(30b)  Optimization of Refrigeration and Storage Systems for Propane and Butane Export

The shale gas boom has changed the energy landscape, not only in the U.S. but also beyond our borders and is impacting World Markets.  With the advent of horizontal drilling and “fracking” in North American Shale Plays, the U.S. has become a net exporter of natural gas liquids (NGL’s), including propane and butane.

This presentation provides an overview of studies which compare options for refrigerating and storing propane and butane for loading on to ocean-going vessels for export from the U.S. The methods evaluated include using a single core-in-kettle chiller, phased chilling using multiple core-in-kettle chillers, an open loop refrigeration design and combining propane and butane chilling into a single refrigeration system.  Storage arrangements such as off-site cavern storage and on-site refrigerated storage also have an impact on refrigeration system design, operation and economics. Very large amounts of power and energy are required for these chilling cycles and the options involved.  This paper includes a summary of the optimal designs resulting from the studies, including an overview comparison of equipment costs, energy costs, and payback periods.