The Bucket Cell - Start to Finish

[WSM]

To encourage circulation, putting the electrodes parallel to the bottom might be an idea. Causing a wider stream of bubbles & heated fluids rather then a narrow, more intense stream.

B!

 

That's one thought, but unless you mount the electrodes through the sidewall of the cell, you'll use more of the hard-to-find and expensive small diameter CP titanium tubing.

 

I believe the vertical, narrow electrodes will encourage more circulation because you'll have a more locallized stream of hydrogen bubbles and heat in one spot in the cell (we call that "hydrogen lift"). As the hydrogen bubbles pour off the cathodes they move directly up, pulling fluid up from below the electrodes. As the bubbles break the surface of the mother liquor they spread out across the surface. The heat and the ionic products of the electrodes follow along and, cooling slightly, drop down at the areas surrounding the electrode area; where they move toward the bottom of the cell and can flow toward the electrodes and start the cycle over. This is similar to the fluid movement in a pot of boiling water (convection currents).

 

This is a wonderful thing because it doesn't promote the "brute force" method of anodic chlorate production, but by creating various ionic species that get moved around the cell by the fluid currents, it encourages the "bulk reaction" of chlorate forming all over the cell at the same time (the way industry optimizes their production of these salts). Along with pH control (admittedly, a greater contributer to the "bulk reaction", described), the cell efficiency can approach and exceed the 90% CE (= more chlorate and faster, because fewer electrons are used to do the work) goal, the best and brightest amongst us seek.

 

I believe pyrojig ran a couple of different bucket cells and observed better natural mixing of the electrolyte using tall, slender electrodes as opposed to square(ish) electodes, with about the same surface area. I believe Swede mentioned something about enhancing the effect by placing a PVC tube around the electrodes while allowing fluid flow over and under the tube (focusing the flow like a chimney).

 

It makes sense to me when I think about it, but then again I haven't tried it your way. Do you want to try the idea and compare them side by side? Let us know if you do, and what help we can offer...

 

WSM

[MrB]

It makes sense to me when I think about it, but then again I haven't tried it your way. Do you want to try the idea and compare them side by side? Let us know if you do, and what help we can offer...

Actually, my observation is based on bubbler type uses, not bubbles & heat from a electrode, and i've got nowhere near the knowledge to set up a experimental bucket cell, so i won't be testing it. It was just a thought, i wanted it thrown out there if someone had overlooked it as being to simple.

 

Where it comes to the use of the tubing, you should be able to get away with a T-shaped electrode, keeping the amount of tubing to the bare minimum. You would need more to reach lower in the bucket, but that should be all.

B!

[pyrojig]

@Wsm..,

I have to say thanks for the nice setup. It will be a work in progress. I will try to keep good notes and pic's as the setup is built .

As for the cells , i did notice a diff in the 5gal setup from other cells I built. The longer electrodes did promote better heat transfer. In my research , it is better to have a hot cell that is consistent in temp.You have two things working together to produce kclo3( heat and electricity). My shorter electrodes caused the cell to only have the top half hot, the rest of the liqueur was ambient temp. not very efficient.

 

I do like the idea of a chimney effect, that would create "draft" vacuum of sorts . Or circular type of electrodes sandwiched in rings.

[pyrojig]

Here is a couple pics of the latest changes to the bucket cell . The electrodes are very close to each other and to avoid a short I have fitted the anode with spacers made of 1/16" viton tube weaved into the mesh of the MMO anode. IT had made a remarkably tight fit. .

http://i918.photobucket.com/albums/ad24/pyrojig/Chlorate%20Designs%20and%20related%20materials/th_Vitontubespacesforelectrodes.jpg?t=1360597957

http://i918.photobucket.com/albums/ad24/pyrojig/Chlorate%20Designs%20and%20related%20materials/th_BCAwithelectrodesandspacers.jpg?t=1360511981

[pyroshell]

Looking good!

 

 

I just played with one of my old cells today. I hooked them up to solar panels. It is a rather high voltage and not that high amp setup. It is nice thought because your power supply will never heat up too much.

It is a 7.8 amp 33 volt setup. It appears too run a rather high efficiency.

I was thinking about a modified mot before this, but I think I will play with these for a little longer.

 

 

Something I never tried, but wondered about is if you could use a ph indicator fluid in you cell to indicate you ph so you would know when to add your HCL?

I always used ph probes. I do not know how this would interact with all of the chemistry going on in your cell. If no one has tried this I might play with it.

[Arthur]

If you want to use solar then remember that some electrodes are destroyed by sitting in the solution with the power off, so you need to separate the electrolyte and electrodes at dark times. Yes the HV (well 18 - 50v ) panels would do with a DC -DC converter to give loads of amps at fewer volts. Plus with the ever varying current from solar, none of the estimates used for replenishment would work. Try with universal indicator, but with all the intermediates in solution being bleaches I suspect that colours may only last for seconds, -you have to read indicator paper as it decolours.

[pyroshell]

If you want to use solar then remember that some electrodes are destroyed by sitting in the solution with the power off, so you need to separate the electrolyte and electrodes at dark times. Yes the HV (well 18 - 50v ) panels would do with a DC -DC converter to give loads of amps at fewer volts. Plus with the ever varying current from solar, none of the estimates used for replenishment would work. Try with universal indicator, but with all the intermediates in solution being bleaches I suspect that colours may only last for seconds, -you have to read indicator paper as it decolours.

Yeah I did not have high hopes for the idea of using a ph indicator fluid.I was mostly wondering if it had been done before.

 

I was not planing to use any kind of dc to dc converter.

 

The electrodes are some cheap, but very durable MMO electrodes I bought a long time ago.

They are some beater electrodes. They are covered with scratches, and they have already been sitting in a concentrated KCL solution for well over a year. I would not care if they were to die tomorrow. I think i will just run them into the ground. I am going to make a very modular cell as soon as i know i will have access to the right equipment.

 

Also the fluctuation from the solar pannels are a lot less then expected.

[WSM]

Yeah I did not have high hopes for the idea of using a ph indicator fluid.I was mostly wondering if it had been done before.

I was not planing to use any kind of dc to dc converter.

The electrodes are some cheap, but very durable MMO electrodes I bought a long time ago.

They are some beater electrodes. They are covered with scratches, and they have already been sitting in a concentrated KCL solution for well over a year. I would not care if they were to die tomorrow. I think i will just run them into the ground. I am going to make a very modular cell as soon as i know i will have access to the right equipment.

Also the fluctuation from the solar pannels are a lot less then expected.

 

If the electrodes have been stored in KCl solution, I expect no damage on them. If stored in the cell liquor, then yes, they may be damaged (particularly the bare titanium cathode and any exposed titanium substrate on the MMO anode).

 

Solar cells can work, but not alone. As a "CO-GEN" part of a complete power system, they could be quite beneficial. We're not talking about a simple hobbyist set up, though. A properly designed and engineered power system with solar CO-GEN (which includes power controls,battery backup, an inverter, etc.) is no trivial proposition. Maintenance alone on such a system could take the fun out of it.

 

It is possible, though.

 

WSM

[taiwanluthiers]

For me, green pyro usually involves a barium compound...

[pyrojig]

Funny guy.

That is a direct way of going green, not something tree huggers may enjoy ( the toxic side effects) LOL

[WSM]

It seems the greatest sticking point to progressing with the bucket cell efficiently is the digital timer for the pH control system. Those timers (as described by Swede) are about $50 delivered, on eBay; but seem to be essential for accurate valve control.

 

Auber is the supplier (see http://auberins.com/ ) and you can see the eBay listing as item 200821796263 and get the details. The timer is accurate from 10ms to 9999 days (about 27 years !!!), and fully programmable, truly amazing for it's size and price. If I could find a similar item for a lot less I'd buy several of them. A useful setup with it is to program it for hourly switching (determined by the length of time required by your setup to deliver the required amount of dilute HCl) and reset to repeat continually.

 

Pyrojig has all the other parts required to plumb the pH control system. I look forward to seeing his progress when he gets the opportunity to finish the assembly. Once it's running, the greater challenge will be processing the material to make it "ready to use" for pyrotechnics (mostly purifying, drying and powdering). I think making the oxidizer is easy, but making it useful is more involved .

 

WSM

[pyrojig]

YA, thats no kidding.. The process of cleaning up the salts , processing, then drying is a task in its self. I wont miss the hand dosing of acid any more. What a task that was!! 3x a day still is not even close enough to get out of the mid high 70%CE range. Some things are better done by a constant drip, v.s. 10 + ml of acid at one shot. This stuff can gas your ass . I got around that by a 1/4" access tube into the cell through the lid. From there I could test ph, and do acid delivery. Still got a small wiff of that stuff every time though .

Ill be getting the timer here shortly, and assembling the complete sys. Sadly Im in fully swing with my business, and time is of the essence. More to come soon!!!

[WSM]

Another sticking point, but one that isn't as hard to solve, is a proper reservoir for the dilute HCl solution. It has a few important features that it must have:

• it has to be compatible with HCl
  
• it has to have high structural integrity (no leaks at all)
  
• it should be stable and not prone to tipping or spilling
  
• it should not allow vapors out but be breathable to maintain a good flow.
  
• having a shutoff valve where the acid exits is a plus for serviceability and maintenance of the system
  
• it should be large enough to hold at least a weeks worth of doses
  
• it should be small enough to be movable, if neccessary
  

These points aren't all, but certainly useful when planning what sort of container to buy or build.

 

I was looking at various tanks offered in the USPlastics Company (a family owned business in Ohio) catalog, and noticed that the cross-linked polyethylene (XLPE) tanks are recommended for HCl (among other things) and considered looking into buying one.

 

Then I realized, I already have a couple ! More than twenty years ago I was in a surplus store in Idaho and bought two XLPE pipet cleaning tanks with lids (they were about $10 each if I recall correctly). It suddenly dawned on me, one of these would be perfect (and I don't have to build one from scratch). All I need to do is add a compatible valve near the bottom of the tank so I can valve off the flow for servicing the system.

 

This is perfect !!! Sometimes being a packrat really pays off !

 

I'll add a photo when I assemble the thing.

 

WSM

[WSM]

...Then I realized, I already have a couple ! More than twenty years ago I was in a surplus store in Idaho and bought two XLPE pipet cleaning tanks with lids (they were about $10 each if I recall correctly). It suddenly dawned on me, one of these would be perfect (and I don't have to build one from scratch). All I need to do is add a compatible valve near the bottom of the tank so I can valve off the flow for servicing the system.

This is perfect !!! Sometimes being a packrat really pays off !

I'll add a photo when I assemble the thing.

WSM

 

I finally dug one out, cleaned it up and photographed it:

 

 

This tank is made by Nalgene and designed to be a pipette cleaner (as mentioned above). The internal dimensions are approximately 7" Diameter by 20" deep, or roughly 3.25 gallons (>12 liters), and completely impervious to hydrochloric acid. Unfortunately it won't hold up to the mother liquor in an active cell, or I might have tried it for that.

 

I'll have to drill and tap a hole for the PVC fitting I plan to use for the bottom side port and try it out. This ought to make a fabulous acid reservoir for my pH control system. I'll add more photos as I get further along...

 

WSM

[pyrojig]

@WSM ...

That is a beauty !!! I think you have a winner!!

 

That volume should be very nice for a few healthy runs. You sure pull out the stops and surprise us at times .

[WSM]

@WSM ...

That is a beauty !!! I think you have a winner!!

That volume should be very nice for a few healthy runs. You sure pull out the stops and surprise us at times .

 

Thanks, pyrojig. I think it'll work out well. Now I wish I bought several more, but I've got way too much stuff stored as it is... ! Maybe I should have a pyrotechnists garage sale .

 

WSM

[WSM]

It seems the greatest sticking point to progressing with the bucket cell efficiently is the digital timer for the pH control system. Those timers (as described by Swede) are about $50 delivered, on eBay; but seem to be essential for accurate valve control.

Auber is the supplier (see http://auberins.com/ ) and you can see the eBay listing as item 200821796263 and get the details. The timer is accurate from 10ms to 9999 days (about 27 years !!!), and fully programmable, truly amazing for it's size and price. If I could find a similar item for a lot less I'd buy several of them. A useful setup with it is to program it for hourly switching (determined by the length of time required by your setup to deliver the required amount of dilute HCl) and reset to repeat continually.

Pyrojig has all the other parts required to plumb the pH control system. I look forward to seeing his progress when he gets the opportunity to finish the assembly. Once it's running, the greater challenge will be processing the material to make it "ready to use" for pyrotechnics (mostly purifying, drying and powdering). I think making the oxidizer is easy, but making it useful is more involved .

WSM

 

I've been working on the timer problem and built a control unit based on the highly variable units available on eBay.

 

When I received the latest timer from overseas, I tested it and programmed it to run for ten seconds less than half an hour (29' 50"), then switch the internal relay on for ten seconds and then reset and start the cycle over again (continuously). I spent the time and mounted the circuitry inside a sturdy PVC electrical panel box pictured below:

 

 

The circuitry involves the timer unit, a solid state relay, the input socket (for the computer power cord used) and a standard 120 Vac dual outlet; all wired to function together.

 

When I ran the system with a desk lamp plugged into the outlet; it counted up to the limit, switched on the lamp for ten seconds, switched off the lamp and started the cycle over again.

 

I used the internal relay of the timer to power the low voltage side of a solid state relay (using an auxiliary 9Volt DC power output on the timer unit). When the relay in the timer switches on it powers the solid state relay which allows the full 120 Vac to switch on and flow through the outlet for the full time programmed (it's programmed for two timing cycles; the first one for the delay and the second one for the "on" phase, in a continuously running cycle).

 

Now to finish the acid reservoir...

 

WSM

[WSM]

Now to finish the acid reservoir...

WSM

 

I finished the acid reservoir last weekend but have been running non-stop at work ever since. I'll show a photo of all the parts when I can get to it. The problem I was having was leaks around the valve. I solved the problem by:

• using extra Teflon tape on the valve threads
  
• adding a PVDF nut to the inside threads of the valve
  
• making TWO Viton gaskets from 1/16" thick Viton sheet and putting one on either side of the reservoir wall
  
• Carefully tightening the whole assembly to the thin (about 1/8" [3mm]) wall of the XLPE reservoir
  

That did the trick! No leaks.

 

The XLPE, Viton, PVC and PVDF materials are all impervious to the HCl solution that they're exposed to. This will be a good thing.

 

WSM

[pyrojig]

Yikes !!! Im getting behind here, WSM. Been awful busy as well. Im going to get the timer in a box and set up a bottle gravity feed( siphon) to the valve. Im thinking about 3' of fall should give enough head pressure to prime and keep the valve operating w/o glitches. Might make a check valve out of a simple jar filled with water and vented . This will keep any back-feeding of the acid vapors from getting airborne( when things get hot in the summer)..

[WSM]

Yikes !!! Im getting behind here, WSM. Been awful busy as well. Im going to get the timer in a box and set up a bottle gravity feed( siphon) to the valve. Im thinking about 3' of fall should give enough head pressure to prime and keep the valve operating w/o glitches. Might make a check valve out of a simple jar filled with water and vented . This will keep any back-feeding of the acid vapors from getting airborne( when things get hot in the summer)..

 

Sounds good. I look forward to seeing your progress. (This isn't a competition, by the way)

 

I think even 2' should provide decent head pressure in a well made siphon system. Keep up the good work and document everything .

 

WSM

Edited May 24, 2013 by WSM

[WSM]

I did a trial set up of the gravity-fed pH control system components. This is Swede's idea originally, but I've adapted it for my experiments. My original idea was to use a precision peristaltic pump with metered tubing to accurately inject precise amounts of HCl solution, but I've been won over by the simple elegance of Swede's gravity fed system.

 

In the two photos attached below you see 1) the system running and 2) the injection cycle (with the green relay LED energized). This was a dry run (no fluids involved), but I plan a wet run when I can determine the amount of HCl delivered per given time increment, and then dial in the time required for the given cell setup.

 

 

I'll use water when testing the quantity of fluid delivered, but acid solution for the running cell. I'll probably use a graduated cylinder to accurately measure the liquid delivery per cycle. The trial program in the timer is set up to run 14 minutes and 55 seconds, and then a 5 second injection cycle before restarting the timing cycle. These times were an arbitrary decision on my part and have nothing to do with a final setup for an actual running cell (which will be determined by experimentation later).

 

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 pH control at all for many years, and they work just fine; but this is an attempt to do better than the 50-60% efficiency (at best), I've done so far.

 

Along with the experimental continuous systems I'm preparing, this pH control setup will be a real gem.

 

WSM

Edited May 28, 2013 by WSM

[NeuroticNurse]

Wow, my chlorate cell compared to that chlorate cell is a rather sad, crappy little decrepit one.

 

It consists of an old 2kg jar of pickles with a mesh titanium piece as the cathode and an MMO mesh anode, open lid, but operated outdoors with a 50AMP/5V supply.

I have previously used an IV line from the hospital to drop HCl acidulated brine into it, but not these days.

Does anybody know, is it necessary to keep pH within the target range? If so, and I neglect to do so, what efficiency of production will I get at pH 11, which it seems to stabilise at?

[pyrojig]

Sadly kclo3 v.s the perc needs much attention to ph control to maximize ones yields. It is common for a cell w/o ph control to [produce good chlorate , but C.E. ( cell efficiency ) goes to about the 50-60% range . With acids and temp control , industry is in the high 90% + . This is key to "making it worth your time " monitor and test the Ph often . It is best to keep it in a 7 (neutral) to 6 ph range and not stray above the 8% .

 

@WSM ;

\ Wow !! That is a simple but elegant setup . I may have to follow your train of thought and finish what we started . I wish there was 48H in a day!!! 24h seems too little .

LOL I just read what you posted WSM above, I jumped on answering the question this fellow asked w/o realizing you already answered it above ... Strange how much we think alike LOL Man am I glad your hear contributing to this thread !! Your are an amazing inspiration .!! Please dont quite till we make a revolutionary change to the production of Perch .

Edited September 21, 2013 by pyrojig

[WSM]

Wow, my chlorate cell compared to that chlorate cell is a rather sad, crappy little decrepit one.

It consists of an old 2kg jar of pickles with a mesh titanium piece as the cathode and an MMO mesh anode, open lid, but operated outdoors with a 50AMP/5V supply.

I have previously used an IV line from the hospital to drop HCl acidulated brine into it, but not these days.

Does anybody know, is it necessary to keep pH within the target range? If so, and I neglect to do so, what efficiency of production will I get at pH 11, which it seems to stabilise at?

 

Hi NeuroticNurse,

 

My first successful cell was a one gallon (3.785 liter) pickle jar with a PVC pipe cap for a lid. It was a learning experience and I've grown a lot since then (in understanding and skill), but that old, inefficient and unregulated cell produced several kilos of potassium chlorate that summer. I think the efficiency was in the 40%-50% range, but it worked anyway!

 

I run my cell outdoors too (I don't like to see my expensive machine tools turn brown) and it works just fine. I don't run my cell very much but I love the challenge of making it better.

 

Welcome to the discussion.

 

WSM

Edited September 22, 2013 by WSM

[WSM]

Sadly kclo3 v.s the perc needs much attention to ph control to maximize ones yields. It is common for a cell w/o ph control to [produce good chlorate , but C.E. ( cell efficiency ) goes to about the 50-60% range . With acids and temp control , industry is in the high 90% + . This is key to "making it worth your time " monitor and test the Ph often . It is best to keep it in a 7 (neutral) to 6 ph range and not stray above the 8% .

@WSM ;

\ Wow !! That is a simple but elegant setup . I may have to follow your train of thought and finish what we started . I wish there was 48H in a day!!! 24h seems too little .

LOL I just read what you posted WSM above, I jumped on answering the question this fellow asked w/o realizing you already answered it above ... Strange how much we think alike LOL Man am I glad your hear contributing to this thread !! Your are an amazing inspiration .!! Please dont quite till we make a revolutionary change to the production of Perch .

 

The ideal goal for pH is 6.8 and that seems to be the sweet spot for highly efficient chlorate production.

 

Thanks for the kind words. You have the parts, now if you can find the time to put them all together and run the thing, that would be great!

 

The perchlorate thing will have to wait till I can log some time with an accurately controlled electric kiln. Once I can roast that experimental anode at the right temperature for the proper amount of time; we'll see if it lives up to the promise and how well it holds up. The whole thing is up in the air and we hope it turns out well!!!

 

WSM

Edited September 22, 2013 by WSM