Chen Jun-Li, Xiao Peng, Zhang De-Xin, Chen Guang-Jin, Sun Chang-Yu, Ma Qing-Lan, Yang Ming-Ke, Zou En-Bao
State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing, China.
Front Chem. 2020 Apr 21;8:294. doi: 10.3389/fchem.2020.00294. eCollection 2020.
Porous materials are deemed to be capable for promoting hydrate formation, while for the purpose of hydrate-based gas storage, those systems containing porous materials often cannot meet the requirement of high storage density. To increase the storage density, an adsorption-hydration sequence method was designed and systematically examined in this study. Methane storage and release in ZIF-8 slurries and fixed beds were investigated. The ZIF-8 retained 98.62%, while the activated carbon lost 62.17% of their adsorption capacities in slurry. In ZIF-8 fixed beds, methane storage density of 127.41 V/V was acquired, while the gas loss during depressurization accounted for 21.50% of the gas uptake. In the ZIF-8 slurry, the storage density was effectively increased with the adsorption-hydration sequence method, and the gas loss during depressurization was much smaller than that in fixed beds. In the slurry, the gas uptake and gas loss decreased with the decrease of the chilling temperature. The largest gas uptake and storage density of 78.84 mmol and 133.59 V/V were acquired in the slurry with ZIF-8 content of 40 wt.% at 268.15 K, meanwhile, the gas loss just accounted for 14.04% of the gas uptake. Self-preservation effect was observed in the slurry, and the temperature for the slowest gas release was found to be 263.15 K, while the release ratio at 10 h reached to 43.42%. By increasing the back pressure, the gas release rate could be effectively controlled. The gas release ratio at 1.1 MPa at 10 h was just 11.08%. The results showed that the application of adsorption-hydration sequence method in ZIF-8 slurry is a prospective manner for gas transportation.
多孔材料被认为能够促进水合物的形成，然而对于基于水合物的气体储存而言，那些包含多孔材料的系统往往无法满足高储存密度的要求。为了提高储存密度，本研究设计并系统考察了一种吸附-水合顺序法。研究了甲烷在ZIF-8浆液和固定床中的储存与释放情况。在浆液中，ZIF-8保留了98.62%的吸附容量，而活性炭损失了62.17%的吸附容量。在ZIF-8固定床中，获得了127.41 V/V的甲烷储存密度，而减压过程中的气体损失占气体吸收量的21.50%。在ZIF-8浆液中，采用吸附-水合顺序法有效地提高了储存密度，且减压过程中的气体损失远小于固定床中的情况。在浆液中，气体吸收量和气体损失量随冷却温度的降低而减小。在268.15 K下，ZIF-8含量为40 wt.%的浆液中获得了最大气体吸收量78.84 mmol和储存密度133.59 V/V，同时气体损失仅占气体吸收量的14.04%。在浆液中观察到了自保护效应，发现气体释放最慢的温度为263.15 K，而10 h时的释放率达到43.42%。通过增加背压，可以有效地控制气体释放速率。在1.1 MPa下10 h时的气体释放率仅为11.08%。结果表明，吸附-水合顺序法在ZIF-8浆液中的应用是一种有前景的气体输送方式。
