采用液化天然气(LNG)冷量的液体空分新流程及其(火用)分析

提出了2种采用液化天然气（LNG）冷量的新流程，并采用Aspen　Plus对流程进行了模拟计算。空气循环膨胀制冷的液体空分流程采用LNG冷量代替了空气外循环制冷，简化了制冷系统，与原始流程相比，液态产品的单位能耗降低约49％；氮气循环膨胀制冷的液体空分流程采用LNG冷量代替了高压氮气外循环制冷，系统所需循环氮气量减少，最高运行压力从4．6MPa降低到了2．6MPa，液态产品的单位能耗降低约53％。对流程的炯分析表明，与原始流程相比，新流程制冷单元的损失大大降低，系统整体的炯效率也得到了提高，LNG冷量回收用于空分流程制冷系统有利于节约生产成本，降低能耗，提高系统能量利用效率。

Scheme analysis on the liquid product air separation plant using the cold energy of LNG

Two different modified air separation systems giving liquid products were designed and the results were compared. Instead of air and nitrogen expanding refrigeration unit, LNG cold energy was used respectively to pre-cool the material air and cycle nitrogen in the two systems. These two systems were simulated with Aspen Plus software and an exnergy analysis was performed. Compared with conventional method without using LNG, the new systems without external air or nitrogen cycle were simpler and more convenient. From the determined results it was found out that the consumed electric energy per-kilogram liquid product decreased about 49% for the first scheme and about 53% for the second scheme after using LNG cold energy, the exergy losses of these two new systems also decreased a lot, and the rational efficiency in- creased about 17% separately. Thus it can be stated that using this new modification in the air separation system much beneficial results were obtained than the contemporary ones.