A new multiphase fluid dynamics model for a commercial ebullated bed hydroprocessor was developed. The impact of the gas–liquid distribution system is now explicitly included through new submodels for bubble size distribution and drag coefficients. The size distribution submodel is coupled with the existing gas–liquid separation submodel to better predict recycled gas and liquid flow rates. Either the mass of the catalyst inventory or recycle pump curve can be specified as inputs to converge the model; the former is not always well known during operation in which case the latter can be used after making a few assumptions. A sensitivity analysis was performed to study the impact of fresh treat gas velocity, catalyst mass, phase properties, and reactor internals on recycled gas and liquid flow rates, bubble size distribution, and bed liquid holdup. A 0.2 mm shift in bubble size distribution toward larger sizes was found to significantly increase bed liquid holdup, suggesting that distributor modification/redesign could help improve the capacity of the hydroprocessor.

中文翻译：

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商业化沸腾床水处理器的流体动力学建模

开发了一种用于商业沸腾床水处理器的新的多相流体动力学模型。现在，通过气泡尺寸分布和阻力系数的新子模型明确包括了气液分布系统的影响。尺寸分布子模型与现有的气液分离子模型结合在一起，可以更好地预测回收的气体和液体的流速。可以指定催化剂库存的质量或循环泵曲线的质量作为收敛模型的输入。前者在操作过程中并不总是众所周知的，在这种情况下，可以在做出一些假设后使用后者。进行了敏感性分析，以研究新鲜处理气体的速度，催化剂质量，相性质和反应器内部因素对再循环气体和液体流速，气泡尺寸分布和床液滞留量的影响。