Application of engineered natural ores to intermediate‐ and high‐temperature CO₂ capture and conversion

Abstract

Integrated CO2 capture and conversion (ICCC) is a promising technology aiming at converting waste CO2 to fuels and high value‐added chemicals. Herein, we described a proof‐of‐concept study of applying engineered natural ores (dolomite, magnesite, and limestone) to two different ICCC processes—intermediate‐temperature ICCC for CH4 production (350–400°C) and high‐temperature ICCC for syngas production (650–700°C). In the former process, a MgO‐based CO2 sorbent prepared from dolomite and magnesite was combined with a methanation catalyst in a dual‐bed configuration, whereby a CH4 yield of 7.1–7.3 mmol/g can be stably achieved per cycle over 20 consecutive ICCC cycles. In the latter process, a CaO‐based sorbent derived from dolomite and limestone was coupled with a reforming catalyst also in a dual‐bed mode, whereby syngas with a H2/CO ratio of 0.9–1.0 can be produced over 20 cycles. This study will expand the application of natural ores in CO2 emission reduction.

Integrated CO2 Capture and Utilization by Combining Calcium Looping with CH4 Reforming Processes: A Thermodynamic and Exergetic Approach

“…The potential of reducing the temperature of calcination has triggered the interest for various integrated CO 2 capture and utilization processes, , while calcium looping coupled with dry reforming of methane (CaL-DRM) has already been widely studied and applied for postcombustion CO 2 capture applications. ,− A major issue of this process is the carbon deposition in the reactive calcination stage. − Although carbon can be gasified by CO 2 in the subsequent carbonation stage, the release of CO with the CO 2 -stripped flue gas raises environmental concerns, , while CO 2 cannot completely gasify all carbon . Another problem is related to the partial oxidation of the Ni surface during exposure under CO 2 during carbonation. , Even though the formed NiO can be reduced from CH 4 in the calcination stage, the inadequate number of Ni active sites in the beginning of the stage can affect the syngas quality.…”

“… 10 , 13 − 17 A major issue of this process is the carbon deposition in the reactive calcination stage. 16 − 18 Although carbon can be gasified by CO 2 in the subsequent carbonation stage, the release of CO with the CO 2 -stripped flue gas raises environmental concerns, 13 , 19 while CO 2 cannot completely gasify all carbon. 16 Another problem is related to the partial oxidation of the Ni surface during exposure under CO 2 during carbonation.…”