CO2 conversion for syngas production in methane catalytic partial oxidation

•CO2 is utilized for syngas production from the catalytic partial oxidation of methane.•A rhodium-based catalyst bed is employed where dry reforming is enhanced.•The effects of altered CO2/O2 and O2/CH4 ratios on CO2 conversion are considered.•The maximum syngas production is exhibited at CO2/O2 = 0.2 when the O/C ratio is 1.•At least 10% and up to 41% of CO2 can be utilized for syngas production in CPOM.

The catalytic partial oxidation of methane (CPOM) involves the interaction among methane combustion (MC), steam reforming (SR), and dry reforming (DR), and CO2 generated from MC is utilized for syngas production in DR. To evaluate the potential of CO2 utilization in CPOM for syngas production, a numerical study is carried out where CO2 is added into the feed gas and CPOM is triggered in a rhodium-based catalyst bed. Two important parameters of CO2/O2 ratio and O2/CH4 ratio (or O/C ratio) in the feed gas are taken into account. The predictions suggest that CO2 addition plays no part in MC, but it retards SR and intensifies DR. The CO2 consumption increases with CO2/O2 ratio; however, the CO2 conversion goes down. As a whole, increasing CO2 addition enhances CO formation but reduces H2 formation. The maximum syngas production is exhibited at CO2/O2 = 0.2 when the O/C ratio is 1. At a fixed CO2/O2 ratio, the maximum H2 yield and CO2 consumption are located at O/C = 1.8 and 1.0, respectively. However, the CO2 conversion monotonically decreases with increasing O/C ratio. Within the investigated range of CO2/O2 and O/C ratios, the H2 yield and CO2 conversion in CPOM are in the ranges of approximately 0.42–1.34 mol(mol CH4)−1 and 10–41%, respectively.

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