Recent Progress in the Integration of CO2 Capture and Utilization

Abstract

CO₂ emission is deemed to be mainly responsible for global warming. To reduce CO₂ emissions into the atmosphere and to use it as a carbon source, CO₂ capture and its conversion into valuable chemicals is greatly desirable. To reduce the transportation cost, the integration of the capture and utilization processes is a feasible option. Here, the recent progress in the integration of CO₂ capture and conversion is reviewed. The absorption, adsorption, and electrochemical separation capture processes integrated with several utilization processes, such as CO₂ hydrogenation, reverse water-gas shift reaction, or dry methane reforming, is discussed in detail. The integration of capture and conversion over dual functional materials is also discussed. This review is aimed to encourage more efforts devoted to the integration of CO₂ capture and utilization, and thus contribute to carbon neutrality around the world.

Keywords: CO2 capture; CO2 conversion; carbon neutrality; integration.

Figure 1

(a) Proposed pathways of carbon capture and subsequent hydrogenation of the captured CO₂ [12]; (b) Formic acid yields in the hydrogenation of CO₂ catalyzed by the PEI–PN/Ir materials as a function of temperature and MW of PEI for PEI₆₀₀–PN/Ir (▪), PEI₁₈₀₀–PN/Ir (•), and PEI_25 000–PN/Ir (▴) [13]. (c) Multiple recycling of the catalyst in biphasic reaction mixture. Yield (%) of formate is relative to the amount of CO₂ captured. Ru–PNP 1: Cat 1 = 10 μmol, T = 55 °C, H₂ = 50 bar, 17.2 mmol diazabicyclo[2.2.2]octane (DABCO) + 3 mL H₂O (CO₂ captured each cycle = 15 mmol), 3 mL additional H₂O–4 mL 2-Methyltetrahydrofuran (2–MeTHF) added for hydrogenation study. Fe–PNP 4: Cat 4 = 20 μmol, T = 55 °C, H₂ = 50 bar, 17.2 mmol DABCO + 3 mL H₂O (CO₂ captured each cycle = 15 mmol), 3 mL additional H₂O–4 mL 2–MeTHF added for hydrogenation study [14]. (d) Proposed reaction sequence for CO₂ capture and in situ hydrogenation to CH₃OH using a polyamine [5].

Figure 2

(a) Preparation of porous organic networks bearing imidazolium salts [17]; (b) Yields of chloropropene carbonate from the cycloaddition of epichlorohydrin and CO₂ catalyzed by PIPs with corresponding QPs and PIP-Me-X, PIP-Et-X, and PIP-Bn-X (X = Cl, Br, and I). Reaction conditions: epichlorohydrin (1.0 g, 10.9 mmol), catalyst (0.05 mmol, based upon the quaternary phosphonium salt), 323 K, CO₂ (ambient pressure), and 24 h [19].

Figure 3

Schematic illustration of the preparation of (a) polyILs@MIL–101 [24] and (b) La–Vim/DUT–5 [27]. The “*” represents the monomer in the polymer.

Figure 4

(a) Schematic illustration of a MOCC membrane reactor with a catalyst bed for electrochemical CO₂ capture and catalytic DMR. TPB: triple phase boundary [31]. (b) Effect of temperature on the DMR performance of a GDC–MC membrane reactor with an NMP catalyst [31]. (c) Effect of temperature on the DMR performance of a GDC–MC membrane reactor with an NMP catalyst and an LNF catalyst [31]. (d) Stability of DOMR performance of the Ag–MC MECC membrane reactor at 800 °C with NMP catalyst. Feed gas: 75 mL min⁻¹ N₂, 15 mL min⁻¹ CO₂, and 10 mL min⁻¹ O₂; sweep gas: 0.94 mL min⁻¹ CH₄ and 50 mL min⁻¹ Ar [32]. The dotted circles and arrows in the figure represent the axes corresponding to the curve.

Figure 5

(a) Schematic illustration of membrane reactor [37]. (b) Comparison of CO₂ flux and recovery of the membrane reactor between experimental results and modeling results. Conditions: sweep: He = 200 mL min⁻¹; feed: CH₄ = 5 mL min⁻¹; S/C = 3; both sides of the membrane were at 1 atm [37]. (c) Schematic illustration of (c1) Membrane reactor; (c2) Co-fed fixed bed reactor; (c3) Charge species transport and surface reactions in the membrane reactor; (c4) Reaction pathway diagram. 2D axial symmetric computational domain of (c5) Membrane reactor; (c6) Co-fed fixed bed reactor [38].

Figure 6

(a) Comparison of cyclic CO₂ capture-release stability of the as-prepared bifunctional materials at 650 °C [48]. (b) CO₂ sorption capacities and CO productivities of Ni/CS, Ni/CS–P30–C and Ni/CS–P30–C–P at 650 °C within 17 cycles [49] (The symbols indicate different preparation methods. The yellow and blue lines represent CO₂ sorption capacities and CO productivities, respectively). Cyclic CO₂ capture and conversion reactions of (c) Ca₁Ni_0.1; and (d) Ca₁Ni_0.1Ce_0.033 [50].