流化床气化炉内冲蚀磨损的多尺度模型及数值模拟方法

Our country is a big consumer of coal, and there are a lot of gas-solid flows in the process of coal combustion and gasification. The equipments and tubes can easily be damaged under the ongoing wear of the coal or ash particles. And this will stop the normal production and cause huge economic losses. Ash-agglomerated fluidized bed gasification is a kind of advanced coal gasification technology developed by our country independently, and has been successfully applied to several sets of industrialization demonstration device. However, during the operation, the erosion of coal or ash particles affected the safety of the equipments, and became one of the major production safety problems. So far, the prediction of the erosion in fluidized bed rely mainly on experience, and the prediction accuracy of traditional energy dissipation model is not high enough to guide the design of fluidized reactor because of the ignoring of the motion directions of particles. According to the findings of that the erosion of equipments is caused by the tangential impact energy, a kind of modeling method of erosion was proposed based on analysis of the tangential impact energy. Using this method, a microscopic scale erosion model and a mesoscopic scale erosion model will be established. The multi-scale models and numerical simulation methods of the erosion of fluidized bed gasifier then will be founded by combining these two models with CFD-DEM and CFD-TFM. And this will used to guide the design of the fluidized bed gasifier, in order to improve the stability of the reactor, reduce operating costs and extend the life of the devices.

我国是煤炭消费大国，煤燃烧和气化过程中存在着大量的气固两相流动，煤粉或灰渣颗粒对设备的长期冲蚀极易造成反应器破坏或管道爆管事故，导致停产并造成巨大的经济损失。"灰熔聚流化床粉煤气化"技术是我国自主研究开发的先进煤气化技术，已成功应用于多套工业化示范装置中，但在运行过程中，煤粉或灰渣颗粒对设备的冲蚀磨损成为影响安全生产最主要的问题之一。迄今为止，流化床内磨损的预测主要依靠经验，传统的能量耗散磨损模型因没考虑颗粒运动的方向对磨损的影响而预测精度较低，无法有效指导流化床反应器的设计。本项目根据研究发现的切向冲击能量是造成壁面磨损的根本原因，提出基于切向冲击能量分析的磨损建模方法，并拟据此建立微观及介观尺度的冲蚀磨损模型，并结合CFD-DEM及CFD-TFM最终形成流化床气化炉冲蚀磨损的多尺度模型及数值模拟方法，用于指导流化床气化炉的设计，达到提高反应器的稳定性、降低运行成本、延长使用寿命的目的。

煤燃烧和气化过程中存在着大量的气固两相流动，煤粉或灰渣颗粒对设备的长期冲蚀极易造成反应器破坏或管道爆管事故，导致停产并造成巨大的经济损失。“灰熔聚流化床粉煤气化”技术是我国自主研究开发的先进煤气化技术，已成功应用于多套工业化示范装置中，但在运行过程中，煤粉或灰渣颗粒对设备的冲蚀磨损成为影响安全生产最主要的问题之一。目前，流化床内磨损的预测主要依靠经验，传统的能量耗散磨损模型因没考虑颗粒运动的方向对磨损的影响而预测精度较低，无法有效指导流化床反应器的设计。针对缺乏解决工程实际问题的应用类磨损预测模型的问题，根据研究发现的切向冲击能量是造成壁面磨损的根本原因，我们提出了基于颗粒切向冲击能的磨损模型（Shear Impact Energy Model，SIEM），并将其应用于流化床、气力输送管道等设备的磨损预测。该模型基于切向冲击能量预测设备磨损，具有很高的预测精度，不但适用于球形颗粒还适用于非球形颗粒，具有普遍的适用性。本项目基于切向冲击能量分析的磨损建模方法，建立了微观及介观尺度的冲蚀磨损模型，并结合CFD-DEM及CFD-TFM形成了流化床气化炉冲蚀磨损的多尺度模型及数值模拟方法，用于指导流化床气化炉的设计，达到提高反应器的稳定性、降低运行成本、延长使用寿命的目的。在本项目的支持下，我们在化工领域顶级期刊《AIChE Journal》、三大化工期刊之一的《Chemical Engineering Science》、颗粒技术的顶级期刊《Powder Technology》等国际著名学术杂志上发表SCI收录论文12篇（发表的SCI论文两年内被引用67次），申请国家发明专利1项，培养博士生/研究生8名。