The rapid integration of intermittent renewable sources into the electricity grid is driving the need for more flexible, low-carbon fossil-fuel plants with lower capital costs. This then drives the need to improve the cryogenic air separation unit (ASU). To address this changing landscape, we explore a Praxair single-column ASU (PSC-ASU) design with the goal of reducing costs and improving flexibility, compared to a conventional double-column ASU. The PSC-ASU incorporates partial air condensation and air pre-separation in the bottom reboiler with a phase separator as well as N₂-enriched vapor condensation in the upper reboiler to decrease energy consumption, as compared to Linde’s single-column ASU. All three of the above-mentioned ASU designs are simulated in Aspen Plus and analyzed. An economic analysis is applied to evaluate the relative cost savings of the PSC-ASU compared to the double-column ASU. Results suggest that the specific energy consumption of the PSC-ASU is significantly lower than that of Linde’s single-column ASU due to a drastically improved oxygen recovery rate. Although this improved oxygen recovery rate is still lower than that of the double-column ASU, the required pressure ratio of the main air compressor is 21% lower than that of the double-column ASU. As a result, the specific energy consumption of the PSC-ASU is only 1.9% greater than that of the double-column ASU for producing 95.1 mol% O₂. However, the PSC-ASU reduces the hourly capital cost by 19% due to the elimination of a high-pressure column. This would effectively decrease the total hourly cost of the ASU, and thus the total hourly cost of low-carbon, fossil-fuel power plants that require oxygen.

间歇性可再生能源与电网的快速整合推动了对资本成本更低的更灵活、低碳的化石燃料发电厂的需求。这进而推动了改进低温空气分离装置 (ASU) 的需求。为了应对这种不断变化的局面，我们探索了普莱克斯单柱 ASU (PSC-ASU) 设计，与传统的双柱 ASU 相比，其目标是降低成本和提高灵活性。PSC-ASU 将底部再沸器中的部分空气冷凝和空气预分离与相分离器以及 N _{2 相结合}- 与林德的单塔空分装置相比，在上部再沸器中浓缩蒸汽冷凝以降低能耗。所有上述三种 ASU 设计都在 Aspen Plus 中进行了模拟和分析。应用经济分析来评估 PSC-ASU 与双柱 ASU 相比的相对成本节约。结果表明，由于氧回收率显着提高，PSC-ASU 的单位能耗显着低于林德的单柱 ASU。虽然这种提高的氧气回收率仍然低于双柱空分装置，但主空压机所需的压力比比双柱空分装置低21%。因此，PSC-ASU 的单位能耗仅比双柱 ASU 高 1.9%，用于生产 95.1 mol% O₂ . 然而，由于取消了高压塔，PSC-ASU 将每小时资本成本降低了 19%。这将有效地降低 ASU 的每小时总成本，从而降低需要氧气的低碳化石燃料发电厂的每小时总成本。