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A hybrid absorption-adsorption method to efficiently capture carbon.

Liu H, Liu B, Lin LC, Chen G, Wu Y, Wang J, Gao X, Lv Y, Pan Y, Zhang X, Zhang X, Yang L, Sun C, Smit B, Wang W - Nat Commun (2014)

Bottom Line: We show that this approach may give a more efficient technology to capture carbon dioxide compared to conventional technologies.Most importantly, the sorption enthalpy is only -29 kJ mol(-1), indicating that significantly less energy is required for sorbent regeneration.In addition, from a technological point of view, unlike solid adsorbents slurries can flow and be pumped.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, P. R. China.

ABSTRACT
Removal of carbon dioxide is an essential step in many energy-related processes. Here we report a novel slurry concept that combines specific advantages of metal-organic frameworks, ion liquids, amines and membranes by suspending zeolitic imidazolate framework-8 in glycol-2-methylimidazole solution. We show that this approach may give a more efficient technology to capture carbon dioxide compared to conventional technologies. The carbon dioxide sorption capacity of our slurry reaches 1.25 mol l(-1) at 1 bar and the selectivity of carbon dioxide/hydrogen, carbon dioxide/nitrogen and carbon dioxide/methane achieves 951, 394 and 144, respectively. We demonstrate that the slurry can efficiently remove carbon dioxide from gas mixtures at normal pressure/temperature through breakthrough experiments. Most importantly, the sorption enthalpy is only -29 kJ mol(-1), indicating that significantly less energy is required for sorbent regeneration. In addition, from a technological point of view, unlike solid adsorbents slurries can flow and be pumped. This allows us to use a continuous separation process with heat integration.

No MeSH data available.


Related in: MedlinePlus

Breakthrough experiment.(a) Bubble column breakthrough experiment for a CO2/N2 gas mixture (z1=0.2065) (303.15 K, 1 bar) carried out in ZIF-8/glycol–mIm slurry, (b) Column breakthrough experiments for a CO2/CH4 gas mixture (z1=0.276) (303.15 K, 1 bar) carried out in both ZIF-8/glycol–mIm slurry and pure water. The x axis is the time of the breakthrough experiment, the left y axis represents the concentration of gas components in outlet gas.
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f4: Breakthrough experiment.(a) Bubble column breakthrough experiment for a CO2/N2 gas mixture (z1=0.2065) (303.15 K, 1 bar) carried out in ZIF-8/glycol–mIm slurry, (b) Column breakthrough experiments for a CO2/CH4 gas mixture (z1=0.276) (303.15 K, 1 bar) carried out in both ZIF-8/glycol–mIm slurry and pure water. The x axis is the time of the breakthrough experiment, the left y axis represents the concentration of gas components in outlet gas.

Mentions: To mimic an actual separation process for capturing carbon in ZIF-8/glycol–mIm slurry, column breakthrough tests using two binary mixtures, CO2/N2 (zCO2=0.2065) and CO2/CH4 (zCO2=0.276), at 303.15 K were performed in a stainless bubbling column (Supplementary Fig. 8). For the CO2/N2 (zCO2=0.2065) mixture, N2 breakthrough occurred within 1 min, whereas CO2 breakthrough occurred after about 17 min for CO2/N2 (Fig. 4a and Supplementary Table 16). After the breakthrough of CO2, notably, the concentration of CO2 in the outlet gas still kept low for a long time; even after 6.7 h, the concentration of CO2 in the outlet gas was still less than half of the CO2 concentration in the feed gas. Similar results were obtained for CO2/CH4 (Fig. 4b and Supplementary Table 17). It should be noted that the slurry used for CO2/N2 was regenerated by purging with Helium at 318.15 K and atmospheric pressure, and then used for CO2/CH4. As the height of slurry in the column is only 1.31 m, the contact time of gas bubbles with slurry is very short. That suggests that this simple bubbling operation gives a high ab(d)sorption rate as most of CO2 in the inlet gas can be removed despite the short contacting time.


A hybrid absorption-adsorption method to efficiently capture carbon.

Liu H, Liu B, Lin LC, Chen G, Wu Y, Wang J, Gao X, Lv Y, Pan Y, Zhang X, Zhang X, Yang L, Sun C, Smit B, Wang W - Nat Commun (2014)

Breakthrough experiment.(a) Bubble column breakthrough experiment for a CO2/N2 gas mixture (z1=0.2065) (303.15 K, 1 bar) carried out in ZIF-8/glycol–mIm slurry, (b) Column breakthrough experiments for a CO2/CH4 gas mixture (z1=0.276) (303.15 K, 1 bar) carried out in both ZIF-8/glycol–mIm slurry and pure water. The x axis is the time of the breakthrough experiment, the left y axis represents the concentration of gas components in outlet gas.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4214418&req=5

f4: Breakthrough experiment.(a) Bubble column breakthrough experiment for a CO2/N2 gas mixture (z1=0.2065) (303.15 K, 1 bar) carried out in ZIF-8/glycol–mIm slurry, (b) Column breakthrough experiments for a CO2/CH4 gas mixture (z1=0.276) (303.15 K, 1 bar) carried out in both ZIF-8/glycol–mIm slurry and pure water. The x axis is the time of the breakthrough experiment, the left y axis represents the concentration of gas components in outlet gas.
Mentions: To mimic an actual separation process for capturing carbon in ZIF-8/glycol–mIm slurry, column breakthrough tests using two binary mixtures, CO2/N2 (zCO2=0.2065) and CO2/CH4 (zCO2=0.276), at 303.15 K were performed in a stainless bubbling column (Supplementary Fig. 8). For the CO2/N2 (zCO2=0.2065) mixture, N2 breakthrough occurred within 1 min, whereas CO2 breakthrough occurred after about 17 min for CO2/N2 (Fig. 4a and Supplementary Table 16). After the breakthrough of CO2, notably, the concentration of CO2 in the outlet gas still kept low for a long time; even after 6.7 h, the concentration of CO2 in the outlet gas was still less than half of the CO2 concentration in the feed gas. Similar results were obtained for CO2/CH4 (Fig. 4b and Supplementary Table 17). It should be noted that the slurry used for CO2/N2 was regenerated by purging with Helium at 318.15 K and atmospheric pressure, and then used for CO2/CH4. As the height of slurry in the column is only 1.31 m, the contact time of gas bubbles with slurry is very short. That suggests that this simple bubbling operation gives a high ab(d)sorption rate as most of CO2 in the inlet gas can be removed despite the short contacting time.

Bottom Line: We show that this approach may give a more efficient technology to capture carbon dioxide compared to conventional technologies.Most importantly, the sorption enthalpy is only -29 kJ mol(-1), indicating that significantly less energy is required for sorbent regeneration.In addition, from a technological point of view, unlike solid adsorbents slurries can flow and be pumped.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, P. R. China.

ABSTRACT
Removal of carbon dioxide is an essential step in many energy-related processes. Here we report a novel slurry concept that combines specific advantages of metal-organic frameworks, ion liquids, amines and membranes by suspending zeolitic imidazolate framework-8 in glycol-2-methylimidazole solution. We show that this approach may give a more efficient technology to capture carbon dioxide compared to conventional technologies. The carbon dioxide sorption capacity of our slurry reaches 1.25 mol l(-1) at 1 bar and the selectivity of carbon dioxide/hydrogen, carbon dioxide/nitrogen and carbon dioxide/methane achieves 951, 394 and 144, respectively. We demonstrate that the slurry can efficiently remove carbon dioxide from gas mixtures at normal pressure/temperature through breakthrough experiments. Most importantly, the sorption enthalpy is only -29 kJ mol(-1), indicating that significantly less energy is required for sorbent regeneration. In addition, from a technological point of view, unlike solid adsorbents slurries can flow and be pumped. This allows us to use a continuous separation process with heat integration.

No MeSH data available.


Related in: MedlinePlus