BJ68
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Aerogel Autoclave
That´s work in progress...
I am building an aerogel autoclave.
It´s consisting of
-2 L autoclave dimensioned for 220 bar (from Ebay), which was modified with an outlet at the bottom for a SS-400-2-4PR (Swagelok) connector.
- Valve SS-31RS4 (Swagelok)
- Backpressure-Regulator 26-1763-24 (Tescom)
- 1/4" Tubing (Swagelok)
- miscellaneous Fittings (Swagelok)
- VOLTCRAFT DOT-150 surface thermometer (HACCP) -50 - +150 °C probe-type K
- Aupoko 1,5m CO2 High Pressure Hose with a 2000 PSI Manometer, 2 × W21.8-14 Thread (Amazon)* for the connection of the CO2-bottle
- Stand for the autoclave
- For close- and opening: KS Tools THE DEVIL peneumatic impact wrench 515.1200 I with 32 mm impact socket 1/2" drive (Amazon)
*= The thread connectorsof the hose are both M10 x 1.0
Pressure messurement and recording:
PCE-932 with PS-100-400 probe (for 400 bar)
Heating:
a) for the autoclave: Ika-Magnetic stirrer with hot plate RCT Standard
b) Heating for the Backpressure-Regulator:
- SHNITPWR power supply 12V 15A 180W (Amazon)
- Sourcing map Silicone-Heating mat, 12V 5W flexible heating foil 50mm Diameter (Amazon)
- Silicone Heating mat, 12V 25W 50X150 mm (Amazon)
- W3230 LCD Digital Thermostate DC 12V 20A (Amazon)
Piezo-Injector-Degasing-Setup:
- modified Germban 0261500065 piezo injector nozzle with a M6 cut on the inlet.
- electrical connection: Injector plug gasoline – DA (FEMALE) 1924067, 4F0 973 702A, 2112985, 0-212986-4, 0071749541-001, 71749541, 07P973702,
1-1703498-1 (Amazon)
- Gas Connector hose made from
a) Aupoko 1,5m CO2 High Pressure Hose with a 2000 PSI Manometer, 2 × W21.8-14 Thread (Amazon)
b) M6x10x30 coupling nut SS304
c) Adapters: S2NCB (Tameson) or "gtm22_m10x10f_m6x10m" (Fittings.space) M6 (male) on M10 x 1 (female)
- Gas-Volumina-Measurement made of
- 1000 ml suction bottle
- with fitting rubber cuffs
- 2000 ml wash bottle
- O2-gas flow meter
- Piezo driving circuit made from:
a) SSR DD220D100
b) inductor 100uH 33mOhm 5A coil
c) Elko 250 V 470 µF
d) ELV Universal Pulse Generator UPG 100
e) Electrophoresis power supply Pharmacia LKB GPS 200/400 (200 V 400 mA)
f) BNC-cable
The autoclave:
The piezo setup:
Gas flow measurement:
[Edited on 11-3-2025 by BJ68]
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BJ68
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Further modification:
The original safety valve was replaced with https://www.reinstgas-druckminderer.de/Sicherheitsueberdruck... which has a setpint of 200 bar and the pressure transducer was moved, because it
was interfering with the use of the pneumatic impact wrench.
According to the manufacturer the autoclave is tested with 250 bar and the "trigger pressure" (Auslösedruck) is 215 bar, so 200 bar is even more
safety for me.
Here pictures of the new setup:
bj68
[Edited on 11-3-2025 by BJ68]
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BJ68
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Part 1: Piezo Valve:
The idea for a piezo actuated valve cam from point 4.3 in this posting: https://illumina-chemie.org/viewtopic.php?p=67284#p67284 which was my first try to synthesize aerogels.
After some research I found out, that such diesel or gasoline piezo injectors are used to inject hydrogen, methane and even water in the cylinder of
engines.
The problem with these injectors is that the driver circuit is very expensive to buy...so I looked for a home-made solution which is cheaper.
Pictures and links to the papers and degassing graphs are @ https://illumina-chemie.org/viewtopic.php?t=6271 (in German).
Part 2: Degassing the old way:
In the paper "A Continuous Extraction and Pumpless Supercritical CO2 Drying System for Laboratory-Scale Aerogel Production" https://www.mdpi.com/2310-2861/2/4/26 there is a other possibility described....here are two HPLC columns used, which are connected through a
capillary tubing.
This attempt was used parallel to the piezo valve trials...
Pictures, Degassing-graphs and more are @ https://illumina-chemie.org/viewtopic.php?p=98947#p98947
bj68
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Osmiridium
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Hi BJ68!
I very much like your project. It's definitely something on my to do list as well.
I assume the pressure vessel from ebay is one of these chinese ones sold there. What can you say about its quality? I assume it's machined from one
piece without any welds? And what wall thickness does it have?
I'm also wondering what kind of gasket do you use for it.
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BJ68
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Yes it´s from a Chinese Vendor, but modified in the workshop of the physic department of the university. They made a outlet at the bottom of the
autoclave, for purging out the ethanol.
Quality from the autoclave itself is good....the welds of the safety installation are not so clean, but they work.
The body is machined form one piece of steel and non magnetic, the cover, nuts and bolts, too.
Seal is metal to metal, the body has a conical seal face and the cover has a kind of notch, which is pressed in. The only disadvantage is that by hand
it´s difficult to get it completely sealed, but with the pneumatic impact wrench it works nicely.
Here is a drawing with the measurements of that autoclave....
bj68
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BJ68
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Autoclave-Update
a) The installation for the safety pressure relief valve and the pressure measurement was new designed, because the connection (with the red seal
ring) was leaky and if you want to turn it, the bolts where in the way.
b) At the outlet for the overcritical drying a HPLC safe guard column was installed to protect the piezo valve from areogel particles, in the worst
case.
c) The CO2-Inlet was made ready and the equipment was tested at least with 86 bar.
d) For all connections Swagelok connectors where used, because they can easily assembled and disassembled without losing their tightness.
bj68
[Edited on 30-4-2025 by BJ68]
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BJ68
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Short Update:
Casting of gel slabs und making the alcogel of them....setup the autoclave und now the first bleed is running, got about 1000 ml in 2 h out. The
regulation of the flow with the bleeding valve (SS-31RS4) works quite well, so the heating capacity at the backpressure regulator is enough to avoid
freezing and blocking the regulator.
Here a few pictures:
The Gel-Slabs:
Gel-Slabs in the Holder:
In Autoclave filled with EtOH
Protection against the liquid CO2:
The setup: I have no CO2 Bottle with siphon tube....
First Bleed:
More in German: https://illumina-chemie.org/viewtopic.php?p=100648#p100648
[Edited on 14-6-2025 by BJ68]
[Edited on 14-6-2025 by BJ68]
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BJ68
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Update:
a) I got a "blow out" and the first batch of gels was completely lost:
https://illumina-chemie.org/viewtopic.php?p=100649#p100649
and
https://illumina-chemie.org/viewtopic.php?p=100651#p100651
b) Used the second batch, which where casted with a layer of agar as separation layer, which was not so a good idea, because they showed a white
crumbly hard layer after the drying process.
The setup worked surprisingly fine, for bleeding the EtOH out, with the bleeding valve and backpressure regulator and even the piezovalve worked.
Data and pictures of this trial can be found under https://illumina-chemie.org/viewtopic.php?p=100673#p100673
Sadly the aerogels have cracks, but not so much like in the 2017 synthesis see https://illumina-chemie.org/viewtopic.php?p=67284#p67284
Now the questions is, what are the reasons for this cracks?
bj68
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