The substantial discoveries of shale gas present many opportunities for the chemical, petrochemical, and fuel industries. As in conventional natural gas, shale gas contains primarily methane, but some formations contain significant amounts of higher molecular weight hydrocarbons and inorganic gases such as nitrogen and carbon dioxide. These differences present several technical challenges to incorporating shale gas with the current infrastructure designed to be used with natural gas. This paper is aimed at process synthesis, analysis, and integration of the production of methanol from shale gas. The composition of the shale gas feedstock is assumed to come from the Barnett Shale play located near Fort Worth, Texas, which is currently the most active shale gas play in the United States. Process simulation using ASPEN Plus along with published data were used to construct a base-case scenario. Key performance indicators were assessed. These include overall process targets for mass and energy and economic performance. A sensitivity analysis is carried out to assess the impact of the methanol selling price and shale gas price on the profitability of the process. Energy integration including process cogeneration was carried out to enhance the sustainability and profitability of the process. Finally, a techno-economic analysis was carried out to estimate the price differential for shale gas at the wellhead compared to pipeline quality natural gas.

Many electrochemical energy-conversion systems are evaluated by polarization curves, which report the cell voltage across a range of current densities and are a global measure of operation and state of health. Mathematical models can be used to deconstruct the measured overall voltage and identify and quantify the voltage-loss sources, such as kinetic, ohmic, and masstransport effects. These results elucidate the best pathways for improved performance. In this work, we discuss several voltagebreakdown methods and provide examples across different low-temperature, membrane-based electrochemical systems including electrolyzers, fuel cells, and related electrochemical energy-conversion devices. We present best practices to guide experimentalists and theorists in polarization-curve breakdown analysis.

During operation, proton-exchange-membrane fuel cells (PEMFCs) are subjected to mechanical and chemical stressors that contribute to membrane degradation, performance loss, and eventual failure. Together, synergistic effects between mechanical and chemical degradation mechanisms lead to accelerated degradation. A physics-based model is developed to understand the synergistic effects of chemical and mechanical degradation and the coupled nature of performance and durability in PEMFCs. The model includes pinhole existence and growth in the membrane, which increases crossover of reactant gases as well as subsequent formation of chemical degradation agents that impact both transport and mechanical properties of the membrane. The fuel-cell model is fully coupled with a mechanical model to determine the stresses on the membrane and subsequent growth of pinholes during transient operation. Simulation results demonstrate pinhole growth under relative-humidity cycling and the resultant increased gas-crossover fluxes and decrease in polarization performance. Furthermore, the model results highlight nonlinearities and the importance of coupling mechanical and chemical degradation models in order to explain membrane degradation under various cycles, and serves as a foundation for examining coupled durability and performance.