Regional LNG: Small scale liquefaction system developed

DES PLAINES, Ill., Oct. 21 -- In a collaborative program with the U.S. Department of Energy (DOE) and Brookhaven National Labs, Gas Technology Institute (GTI) has completed testing on a new small-scale natural gas liquefier for use in liquefied natural gas (LNG) vehicles, utility peakshaving applications, remote gas recovery, and liquefaction of renewable resources such as digester or landfill gas.

The system, which uses a multi-component mixed refrigerant process designed and built by GTI, is sized to produce 1000 gallons of LNG per day, and reached levels of 1400 gallons/day during testing. GTI demonstrated the LNG production system's capability by fueling 20 LNG-powered street sweepers produced by a Chicago-area specialty vehicle manufacturer for a California municipality.

GTI's testing verified the expected performance of the system and its capability of producing LNG from low-pressure (20-60 psig) natural gas. The liquefier's refrigerant loop achieved temperatures as low as -300 degrees F within its heat exchanger, and LNG was produced at -225 degrees F to -245 degrees F, depending on pressure levels.

"A unique aspect of this mixed refrigerant liquefaction system is the ease of starting and stopping it," says Bill Liss, GTI's Director, Advanced Energy Systems. "During testing, the unit cycled at least once each day. After a brief re-start period for cool down, the liquefier again produces LNG the next day. Once at steady state, the unit was shown to be very stable."

The 1000-gallon per day liquefaction system is skid mounted (approximately 8' by 14') and uses a natural gas engine to drive the refrigerant compressor. The pre-fabricated, transportable features of the system make it suitable for ease of movement and start-up. The gas engine helps avoid the expense and time of higher voltage, multi-phase power lines. GTI believes the system is readily scalable in capacity ranging from 5000 to 10,000 gallons/day.

"Historically, LNG plants have been much larger in scale," continues Liss. "These results may serve as a breakthrough for creating smaller, more cost- competitive plants."

GTI is the leading research, development and training organization serving energy markets. GTI is dedicated to meeting the nation's environmental and energy challenges by developing technology-based solutions for consumers, industry, and government. (*)

Source: Gas Technology Institute