高压聚乙烯装置料仓脱气数学模型

以费克第二扩散定律为核心,结合非连续操作过程中聚乙烯颗粒的停留时间分布函数,推导出高压聚乙烯装置料仓脱气数学模型。该模型可定量计算料仓脱气过程中的通风量、料仓出口乙烯含量和聚乙烯颗粒最小脱气时间。运用料仓脱气数学模型可在料仓内一定初始乙烯含量下,预测出为使乙烯含量降低到某一标准所需的通风量以及达到安全生产要求所需的最小脱气时间。料仓出口气体中乙烯含量的计算值与工业装置的实际值基本吻合,证明料仓脱气数学模型具有较高的准确度。该模型求解过程简单,为料仓的安全运行、节约能源及优化操作提供了理论指导。

Mathematical Model for Purging Process of Silos in High-Pressure Polyethylene Plant

Based on the resident time distribution function of polyethylene particles in the silos of high-pressure polyethylene plant and Fick's second diffusion law,a mathematic model describing the purging process inside the silos was deduced to investigate the ethylene distributions and their variations versus time in the silos.This silo purging model can be used to quantitatively calculate purging air flow rate,outlet ethylene concentration and minimum residence time of polyethylene particles in the purging process.This model is particularly suitable for polyethylene industrial process due to its simple calculation.By using this model,minimum purging air flow rate under the given inlet ethylene concentration can be calculated and the minimum time which the purging process needs for safe operation can also be obtained.The comparison between the model prediction and the industrial data proved high accuracy of the model.The silo purging model can provide reliable guidance for the safe operation and process optimization of high-pressure polyethylene silos.