Two schemes are conceivable for boosting such a cryogenic liquid as LNG: pump-based and PBU (pressure boosting unit)-based boosting. In the former, the turbo-cryogenic machine, the pump, is often a source of great concern due to the following reasons:
-Large fixed capital cost
-Complicated operation including cooldown
-High failure rate and subsequent maintenance
-No maintenance onboard
In the PBU-based scheme, part of the liquid inventory is vaporized by the PBU to pressurize the whole storage tank. This scheme is difficult to apply to a large tank because
-The design pressure of the storage tanks has to be increased.
-It is not easy to control pressure of a large storage tank by heating.
-All fluid in the tank needs to be heated to create sufficient pressure; this takes unduly long time for a large tank.
So, the PBU scheme is applicable only to small storage tanks.
Solution by Lattice Technology
The Pump-free Booster of LATTICE Technology utilizes two small boosters instead of a pump. There are no moving parts. Each booster is equipped with a mini-PBU which is to pressurize the booster itself, not the main storage tank. Two boosters are operating in a proper way to guarantee continuous supply of pressurized LNG.
There are two process configurations: parallel and series. In the former, the two boosters operate in an alternating way; one is exporting the pressurized LNG while the other is charged with low-pressure LNG. To the contrary, in the latter configuration the first booster sends pressurized LNG in an intermittent way, and the second boost continuously exports the pressurized LNG.
The pump-free boost can be used for generator engines as well as the DFDE engine. It can also replace the priming pump of the MEGI engines.
▲Parallel configuration ▲Series configuration
The synergic effect magnifies if the pump-free booster is combined with the LPV LNG fuel tank for the LNG fuel gas supply system.