Oxidative coupling of methane: a comparison of different reactor configurations

A quantitative comparison of the performance of the most common reactor configurations proposed for the oxidative coupling of methane (OCM) is made on the basis of numerical calculations with phenomenological reactor models. The configurations that are analyzed can be divided into two main categories, namely, packed-bed reactors (including conventional packed beds with external cooling, packed-bed membrane reactors, and adiabatic packed beds with post cracking) and fluidized bed reactors (bubbling fluidized bed reactor, circulating fluidized bed reactor, and fluidized bed membrane reactor). The challenges in both configuration types, mainly the heat management in the case of the packed-bed reactors and the low C ₂₊ yields obtained in fluidized bed reactors, are evaluated and quantified. To ensure a fair comparison, La ₂ O ₃ /CaO is chosen as the OCM catalyst for all the considered cases, mainly in view of the availability of a comprehensive kinetics model. The results show that, with conventional configurations, it is not possible to achieve high C ₂₊ yields that are needed to make the process economically viable. However, the results also indicate that the C ₂₊ yield can be significantly improved by feeding the oxygen distributively along the reactor axial length.