The Anonymous Widower

Could A Highview Power CRYOBattery Use A LNG Tank For Liquid Air Storage?

This Google Map shows a 3D image of liquified natural gas (LNG) tanks at South Hook LNG Terminal near Milford Haven.

Note that images of these tanks under construction on the Internet, show that there is an underground portion of the tanks.

This page on the CIMC-ENRIC web site is entitled Successful Delivery Of 5,000M3 LNG Single Containment Tank Project. The page shows the design of the LNG tank.

As the density of liquid air is 870 kg/m³, a 5,000 cubic metre tank would contain 4,350 tonnes of liquid air at −194.35 °C and atmospheric pressure.

How much energy would be needed to create 4,350 tonnes of liquid air?

In this document, this is said about compressing natural gas with an electric drive.

It is the most-energy efficient technology with 230 kWh per ton of LNG.

As air and natural gas have molecules of similar weight, would 230 kWh per tonne be applicable to liquid air.

If it is, then around a GWh of electricity will be needed to create the liquid air.

This Wikipedia entry is entitled Cryogenic Energy Storage and describes Highview Power’s CRYOBattery.

This section describes the operation of the CRYOBattery.

When it is cheaper (usually at night), electricity is used to cool air from the atmosphere to -195 °C using the Claude Cycle to the point where it liquefies. The liquid air, which takes up one-thousandth of the volume of the gas, can be kept for a long time in a large vacuum flask at atmospheric pressure. At times of high demand for electricity, the liquid air is pumped at high pressure into a heat exchanger, which acts as a boiler. Air from the atmosphere at ambient temperature, or hot water from an industrial heat source, is used to heat the liquid and turn it back into a gas. The massive increase in volume and pressure from this is used to drive a turbine to generate electricity.

Note.

1. The Claude cycle is described in this Wikipedia entry.
2. The liquid air takes up one-thousandth of the volume of the gas.
3. Wikipedia suggests that Highview claim the process has a round trip efficiency of 70 %.

Having done calculations in the past with chemical reactions in a series of large vessels, the dynamics can be strange and I wouldn’t be surprised that as Highview learn more about the process and add more and better ways of recycling heat and coolth, efficiencies will improve.

Certainly, in the process I mathematically-modelled in the 1970s, when I worked for ICI, I remember that one large reaction vessel performed better than four or five smaller ones with the same total volume.

Hence my thought that perhaps one large containment tank could be the most efficient design.

I also think, that the design of LNG tanks must have improved significantly over the last few years, as the transport of LNG has increased in importance.

August 1, 2022 - Posted by AnonW | Energy, Energy Storage | CRYOBattery, Highview Power, Liquified Natural Gas