(390f) Advancing Export Terminal Technology: An Optimized Process for the Refrigeration of Cryogenic Hydrocarbons

As a result of the “shale revolution” in the United States, the availability of competitively priced chemical pre-cursor feedstocks, primarily ethane and propane, has resulted in increased grassroots construction and/or expansion of various petrochemical complexes along the gulf coast. Thanks to this build-out, domestic production of petrochemical commodities, like ethylene and propylene, is expected to greatly outpace domestic consumption. Excess US domestic production and the resulting lower prices will lead to escalating international demand for these commodities overseas; domestic petrochemical producers are looking at large consumers in China, India, and Europe to take up the slack and import this excess production. In order to export these feedstocks, refrigeration units are required to chill the hydrocarbons to cryogenic temperatures. Installation of the most efficient refrigeration process at the export terminal is vital for the terminal owner to maximize their investment potential.

This paper presents the technical design for an ethylene export terminal utilizing two (2) different refrigeration processes: the traditional open cycle (OC) and a more advanced single mixed refrigerant (SMR) scheme. The two processes were modeled in-house at Chiyoda using the generic concepts of refrigeration cycles and UNISIM Design suite 450 simulation software. Each process is optimized through adjusting the available process variables to achieve an overall efficient refrigeration process for an ethylene production rate of 100 metric tonnes per hour (mt/hr). The technical design is concluded by defining major equipment sizes, layout, and a relative cost for the units. While the technical paper will focus on ethylene, similar results can be obtained for other hydrocarbons including ethane and propylene.