New environmentally attractive separation technology for flue gas mixture

Separation of gaseous mixtures produced from any process plant can be a major issue for the industry. In comparison to other separation techniques available, hydrate formation can be an appropriate choice in terms of fuel efficiency and degree of separation. In this work, a three-stage process was designed to capture CO₂ from a hypothetical flue gas mixture (comprising 15 mol% CO₂+ 85 mol% N₂). For the hydrate based CO₂ capture process, a detailed analysis was carried out covering the material and energy balance, energy integration and economic analysis. The results show that, at steady state, 91% of the CO₂ in the flue gas can be recovered, resulting into two streams: Stream-A (94 mol% CO₂ + 6 mol% N₂) and Stream-B (1.5 mol% CO₂ + 98.5 mol% N₂). Per 100 mol of the flue gas feed, 3.9 MW of energy is required to achieve such degree of separation. This amount was reduced to 2.4 MW after energy integration was applied to the process. Overall, the process can help in reducing CO₂ emission via flue gas because of the huge difference in the carbon foot print of its energy requirement (500 g CO₂ per kWh) and the amount of CO₂ captured by the process (2190 g CO₂ per kWh).