特种高效填料用于13C分离的计算传质学研究

由于碳同位素分离系数仅为1.007，分离难度大，要获得99%¹³C的高丰度产品，需要近三千块理论级数，为有效降低工程化实施难度，需要采用特种高效填料实现¹³C的分离。为准确预测¹³C分离用低温精馏塔的传质性能，本文运用计算流体力学方法（CFD），对自主研制的高比表面高效规整填料PACK¹³C进行计算传质学分析。通过研究气液两相在两片填料片组成的精馏单元内部相互传质现象，提出了一种耦合传质效率的CFD计算方法；并实现由局部精馏单元的传质模拟计算推广到对整塔传质性能的模拟预测。结果显示，计算传质学模拟值与低温精馏分离¹³C同位素的传质实验值吻合较好，等板高度（HETP）的模拟值与实验值平均相对误差为10.15%；分离功模拟值与实验值的平均相对误差为9.1%。本研究方法可推广运用于¹³C产业化装置的传质性能预测。

Computational Mass Transfer Study of Special High-efficiency Packing Used in the Separation of Carbon-13

The separation of stable isotope carbon-13（¹³C） is very difficult because the separation coefficient is only 1.007. So it is necessary that nearly three thousand theoretical stages should be required to obtain a high abundance product of 99 atom%¹³C. In order to effectively reduce the difficulty of engineering implementation, it is necessary that high-efficiency packing should be used in the separation of¹³C. In this paper, the mass transfer analysis of the self-developed high-ratio surface efficient structured packing PACK ¹³C was carried out by means of computational fluid dynamics（CFD）, which was for accurately predicting the mass transfer performance of cryogenic rectification for¹³C separation. A kind of CFD calculation method for coupling mass transfer efficiency that the mass transfer performance of the entire column was extended from the simulation of the local rectification unit was established, which was obtained by the study on the mutual mass-transfer of gas-liquid two-phase inside the rectification unit consisting of two sheets of packing sheets. The results showed that the calculated mass transfer simulation values were in good agreement with the mass transfer experimental values of ¹³C isotopes separated by cryogenic rectification. The average relative error between the simulated value and the experimental value of the equivalent plate height (HETP) was 10.15%, and the average relative error of the separated work was 9.1%. This research method can be applied to the mass transfer performance prediction of¹³C industrialization equipment.