High efficient separation of H2/CH4 using ZIF-8/glycol-water slurry: Process modelling and multi-objective optimization

Hydrogen (H2) is expected to play a vital role in future global energy system. The efficient and low-energy consumption process for H2/CH4 separation from hydrogen rich industrial off-gas is still a key challenge. The absorption-adsorption process for H2/CH4 separation using ZIF-8/glycol-water slurry is a promising alternative technique due to its high sepa-ration efficiency, mild operation conditions and continuous operation mode. We proposed two process configurations: a decompression desorption process A to obtain 99.5 mol% H2; and a process B combined with decompression and H2 stripping desorption to attain 99.99 mol% H2. The detailed process modelling and multiple objective optimizations for two processes are conducted to determine optimal operation conditions, stream charac-teristics, and unit energy requirements. Results show that the H2 recovery ratio and total unit energy consumption reaches 99.70% and 0.3876 kW center dot h/Nm3 for Process A; 99.47% and 0.4608 kW center dot h/Nm3 for Process B, respectively. It indicates the novel process can simulta-neously achieve high purity and high H2 recovery with low energy consumption. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.