WSM Posted January 8, 2014 Posted January 8, 2014 (edited) [quote name="pyrojig" postHere is the starting materials soon to be fabricated into a working cell. Excellent! It looks like you're on your way. Keep us up to date on your progress. WSM Edited January 8, 2014 by WSM
pyrojig Posted February 5, 2014 Posted February 5, 2014 Please forgive the long pause in posts . I have had some unique issues with the site locking my IP out . I was in the middle of loading some pics of the bucket cell in operation and it zapped me like a spammer. I was unable to get onto the site for 10days . .
pyrojig Posted February 5, 2014 Posted February 5, 2014 http://i918.photobucket.com/albums/ad24/pyrojig/photobucket-21582-1390616701418.jpg Here is the bucket cell upon startup .
pyrojig Posted February 5, 2014 Posted February 5, 2014 And the acid reservor . A complete system pic will be on the way as well as a digitally monitored ph controlled sys completed .http://i918.photobucket.com/albums/ad24/pyrojig/photobucket-14211-1390616682905.jpg
pyrojig Posted February 6, 2014 Posted February 6, 2014 One thing that I noticed about the tight arrangement of the electrodes, is it runs hotter , and attracts "stalagtites " of salt . I believe that this is due to the diff in temp being hot and attracting a seeding area. It seems that the only way to fix this new prob is to place the electrodes apart a little further , and maybe reduce the electrolyte level down more. It sits at the second ring down mark on the bucket. About 3+ in down from the BCA. The boiling solution may be splashing on this creating the prob. as well. My only fear is that the salt may bridge the electrodes and create a short or resistance , effecting the PS. So far it has not been a issue, http://i918.photobucket.com/albums/ad24/pyrojig/photobucket-10857-1390616624639.jpg
frank Posted February 6, 2014 Posted February 6, 2014 Quote: "These pH adjusting systems are nothing trivial and fairly expensive, but if you want to improve efficiency and break the magical 90% efficiency threshold, then this is an elegant solution. I've run little batch cells with no .." A quick, cheap, easy and reliable way to add acid is to use a medical infusion pump. These things are built to high standards, can be bought for damm all, and will work for years with a piece of silicon tubing and a reservoir. They are easily adjusted for most cell sizes etc etc.http://www.ebay.co.uk/itm/Pallet-Job-Lot-40x-Imed-Gemini-PC-1-Infusion-Pumps-/151211525300?pt=UK_BOI_Medical_Lab_Equipment_Medical_Equipment_Instruments_ET&hash=item2334e8c4b4#ht_862wt_722 I picked one up for about 20 bucks. Frank
pyrojig Posted February 6, 2014 Posted February 6, 2014 Hey that is clever!! I love the creativity of the folks on this site!!! When we put our heads together , we can accomplish anything. Thank you for sharing some nice ideas . It seems like a all-in-one unit. Built the way we are doing it will cost close to double that .You might be onto something great here .
pyrojig Posted February 11, 2014 Posted February 11, 2014 (edited) Here is the last pic of what happens when you let the salt stalactites keep growing for a few days. After cleaning the salt off the electrode shanks, the amp load dropped about 2 amps.This leveled out the sys at 32.4 v.s the 34.5 it was at prior to cleaning . A revamp on the electrodes is on the way ,we'll try and fix this new annoying issue. http://i918.photobucket.com/albums/ad24/pyrojig/photobucket-10844-1392092739080.jpg Edited February 11, 2014 by pyrojig
schroedinger Posted February 11, 2014 Posted February 11, 2014 Wow thats a lot. How hot is your cell running?
pyrojig Posted February 11, 2014 Posted February 11, 2014 good, but this is a concern , and may be a power eating salt bridge.
schroedinger Posted February 11, 2014 Posted February 11, 2014 Well i'm asking, mcause i had the same problem ones, occuring on very hot cell. But not very much on cells with lower temperature (up to 60ºC)
pyrojig Posted February 11, 2014 Posted February 11, 2014 Well the cell is averaging 45-50*c . It is the electrodes that are freak'n hot. My Anode is 180-200*c and the cathode is about half that . If it wasnt for the kynar fittings the electrodes would melt the lid like butter. I am amazed these fittings can take such high temps (up to 400*F range for example). I believe that the extreme diff in heat is the prob, and larger electrode arms are in call for. WSM said that we should try up to 3/8 to 1/2 dia size .
schroedinger Posted February 12, 2014 Posted February 12, 2014 Well that sounds a litlle to hot for me. What type of electrodes are you using, couldn't find any thing about that. Also how big is the surface area?
pyrojig Posted February 16, 2014 Posted February 16, 2014 The electrodes where sized to fit a 25A draw. about 1.5 in wide and 8 " in length . The anode is boxed in by two cathodes . The electrode arms are cp TI tube 1/4 " approx . and filled with solder. ( thanks to WSM) . These may be a bit undersized due to the large amount of heat produced at the round shanks of the electrode ,and the electrical connections . I am fighting salt buildup on the electrode arms almost every 3rd day. It is a pain to deal with , but more so a worry it is drawing current away from the electrodes doing the work.
Arthur Posted February 16, 2014 Posted February 16, 2014 The Iwaki bellows pumps from photoprocessing machines should stand strong acids and can be chosen and adjusted to deliver very tiny amounts per stroke. Adding a timer to allow only a few strokes per hour will allow tiny volumes to be added, adjustable right up to 100's of ml per minute. The pump controller could well be connected to a process control unit or set at a guestimate based on the cell current. One of the great needs of a cell is unattended running time so automation of the cell additions could help.
MrB Posted February 16, 2014 Posted February 16, 2014 I am fighting salt buildup on the electrode arms almost every 3rd day. It is a pain to deal with , but more so a worry it is drawing current away from the electrodes doing the work. The buildup happens above the surface of the fluids, right? Add a bit of silicone tubing so the titan isn't exposed to air? B! 1
pyrojig Posted February 17, 2014 Posted February 17, 2014 This may work, but the heat of the anode shank is reaching 200*C. I think the only options would be viton tubing or teflon type material for this approach . But I think you are on the right track. The use of round electrode shanks is to allow them to be easily adjusted in height . This will not be possible with the compression type fittings in the BCA. But on another note once we get the sys to the sweet spot w/o bugs , I can take that approach and the electrodes will be stationary in height .
schroedinger Posted February 17, 2014 Posted February 17, 2014 (edited) If they get 200ºC hot, then you need to change your set up. Thats way to hot. Drop your current to a level where they don't go higher than 80 ºC. If you wan't the high current, add a 2nd shank to your anode.80ºC cause you cell is ment to run at a little less temperature and many mmo types can handle much more temperature over a long time very well The salt growing happens mostly because of the spray generated by the rising gas. If you heat up you electrodes this much, everything instantly evaporates and the salt is left behind. At lower temperatures most of the spray cqn run back ingo the cell. Edited February 17, 2014 by schroedinger
bikemaster Posted February 18, 2014 Posted February 18, 2014 An other way to go is to use an heatsink on each electrode. You can use a CPU heatsink like this one (http://www.build-your-own-computer.net/image-files/cpu-cooling-02.jpg) and drill an hole in the center that match the diameter of your electrodes. It will help to dicipate some heat and keep everyting cooler.
pyrojig Posted February 19, 2014 Posted February 19, 2014 A brief conversation with WSM is leaning me to the way I used to run my older cells( with the liqueur 1/2- 1/4" from the lid. It will keep the shanks in the solution and any buildup will quickly dissolve away. The use of heat sinks is not what Im after ( i want a simple setup) , but not a bad idea. I believe that the raised liqueur level will dissipate the heat somewhat , and changing the shanks to a larger Dia next( like 3/8" or larger), if that doenst do the trick.
pyrojig Posted February 26, 2014 Posted February 26, 2014 Well, a quick update on the cell. The raised liquid level appears to really help the annoying build up on the electrodes ......, but another prob arises where one leaves . I not have to really tighten up all ports and plugs in the BCA . Salt creep is a big prob now. The liqueur is now about 1/4 - -1/2" in below the BCA. Some rusting is now on the bolts of the BCA . I must get out the roll of teflon and rtv to tightening up things here. Still waiting to get to the half way point of Amperage to pull the plug and assess the CE as well as the formation of crystals and their shape in such a caustic environment. This will give me a comparison for the ph controlled v.s. the non controlled. It has been about a few days short of a month and it seem twice as long as any other run i have ever done. Wsm thinks that most of my CE may be "going up in heat" v.s. putting the power at the electrode and doing work in the cell.
WSM Posted March 2, 2014 Posted March 2, 2014 Well, a quick update on the cell. The raised liquid level appears to really help the annoying build up on the electrodes ......, but another prob arises where one leaves . I not have to really tighten up all ports and plugs in the BCA . Salt creep is a big prob now. The liqueur is now about 1/4 - -1/2" in below the BCA. Some rusting is now on the bolts of the BCA . I must get out the roll of teflon and rtv to tightening up things here. Still waiting to get to the half way point of Amperage to pull the plug and assess the CE as well as the formation of crystals and their shape in such a caustic environment. This will give me a comparison for the ph controlled v.s. the non controlled. It has been about a few days short of a month and it seem twice as long as any other run i have ever done. Wsm thinks that most of my CE may be "going up in heat" v.s. putting the power at the electrode and doing work in the cell. I'm not completely sure but electrically that makes the most sense. Besides creating more problems for the stainless steel screws exposed to the liquor (and fewer salt deposits), let's see how this run changes (especially the efficiency). Thanks for keeping us up-to-date with the progress and functioning of your bucket cell. WSM
pyrojig Posted March 8, 2014 Posted March 8, 2014 (edited) Well, this has been a very long test phase for 1 run. The target AMP drop is about 19-20A when the plug will be pulled, the electrolyte processed ,filtered, and recharged again . I am sitting around the 23-24A range now. I am now at the 30day mark from startup . The cell was run W/O ph control as a comparison to running ph controlled. I hope to cut the run times down to 1/2 that ( maybe 15days at most) . I threw out a interesting idea to WSM to chew on . Any others following this are welcome to chime in as well with ideas. It seems that the system I ran with larger electrodes spaced further apart ( 3") produced more chlorate ( better CE ) than the use of smaller electrodes with tight tolerances (1/8"). The Amp draw was adjusted by the spacing of the electrodes in the cell by distance. The smaller fixed electrodes do not have that option ( they are build specific for a certain Amp draw.) Is there any gain by using the larger electrodes spaced further apart to get " more surface area working for you in the cell? Edited March 8, 2014 by pyrojig
Arthur Posted March 8, 2014 Posted March 8, 2014 IMO high current density can cause damage to the electrodes, so moderate current density lets the electrodes last longer. As a hobby system this may be less important than in a commercial system.
Arthur Posted March 8, 2014 Posted March 8, 2014 Somewhere I have seen a figure for amphours required per gram of chlorate, maybe a search will find it
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