Smart LNG regasification
Smart LNG regasification
(OP)
Hello,
Having been recently involved in a few LNG regasification projects I noticed that most of the recent LNG regasification terminals seem to derive the energy for LNG regasification from cooling down seawater or burning gas. When you consider the amount of energy involved in LNG liquefaction this is a bit of a pity, especially if you consider that more efficient processes exist for instance:
1- Using "free" warm water from a power plant or other industrial facility to supply the energy for vaporisation
2- Using a Rankine cycle to warm up LNG AND generate power
I would be interested in hearing from recent applications involving any of the previously mentionned technologies (in particular the second one) and why Rankine cycle are not more widely used.
I would also be interested in examples of integration of LNG terminals with other industries (CO2 production, Liq N2 production etc...)
Having been recently involved in a few LNG regasification projects I noticed that most of the recent LNG regasification terminals seem to derive the energy for LNG regasification from cooling down seawater or burning gas. When you consider the amount of energy involved in LNG liquefaction this is a bit of a pity, especially if you consider that more efficient processes exist for instance:
1- Using "free" warm water from a power plant or other industrial facility to supply the energy for vaporisation
2- Using a Rankine cycle to warm up LNG AND generate power
I would be interested in hearing from recent applications involving any of the previously mentionned technologies (in particular the second one) and why Rankine cycle are not more widely used.
I would also be interested in examples of integration of LNG terminals with other industries (CO2 production, Liq N2 production etc...)





RE: Smart LNG regasification
Way back in the 70's I worked at a place where they used Tubine driven pumps to boost the pressure to 1000 psig, then the cryogenic liquid was vaporized in the exhaust.
RE: Smart LNG regasification
I think I know the plant that Dcasto refers to and if it is the one I am thinking of, I noticed that at the time of expansion they didn't repeat their initial design.
It is all economics. Al Gore may want to save the planet, but the bankers own it. ROI rules.
rmw
RE: Smart LNG regasification
RE: Smart LNG regasification
I once proposed we run a coil through the exhaust on an engine to make warm water for coffee and pipe it around the plant, what a waste of hot exhaust and not enough coffee drinkers.
RE: Smart LNG regasification
rmw
RE: Smart LNG regasification
RE: Smart LNG regasification
RE: Smart LNG regasification
RE: Smart LNG regasification
There is another smarter way to regas the LNG applies at sites that adjust the wobbe index by addition of inerts, such as N2 and CO2. Conventional ways of producing N2 are quire expensive and energy ineficient- cryogenic distillation or PSA pressure swing absorption. One unconventional way to produce an inert stream is to fire a boiler with LNG fuel gas, operate it at very low O2 levels ( and at a positive draft), to produce an exhaust gas that is nearly completely composed of H2O, N2, and CO2. The H2O can be removed by condensing heat exchangers and/or desiccants, andthe remaining N2 and CO2 can be cooled to low temperatures prior to compression by passing thru a HX that is also warming up the cryogenic LNG. At the right combination of T and P, one can alsostripout most of the CO2, if that is needed for pipeline corrosion concerns.
Still another means of making use of the -273 F LNG stream is to use this stream to cool the inlet air flow to a cryogenic gas distillation facility; the N2 is used for LNG conditoning / wobbe adjustment, while the O2 is sold to hospitals or welders gas.
RE: Smart LNG regasification
The two other idear are quite good too - but perhaps not requiring energy to this scale!
Best regards
Morten
RE: Smart LNG regasification
There are patented processes the also remove the C2, as well as the C3+ , at the regas terminal, and some are being implemented at new regas sites as we speak. Unless there is a local consumer that can absorb the C2 via pipeline, there is supposedly a shortage of seaworthy tankers that can ship the C2. But, not my area of expertise.
RE: Smart LNG regasification
Therefore, I guess to answer your question in a sentence, I don't see there is any technical difficulties in reusing the LNG 'cold energy', but I am afraid the cost would be a main issue. I personally tend to believe the condition of downstream market for the 'by-product' such as LN2, LO2 or LAr and CO2 and overall effects including both environmental one and effects to local community would be considered at the same time to decide the final design. Unfortunately, these factors are in generally belong to different sectors (most common case all over the world), which means a more overall consideration would probably merely be an illusion.