Numerous models have been developed in Aspen Plus for the combustion of different coal types in fluidized bed reactors. However, these models are case-specific, particularly with respect to coal type and bed reactor type, implying limitations to general application of these models. Moreover, these processes were generally developed step-wisely by employing a series of model blocks to simulate fluidized bed reactors in Aspen Plus. In this study, a novel hybrid approach for modelling coal combustion has been implemented to comprehensively design a model for conversion of low-grade coal under various operating conditions. The proposed model combines sequential modelling of drying/pyrolysis (devolatilization) and combustion of coal by means of conventionally used units (RYIELD and RGIBBS), and a newly used unit (FLUIDBED) in Aspen Plus. The model validation was performed by experiments on the combustion of low-grade coal in a pilot-scale circulating fluidized bed reactor (CFBR). Experimental data were used to further calibrate the Aspen Plus model and decrease model uncertainties. The results obtained from the developed simulation model were found to be in good agreement with the experimental data. Discrepancies of less than 15% were observed, in most of the predictions of molar fractions for the resultant flue gas composition, including NO_x and SO_x, emissions which were at ppm levels. As a result, the model can easily be used for design, scale-up, and simulation of coal combustion as well as for other feedstock like biomass in fluidized bed with process optimization based on sensitivity analysis.

中文翻译：

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流化床燃烧新工艺模型的开发与验证：在低品位煤高效燃烧中的应用

Aspen Plus 已经开发了许多模型，用于在流化床反应器中燃烧不同类型的煤。然而，这些模型是特定于案例的，特别是在煤类型和床反应器类型方面，这意味着这些模型的一般应用受到限制。此外，这些过程通常是通过采用一系列模型块来模拟 Aspen Plus 中的流化床反应器来逐步开发的。在这项研究中，已经实施了一种新的煤燃烧建模混合方法，以综合设计各种操作条件下低品位煤的转化模型。所提出的模型通过常规使用的单元（RYIELD 和 RGIBBS）以及 Aspen Plus 中新使用的单元（FLUIDBED）结合了煤的干燥/热解（脱挥发分）和燃烧的顺序建模。模型验证是通过在中试规模的循环流化床反应器 (CFBR) 中对低品位煤的燃烧进行的实验进行的。实验数据用于进一步校准 Aspen Plus 模型并降低模型的不确定性。发现从开发的模拟模型获得的结果与实验数据非常吻合。观察到的差异小于 15%，在大多数对所得烟气成分摩尔分数的预测中，包括 NO 发现从开发的模拟模型获得的结果与实验数据非常吻合。观察到的差异小于 15%，在大多数对所得烟气成分摩尔分数的预测中，包括 NO 发现从开发的模拟模型获得的结果与实验数据非常吻合。观察到的差异小于 15%，在大多数对所得烟气成分摩尔分数的预测中，包括 NO_x和 SO _x，排放量为 ppm 级。因此，该模型可轻松用于设计、放大和模拟煤炭燃烧以及其他原料（如流化床中的生物质），并基于敏感性分析进行工艺优化。