Abstract:

Capturing CO₂ released from large point sources such as power plants is an option to reduce man-made CO₂ emissions. As a new gas separation and purification technology, the hydrate method is key to strengthening the formation rate and water-to-hydrate ratio. In this study, a self-developed spray hydrate reactor was used to carry out carbon capture experiments with large and small water volumes (640 and 160 ml). And the carbon capture efficiency and hydrate growth characteristics were investigated under the nozzle aperture diameters of 0.1 and 0.8 mm, and different concentrations of kinetic promoters: sodium dodecyl sulfate (SDS) and L-methionine (L-Met). The experimental results show that the 0.1 mm aperture nozzle is favorable for CO₂ capture. For both L-Met and SDS systems, the final amount of CO₂ gas trapped in per mole of solution is an order of magnitude higher than that in pure water, and the efficiency of the promoter is better at a lower concentration 0.1% (mass) than that at a higher concentration 1% (mass). The final gas consumption of the SDS system in the large water volume experiment is the highest at 0.0848 mol /mol H₂O, 1.4 times that of the L-Met system, but the capture rate of the L-Met system is better than that of the SDS system. In the small water volume experiment, the gas capture amount and capture rate of the L-Met system are better than that of the SDS system. The growth angle of hydrate wall-climbing is 1.8 times that of 1% (mass) at 0.1% (mass) promoter. Such combination of L-Met solution with concentration 0.1% (mass), a nozzle with aperture 0.1 mm, and an injection method with small rate 3.33 ml/min, represents the best performance of promoting hydrate-based CO₂ capture. The results provide reference and basic experimental data for the enhancement of CO₂ capture in flue gas by hydrate method in spray reactor.

Key words: hydrate, CO₂ capture, flue gas, spray, promoters, hydrate morphology

摘要：

对发电厂等大型点源释放的CO₂捕集是减少人为CO₂排放的一种选择，水合物法作为一种新型气体分离提纯技术，形成速率和水转化为水合物比率的强化是该技术关键。利用自主开发的喷雾水合物反应器进行了大水量（640 ml）和小水量（160 ml）碳捕集实验，考察了喷嘴孔径（0.1 mm和0.8 mm）、不同浓度十二烷基硫酸钠 （SDS）和L-蛋氨酸（L-Met）动力学促进剂对碳捕集效率及水合物生长特性的影响。实验结果表明：0.1 mm孔径喷嘴有利于CO₂捕集。L-Met和SDS体系每摩尔水最终圈闭的CO₂较纯水体系均提升1个数量级，而且低浓度（质量分数0.1%）促进剂效率优于高浓度（质量分数1%）。大水量实验SDS体系最终气体消耗量最高为0.0848 mol /mol H₂O，为L-Met体系的1.4倍，但捕集速率L-Met体系优于SDS体系。小水量实验L-Met体系气体捕获量与捕集速率均优于SDS体系。促进剂浓度为0.1%（质量分数）时水合物爬壁生长角度是1%（质量分数）的1.8倍。综合评估，0.1%（质量分数）L-Met、0.1 mm喷嘴和小水量（3.33 ml/min）的注液方式共同作用，碳捕集性能最佳。上述实验结果为强化喷雾反应器中水合物法捕集烟道气中CO₂提供参考与基础实验数据。

关键词: 水合物, 二氧化碳捕集, 烟道气, 喷雾, 促进剂, 水合物形态