pyrojig Posted July 29, 2011 Posted July 29, 2011 (edited) LOL.. I almost spit up my coffee reading this !!! Thanks I needed a good laugh\ I too am not sure why the hotter cell is more efficient. I have done some research that shows that it is so , but im not sure what as well. When the cell is pH controlled the current efficiency goes up as temperature goes up. As a rough figure you can expect a 6% increase in current efficiency as you increase the temperature of your cell from 30 to 80C. Here is a quote from a very good site : http://www.oxidizing...e/reaction.html I also read that the "hot" cell is hard on the MMO anode ... But what is considered too hot? Edited July 29, 2011 by pyrojig
oldmanbeefjerky Posted July 30, 2011 Posted July 30, 2011 darn.....i would have thought that was it. sorry ,my bad s hey doesn't the resistance go up as the cell temperature rises? just a thought.i think ill refrain from making uninformed statements for a while....
WSM Posted July 30, 2011 Posted July 30, 2011 (edited) Well, all this talk about starting cells motivated me to renovate my original cell and try a new configuration of electrodes. First I took a scrap of MMO mesh that is 2" x 3" (~ 50mm x 75mm) and welded a 6 mm tubular titanium lead to it and filled it with lead-free solder. I drilled and tapped the other end of the tube to make an electrical connection with a stainless steel machine screw and washers. Now for a cathode I took two scraps of ~1mm CP titanium plate the same size as the MMO, welded them together with five pieces of CP titanium ribbon between the plates about 30mm long x 6mm wide and 0.7mm thick. I also welded a 6mm CP titanium tubular lead to it and finished it the same as for the MMO. When the electrodes are together (MMO between the plates of the cathode), the tubular leads are parallel but about 25mm apart. I modified two PVDF compression fittings to mount the electrode leads into the PVC pipe cap which serves as a lid on the (pickle jar) cell. I will continue this narrative later as an edit. Okay, I'm back. I filled the jar with KCl solution I made up a long time ago (Hey, where'd these little bugs come from?), Placed the lid on and hooked up the leads from my little 30 Amp power supply (it's about 2" x 5" x 8" and is rated for 5Vdc, 30A). The leads are stranded copper 10 gauge with crimped on eye lugs, so no problems. The voltage adjust trimmer is set as low as it'll go and when I fire it up the gages read 4.3Vdc and 20 A. The cell is bubbling away but all the fine hydrogen bubbles are staying on the top half of the jar . Off to the shop I go and grab an aquarium pump and rig a tube down to the bottom of the cell to stir things up. It works like a champ and I let it run. Too bad I got over-zealous and put too much salt solution in the jar . In no time the jar is streaked with salt drips down the sides. When the system had run for about a day, The salt streaks stopped, due to the lower levels (water consumption, splashing and evaporation). The cell is running hotter than I'm used to but with the larger electrodes and close setting (they're ~3mm apart) it appears normal. The temperature of the jar is 55oC (131oF) and almost uncomfortable to the touch. The vent tube smells strongly of bleach when I get close enough to catch a whiff (not over-powering, just unmistakable). I was dissappointed when I didn't see crystals dropping to the bottom of the jar (like before)... till I reallized that I WON'T see them at this temperature ! When I let the cell solution cool to below 30oC the crystals will start forming and drop like snowflakes. This cell is just to test the electrodes. It is unregulated and doesn't have pH control; just a simple batch cell. Here's a photo of the setup (it's not pretty; just a quick, simple test). It's not the finest equipment I use but it works for a quick test ! WSM Edited July 30, 2011 by WSM
WSM Posted July 30, 2011 Posted July 30, 2011 It's not the finest equipment I use but it works for a quick test ! WSM I have to mention, the salt streaks are KCl, not chlorate... yet ! I'll show the yield later . WSM
oldmanbeefjerky Posted July 31, 2011 Posted July 31, 2011 (edited) hey, its better than what im going to be using until i make a permanent cell. though ill be using a bigger pickle jar ive been looking for power supplies like the one you have there, but i never seem to be able to get any below 5v, though im only looking at jaycar catalogs (the big one ,not magazines), well, non that deliver more than 8 amps anyway. that lid is aluminium right? does the cell fumes eat away at that or does it make a protective oxide that stops corrosion like titanium does? Edited July 31, 2011 by oldmanbeefjerky
WSM Posted July 31, 2011 Posted July 31, 2011 hey, its better than what im going to be using until i make a permanent cell. though ill be using a bigger pickle jar ive been looking for power supplies like the one you have there, but i never seem to be able to get any below 5v, though im only looking at jaycar catalogs (the big one ,not magazines), well, non that deliver more than 8 amps anyway.that lid is aluminium right? does the cell fumes eat away at that or does it make a protective oxide that stops corrosion like titanium does? Hi OMBJ, That power supply IS 5Vdc, but it has a voltage adjust trimmer (adjustment potentiometer) so I turned it as low as it'll go (4.3Vdc). Moving the electrodes further apart also lowers the voltage by increasing the cell's internal resistance. I got lucky with that power supply. I got it at a local electronics supply store for less than $20 several years ago, as well as the 30A ammeter with a shunt (roughly $15). Later I got a second power supply just like the first, for the same price. I've considered wiring them together in parallel to get the same voltage but double the current. The only problem with that idea is I bought a much larger power supply on eBay that delivers 5Vdc and 60A and the voltage can be adjusted between 3.5V and 6.5V, so no need to mess with the two smaller ones. That lid is a PVC pipe cap. Aluminum would be a poor choice all around. PVC is an excellent material for cells as long as you stay below 60oC. Also, it's easy to machine and solvent weld when fabricating tankage for your cell. WSM
Arthur Posted July 31, 2011 Posted July 31, 2011 For all of you doing electrolysis, please protect the electronics! One good mist spray from the cell will start to wreck the electronics.
oldmanbeefjerky Posted July 31, 2011 Posted July 31, 2011 yes i know,its kinda lesson 1 stuff that you know oxygen and chlorine destroy metal. also wsm, i could have sworn that lid was aluminium ,so shiny and metalic, though on second look i see it is more like a spray can lid that an aluminium cap. that power supply your using (or the type anyway) thats what most everyone is using for the cells right? since my ATX can only get to 30 amps, i think i might change to one of those power supplies , since ide like to run it at about 3v at over 10A, which is the maximum for my ATX.Its funny, because when i started out, i always thought 12v was what your meant to run it at, then i find out it wrecks the anode, and your meant to use 5V, and now, it turns out 3v is what your meant to run it at! or at least are recommended to run it at. that power supply, the bigger one, are you certain that it still maintains at that high current with the lower voltage settings? because if it does thats just awsome, i must get me one like that! Since coming here it turns out everything ive ever done has been wrong. which i mean in a good way.
Tesla Posted July 31, 2011 Posted July 31, 2011 yes i know,its kinda lesson 1 stuff that you know oxygen and chlorine destroy metal. also wsm, i could have sworn that lid was aluminium ,so shiny and metalic, though on second look i see it is more like a spray can lid that an aluminium cap. that power supply your using (or the type anyway) thats what most everyone is using for the cells right? since my ATX can only get to 30 amps, i think i might change to one of those power supplies , since ide like to run it at about 3v at over 10A, which is the maximum for my ATX.Its funny, because when i started out, i always thought 12v was what your meant to run it at, then i find out it wrecks the anode, and your meant to use 5V, and now, it turns out 3v is what your meant to run it at! or at least are recommended to run it at. that power supply, the bigger one, are you certain that it still maintains at that high current with the lower voltage settings? because if it does thats just awsome, i must get me one like that! Since coming here it turns out everything ive ever done has been wrong. which i mean in a good way. So the optimum voltage is 3v not 5v?
WSM Posted July 31, 2011 Posted July 31, 2011 So the optimum voltage is 3v not 5v? Hi Tesla, Well, the textbook voltage for chlorate production is 3.6Vdc. I've run cells from 3.2 to 4.8 Volts. I have a friend who runs his continuous system at roughly 2.8 Volts and it's very easy on the electrodes. MMO is so hardy I think it can handle a fair amount of abuse; but there are limits. The 5 Volt side of a computer power supply is probably the best one to use in most cases for most users. Unless using a power supply with variable voltage, one can lower the voltage by moving the electrodes apart from each other and letting internal cell resistance keep the voltage at the desired level. WSM
WSM Posted July 31, 2011 Posted July 31, 2011 For all of you doing electrolysis, please protect the electronics! One good mist spray from the cell will start to wreck the electronics. Right you are, Arthur! I didn't worry about this setup because with the PVC lid any spray was caught and condensed under the lid and, at most, ran down the sides of the cell. Also, I lifted the power supply off the vinyl mat and propped it up with two blocks of wood (mostly for ventilation but also to prevent any moisture from getting to the metal case from underneath). With my more advanced cells I'm using larger and more complex power supplies (read expensive and hard to find) which allow variable voltage and current. I am definately designing separation and protection for those . Thanks for the warning. All those new to electrochemistry are well advised to heed Arthur's warning. WSM
WSM Posted July 31, 2011 Posted July 31, 2011 (edited) yes i know,its kinda lesson 1 stuff that you know oxygen and chlorine destroy metal.also wsm, i could have sworn that lid was aluminium ,so shiny and metalic, though on second look i see it is more like a spray can lid that an aluminium cap.that power supply your using (or the type anyway) thats what most everyone is using for the cells right? since my ATX can only get to 30 amps, i think i might change to one of those power supplies , since ide like to run it at about 3v at over 10A, which is the maximum for my ATX.Its funny, because when i started out, i always thought 12v was what your meant to run it at, then i find out it wrecks the anode, and your meant to use 5V, and now, it turns out 3v is what your meant to run it at! or at least are recommended to run it at.that power supply, the bigger one, are you certain that it still maintains at that high current with the lower voltage settings? because if it does thats just awsome, i must get me one like that!Since coming here it turns out everything ive ever done has been wrong. which i mean in a good way. Hi OMBJ, I think the 5Vdc output will work for you (give it a try). My large power supply (which weighs about 20 kilos and is designed to be rack mounted) is rated at 5Vdc and 60A. Luckily, it has a voltage adjust trimmer which allows a voltage range of 3.5 to 6.5 Volts. It's a workhorse and will go on and on (unless I destroy it somehow). It's also protected by a circuit breaker in case I accidently short the electrodes, so it ought to be okay. I also have a little beast I bought from Swede which is rated at 5Vdc and 120A (0.6 KVA)! Besides those I have two adjustable power supplies with ranges of 0-40Vdc and 0-75A (3.0 KVA), and 0-10Vdc and 0-150A (1.5 KVA). Those two are the crowning jewels of my power supplies and the ones for serious experimentation. I have rubber electrical gloves with leather keepers to use if I ever have to move the cables while energized (probably will never happen). I also have access to a 10 calorie face shield to use in such an event, as well as FR clothing. I don't believe in taking unneccesary chances with my health and well-being, if I can help it! It is very good to network. Friends will help you stay on the right path and (hopefully) keep you safe. WSM Edited July 31, 2011 by WSM
Arthur Posted July 31, 2011 Posted July 31, 2011 When I worked in a multi KA electroplating facility, the rectifiers were in a cabinet with fans and filters just to keep the corrosion down. I've been wondering whether the electronics could be in a fan cooled box with the airflow passing over a venturi so that airflow actually created a slight depression in the head of the cell, so that you could direct the fume laden effluent to somewhere less sensitive. IIRC Swede was using 5v for chlorate and about 6.5 - 7 volts for the perc step.
WSM Posted July 31, 2011 Posted July 31, 2011 When I worked in a multi KA electroplating facility, the rectifiers were in a cabinet with fans and filters just to keep the corrosion down. I've been wondering whether the electronics could be in a fan cooled box with the airflow passing over a venturi so that airflow actually created a slight depression in the head of the cell, so that you could direct the fume laden effluent to somewhere less sensitive.IIRC Swede was using 5v for chlorate and about 6.5 - 7 volts for the perc step. Hi Arthur, I like the idea of a fan-cooled cabinet for the power supply, but I believe it best to use a separate system to ventilate the cell area. I'd rather not combine them and find out later that hot, moist salt spray somehow got into my precious power supply !!! I believe you are correct about Swede's systems. WSM
pyrojig Posted July 31, 2011 Posted July 31, 2011 Expensive is correct on those larger Amp Power supplies !!!! I am looking for one at the moment( if anyone had a lead on where to find one under 100$) I have the converted atx PS as well, but a controlled system would be a jewel ... From what I have learned the chlorate production is really good at 5v, and for a amateur ( not industrial) setup , it is the best option to obtain the highest A out of your PS. I always keep the PS away from the cell( mine is bench mounted above the cell to avoid condensation and damage to the PS. Hi Arthur, I like the idea of a fan-cooled cabinet for the power supply, but I believe it best to use a separate system to ventilate the cell area. I'd rather not combine them and find out later that hot, moist salt spray somehow got into my precious power supply !!! I believe you are correct about Swede's systems. WSM
WSM Posted July 31, 2011 Posted July 31, 2011 Well, the current dropped to 11A (nearly half the starting current), so I shut down the run, pulled the electrodes out of the solution and am letting things cool down. I also noticed crystals starting to form on the bottom of the cell (and starting to clog the air tube ). I put a piece of lumber over the opening to keep debris from getting into the cell as it cools. Later, I'll wipe the salt streaks off the jar and photograph the resulting crystals and post it here. Over all the electrode test is a success. The configuration used seems very efficient and maximizes the potential of the anode material. Also, it's no surprise the run was fairly short (about 2-1/2 days), while it was running harder and faster than my earliest cells. I'll take a closer look at the electrodes later and report on what I see. WSM
oldmanbeefjerky Posted July 31, 2011 Posted July 31, 2011 (edited) on my first cell run with an ATX, i didnt use ventilation or anything. where it was didnt bother anyone though.i recently glimpsed at the old atx (we had no clue at the time how to use it, but the 3v setting seemed to work anyway), and the insides are completely black and brown from corrosion, and thats just from running the cell 30cm from the atx at 3v 2A max on the standby power.i was really hoping i could put them together in parralel for higher currents, but i dont wanna pay for new ATX's, even at the dump where they cost a silly $10ea. so im currently on the hunt for one. hey wsm, what would you say your cell efficiency was in this run? Edited July 31, 2011 by oldmanbeefjerky
patsroom Posted August 1, 2011 Posted August 1, 2011 [Expensive is correct on those larger Amp Power supplies !!!! I am looking for one at the moment( if anyone had a lead on where to find one under 100$) I have the converted atx PS as well, but a controlled system would be a jewel ... From what I have learned the chlorate production is really good at 5v, and for a amateur ( not industrial) setup , it is the best option to obtain the highest A out of your PS.] pyrojig Just a quick note: on e-Bay there is a power supply for about $27.00 dollars. It has free shipping so that is not to bad.But there are other power supplies on e-Bay and sometimes you find what you want at a good price too! DC 5V 20A (100W) Regulated Switching Power Supply Unit
WSM Posted August 1, 2011 Posted August 1, 2011 hey wsm, what would you say your cell efficiency was in this run? Hi OMBJ, Probably less than 50%. Most of the energy was used turning salt into bleach. A second run would probably be better since the solution is now full of dissolved chlorate. If I hook up an acid injection system it would likely get over 85% CE. I won't know the actual CE% till I weigh the harvested crystals and compare to the concentration of the beginning solution. Bleach and pool acid , now there's a combination !!! I'm not sure whether to run it again or store it till I get back from Fargo, ND? WSM
pyrojig Posted August 1, 2011 Posted August 1, 2011 [Expensive is correct on those larger Amp Power supplies !!!! I am looking for one at the moment( if anyone had a lead on where to find one under 100$) I have the converted atx PS as well, but a controlled system would be a jewel ... From what I have learned the chlorate production is really good at 5v, and for a amateur ( not industrial) setup , it is the best option to obtain the highest A out of your PS.] pyrojig Just a quick note: on e-Bay there is a power supply for about $27.00 dollars. It has free shipping so that is not to bad.But there are other power supplies on e-Bay and sometimes you find what you want at a good price too! DC 5V 20A (100W) Regulated Switching Power Supply Unit I am looking for a supply in the 50A + range... at the moment .. But thanks for the tip.. I have been watching ebay as well. I found a 30A one for that same price... but Im still searching .
WSM Posted August 1, 2011 Posted August 1, 2011 Expensive is correct on those larger Amp Power supplies !!!! I am looking for one at the moment( if anyone had a lead on where to find one under 100$) I have the converted atx PS as well, but a controlled system would be a jewel ... From what I have learned the chlorate production is really good at 5v, and for a amateur ( not industrial) setup , it is the best option to obtain the highest A out of your PS. I always keep the PS away from the cell( mine is bench mounted above the cell to avoid condensation and damage to the PS. To protect my expensive variable power supplies, I'm considering mounting them away from the wet lab and supply power to the cells via an electric bus, i.e., solid copper bars (much as is done industrially). The bus bars will still need to be protected but that's much simpler than protecting the power supply, plus the bus is easier to replace, if neccessary. My best power supplies were obtained locally. I'm fortunate to have an industrial surplus yard less than 50 miles from my home. That's where I bought my best two supplies and they were lucky finds (most of what they have wouldn't do or are too expensive, even as surplus). eBay seems to be a reasonable source for power supplies (I got one there). Shipping is the main problem. The 5Vdc 60A unit I got on eBay cost more to ship than the price of the item, and it was only one state away! Across the country, the shipping could easily triple the cost of the item (those things are heavy). WSM
WSM Posted August 1, 2011 Posted August 1, 2011 (edited) Here are photos of the crystals in the bottom of the cell jar: These are clearly chlorate with that distinctive flake crystal shape ! I'll harvest them later but the liquor will be used in other experiments. Happy Day! WSM Also, the tubular leads filled with lead-free solder worked well. They were warm to the touch but much cooler than would damage the plastic (PVDF) compression fittings that held them. Over all, a total success! Edited August 1, 2011 by WSM
Bonny Posted August 1, 2011 Posted August 1, 2011 on my first cell run with an ATX, i didnt use ventilation or anything. where it was didnt bother anyone though.i recently glimpsed at the old atx (we had no clue at the time how to use it, but the 3v setting seemed to work anyway), and the insides are completely black and brown from corrosion, and thats just from running the cell 30cm from the atx at 3v 2A max on the standby power.i was really hoping i could put them together in parralel for higher currents, but i dont wanna pay for new ATX's, even at the dump where they cost a silly $10ea. so im currently on the hunt for one. hey wsm, what would you say your cell efficiency was in this run? Why are you so set on running at 3V??? Unless you have a poor quality anode, set it up on 5V and start pounding the current in! Just reading this thread shows proven good results running 5V. If I was going to do anything in parallel, I'd be doubling the atx's at 5V to pump 40-60A.
oldmanbeefjerky Posted August 1, 2011 Posted August 1, 2011 Good for you! , in the non sarcastic way I think if you look hard enough, you can find some ATX power supplies for the bigger more expensive computers which have a maximum amperage of 45A (at 5V setting), but i dont think they ever get bigger than that, and often the computers they come out of would never be damaged so much that it wouldnt be worth repairing. but still, they exist, or so ive heard. or perhaps they might be webserver PS, i dont exactly recall
Bonny Posted August 1, 2011 Posted August 1, 2011 Good for you! , in the non sarcastic way I think if you look hard enough, you can find some ATX power supplies for the bigger more expensive computers which have a maximum amperage of 45A (at 5V setting), but i dont think they ever get bigger than that, and often the computers they come out of would never be damaged so much that it wouldnt be worth repairing. but still, they exist, or so ive heard. or perhaps they might be webserver PS, i dont exactly recall I think you missed the point. Set your cell up with the 5V 30A and you'll be making chlorate faster than most amateurs would ever use it. Unless you plan on selling it or something, I don't really see any need to produce more. Once the first run is done, you have a second batch going before you likely use the first, and then just keep going. I don't plan on getting a larger power supply, but was simply stating that I would add another at 5V and not 3V.
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