Abstract Pressure retarded osmosis (PRO) is technically feasible to extract salinity gradient energy, which represents a potential source of clean and renewable energy of enormous amount. Specific energy used in the assessment of economic viability of a pressure retarded osmosis (PRO) is commonly determined by normalization of the total energy with the combined volume of feed and draw waters indiscriminately. Such a specific energy may not be appropriate to serve this purpose because it does not reflect the enormous impact of the different pretreatment costs for feed and draw waters. In this article, expression for maximum available salinity gradient energy is derived by construction of a reversible PRO process. By introduction of a new concept of equivalent volume, the specific energy from salinity gradients can be rigorously analyzed for PRO process with different costs in pretreatment of low and high salinity waters. The feed fraction to maximize the specific energy in PRO is analytically determined to be 1-1/e (≈ 0.632) when the cost for pretreatment of feed and draw waters are equal. Furthermore, higher peak specific energy occurs at lower feed fraction as the cost for draw water pretreatment decreases.

中文翻译：

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限制来自压力延迟渗透的可提取能量，对进料和出料解决方案具有不同的预处理成本

摘要 压力延迟渗透（PRO）在提取盐度梯度能量方面具有技术可行性，是一种潜在的清洁和可再生能源的巨大来源。用于评估压力延迟渗透 (PRO) 经济可行性的比能量通常通过将总能量与进水和取水的总体积不加区别地归一化来确定。这种特定的能量可能不适合用于此目的，因为它没有反映给水和取水的不同预处理成本的巨大影响。在本文中，最大可用盐度梯度能量的表达式是通过构建可逆 PRO 过程推导出来的。通过引入等效体积的新概念，在低盐度和高盐度水的预处理中，对于具有不同成本的 PRO 工艺，可以严格分析盐度梯度的比能量。当进料和取水的预处理成本相等时，用于最大化 PRO 中比能的进料分数经分析确定为 1-1/e (≈ 0.632)。此外，随着提取水预处理成本的降低，较高的峰值比能出现在较低的进料分数。