Development of a ceramic membrane for upgrading methane to high-value-added clean fuels

摘要

The upgrading of natural gas (which consists mostly of methane) to high-value-added clean-burning fuels such as dimethyl ether, alcohols, and pollution-fighting fuel additives is driven by the abundance of natural gas discovered in remote areas. Recently, extensive efforts have focused on both direct and indirect conversion of methane to these value-added products. Indirect routes require the partial oxidation of methane to synthesis gas (syngas, CO + H2) in a first stage. The syngas is then converted to upgraded products in a second stage. The most significant cost associated with partial oxidation of methane to syngas is that of the oxygen plant. In this paper, we offer a technology that is based on dense ceramic membranes and that uses air as the oxidant for methane-conversion reaction; thus eliminating the need for the costly oxygen plant. Certain ceramic materials exhibit both electronic and oxide-ionic conductivities. No external electrodes are required and such a system will operate without an externally applied potential. Oxygen is transported across the ceramic material in the form of oxygen anions, not oxygen molecules.