关键词: 反渗透, 压力延迟渗透, 脱盐, 优化, 模型, 标准化比能耗, 无量纲参数

Abstract:

This article presents a model-based optimization of the hybrid desalination system of reverse osmosis and pressure retarded osmosis with open-loop and closed-loop configurations. First, a constrained nonlinear optimization model for both configurations is formulated to minimize the normalized specific energy consumption (NSEC). In this optimization model, a set of dimensionless parameters in relation to membrane area, operating and design variables are used to build characteristic equations and simply the model formulation. To compare fairly, the pre- and post-treatment energy consumptions are considered as calculating NSEC of the open-loop hybrid configuration. By solving this model, the underlying impacts of the total dimensionless membrane area and water recovery ratio on NSECs, the membrane allocation, and the applied pressure are systematically explored. The results show that when the water recovery rate is at a normal level (≤0.55) and the total system area is sufficient (≥0.9), the closed-loop structure has a clear advantage over the open-loop structure in terms of energy saving and reduction of pretreatment costs.

Key words: reverse osmosis, pressure retarded osmosis, desalination, optimization, model, normalized specific energy consumption, dimensionless parameters