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Author: Subject: Birkeland-Eyde reactor for making nitric acid.
WGTR
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[*] posted on 20-11-2014 at 21:28


Thanks for the pointers. I'm trying water-cooled copper capillary tubing right now, to see how that holds up. After all, that's how it worked in industry. The electrodes are holding up somewhat, but there are a few things that I need to adjust in the arc. I'm not spreading the arc far enough yet, and the current is being concentrated too much in certain areas of the electrodes. Aside from that, the water is keeping them cool. I'm using a DI water supply right now, with no recirculation (just runs down the sink). Water runs through the positive electrode, and exits through rubber tubing to the negative electrode. The water is not even warm as it exits.

As I ponder my previous post, I realized that I completely missed something obvious. In the original Birkeland-Eyde reactor design, the supply voltage was 5000VAC, at something like 40A. This is, of course, for a full sized reactor. The current limiting was provided by inductive ballast.

This inductive ballast causes the arc voltage to swing not only below, but above the supply voltage. Think of the arc as if it were a MOSFET in a flyback converter. When the FET is on (low arc voltage), the inductor charges up. When the FET turns off (arc blown out to the edge of the reactor), the inductor dumps its energy through the load resistance. If the load resistance is very high, then the voltage across the FET (arc voltage) can rise to very high levels, at least until the FET avalanches (arc voltage in this case may rise to 10's of thousand of volts). This is a weak analogy, and what is happening in the arc is more complicated than this, but it's the general idea.

Up until now I have been using a 150VDC supply that is current limited to 3A, and with 30 ohms of ballast resistance. Since there is a large output capacitor on the power supply, the voltage does not rise fast enough when the supply goes into current limit. Using the ballast resistor gives a much more stable arc for this reason. Arc spreading is accomplished with an electromagnet that is driven from 10-60Hz AC. The electromagnet core is ground to a point, like in the original reactors. Since I am using a ballast resistor, not an inductor, the arc voltage can never rise above 150V. Resistors don't store energy like inductors do.

The next order of business is to calculate what kind of ballast inductor that I need. It will be determined by load current, electromagnet frequency, and efficiency, among other things. Hopefully my 1cm diameter arc will spread to a 10cm arc with this modification.

Once I get certain issues ironed out, I'll probably start posting pictures.
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sclarenonz
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[*] posted on 27-12-2015 at 18:46


Will it work?

the titanium dioxide on carbon will take the hydrogen from the water ?

and the flyback can be placed in the magnetron ?

I saw that the magnetron has an input of 4000 volts, the flyback has in its output 30 000 volts, as there is no coil or electronic part within the magnetron believe he can mutiplicar this value?

please help me

g4719.png - 393kB
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[*] posted on 19-1-2016 at 07:05


I'm going to attempt to make nitric acid in a few months with a zvs driven flyback transformer.
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[*] posted on 2-2-2016 at 20:12


Made it. Two minutes will let it redden litmus paper.

[Edited on 3-2-2016 by Hawkguy]

12647868_656834514454939_446259719_n.jpg - 45kB
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j_sum1
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[*] posted on 2-2-2016 at 21:15


Woot Hawkguy! That is some accomplishment!
Well done.




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