Abstract:

The conversion and selectivity of an extremely large multi-tubular fixed-bed reactor of industrial level remarkably relate to the distribution homogeneity of temperature and flow of heat transfer medium in shell side. In this work, through introducing two items of resistance source and a dispersed heat transfer source, the distribution of temperature and flow in the shell of a multi-tubular fixed-bed reactor of industrial level for butane oxidation to maleic anhydride was investigated by CFD simulation. Subsequently, effects of the window size and the location of baffles on the pressure drop of shell side and the distribution of temperature and flow were studied. It showed that the pressure drop of the shell side achieved by simulation are in good agreement with that by calculation of experimental equations, and the simulated temperature distribution of shell side is in accordance with industrial experimental data. With an increase in window area of the baffles, the pressure drop of shell side exponentially decreased, the range of large temperature difference (with a radial temperature difference greater than 2 K), and the radial temperature difference increased. With a decrease in height of the first baffle, both the range of large temperature difference and the radial temperature difference reduced, while the pressure drop of shell side did not show any consistent changes. Here the modeling strategy can be a good way to optimize the design of extremely large multi-tubular fixed-bed reactor of industrial level.

Key words: fixed-bed reactor, CFD simulation, optimal design

摘要：

工业级大型列管式固定床反应器壳程温度场与流场的均匀程度与反应的转化率及选择性密切相关。通过添加阻力源项和分散热源项，对工业级全尺寸错流列管式固定床壳程流场及温度场进行了CFD模拟研究，并进一步考察了折流板窗口区大小及其位置对壳程压降与温度分布的影响。结果表明，模拟得到壳程压降与由经验公式计算得到的压降较为接近，且壳程温度分布与工业实际数据吻合；增大窗口区面积，壳程压降呈现指数下降，同时高温差区（径向温差大于2 K）的范围与径向温差变大；随着第1块折流板位置降低，高温差区范围及径向温差均减小，但压降并不呈现规律性变化。模拟方法可用于工业级大型列管式固定床反应器的优化及设计。

关键词: 固定床反应器, 计算流体力学, 优化