructed a dedicated dataset involving proximate analysis, ultimate analysis, elemental molar ratios, maceral composition, and pyrolysis conditions by systematically collecting experimental data from associated literature. Subsequently, a feedforward neural network model for multi-target regression was established for the basic prediction of pyrolysis product yields. Accordingly, this study identified primary factors controlling the pyrolysis product distribution of tar-rich coals by combining Van Krevelen diagrams, Spearman correlation analysis, and feature contribution analysis based on SHapley Additive exPlanations (SHAP) values. Finally, through pyrolysis experiments under 400‒600 ℃, this study validated the model’s capability to reproduce the major temperature response patterns of the pyrolysis products of the tar-rich coals.
    Results and Conclusions The established feedforward neural network model effectively reproduced the typical temperature response patterns of the pyrolysis products of tar-rich coals. Specifically, with an increase in the pyrolysis temperature, the char yield decreased, the gas yield increased, the water yield increased overall, and the tar yield increased initially and then decreased. This model exhibited an average coefficient of determination (R2) of 0.89 and an average root mean square error (RMSE) of 1.53 on the testing set. Among primary influencing factors, coal properties, particularly carbon content, vitrinite content, and volatile constituent content, generally produced more significant impacts on the product distribution than external operating parameters like heating rate and particle size. Experimental validation demonstrates that good agreement existed between predicted and experimental gas and char yields, while the tar yield was slightly overestimated under high-temperature conditions. Therefore, future improvement should focus on sample coverage and secondary pyrolysis under high-temperature conditions. The results of this study reveal the basic distribution patterns of the pyrolysis products of tar-rich coals and verify the capability of the established feedforward neural network model to reproduce the major temperature response trends of the pyrolysis products of tar-rich coals. These results will provide references for the resource evaluation, pyrolysis experimental design, and product control research of tar-rich coals.

     

/

返回文章
返回