State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University

富油煤地下原位热解作为近年来提出的一项高效、环保的煤炭利用新技术,该过程中热量及物质的传递特性尚不清楚。重点考虑原位热解过程中的耦合传热、流体流动和化学反应,采用模拟的方法研究了不同加热条件和流体通道布置(介质入口温度分别为673K,723K,773K,823K和873K;介质入口速度分别为0.1m/s,0.2m/s,0.5m/s,1.0m/s,5.0m/s和10.0m/s;注热井数量分别为一口、两口和四口;水平裂缝数量分别为一条、两条和三条)下大尺度富油煤层的热质传递特性。结果表明:不同入口温度下的平均温度差距随注热时间的延长而逐渐增大;适当增大流体入口速度有助于加快煤层整体升温和热解反应速率,注气速率阈值与模拟参数密切相关,本研究条件下注气速率阈值为5.0m/s;能否显著提高原位热解效率,则取决于流体通道布置是否明显改善了流体域分布不均的问题,针对不同的布井方式和水平裂缝数量,四井注热的总热解时长比单井注热的总热解时长短6个月,三条裂缝布置的总热解时长比单条裂缝布置的总热解时长短4.5个月。

Recently, in-situ pyrolysis of tar-rich coal has been proposed as a new technology for coal utilization that is both efficient and environmentally friendly, but the heat and mass transfer characteristics in this process are remain unclear. This paper focused on the coupled heat transfer, fluid flow, and chemical reaction during in-situ pyrolysis, and the heat and mass transfer characteris‐ tics of large-scale tar-rich coal seams under various heating conditions and fluid channel arrangements (the medium inlet temperatures are 673 K, 723 K, 773 K, 823 K and 873 K, respectively; the medium inlet velocities are 0. 1 m/s, 0. 2 m/s, 0. 5 m/s, 1. 0 m/s, 5. 0 m/s and 10. 0 m/s, respec‐ tively; the number of hot injection wells are 1, 2 and 4, respectively; the number of horizontal cracks are 1, 2 and 3, respectively) were investigated by simulation method. The results demonstrate that the average temperature difference at various medium temperatures increases gradually with the exten‐ sion of heat injection time. Appropriately increasing the medium inlet velocity is helpful to increase the overall heating rate and pyrolysis reaction rate of coal seam. The gas injection rate threshold is closely related to the simulation parameters, and the gas injection rate threshold is 5. 0 m/s in the study. Whether the in-situ pyrolysis efficiency is obviously enhanced depends on whether the fluid channel arrangement significantly improves uneven distribution of the fluid domain. According to different well layouts and different number of horizontal cracks, four wells mode has a total pyrolysis time that is 6 months less than single well, and three cracks mode has a total pyrolysis time that is 4. 5 months less than that of single crack.

陕西省重点研发计划项目(2024GX-YBXM-478)、中央高校基本科研业务费项目(xzy022024076)和华能集团总部科技课题“HNKJ20-H87能源安全技术专项”资助项目.

陈美静,王长安,袁天霖,等. 富油煤原位热解反应机理及热质传递特性的数值模拟研究[J]. 煤炭转化,2025,48(2):1-15.

CHEN Meijing,WANG Chang’an,YUAN Tianlin,et al. Numerical simulation of reaction mechanism and heat and mass transfer character‐istics during in-situ pyrolysis of tar-rich coal[J]. Coal Conversion,2025,48(2):1-15.