Talk:Desalination

What is "pressure barrier osmosis"? Google finds only Wikipedia articles. This term appeared first in water resources (first version).--80.137.207.121 21:18, 13 Aug 2004 (UTC)

I haven't been able to find anything to confirm the existance of such a thing. Failing the arrival of confirming references that I can actually see, I will probably remove the reference to "pressure barrier osmosis" next month. --Coro 21:58, 29 Mar 2005 (UTC)

I never heard of it either. Probably a confusion with reverse osmosis. pstudier 01:19, 2005 Mar 30 (UTC)

Energy

How much energy is needed to desalinate a cubic meter of sea-water? Someone please add this to the article.

—The preceding unsigned comment was added by 83.249.20.138 (talk) 19:52, 8 December 2006 (UTC).

Gas Hydrates.

The interest in ethane (gas) hydrates is more to do with mining them from the sea floor for their gas and water components to be separated. While being researched for desalination it is certainly not a major process. Moreover it does not yet produce water fit for drinking. I have relegate the process to the list of possible methods... perhaps it can be expanded on its own article. CustardJack 12:03, 10 May 2005 (UTC)

I am not sure what Membrane Distillation means. I suspect that it is an old-fashioned term for Membrane Processes and therefore should be removed, since they exist as separate entries under Reverse Osmosis and Nanofiltration (which I have added). However, it may mean what are generally termed "Hybrid Plants", which combine distillation, ie evaporation, with membrane processes and an electricity generating station. This alternative provides flexibility because of its two sources of energy: electricity for the membrane process and low-pressure steam from the power station for the thermal evaporation process (MSF or ME).

WuLouis

Hello WuLouis,

Membrane distillation is a process using material like Gore-Tex for desalination. There have been small applications been set up and research is going on in Germany. Plus for this process is low temperature and pressure. Scaling and fouling is very low! GOR better PR has to be improved during ongoing research at the moment. See also http://de.wikipedia.org/wiki/Membrandestillation

Claus Mertes

Totally forgetting my lack of German, I tried to take a look at the referenced article. Needless to say, I didn't get very far. Any chance of somebody translating to an English version?--Coro 00:09, 4 March 2006 (UTC)

You could try [1]. This is Google's translation of the web page. It seems to me that this would require the same amount of heat as any conventional distillation, but at a lower temperature. Not sure what it's advantage over vacuum distillation. Hope this helps. pstudier 01:55, 4 March 2006 (UTC)

Misplaced item?

The sentence "While SDSU Center for Advanced Water Technologies [2] and Professor Ronald A. Newcomb has worked with a local company (Aqua Genesis Ltd.) to assist in the development of geothermally powered desalination. [3]" towards the top of the page seems a) to be advertising and b) out of context where it has been placed. Geothermally powered desalination is not a major desalination technology at present. Wulouis

In looking at it, I'm having to agree. That section is supposed to be for currently established methods. I will be moving that stuff down to the experimental section.--Coro 01:10, 26 January 2006 (UTC)

Spray method

Does anyone recall a method involving spraying the saltwater (creating a fine mist), making distillation require vastly less energy? Apparently boiling the mist saltwater was much easier than boiling it as a liquid.

First time thermal desalination was published

I did try to find out when thermal desalination (MSF) first was published and fond a Process scheme of a multi stage flash (MSF) evaporator published 23. – 26. May 1934 in Germany during a seminar of “Schiffstechnische Gesellschaft” by Mr. R. Blaum called “Process scheme of a 3-stage flash evaporator plant with brain recirculation” I do have a scan of the process if wanted because I do not know how to get it in here.

Claus Mertesböy

Postwar, R.S. (Bob) Silver, a Scottish professor of engineering (and poet and playwright), did a thermodynamic analysis that showed multi-stage flash and reverse osmosis were clearly the best processes. Reverse osmosis was at the time technologically infeasible, and I believe that Silver's MSF design was the first continuous-flow process to be commercially implemented, in Kuwait. He was given a UNESCO gold medal for this invention. Bob told me that patents were drafted but did not succeed in catching very much of the huge money that American companies subsequently made. I am not sure how Blaum fitted in; Bob is no longer with us, but his published papers on the subject might say. - AG, Stockport.

Economics

I added a bunch of disclaimers to the economics section, as it is simple stated facts without references. If anyone has any real information as to the economics and costs of construction/maintenance/etc, I think it would be extremely useful.Dirtyharry2 00:27, 26 September 2006 (UTC)

Carbon emissions from desalination

I suggest a paragraph or two about carbon dioxide emissions (greenhouse gas) from desalination would be appropriate in this discussion. If the energy intensity of desalination is quantified, it will then be possible to estimate greenhouse emissions for a given electricity source (e.g. coal etc). I do not know the amount of energy required for desalination, but I can quantify the emissions relative to the energy requirement.