Abstract:

A novel ammonia-based CO₂ capture process was proposed in the paper. The process uses magnetically gas-solid-liquid bed as the reactor in which the ferromagnetic particles suspend in aqueous ammonia solutions under the influence of external magnetic field (EMF). A continuous of CO₂ passed through the reactor was absorbed by aqueous ammonia. Experiments in a laboratory-scale apparatus were carried out to investigate the roles of EMF. The results showed that the highest CO₂ absorption efficiency with 8 mT EMF and 2 g·L^-1 nano-magnetic particles reached 94.3%, more than 8.8% compared to that without EMF and nanoparticles. CO₂ absorption efficiency with EMF and nanoparticles increased significantly under the conditions of low concentration aqueous ammonia (5%—8%), large flux of simulated flue gas (3.5 L·min^-1) and low absorption temperature (22—36℃). The enhancement of CO₂ absorption under the influence of EMF and nanoparticles should be attributed to good gas-liquid contact, large mass transfer coefficient and high reactivity of aqueous ammonia.

Key words: CO₂ capture, magnetic field, aqueous ammonia solution, absorption, nanoparticles

摘要：

开发了一种新型磁场辅助氨法烟气脱碳技术。含碳烟气通入混有磁性颗粒的氨水溶液，在外加磁场的作用下发生脱碳反应。对该技术的运行特性开展了实验研究。结果表明，外加8 mT恒稳磁场，2 g·L^-1纳米级Fe₃O₄颗粒，氨水的CO₂脱除效率比不添加磁场和颗粒时最多可提高8.8%。外加磁场可以有效提高低浓度氨水的CO₂脱除效率。在模拟烟气流量增加时，外加磁场能有效减缓CO₂脱除效率下降的趋势。同时，外加磁场使得CO₂脱除效率曲线向低温方向移动5℃，有助于提高低温条件下的CO₂脱除效率。磁场可提高气液接触效率、降低相间传质阻力、增强氨水反应活性，从而提高氨水吸收CO₂性能。

关键词: 二氧化碳捕集, 磁场, 氨水, 吸收, 纳米颗粒