(30f) Comparison of Present Day Peakshaving Liquefaction Technologies

While base load LNG plants provide a large quantity of the LNG market, there is an increasing need for small-scale plants to provide LNG for distributed markets. The small scale LNG industry in the US was initially developed in the 1960-70 time period and generally consisted of peak shaving facilities for winter gas supply. The numerous facilities developed during that time period are now reaching the end of their useful life and are being replaced with new, modern designs which are more efficient and easier to operate.

The selection of the appropriate LNG technology can be a difficult process. Although efficiency, ease of operation, and capital and maintenance costs are usually the main decisive factors, site specific requirements, such as pipeline available pressure and tail gas allocation, can also play a big role during the selection process. In addition, these main factors are sometimes sacrificed in favor of City and/or State regulations, or simply operator preference.

This paper will cover a detailed comparison of three widely used peak shaving liquefaction technologies. For a fixed LNG production, three simulated cases will be developed to show the differences between a Nitrogen Expander Cycle, an Open Expander Cycle, and a Single Mixed Refrigerant (SMR) Cycle.