Desalinization Costs.

[Duke Leto]

I know removing the cost of desalinization is a major dream of Lerner’s, and I don’t want to be a spoiler, but I’ve been looking at the documentation on desalinization and looks to me like the energy component in the process is only 50% of the total cost. Now if desalinized seawater costs $6 per 1000 gallons now, that would presumably mean that the cost would be cut to $3 as compared to the $0.90-2.50 conventional freshwater costs.

Maybe it’s just me but I don’t see that as a financial knockout blow. Unless there are even more energy intensive methods that minimize the equipment and labor costs.

Maybe I’m missing something.

Just a random insomniac brainfart from an individual who also toys playfully with futures market manipulation scenarios that might force, for example, Koch Industries’ Financial Derivatives division into a zero-out margin call situation within days of a surprise announcement of a fully operational FF generator.

Or a method of alleviating the European Sovereign Debt crisis profitably. Basically you a sell a trillion dollars worth of Credit Default Swaps on Greek Debt and use the proceeds to refinance the entirety of the Greek debt. Then the value of the CDSes you sold declines to nothing while the poor bastards who bought them from you have to pay you the maintenance premiums.

All rather evil.

In other words I need to cease mentally ruminating and actually work on my nefarious plans to become an accredited investor.

(If you see a bedraggled ogrish man with a crazy gleam in his eye walk into LPPX with a sack full of $2-5 Million wanting to buy options to buy $50-70 Million in common stock, Rezwan, that man will be me.)

[zapkitty]

Duke Leto wrote: I know removing the cost of desalinization is a major dream of Lerner’s, and I don’t want to be a spoiler, but I’ve been looking at the documentation on desalinization and looks to me like the energy component in the process is only 50% of the total cost. Now if desalinized seawater costs $6 per 1000 gallons now, that would presumably mean that the cost would be cut to $3 as compared to the $0.90-2.50 conventional freshwater costs.

Maybe it’s just me but I don’t see that as a financial knockout blow. Unless there are even more energy intensive methods that minimize the equipment and labor costs.

Maybe I’m missing something.

The cost of the technology of current desalination procedures is driven by the need to reduce energy usage. Bring the cost of energy down and much cheaper desalination tech becomes viable again.

BTW… If you see a bedraggled ogrish man with dark glasses and a white cane walk into LPPX with $2-5 wanting to buy options to buy $50-70 in common stock, Rezwan, that man would be me 8)

[Duke Leto]

Tell me more Mr. Kitty. It’s much better than balancing my checkbook!

[zapkitty]

Duke Leto wrote: Tell me more Mr. Kitty. It’s much better than balancing my checkbook!

Reduce the issue to lowest common denominators… the current multi-stage flash distillation process with its graduated stages of vacuum chambers, countercurrent heat exchangers and the myriad of pipes, pumps, valves and controls to make it all work… and contrast with the waste heat from an FF unit evaporating seawater straight up, without vacuum tricks, and condensing the steam on a nearby air-cooled surface.

No matter how sophisticated you make a real-life FF desalination unit the cost will be only a fraction of the cost of using current tech.

[Duke Leto]

zapkitty wrote:

Tell me more Mr. Kitty. It’s much better than balancing my checkbook!

Reduce the issue to lowest common denominators… the current multi-stage flash distillation process with its graduated stages of vacuum chambers, countercurrent heat exchangers and the myriad of pipes, pumps, valves and controls to make it all work… and contrast with the waste heat from an FF unit evaporating seawater straight up, without vacuum tricks, and condensing the steam on a nearby air-cooled surface.

No matter how sophisticated you make a real-life FF desalination unit the cost will be only a fraction of the cost of using current tech.

Coolness!

[tcg]

As a Southern California resident living at the end of the supply pipe, I currently pay $2.60 per unit (750 gallons), not counting meter fees. This works out to about $3,50 per 1000 gallons. Our cost is about average for this region, and several newer communities nearby pay at least 50% more. Every time we turn around, the price goes up. The figures cited by the Duke look very attractive to me. We have already built a reverse osmosis plant up the coast, but it was shut down because of the high cost of electricity. My town fronts on the Pacific Ocean, and desalinated water would be in unlimited supply, starting out being very competitively priced. We no longer would have to pray for heavy snowfall in the Sierras and the Rockies, nor fight with 50 million other people for the last drop in a shortage.

I say bring it!

TCG

[Duke Leto]

No, zapkitty’s right. The current Desal process is obviously too equipment intensive by comparison to just boil and coalesce. If he’s right then 50 cents might not be unrealistic.

Then and again I’m barking mad.

[zapkitty]

Duke Leto wrote: No, zapkitty’s right. The current Desal process is obviously too equipment intensive by comparison to just boil and coalesce. If he’s right then 50 cents might not be unrealistic.

Then and again I’m barking mad.

You ARE mad… it would be much cheaper 😉

The following calculations are BotE, don’t count plant costs (but those will be dirt cheap compared to current desal gear) and assume 100% efficiency in applying the FF heat to the water… but this will still get you within an order of magnitude or two of the cost:

amount water at 20 degrees c (kg) 1000
(1 metric ton seawater)

spec heat water (kj/kg) 4.186
latent heat (kj/kg) 2260
delta t (c) 80

1st step raise to 100c (kj) 334880
2nd step vaporize (kj) 2260000
total (kj) 2594880

FF kilowatts thermal (kwt) 7000

process time (sec) 370.7
process time (min) 6.18

Yep, even the waste heat from a 5 MWe fusion reactor takes over 6 minutes to boil away one ton of water.

daily water output (tons) 233.07

kwh in a day 24
FF elec cost kwh (cents) 0.2
desal power cost per day (cents)… 4.8

power cost 1 ton water (cents) 0.021

Lerner-hakase has it right… FF fusion desal makes water problems simply go away.

[delt0r]

Desalination is much less energy intensive than boiling water. Because that steam can be used to heat the incoming water. ie recycle the heat. Staged flash desalination needs a “lot” of power but its all low grade heat (less than 100C since it runs at partial vacuum) and it is *way* less than the latent heat requirement to vaporize the water processed.

[zapkitty]

delt0r wrote: Desalination is much less energy intensive than boiling water. Because that steam can be used to heat the incoming water. ie recycle the heat.

Certainly, more efficient engineering will reduce water costs further. It’s just that a straightforward method makes for a nice upper limit on BOTE calculations… “The final product cost should be no more than $X” 🙂

delt0r wrote: Staged flash desalination needs a “lot” of power but its all low grade heat (less than 100C since it runs at partial vacuum) and it is *way* less than the latent heat requirement to vaporize the water processed.

But the cost of the water rises because of the costs of the vacuum chambers, associated gear and maintenance… and FF units would have power to spare.

[tcg]

Using Zapkitty’s figure of 233 tons of purified water per day from a 5 MW power plant, I did the math to calculate how many homes would that quantity serve in the area where I live.

Hereabouts, typical annual water usage is about four acre-feet per acre for typical residential use, inside the house and for landscaping — rainfall only is about one foot per year during winter, so we have to irrigate everything all the time. From these numbers the average house ( at five per acre ) would use 34,400 cu. ft. of water per year, or about 97 per day, about 800 pounds.

The figure of 233 tons per day times 2000 divided by 800 yields the number of houses which would have enough water, 580 in a community which has 7,500 houses. But wait! I have already calculated that it would take about a dozen 5MW plants to supply enough electricity for 7,500 houses, so 580 X 12 = 6960 homes.

Even considering that efficiencies would not be 100%, I am still mightily impressed with these numbers. It looks like the “waste” heat from power generation could supply at least half of our exorbitant water usage at absurdly low prices. The supply described above, coming from seawater, would be uninterruptable, and the means to secure the remainder of our water usage cheaply from the same source look very feasible.

TCG

[zapkitty]

tcg wrote: The figure of 233 tons per day times 2000 divided by 800 yields the number of houses which would have enough water, 580 in a community which has 7,500 houses. But wait! I have already calculated that it would take about a dozen 5MW plants to supply enough electricity for 7,500 houses, so 580 X 12 = 6960 homes.

… errr… I use metric tons…

… but keep forgetting to use the “tonnes” spelling… actually I just don’t like it… a decidedly provincial Hoosier, that’s me…

So, with the parameters you give above, a dozen FF units will desalt enough water for 7705 homes.

Beyond breakeven! Could this be called Net Water? 🙂

[tcg]

Sweet! A most welcome correction.

Net water — I like it. The fact that it can be obtained with waste heat especially puts a smile on my face.

I hope the gizmo will prove itself. I can hardly wait to pitch independence in both water and electricity to my City Council.

TCG

[JimmyT]

I read an interesting scheme for desalinating water a few years back which might play well with this technology. Rather than using distillation it uses fractional crystallization.

Basically you pump seawater up to the high Sierras during the winter and spray the water on the mountain slopes. Relatively fresh water crystallizes as ice or snow and concentrated brine drains away (back to the ocean presumably). When spring comes the ice melts and vola! Potable water. It does contain some salt, but so little that it can’t be tasted.

The high alcohol content of a couple of liquors is obtained this way too. Apple jack is one. Don’t know the other off hand. In this case the high alcohol content is poured off and saved and the relatively alcohol free ice is discarded.

[zapkitty]

JimmyT wrote: I read an interesting scheme for desalinating water a few years back which might play well with this technology. Rather than using distillation it uses fractional crystallization.

Basically you pump seawater up to the high Sierras during the winter and spray the water on the mountain slopes.

… hmmm… it seems that the cost of pipelines and pumping and spraying and recollecting the water would have to be greater than simply desalinating the water by the seaside and pumping fresh water to wherever it is needed. The free temperature difference offered by natural cooling would be more than offset by the added costs of manipulating the water to try to take advantage of the cooling.

The vicious circle again… the only reason someone would look into such a idea is the cost of energy. Make the cost of energy a non-issue and the idea becomes a non-issue.

And as climate change impacts the Sierras (and it will) the water shortages brought on by the decreasing snowpacks will be mitigated by the availability of fresh water from the seaside… and if it gets so bad that the Sierra ecology itself can’t take it any more then pump up [em]fresh[/em] water from the seaside and spray it on the slopes…

Aneutronic fusion would change a lot of perspectives.

JimmyT wrote: Relatively fresh water crystallizes as ice or snow and concentrated brine drains away (back to the ocean presumably).

As co-opted and as cowed as the Sierra Club has become I’d think even they would object to brining the Foothills vineyards 🙂

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