基于代理模型的含盐废水多级纳滤系统的过程优化设计

基于道南细孔-介电DSPM-DE模型，开展了工业含盐废水多级纳滤分离系统的代理模型构建与优化研究。首先，利用高维模型表征的数学建模方法，构建与原有纳滤理论模型有高拟合度的高精度代理模型。基于此代理模型，进一步构建膜法分盐工艺中的多级纳滤分离的数学优化模型，并以分离单位质量NaCl的比能耗为优化目标，讨论在给定设计参数的条件下进料液中Cl^-]/\mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}-}]的变化对不同级数纳滤系统的分盐性能及最优操作条件的影响。优化结果显示，进料Cl^-]/\mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}-}]的增加有利于提高NaCl总回收率和降低分盐比能耗。在相同的纳滤膜投资成本下，双级系统在降低能耗方面更胜一筹，与单级系统相比最高可节能5.84%。

Surrogate model-based optimal design of multi-stage nanofiltration separation system for saline wastewater

Based on Donnan steric pore model with dielectric exclusion (DSPM-DE), this work develops a surrogate model for the multi-stage nanofiltration separation of industrial saline wastewater. Firstly, a high-fidelity surrogate model with a high fitting degree is established to describe the DSPM-DE-based nanofiltration process via high dimensional model representation. On this basis, we construct the optimization model of multi-stage nanofiltration separation for minimizing the specific energy consumption (SEC) of unit NaCl separated. The impacts of the changing feed ratio Cl^-]/\mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}-}] on the separation performance and optimal operating conditions of the nanofiltration system are investigated under the given design parameters. The results indicate that an increased feed ratio Cl^-]/\mathrm{S}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{2}-}] is beneficial to improve the total recovery of NaCl and to reduce the SEC. Under the same investment cost of nanofiltration membranes, the two-stage system is superior in reducing energy consumption, and can save up to 5.84% compared with the single-stage system.