Role of hydrogen to promote hydrate formation of flue gas mixture of CO2 and N2 in silica nanofluid of single-step origin

Abstract

This study explores the role of hydrogen as doping agent to enhance CO2 hydrate formation in water and polymer (polyacrylamide, PAM) solution in the presence of varying composition of N2 (0–80 mol%). CO2 storage capacity in clathrate hydrate was explored in the presence of varying quantity of nitrogen (N2) to mimic a flue gas mixture, where N2 composition was gradually increased to simulate effluent gas composition. The silica nanofluids of varying size (35–39 nm, 0.1–1 wt%) were used to accelerate the rate of gas solubility and hydrate formation. All experiments were performed with an initial pressure of 50 bar and ambient temperature while an rpm of 350 was maintained to ensure agitation in the pot. No gas-hydrate was observed in flue gas mixture containing N2 > 45 mol% in both water and PAM solution. To induce hydrate formation in high quantity of N2, the role of hydrogen as a promoter was explored in low dosage volume (1 mol%). The inclusion of hydrogen helped to form gas hydrate for a mixture containing 50 mol% N2. Further, inclusion of silica nanoparticle (1 wt%) increased the rate of gas consumption and hydrate formation for flue gas mixture of 50 mol% N2, indicating positive effect of silica nanoparticle on hydrate formation. From the experimental data, it could be established that silica nanofluid had a positive impact on formation of CO2 hydrate. Gas consumption increased by atleast 12% during dissolution and over 25% during crystallization thus, increasing nanoparticle concentration was beneficial for stimulating gas consumption. The results indicate favorable role of SiO2 nanoparticle and hydrogen on carbon storage of impure gas mixtures exhibiting high amount of N2 (50 mol%).