Key Laboratory of Ocean Energy Utilization and Energy Conservation of the Ministry of Education, Dalian University of Technology, Dalian 116024, China.
Thermochemistry Laboratory, Liaoning Province Key Laboratory of Thermochemistry for Energy and Materials, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Environ Sci Technol. 2021 May 4;55(9):6206-6213. doi: 10.1021/acs.est.0c06407. Epub 2021 Feb 17.
Carbon storage in the form of solid hydrate under seafloor has been considered to be promising for greenhouse gas control. Yet, open issues still remain on the role of the organic matters abundant in marine environments in the kinetics of hydrate formation; of particular interest is the involvement of the acid-dissolvable organic matters accompanying the acidification upon CO injection. In this work, the CO hydrate formation in the presence of the organic matters was monitored through the low-field nuclear magnetic resonance technique. It was found that the organic matters could kinetically promote the formation of CO hydrate; this effect was further enhanced by the sulfur-containing acid-dissolvable organic matters. Water in the large pores was preferentially consumed; the following water conversion facilitated by the organic matters would result in a fragmentation of the large pores into separated small pores isolated by the hydrate clusters. Consequently, a further enhancement of the gas-water contact is suggested as the existence of substantial hydrate patches could act as a mass transfer barrier. Our findings expand our understandings on the kinetics of CO hydrate formation in the presence of the organic matters and indicate the stability zone of gas hydrate a kinetically favorable geological setting for CO sequestration.
海底以固态水合物形式储存碳被认为是控制温室气体的一种很有前途的方法。然而，在水合物形成动力学中，海洋环境中丰富的有机物的作用仍然存在一些问题；特别值得关注的是伴随 CO2 注入酸化而产生的可酸溶有机物的参与。在这项工作中，通过低场核磁共振技术监测了有机物存在时 CO2 水合物的形成。结果发现，有机物可以在动力学上促进 CO2 水合物的形成；含硫可酸溶有机物进一步增强了这一效果。大孔中的水优先被消耗；随后，由有机物促进的水转化会导致大孔碎裂成由水合物簇隔开的独立小孔。因此，建议进一步增强气-水接触，因为大量水合物斑块的存在可以作为传质障碍。我们的发现扩展了我们对有机物存在下水合 CO2 形成动力学的理解，并表明了在动力学上有利于 CO2 封存的气体水合物稳定带的存在。
