Chemistry

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Chemistry

Postby Neutron » Sat Nov 24, 2012 7:05 am

I have been recently researching upon "Production of Water". I know that water can just be made by exploding hydrogen in presence of oxygen (2H2 + O2 = 2H2O) ... but the thing is explosion itself is very risky and would require a lot of heat. The other method is to desalinate ocean water. This can be a pretty good process. Also, I suppose if we can do this process at a large scale, it could stop the rising of sea level. But the main problem in this process is the cost. Rich countries like U.A.E etc are only capable enough to conduct it.
So basically the challenge here is to effectively reduce the cost of production of potable water from ocean. Can the process of co-generation be used (for distillation)? Heat from the thermal power plant, flue gases or even biodiesel from algae be used to lower the cost? I heard Electrodialysis can also be used to turn sea water to potable water. But is it expensive? Is the outcome better? Also sequential freezing can be done to remove salts and particles from water. Yet again Reverse Osmosis is also present. It's the only process currently being used by many countries. But the water produced is not sufficient.
Hence I urgently need help with reference to the points i mentioned above. Also extra points and knowledge will be hugely appreciated.
(Please reply, it's urgent)
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Re: Chemistry

Postby kgudger » Sat Nov 24, 2012 7:05 pm

Hello and welcome to the forums.

Most of your questions you can find answers to by using a search engine. At this grade level we will expect you to try that first, then get back to us with more detailed questions.

On this subject, you might want to look into this article: http://web.mit.edu/newsoffice/2012/graphene-water-desalination-0702.html
There's a lot going on with desalination, so I imagine it's the most cost effective method (even though it is relatively energy expensive.)

Let us know how your research goes.
Keith
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Re: Chemistry

Postby Neutron » Mon Nov 26, 2012 4:49 am

I have seen the link you have give me for reference.Using graphene as an alternative is a really good idea but still it's far from perfection. I am actually looking for ways of reducing costs as well as increasing output of clean water from desalinated one. I have thought about using micro-waves as an alternative to reverse osmosis. Using microwaves to distill will be cheap. But the main factor is will the water be exposed to radiation?
please rely
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Re: Chemistry

Postby wendellwiggins » Tue Nov 27, 2012 11:08 am

Hello Neutron,

Microwaves have no lasting effect on water other than to heat it up.

Microwaves would be much more expensive as a distilling method than simply using the same electricity to run a heating coil. The microwave generator is not 100% efficient.

WW
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Re: Chemistry

Postby Neutron » Tue Nov 27, 2012 10:35 pm

Okay, so using microwaves wont better the things. Freezing the saline water can be a method but i think that depends very much on the topography too. Concentrating sunlight and using heat for desalination may have been tried out before too. The method which caught my eye was vacuum distillation and ion exchange. One of my friend here has claimed to reduce upto 35% of the cost of biodiesel production. He says it will be that diesel will be available at about Rs. 15- Rs.16 (that's about USD 0.27) then that will decrease my cost of production if distillation is used. Now the main part. Reverse Osmosis constantly requires force to be created in water so that it can pumped through the membranes. Using a centrifuge with graphene sheets present in the outer rim can create such a force in water. Graphene being able to reduce energy consumption up 15% and the centrifuge itself may use lesser power than RO itself. Please reply to my findings, it's urgent :)
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Re: Chemistry

Postby Neutron » Thu Nov 29, 2012 6:50 am

I have kind of changed the theme of my science project...i would be participating in google science fair 2013 ... countries like mine (India, pakistan, bangladesh, african countries) have a huge deficit of water ... the basic requirement of water per person per day is about 30 litres (which is 20-40 litres short than the countries like USA etc) again,from the given 30 litres, 20 -25 litres are wasted as sewage. If we could install water treatment centres per phase then the wasted water will be again re circulated. Water tanks per phase can be constructed with help of PPP (Public Private Partnership ... so that all the water production cost can be met)... apart from this we would desalinate 10000 litres of sea water per day (0.667 kcal per 1 litre of water) to reduce the cost ,i have come with an idea of desalinating with centrifuge(industrial) surrounded with graphene sheets ... the centrifugial force will drive brine through graphene to produce fresh water
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Re: Chemistry

Postby Craig_Bridge » Thu Nov 29, 2012 5:50 pm

Neutron wrote: the centrifugial force will drive brine through graphene

Engineers often have to remember the "KISS" principle - "Keep It Simple, Stupid". The more complexity in a design, the more things to go wrong and the higher the cost.

Centrifuges are an expensive way to generate pressure and they don't lend themselves to an enclosed continuous system and the amount of moving parts and potential for leaks is high. In other words, needless complexity.

Gravity is your friend. Water distribution requires pressure. Consider pumping brine into a tall storage tank and putting the graphene filter at a lower point in the system. This kind of a design allows for independent parallel pumps and filters that can be independently maintained without shutting down the entire system.
-Craig
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Re: Chemistry

Postby Neutron » Fri Nov 30, 2012 3:01 am

thank you so much craig ^_^
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