Direct Conversion of Shale Gas Alkanes to Commodity Chemicals

A viable direct shale gas to fuels process could offer substantial energy savings with significantly reduced process complexity and capital intensity, and enable a gas-to-fuels route that will utilize the newly abundant supplies of relatively inexpensive unconventional shale gas, and is equally applicable to conventional gas and co-produced gas. This objective has faced the central challenge that reaction rates and products yields high enough to be economic are accompanied by overreaction to full combustion products. The key methane activation step can be moderated and controlled by our reactor design capable of controlling mass transfer in a high rate of heat transfer operating regime and so limiting overreaction. We will develop an integrated process combining alkane activation via oxidative coupling to form ethylene or higher alkene oligomers, which will be followed by direct-fed integrated ethylene to fuels process. While extensively investigated, this direct pathway is problematic due to reaction engineering constraints. Common features of both the oligomerization and ethylene polymerization reactions include potential to overreactions, especially to combustion products or waxy polymers, reaction rate limitations related to mass transfer, or need to moderate reaction rates due to excessive adiabatic heat of reactions. PCIs reactor technology has been developed to overcome these limitations while maintaining effectiveness of the catalysts. Catalyst performance for the direct alkylation step to date has been limited not only by catalyst activity but also by reactor constraints. We will down-select catalyst formulations that not only provide high selectivity to alkenes, but also those that work best in our reactor configuration. Zeolite-, sulfide-, and mixed oxide-based catalysts are examples of those that could provide the required level of activity for a commercially viable process. In Phase I we will determine the benefits of PCIs reactor technologies for improving aspects of the integrated process, with the goal of developing a pilot demonstration unit for shale gas conversion in Phase II. Success would simultaneously cut the costs of transportation fuels while also improving American energy independence and reduce greenhouse gas emissions. We expect to realize an added benefit of from 1 to at least 4 $/MMBTU of shale gas, compared to current wholesale value of about 3.6 $/MMBTU.