二氧化碳-氮气混合气体在微粉硅胶中生成水合物的 实验研究

空气中CO₂含量的增加导致了全球气候变暖问题。气体水合物能够有效分离出电厂尾气中的CO₂,对改善环境具有重要意义。考察了微粉硅胶（silica gel）中80mol% N₂与20mol% CO₂混合气体水合物形成特性,选取压力范围为6.0 ~ 8.0 MPa,温度范围为 -20 ~ -5℃。研究发现,N₂与CO₂混合气进入反应釜后,直接生成水合物,诱导时间小于1 min。压力越高、温度越低,生成水合物的相对气体消耗量越大,最大的相对气体消耗量为0.115 (mol/mol),水的转化率最大为77.02mol%,前30 min水合物生成速率与压力无关。水合物气体消耗量越大,反应釜中剩余N₂组分的含量越大,最大为90.95mol%。水合物生成驱动力越低,水合物中CO₂ 组分越高。在6.0 MPa、-5℃下,水合物中CO₂组分最大为65.70mol%。

Investigation on CO2/N2 Mixed Gas Hydrate Formation in a Silica Gel Bed

The increase of carbon dioxide content in the air leads to global climate problems. Gas hydrate can effectively separate carbon dioxide from power plant flue gas, which is of great significance to improve the environment. In this work, the CO₂/N₂ mixed gas hydrate formation in silica gel bed was studied under pressure and temperature ranges of (6.0 - 8.0 MPa) and (-20 - -5^oC), respectively. Results showed that the mixed gas hydrate formed immediately when the flue gas was pressurized into the reactor, and the induction time was less than 1 min. The normalized gas consumption was larger at higher pressure or lower temperature. The largest normalized gas consumption was 0.115 (mol/mol), and the highest water conversion was 77.02mol%. Pressure had no effect on the normalized rate of gas consumed for the first 30 min. The gas proportion of N₂ in equilibrium gas increased with the final gas consumption increase. The highest gas proportion of N₂ in equilibrium gas was 90.95mol%. CO₂ proportion in the hydrate was higher at lower hydrate formation driving force. The highest CO₂ proportion in the hydrate was 65.70mol% at 6.0 MPa and -5^oC.