Ethane recovery is a vital step in natural gas processing and can provide raw material for ethylene production. The widely used cryogenic separation process is energy intensive, and the absorption-adsorption coupling process based on porous ZIF-8 slurry (SorbPro I) has been proven to be more energy-efficient. To further reduce energy consumption, this paper proposes a novel process with two absorption-adsorption columns (SorbPro II) and establishes its mathematical model by equilibrium stage method. Taking the natural gas with an ethane content of 6.19 mol% at 300,000 Nm/d as a case study, the operating parameters of SorbPro I and SorbPro II are optimized by sensitivity analysis, and ethane recovery ratio of both processes can reach 90 %. The techno-economic/energy consumption evaluations of the two processes are conducted. Results show that the total annualized cost and the energy consumption per Nm feed gas of SorbPro II are 41.7 % and 47.7 % lower than those of SorbPro I, respectively. It indicates that SorbPro II has the same separation performance as SorbPro I, but is more economical.

中文翻译：

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使用 ZIF-8/水-乙二醇浆液从天然气中回收乙烷的新工艺：技术经济和能耗评估

乙烷回收是天然气加工中至关重要的一步，可为乙烯生产提供原料。广泛使用的低温分离过程是能源密集型的，而基于多孔ZIF-8浆料（SorbPro I）的吸收-吸附耦合过程已被证明更加节能。为了进一步降低能耗，本文提出了一种双吸收-吸附塔的新工艺（SorbPro II），并采用平衡阶段法建立了其数学模型。以300,000 Nm/d乙烷含量6.19 mol%的天然气为例，通过灵敏度分析对SorbPro I和SorbPro II的操作参数进行优化，两种工艺的乙烷回收率均可达到90%。对这两个过程进行了技术经济/能耗评估。结果表明，SorbPro II 的年化总成本和每 Nm 原料气能耗分别比 SorbPro I 低 41.7% 和 47.7%。这表明SorbPro II具有与SorbPro I相同的分离性能，但更经济。