Abstract Pressure-retarded osmosis has enjoyed increasing research interest over the last decade. Recent studies focusing on single-stage PRO designs have raised doubts regarding the long-term economic viability of the technology. While most of the analyses are based on single-stage operation, comprehensive analysis of multistage PRO which shows promise for better energetic performance is absent. Previous studies on multistage PRO differ in their design philosophies and performance metrics, leading to an incomplete assessment regarding the potential benefits of multistaging. In this paper, we develop a unifying framework to classify several existing multistage configurations. In addition, we analyze the multistage PRO system from a thermodynamic perspective. Among the two major multistage design strategies, namely interstage pressure control and independent feed inputs to each stage, we found the latter to be more effective towards increasing net power density. In comparison to a single-stage device, a 10-stage system achieves around 9% higher net power density while using the same membrane area.

中文翻译：

---

多级压力延迟渗透配置：统一框架和热力学分析

摘要 压力延迟渗透在过去十年中受到越来越多的研究兴趣。最近针对单级 PRO 设计的研究对该技术的长期经济可行性提出了质疑。虽然大多数分析都基于单级操作，但缺乏对多级 PRO 的综合分析，该分析表明有望获得更好的能量性能。以前对多级 PRO 的研究在设计理念和性能指标上有所不同，导致对多级潜在好处的评估不完整。在本文中，我们开发了一个统一框架来对几种现有的多级配置进行分类。此外，我们从热力学角度分析了多级 PRO 系统。在两大多阶段设计策略中，即级间压力控制和每个级的独立进料输入，我们发现后者对于增加净功率密度更有效。与单级装置相比，10 级系统在使用相同膜面积的情况下可实现高出约 9% 的净功率密度。