(578d) Plant-Wide Modeling, Techno-Economic Analysis and Optimization of the Shale-Gas to Dimethyl Ether (DME) Process Via Direct and Indirect Synthesis Route

Mevawala, C., West Virginia University
Bhattacharyya, D., West Virginia University
Jiang, Y., West Virginia University
Due to the uncertainty in supply and prices of petroleum-based fuels, various alternative, clean fuels are being investigated. Dimethyl ether (DME) is a potential alternative to petroleum-based fuel because it is non–toxic, eco- friendly, has minimal particulate emissions, and has properties similar to LPG and diesel with a very high cetane number (55- 60)1. DME can be produced from a variety of feed stocks like coal, biomass, natural gas, and shale gas via direct or indirect synthesis route. Studies have shown that direct synthesis route has a higher DME production compared to indirect synthesis route. Currently, majority of the DME is produced commercially from coal via indirect synthesis route in the Asia-pacific region. However, in the United States, shale gas is available in abundance and seems to be a more attractive feedstock. Very limited studies are available in the open literature on techno-economic evaluation and optimization of shale gas-to-DME process via direct and indirect synthesis routes. The focus of this presentation will be on the process synthesis, economic evaluation, and optimization of the shale gas-to-DME process via direct and indirect synthesis in a multi-software environment.

In this study, plant-wide models for shale gas-to-DME synthesis processes via direct and indirect routes are first developed in Aspen Plus V8.4®. Kinetic models of the pre-reforming reactor, autothermal reforming reactor and DME synthesis reactors are developed and validated with the experimental data. For acid gas removal (AGR), two technologies, namely the Rectisol and MDEA/PZ technologies, are evaluated. A novel DME separation process that can efficiently separate DME, syngas and CO2 has been developed. Binary interaction parameters for the vapor liquid equilibrium (VLE) model of the methanol-CO2, DME-CO2, DME-H2O and DME-CO mixtures are regressed using the experimental data. Aspen Energy Analyzer V8.4® is used to design an optimal heat exchanger network by pinch analysis and the heat exchangers are sized rigorously using Aspen Exchanger Design and Rating V8.4®. The modeled equipment is mapped using the Icarus database in Aspen Process Economic Analyzer V8.4® (APEA) and economic evaluation is performed. An optimal design of the process is obtained by maximizing the Net Present Value (NPV) by using a multi-software platform comprising of Matlab, Microsoft Excel, Visual Basic, Aspen Plus, and APEA.

To summarize, the presentation will focus on the following aspects:

  • Synthesis of the plant-wide models for DME synthesis following direct and indirect routes
  • System level energy analysis of shale gas-to-DME production processes for varying H2/CO ratio, CO2 capture rate, and AGR technology
  • Uncertainty analysis due to the raw materials price, product price and scale of the plant
  • Optimal design of the process by maximizing NPV


Ogawa, T.; Inoue, N.; Shikada, T.; Inokoshi, O.; Ohno, Y. Direct Dimethyl Ether (DME) Synthesis from Natural Gas. Studies in Surface Science and Catalysis Natural Gas Conversion VII, Proceedings of the 7th Natural Gas Conversion Symposium. 2004, 379–384.