Energy integration of methaneʹs partial-oxidation in supercritical water and exergy analysis

In this work, we examined the exergy losses of reaction pathways that have been reported in the literature in the context of an integrated methanol production and electrical power flow sheet. Three reaction pathways were examined: (i) complete oxidation, (ii) partial oxidation to produce only methanol, and (iii) partial oxidation to produce methanol and carbon monoxide. The latter was based on experimental data reported for reactions in supercritical water. It was found that there were optimum feed ratios that minimized reactor heat requirements and maximized electrical work output. An exergy analysis showed that the largest irreversibilities occurred in the reactor itself and that the partial oxidation of methane to produce methanol and carbon monoxide gave reactor irreversibilities that were lower than for the total oxidation reaction pathway. Conversion of methane to methanol and carbon monoxide in supercritical water can be accomplished by supplying only chemical exergy.