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Author: Subject: Building an Ostwald reactor
plante1999
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Building an Ostwald reactor

So, I re-started my Ostwald reactor project. I had already made some nitrate, but the yield was low, and I found the ammonia to be too concentrated. I also found that pressurized ammonia was WAY better. Today, I bought PVC pipes for house water line. 5/8 O.D. but is sold as 1/2. I also bought a few PVC elbow. Found that borosilicate glass softened, and on the pressure may make hole in the reaction tube, I tried copper tube, but the heat transfer was way too fast, the tube was not even dull red, and the two PVC elbows had already melted...
I have platinized asbestos as the catalyst that work very well and a 50 gallon air tank for my experimentation, with variable pressure adjustment, from 1 to 100 PSI. I also have 7 feet of PVC tubing and an old fire extinguisher as the tank. However I would like a valve instead of a burst of gas, as such I could get a perfect flow.
My project consist to make a complete system, I would plug the air line to it, regulate ammonia flow and lets running, a system of about one cubic foot. It may, or may not be pressurized, all my actual pieces can handle 400 PSI, but some part I could add may no be as resistant.

Now, here is the actual problem I have:
I need a valve to put on the fire extinguishor, a valve that handle 200 PSI, or a new gas tank

A way to fill the ammonia tank with ammonia

A quartz, or ceramic tube that have 5/8 O.D, as copper transfer heat too fast, and borosilicate simply soften and become dangerous.

I have a very small budget

What is good:
I have a good supply of air

A lot of random iron pieces for the frame

7 feet of PVC tubing, suitable for nitric acid and NOx

Platinized asbestos

Nichrome wire heating element from an old stove

A LOT of asbestos

A 60 year old fire extinguisher

A camera to take pictures for all of you (If you want me to take a picture of something, ask me)

Thanks!

phlogiston
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What if you put some isolation around the copper tubing? Or perhaps another metal that doesn't conduct heat so well?

[Edited on 10-2-2013 by phlogiston]

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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer
plante1999
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I don't think isolation would help, I would think it would be worst. Another metal might be good, But we need a metal that do not oxidize readily, as TM oxide catalyze formation of N2 instead of NO. Metals like aluminium are good (because there oxide is rather inert), and Gold is good, because it doesn't oxidize readily.

elementcollector1
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Gold plating, maybe?

Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
plante1999
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With help of some members here, I was able to find a way to turn my extinguisher to a gas tank for 20$. The tank can handle 400 PSI, which is way more than needed. I also found a way to make gas absorption system, without any hassle of opening the reactor, like industrial set-up. I only need to open a valve to get the acid, and another to add water. Someone also gave me the idea of a safety gas release valve, which I will add for safety. All tubing/valve before the reaction tube will be made of S.S and teflon. After the tube everything would be made of PVC with a gas absorption system similar to this one: The green part is a filter, the brown is quartz sand, the red X are valves. The top one is used the refill with water. There is three absorption system, the last one with urea to neutralize the gases. There is a valve at the end of the last absorption system to regulate pressure, a pressure gauge should be added for safety. Now there is still three main problem: I still need a 5/8 O.D (16mm) quartz/ceramic tubing by 12 inch (If someone have one, and want to donate it or sell it cheaply, send me a U2U) I need to make liquid ammonia with calcium chloride and snow I need more funds, Only the S.S cost 56$, so yea. I will try to sell a few things I do not need anymore to get more fund for this project, but one can donate, or buy chems/material from me to fund the project. I talked about that with bromic acid, and come to conclusion I needed fund raising.

[Edited on 10-2-2013 by plante1999]

[Edited on 10-2-2013 by plante1999]

blogfast25
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Photos would make things a lot clearer, in my opinion...

plante1999
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I did some work on the reactor today, I made the three gas absorption chamber, I only need 6 valves and this part is done. I also took a picture of the very old fire extinguisher (dated from 1954 or 1964) and the nichrome wire. The chambers look sturdy, I got some sponge for the filter, but I'm not sure they are suitable.
Actually the fire extinguisher is tested at 500 PSI.

Pictures:

[Edited on 10-2-2013 by plante1999]

phlogiston
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What is your source of ammonia and how are you planning to fill the tank with it at pressure?
Also, are you planning to have the reaction tube at above-atmospheric pressure?

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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer
plante1999
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I will make ammonia using Drano and urea, and I will condense the ammonia in the cylinder. When condensed, I will put the valve on the cylinder.

The system will probably be pressurized. The stainless I'm planning to use is rated at 350 PSI, and the PVC 400. The maximum pressure I would possibly use is 150 PSI, but I will probably use 50 PSI.

blogfast25
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Small leaks of ammonia may render your process very stinky. Just filling up 0.5 L bottles with 0.88 SG ammonia solution stinks out my warehouse!

Your ammonia condenser for example is unlikely to trap ALL NH3(g), so you need to deal with the 'off gases'...

[Edited on 11-2-2013 by blogfast25]

Doc B
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An LPG gas bottle is refillable, fitted with a valve, available readily and in various sizes, cheap even if bought new.

To fill the ammonia at pressure I would suggest a diaphragm pump. I have one that both sucks and blows (teehee, who thought that was possible?) it's intake and output are inline so that it blows what it sucks at pressure and vise versa. If you would like more details let me know.

Regarding the tube, would ceramics be a suitable alternative?
plante1999
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 Quote: Originally posted by blogfast25 Small leaks of ammonia may render your process very stinky. Just filling up 0.5 L bottles with 0.88 SG ammonia solution stinks out my warehouse! Your ammonia condenser for example is unlikely to trap ALL NH3(g), so you need to deal with the 'off gases'... [Edited on 11-2-2013 by blogfast25]

Yea the filling will be done outside, and when the bottle will be closed, it will be put on the system, inside.

Doc B, I'm not sure a diaphragm pump can make enough pressure to make liquid ammonia.

Ceramic would be a suitable alternative.

Doc B
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If the vapor is cooled to 0'C then you'd only need 45psig, being only twice atmospheric pressure.

http://www.rowe.com.au/CatPDFs/274-281.pdf
On p7 you'll see the pump and if you can find the specs for the Dynavac heavy duty vacuum pump/compressor it will allow you to calculate temperature to pressure ranges that might be feasible for you. Plus I'd really like to know the specs as I picked one up for $60 and haven't been able to find any such data online or elsewhere so please let me know if you do. Ceramic pipe is available at plumbing and gardening stores or perhaps even scrap from residential or industrial construction etc. might be worth checking out? Doc B Hazard to Others Posts: 107 Registered: 5-4-2012 Member Is Offline Mood: No Mood You could also find a ball valve in the PVC or plumbing section of the hardware store. I don't know about the PVC one but expect it would be rated at pressures similar to the pipe which would be a go, if there is one that fits. The other option is the chrome plated Teflon ball type available in many sizes for less than$20. Hope that's some help to you, good luck!
Magpie
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 Quote: Originally posted by plante1999 Now, here is the actual problem I have: I need a valve to put on the fire extinguishor, a valve that handle 200 PSI, or a new gas tank A way to fill the ammonia tank with ammonia

A few years ago I made a very small tank out of a pipe nipple to contain liquid ammonia. The generated gaseous ammonia was liquidfied by condensing it in a Dewar containing solid CO2/acetone. The liquid NH3 was then poured into the tank equipped with a valve. I describe this in a forum thread somewhere. Garage chemist was also doing this at the same time only he caught the gaseous ammonia in a large plastic bag. This was then compressed and liquified in a lecture bottle using a fridge compressor, IIRC. He has also reported his results on this forum.

Be careful that the wetted surfaces of your ammonia carrying pieces are not composed of copper or brass or they will corrode.

I bought a special pressure gauge (0-450 psi) and pressure relief valve (350 psi) having wetted parts made of ss for handling ammonia from this vendor:

http://www.murrayequipment.com/dyncat.asp?Categ=NH3%20Produc...

You should be able to find a small ss needle valve for not too much money.

You should pressure test your pressure vessel and piping using a liquid to 150% of the intended operating pressure. This is standard practice per ASME. DO NOT TEST WITH A GAS - TOO DANGEROUS!

 Quote: Originally posted by plante1999 What is good: A LOT of asbestos

I'm jealous.

[Edited on 11-2-2013 by Magpie]

[Edited on 11-2-2013 by Magpie]

The single most important condition for a successful synthesis is good mixing - Nicodem
phlogiston
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Perhaps you can use the quartz glass tube from a tubular halogen lamp?
Alternatively, perhaps you can drill a hole through a resistant brick (or file a little gutter on the surface of two blocks and fit them together, so you can more easily (dis)assemble the reactor, having access to its entire length.

In what form is the asbestos you have?

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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer
Magpie
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Maybe I just missed it but what is the operating temperature and pressure of the reactor vessel?

The single most important condition for a successful synthesis is good mixing - Nicodem
plante1999
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Doc B, I'm intended to liquefy the ammonia. I have many format of asbestos, such as sheet, paper, wool, plate etc...
Maybe I didn't specify, but I intend to use two of these connector for the system: They are avaible for 16 mm and 10 mm:
http://www.ebay.com/itm/270963331874?ssPageName=STRK:MESINDX...

The temperature is 800 to 900 centigrade.

I do not own dry ice, and not sure if I can get some, but I was planing to use CaCl2 + snow, outside, when the temperature will be - 30. The mixture is supposed to get to -40.

phlogiston
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Then perhaps you can fashion a reaction channel out of a few sheets of asbestos plate? Take two large sheets and sandwich two small sheets in between, leaving a channel of the desired diameter in between.

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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer
Magpie
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I have little doubt that you can make NO/NO2/N2O4 with your Ostwald reactor, even at atmospheric pressure. Although I didn't see this mentioned I assume you plan to use this to make HNO3. I think that this is where the real challenge will be. Industry uses an efficient gas absorbtion tower that has many plates or much packing (ie, is tall), is cooled, and is operated at about 100 psi according to Shreeve.

Granted Shreeve is an old reference. I would check the most recent Kirk-Othmer or Ullman encyclopedias.

Don't get me wrong, I admire and support you giving this a try. I just want to help you think this project through before you spend too much time and money.

The single most important condition for a successful synthesis is good mixing - Nicodem
plante1999
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Well, as you may not know, I already tried the process, and got some yield at atmospheric pressure. I made 50g of sodium nitrate, which I used to make nitric acid, the same that burned my face, so yea. Like I said, I'm planning to run it at pressure, about 50 PSI to 150.

http://hclo3.weebly.com/ostwald-process.html

Yea, money... I can still use the reactor to make other chems, like sulphuryl chloride or mercury... I simply need to change the reaction tube, and wash everything.

If I make lab scale industrial processes book, I assure you I also use most industrial chemistry encyclopedia, such as Ulmann's.

[Edited on 11-2-2013 by plante1999]

Magpie
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Here's a supplier for quartz tubing:

http://www.technicalglass.com/product_pages/fused_quartz_tub...

The single most important condition for a successful synthesis is good mixing - Nicodem
Magpie
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Here's some ammonia liquefaction experience that may prove useful:

The single most important condition for a successful synthesis is good mixing - Nicodem
plante1999
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Interesting, I wanted to put a filter for the gas, but with all this rust, I would probably need a S.S tank, as in most industrial chemistry books, they explain the catalyst poisoning by dust in the ammonia flow. I wonder if the supplier Magpie showed would ship to Canada.

plante1999
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I made a list of item needed, I may have forgot some. I didn't include cheap one I already had (PVC pipes for example).
Some have links, some do not.

Hope it help to clear out a few things. I'm also trying to make a diagram for the system, one with most basic material, one with more material.

Attachment: Here is a list of material I would need to build the reactor.docx (12kB)