Syngas Production by Partial Oxidation of Methane and CO2 Conversion Using Chemical Looping Method

Syngas (a mixture of hydrogen and carbon monoxide) could be produced by natural gas (methane) with steam or oxygen. The current methods such as catalytic reforming and autothermal deal with high energy consumption and cost demands. As an alternative, chemical looping reforming could be used with versatile features such as no need of pure oxygen, low CO2 reduction and better process integration. In the current article, a dynamic chemical looping process is employed to produce syngas resulted in the reduction of a perovskite oxygen carrier from methane. After that, the re-oxidation is performed in two steps with both CO2 and Air. The perovskite catalyst, synthesized by combustion method, was tested in a fixed-bed reactor in a dynamic manner. In the reduction reactor, however, the syngas was produced in a limited time. The CO2 produced during the reduction was below 5%, which is lower than that of the common methods. By continuing the reduction reactions, a high amount of hydrogen is produced, but solid coke is formed too. Hence, the reduction is partially performed. To compensate the consumed oxygen of the perovskite lattice, at first, the greenhouse gas of CO2 is injected into the reactor, followed by oxidation by Air. Moreover, the coke removal (combustion) is performed during these two oxidation steps. The results show that, the methane conversion is reached to 90% during the first 30 min of the reduction. A vast majority of CO2 is converted to CO in only 17 min of the first oxidation step. In addition, the time that is required for air-re-oxidation to remove the cokes is equal to 20 minutes. Finally, according to the obtained results, both CO2 and Air could not only remove the formed solid carbon, but it also compensated the oxygen vacancies inside the lattice.