Only " Tibet Water to Xinjiang Project" can save China from severe economic&social unrest

antiterror13 said:

where did you get the figure of 5m3 per day? thats simply impossible .. 150L per day is normal, but American use more than that like 600L per day

I think you are confused by just divided country water usage and population .... which mostly used for agriculture, animal farm and industry. But for household water usage, most likely around 150L per day or less for China

Water quality for household requires very high but for agriculture, animal farms and industry, much less

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It's total water consumption. The comment is a response to total water consumption by coastal provinces regardless if it is agriculture, industrial or personal usages all to be by desalination.

Like I said 4000 people per plant without distribution. So with 4000 people they need to come up with $100M to build it, that's $250k per person. You know how a water treatment plant for half a million people cost? It's around $20M. Because the most expensive parts of a desalination plant is the membranes and high power usage.

High pressure pumps are used for reserve osmosis (1/3 to 1/2) water stream. The membranes needs to be cleaned constantly, typically trained (parallel) operation, so one cycle is in cleaning with an weak acid or caustic and another in operation. Membrane replacement every 5 years or so due to calcium scaling that acid cleaning won't even get out.

Inst said:

Problem with desalinization is piping; it's not that different from digging a vast canal to extend the Pacific into Central Asia in that, sure, it'd be beneficial, but how are you going to pay for it?

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Like I said I didn't include distribution piping. In Alberta, the rule of thumb is $1M per km for 3 or 4" piping above ground. For a desalination plant to reach customers, will need booster pumps everywhere and much bigger piping, probably all underground. Even at 1/3 cost of Canada, it will still be collosal.

PiSigma said:

A small fleet of reactors? Think the entire earth's power generation x 3.

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I specifically stated molten salt reactors, not any nuclear reactor. The benefit of using MSRs for distillation is that their operating temperatures are around 700°C, while a pressurized water reactor operates at around 300°C; this allows an MSR to heat a larger volume of seawater to the operating temperature of a multiple effect distillation system for the same volumetric flow rate of coolant going through the heat exchanger. They also operate at ambient pressure, so they're smaller, simpler and cheaper to build than PWRs.

Reverse osmosis is a pretty stupid way to do desalination. It's 100% electrical and can't use waste heat from power generation.

A few discussions are going into the deep end. Let's try to set the premises straight.

(1) We are talking about making the coastal region of China water independent. No one is advocating sending water from the coastal region uphill to the central plain and further to the western plateau.

(2) We are not talking about how to supply everyone's need in the coastal area by desalination alone. A combination of desalination, reclamation (of used water that would otherwise be discharged into the river or sea), and preservation. Also, there are local rainfall which is being preserved through water catchment and reservoirs. This 4 prone approach is what Singapore has deployed successfully to become water independent. So can China.

ZeEa5KPul said:

I specifically stated molten salt reactors, not any nuclear reactor. The benefit of using MSRs for distillation is that their operating temperatures are around 700°C, while a pressurized water reactor operates at around 300°C; this allows an MSR to heat a larger volume of seawater to the operating temperature of a multiple effect distillation system for the same volumetric flow rate of coolant going through the heat exchanger. They also operate at ambient pressure, so they're smaller, simpler and cheaper to build than PWRs.

Reverse osmosis is a pretty stupid way to do desalination. It's 100% electrical and can't use waste heat from power generation.

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What you describing is a co-gen, which is great if you need the power. But the problem with heating water to 300C, is that the piping class gets very expensive. Construction also becomes expensive since welding becomes a lot harder for 900# and 1500# piping.

You can't remove salt from water by distillation, and evaporator have chloride residues so water disposal is still an issue. The downside for your blowdown system is materials, probably need hastiloid C for pumps and piping, which is 3x the cost of carbon steel.

If you ever do a pinch analysis of nuclear reactor with water to creat potable water you will find it is not efficient because of high heat wastage.

Reverse osmosis is excellent because it can remove salts and other unwanted pollutants with minimal use of chemicals for water treatment. Evaporator uses huge amounts of Magox for treating, which is expensive. And then add in caustics for cleaning, lime, flocculant, and coagulant, the chemicals can get expensive very fast.

Rettam Stacf said:

A few discussions are going into the deep end. Let's try to set the premises straight.

(1) We are talking about making the coastal region of China water independent. No one is advocating sending water from the coastal region uphill to the central plain and further to the western plateau.

(2) We are not talking about how to supply everyone's need in the coastal area by desalination alone. A combination of desalination, reclamation (of used water that would otherwise be discharged into the river or sea), and preservation. Also, there are local rainfall which is being preserved through water catchment and reservoirs. This 4 prone approach is what Singapore has deployed successfully to become water independent. So can China.

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He said coastal provinces... So the expectation is send water at least 400-500 km inland to the border of Anhui or Jiangxi for example... Plenty of hills and mountains in the way.

If you define coasta area as within 20km of ocean, then it needs to be defined, which was not... So don't move the goal post!

AndrewS said:

And yet that great Libyan water project only supplies the water needs of 4 million people.

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Yes, and perhaps made country located in a desert to be self sufficient of water and agricultural products. Anyway we can simplify to the fact of 2 billion people have not access to clean water. So the cost should not be considered as a logistic cost. Its a matter of health somehow. Finding the most efficient way to do that, has to be the matter of consideration

Can’t a nuclear powerplant be used in conjunction to desalination? Nuclear plant does requires a lot of water cooling purposes. That vapour can be condensed for pure water ? Does sea water salt or radioactivity poses serious issue ?

PiSigma said:

It's total water consumption. The comment is a response to total water consumption by coastal provinces regardless if it is agriculture, industrial or personal usages all to be by desalination.

Like I said 4000 people per plant without distribution. So with 4000 people they need to come up with $100M to build it, that's $250k per person. You know how a water treatment plant for half a million people cost? It's around $20M. Because the most expensive parts of a desalination plant is the membranes and high power usage.

High pressure pumps are used for reserve osmosis (1/3 to 1/2) water stream. The membranes needs to be cleaned constantly, typically trained (parallel) operation, so one cycle is in cleaning with an weak acid or caustic and another in operation. Membrane replacement every 5 years or so due to calcium scaling that acid cleaning won't even get out.

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desalination is NOT for agriculture! ... absolutely not, it won't work, no matter how you cut it. "dirty" water for agriculture is totally fine

antiterror13 said:

desalination is NOT for agriculture! ... absolutely not, it won't work, no matter how you cut it. "dirty" water for agriculture is totally fine

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I'm not pitching desalination for agriculture. I'm saying how unfeasible it is due to high cost. It is zeea5kpul that was saying all water usage for coastal provinces should be from desalinated sea water. All my posts are proving his idea as unfeasible from an economic point of view.

And sea water can't be used for agriculture... Because salt.