Scale-up of high temperature/high pressure vessel

[Letsby_Avenue]

Hello,

I am researching on behalf of a scientific team that has built a small scale vessel to heat a specimen inside a chamber (300C) under high pressure (3500 psi). It is a basic extreme pressure cooker. We want to scale-up the chamber to higher proportions so that the samples created can be greater in size. We believe that a custom high temperature high pressure vessel that can have a large enough door/entry point to insert the samples, would work.

We would ideally like three pressure vessels that could hold a chamber containing the specimens. The chamber which holds the specimens (not vessel) would be pill shaped, with the larger number being the circumference of the pill, and the smaller the depth needed. Sizes we would like would be:

1ft x 0.5 ft
4ft x 2ft
10ft x 5ft

Our smallest two vessels would ideally be able to fit more than one pill chamber of the above dimensions. The samples will contain a mixture of water and powdered bentonite clay, so we need a vessel that can hold this weight. I am not sure if frames can be built inside vessels to hold the chamber containing the samples - I am happy to go with your suggestions.

From our findings that created the ideal sample, the pressure vessel would need to be able to run continuously for 24 hours or more per cycle to get the results we need. The clay pill we are heating up has to be at 300C, so we might need the autoclave to heat above this for this to be achievable.

We are looking for a pressure vessel that is economical and quiet/silent to run. I have attached our small scale circuit.

Do you think an autoclave or high pressure vessel heated with heater bands (replicating our model) would be most economical? Are there any other options you can think of to streamline the process?

https://files.engineering.com/getfi...le=Screenshot_2022-07-12_at_04.31.30_copy.png

Thanks so much!

 

[Compositepro]

Unless you need to deal with gasses or mixing while processing you should be making samples in compression molds in a press. Presses are often hydraulic but screw presses also are used.

 

[EdStainless]

What gas will be in the vessel?
What is given off when you heat?
How do you build pressure?
I would look into electrical resistance heating elements inside the vessel around your crucible (pill).

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[Letsby_Avenue]

Compositepro - do screw presses go up to 3500 psi? Could the inner 'pill' be heated to 300C whilst it is being pressed this way? That would be quite a good solution otherwise. I would much rather go for a simpler system like this which I thought of initially, but the high temp/high pressure needed didn't seem attainable.

EdStainless - we used compressed air to remove need for another gass and therefore make it simpler/more economical. We built pressure with the air compressor in the diagram and I don't know what you mean by what is given off when we heat. I am looking for options to up-scale the prototype we built. There might be other options out there we haven't thought of. Thanks

 

[Compositepro]

Presses are just clamps, and are rated in tons force of load. The mold or "tool" between the plattens, determines the pressure generated by the force. The plattens often have heated faces that are insulated from the main structure by ceramic insulation. But you can also just heat your mold directly and insulate it from the plattens. A push of a button opens and closes the press/mold. Compression molds often do not have seals. There is just a tight clearance (0.005") between the mold cavity and the plug that fits the cavity. This is useful to allow air to escape.

 

[Letsby_Avenue]

Excellent info, thank you.

You'll have to forgive me as I haven't used them before, but as the mixture will be bentonite clay & water that we want to solidify, would it be fine using a press? Seems like it would escape or stick to the press - perhaps through the air escape. Would there be an option to contain the mixture and be able to put pressure on it? Thanks again.

 

[weeeds]

We are currently building a very large autoclave designed by a company in Texas but yours seems to be an unusually high pressure, which will be a challenge. You can look at this website and contact them if it looks like they can be of service:

http://www.thermalequipment.com