Experimental investigation for comparative effectiveness of CO2+N2 and CO2+N2+H2 on integrated methane production and carbon storage from natural hydrate media. Issue 2 (April 2023)

• Record Type: Journal Article
• Authors: Chaturvedi, Krishna Raghav; Sharma, Tushar; Trivedi, Japan; Kumar, G. Suresh
• Is Part Of: Journal of environmental chemical engineering. Volume 11:Issue 2(2023)
• Publication Date: 2023-04
• Subjects: Carbon storage -- Gas hydrates -- Hydrogen -- Gas chromatography; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2023.109388
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: CH4 hydrates have recently been hailed as a promising new sustainable energy source. The replacement of CO2 within natural gas hydrates is a method that may be used for simultaneous energy production and carbon dioxide storage. In the marine settings of Krishna Godavari basin, pressure and temperature circumstances prevent the faster replacement of hydrate reservoirs by injected CO2 . In this work, using a depressurization method and CO2 -N2 gas (as a standing for flue gas exhaust) injection, it was tested whether it was technically feasible to recover CH4 while ensuring long term CO2 storage. The presented experiments have demonstrated that injecting gas with a low N2 concentration (up to 40%) happens to cause a significant co-growth in hydrates of mixed nature, as indicated by observed data, along with recovery of CH4 . While the results showed that gas injection synthesis of CH4 and its replacement by CO2 was feasible in marine settings, careful attention was required to the proportions of the injected mixed gases. Herein, the role of hydrogen in low concentration is essential; thus, its role as a diluent must be explored separately. Beyond a certain threshold of N2 in the mixed gas, low CH4 recovery (i.e. less than 10 mol% was observed). Alternatively, when a higher concentration of N2 was injected along with H2, it was possible to see a continuous dissociation of CH4 hydrate, even at 45% N2 . Beyond 40 mol% N2, low CH4 recovery (i.e., less than 10 mol%) was observed due to a replacement ratio of less than 0.27. Alternatively, when a higher concentration of N2 (45 mol%) was injected along with 1 mol% H2, it was possible to notice a continuous dissociation of CH4 hydrate. The findings of this study, indicate the feasibility of injecting mixed flue gas compositions (CO2 +N2 ) along with low concentration of H2, as a diluent, for recovery of CH4 from a natural gas hydrate reservoir. Highlights: CH4 hydrate formation explored in deep-oceanic sediments to mimic Indian conditions. Observed feasibility of CH4 -CO2 (gas) replacement using depressurization. Insignificant gas replacement observed for N2 composition ∼45 mol%. Inclusion of H2 up to 1 mol% promoted gas replacement even at N2 > 45 mol%. Proposal of H2 storage as solid gas hydrates for long-term/large-scale durations.