Tools for Solving or Slowing Down Ocean Acidification?

[dewline]

Ian Gould, my partner on the Local Hero comics project, pointed this one out to me this morning:

https://phys.org/news/2017-10-nrl-patent-carbon-capture-devicea.html

Useful or not?

Comments

[neowolf2]

Any device that produces fuel from CO2 will consume a very large amount of energy, much more than just sequestering of captured CO2. The energy content of the fuel has to come from somewhere.

I'm more interested in processes that react CO2 with magnesium-bearing silicates, like olivine or serpentinite. These reactions are mildly exothermic, and the carbonates that are formed are stable over geologic time periods.

In the short term, any CO2 capture process that yields pure CO2 will mostly be used for enhanced oil production, as oil producers are willing to pay for this CO2, and that will always be cheaper than doing something else to it.

[armiphlage]

From a military viewpoint, production of synthetic JP5 will enhance safety and operational efficiency on nuclear-powered aircraft carriers.

A Bush-class carrier has nearly nine million litres of liquid jet fuel for its aircraft. This is a fire hazard, and (unless the fuel tanks are completely full), negatively impacts stability due to the free surface effect. After accounting for fire suppression systems and fuel handling equipment, more than 10,000 cubic metres would be devoted to jet fuel.

A much smaller JP5 tank, continually refilled from a synfuel plant powered by the nuclear reactor, could meet the operational needs of the carrier while reducing the risk of fire, and possibly even saving space.

[dewline]

"...negatively impacts stability due to the free surface effect."

I suspect that translates to layperson's technical speech as "you really don't want that fuel sloshing around in a less-than-full tank. Especially during a high-speed turning of the ship."

[armiphlage]

Precisely.

My Naval Architecture class was only a few years after the Spirit of Free Enterprise disaster, so it really stuck in my head.

The scary bit is that the free surface effect ruins stability even if the ship is perfectly still. It moves the effective centre of mass up vertically, until it is above the centre of buoyancy. Moving the fuel tanks down below the waterline doesn't help, either.

To avoid it, you need many small fuel tanks, packed full of baffles, with the longest dimension of the tanks parallel to the keel. Then you completely drain one tank at a time. Of course, doing that throws off your trim, which has its own impact on stability.

https://en.wikipedia.org/wiki/MS_Herald_of_Free_Enterprise

[armiphlage]

CO2 is also useful for increasing yields in greenhouses. Ontario greenhouses usually use natural gas or propane for supplemental CO2, but some growers prefer to buy liquid CO2 to avoid problems with contamination, heat, and moisture.

Coastal countries with intensive greenhouse production and frequent excess wind power (i.e. the Netherlands) might produce ocean-extracted CO2 at off-peak hours for agricultural purposes.

http://www.omafra.gov.on.ca/english/crops/facts/00-077.htm