Ideas As a Process Intensification Tool Applied to Process Networks Containing Membrane Reactors

Process intensification is a strategy that can make dramatic reductions (order 100 or more) in the size of a chemical plant while meeting production objectives¹. More recently, process intensification can be defined as “any chemical engineering development that leads to substantially smaller, cleaner, and more energy efficient technology²”. In this work, the Infinite-DimEnsionAl State-space (IDEAS) conceptual framework is employed as a process intensification activity applied to process networks containing membrane reactors. The IDEAS framework enables a broad search of the design state-space to identify optimal process networks through the formulation of linear programs. This framework can assess fundamental performance limitations of networks of technologies under consideration in order to identify intensified designs. The IDEAS methodology for membrane containing networks will be applied to a case study featuring natural gas based hydrogen production, where energy efficiency will be intensified.

Membrane reactors are an emerging technology in the steam-methane reforming (SMR) process; these reactors typically involve simultaneous reaction and separation³. The biggest advantage of this technology is that it allows in situ separation, which gives rise to a high-purity product. This is particularly useful in driving the forward reaction of equilibrium limited reactions, as product is continuously removed from the reactor. The use of equilibrium reactor models allows for the search of intensified designs to be carried out in the lower-dimensional space of atomic fraction ratios, rather than the space of species mole fractions.

The process network considered will feature pressure changing devices, equilibrium reactors, a heat exchange network, flash separators, ideal separators, and membrane reactors. Operating and capital cost studies are all presented to determine the process network’s cost relative to traditional steam methane reforming.

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3. Soltani, S., Sahimi, M., and Tsotsis T.T., “Catalytic Membrane Reactors: A Brief Overview”, Encyclopedia of Membrane Science and Technology, Eric. M.V. Hoek and Volodymyr V. Talabar Editors, John Wiley & Sons, 2013.