(685e) Techno-Economic Optimization of a Microwave-Assisted Methane Dehydroaromatization Process

According to Energy Information Administration there is progressive increase in shale gas production. Direct non-oxidative methane dehydroaromatization in microwave(mw)-assisted reactor is one of the promising conventional processes for excellent product selectivity and less severe operating conditions.

A dynamic, non-isothermal, multi-scale model of a MW-assisted fixed-bed reactor has been recently developed. The model includes a detailed sub-model for inter and intra-particle mass transfer and a reaction kinetic model including coke formation and catalyst deactivation. A comprehensive heat transfer model has been developed considering heat transfer between metal sites, support sites and the gas with catalyst particles and between bulk and catalyst particles. MW absorption by both metal and support sites area is considered. Maxwell’s equations are used for modeling MW penetration into catalyst particles.

Considerable improvement has been made in our in-house MW-assisted reactor by substantially increasing the product yield and reducing coke yield. The new laboratory data are reconciled for satisfying mass and atom balance by developing a dynamic data reconciliation approach. Reconciled data are used to estimate parameters for kinetic model. Lab-scaled reactor model is scaled up to commercial scale reactor and plantwide-model is set up with appropriate separation steps for efficient product recovery.

Economic analysis of the process is undertaken by exporting the plantwide-model developed in AspenPlus to Aspen Process Economic Analyzer. Capital costs and efficiency of MW reactor are estimated based on in-house data. Operating costs are evaluated based on results from the plantwide-model while cost of the catalyst and its replacement schedule are estimated based on in-house data. Economics of the MW-assisted process are compared with conventional multi-step natural gas-to-aromatics production process via methanol synthesis. Impact of various economic and process parameters on key economic measures such as IRR and NPV is studied. Electric equivalent efficiency of the MW-assisted process is also compared with conventional process.